*$& 
 
 UNIVERSITY FARM 
 
 
i.l V 
 
 SCIENTIFIC BOTANY; 
 
 OR, 
 
 BOTANY AS AN INDUCTIVE SCIENCE. 
 
 BY 
 
 DK, J. M. SCHLEIDEN, 
 
 EXTRAORDINARY PROFESSOR OF BOTANT IN THE 
 UNIVERSITY OF JENA. 
 
 TRANSLATED BY 
 
 EDWIN LANKESTER, M.D. F.R.S. F.L.S. &c. 
 
 LECTURER ON MATERIA MEDICA AND BOTANY AT THE ST. GEORGE'S 
 SCHOOL OF MEDICINE, LONDON. 
 
 LONDON: 
 
 PRINTED FOR 
 
 LONGMAN, BROWN, GREEN, AND LONGMANS, 
 
 PATERNOSTER- ROW. 
 
 1849. 
 
LONDON : 
 
 SroxTrswooDEs and SHAW, 
 New-street- Square. 
 
TRANSLATOR'S PREFACE. 
 
 IN producing this work of Professor Schleiden in an English dress, 
 I feel that the reputation of the Author and the Work alike render 
 any apology unnecessary ; but I am conscious that I owe some 
 explanation to the Public, both as to the manner of the trans- 
 lation and the delay in its appearance. 
 
 The second German edition of this Work, of which the present 
 volume is a translation, was accompanied with a Methodological 
 Introduction, intended as a development of those general principles 
 of science, which are derived from a study of the observing mind, 
 and the observed external nature. As the discussion of these 
 general principles occupies a considerable space in the original, and 
 it was deemed desirable not to increase the bulk of the present 
 Work, this Introduction has been omitted. In its place I have, 
 however, inserted a short summary of these observations, as they 
 have been given by the Author himself in his "Grundriss der 
 Botanik," which work consists of the text of the present volume 
 without the explanatory comments. This summary is given in the 
 four first paragraphs of the present translation.* In the original 
 Introduction a considerable portion is occupied with the description 
 of the microscope, and its application to scientific researches ; as 
 the observations of the Author seem to me to be judicious, and 
 we have none of precisely the same kind in our own language, and 
 especially as this book may fall into the hands of students who 
 are not acquainted with the powers or the manner of using this 
 instrument, I have thought it right to reproduce this portion of 
 the Introduction, f 
 
 With the exception of those parts of the Introduction referred 
 to, and in not more than two or three instances, of matters in 
 the notes that were not deemed relevant to the translation, nothing 
 has been omitted in the present Work. 
 
 * As general introductions on the principles involved in scientific inquiry, we have 
 in our own language two admirable works, Sir John Herschell's " Discourse on the 
 Study of Natural Philosophy," and Professor Whewell's " Philosophy of the Inductive 
 Sciences." 
 
 t Appendix D. 
 
IV 
 
 I feel that some portions of the Translation are open to the 
 charge of inelegance, and this has arisen from my anxiety rather 
 to give a correct notion of the Author's meaning than, by the use 
 of other language, to diminish the force of the original. 
 
 The delay in the publication has been owing in part to ill-health, 
 and in part to the pressure of other engagements. I have only 
 now been enabled to produce it thus early in the year through the 
 kind assistance of my friend, Mr. Arthur Henfrey, who has not 
 only revised the whole of the Morphology, but translated several 
 sheets. I am also indebted to Mr. Henfrey for the translation of 
 the new matter in the third German edition of the Work, which 
 will be found in the Appendix. I have likewise to offer my thanks 
 to my friends, Dr. Day and Mr. Busk, for much valuable assistance ; 
 and to another friend, for kindly revising the proof-sheets of the 
 whole Work. - 
 
 22. Old Burlington Street, London, 
 April, 1849. 
 
CONTENTS. 
 
 Page 
 INTRODUCTION. 1 4. ....... l 
 
 FIEST BOOK. 
 
 CHEMISTRY OF PLANTS. 
 
 CHAPTER I. 
 
 THE INORGANIC ELEMENTS. 5 7. . . 3 
 
 CHAPTER II. 
 
 ON THE ORGANIC ELEMENTS. 8 13. 
 
 SECTION I. 
 Of the assimilated Bodies ...... 8 
 
 SECTION II. 
 
 Of the remaining Organic Substances formed under the Influence of 
 Vegetation ........ 25 
 
 SECOND BOOK. 
 
 ON THE PLANT-CELL. 
 
 CHAPTER I. 
 
 FORM OF THE PLANT-CELL. 14 29. 
 
 SECTION I. 
 The Cell regarded as an Individual . 31 
 
 SECTION II. 
 
 Of Cells in combination, and intercellular Formations . . .51 
 
 A. Parenchyma . . . . . . .51 
 
 B. Intercellular System .... .52 
 
 C. Vessels . . . . .54 
 
 D. Vascular Bundles . . . . . .55 
 
 E. Tissue of the Liber . . . .64 
 
VI CONTENTS. 
 
 Page 
 
 F. Liber Cells . . . . . . .64 
 
 G. Milk Vessels ....... 64- 
 
 H. Fibrous Tissue . . . . . . .68 
 
 I. Epidermal Tissue . . . . .68 
 
 a. Epidermis . . . . . . .68 
 
 b. Appendicular Organs . . . . .69 
 
 c. Cork ....... 69 
 
 d. Root Sheath 69 
 
 CHAPTER II. 
 
 ON THE LIFE OF THE PLANT-CELL. 30 4:9. 
 
 SECTION I. 
 
 Functions of the Individual Cell . . . . .80 
 
 I. On the Absorption of Foreign Agents . . . .80 
 
 II. On the Assimilation of the absorbed Matters, and Secretion . 83 
 
 III. Of the Excretion of Substances from the Plant- Cell . . 88 
 ]V. Disposition of the assimilated Matters . . . -89 
 
 V. Motions of the Cell-contents . . . . .92 
 
 VI. Motions of the Vegetable Cells . . . . .98 
 
 VII. Reproduction of the Cell . . . . .102 
 
 VIII. Of the Termination of Cell Life . . .104 
 
 SECTION II. 
 
 Life of the Cell in connection with others. 50-64 . . 106 
 
 I. General Modification of the Life of Cells in consequence of the 
 
 Association of several Cells . . . .107 
 
 II. Peculiarities in the Life of entire Tissues . . . .110 
 
 THIRD BOOK. 
 
 MORPHOLOGY . . . .124 
 
 CHAPTER I. 
 
 GENERAL MORPHOLOGY. 66 77 . 1 W 
 
 CHAPTER II. 
 
 SPECIAL MORPHOLOGY. 78 182 . .138 
 
 SECTION I. 
 
 The Angiospora? . . . . . . . .143 
 
 I. Algse ........ 145 
 
 II. Fungi 151 
 
 III. Lichenes (Lichens) . . . . . .157 
 
 Appendix (Charae). . 162 
 
 SECTION II. 
 
 The Gymnosporae . . . . . . . .164 
 
 A. Asexual Plants . . . . . .166 
 
 a. Rootless Agamae. 
 
 IV. Liverworts 168 
 
CONTENTS. VII 
 
 Page 
 V. Mosses ..... . 174 
 
 b. Agamic Plants, having Roots. 
 Vf. Club-mosses (Lycopodiaceae) . . . .189 
 
 VII. Ferns (Filices) 192 
 
 VIII. The Horse-tails (Equisetacea?) . . . .198 
 B. Sexual Plants . . . 201 
 
 a. Plantae athalamicae. 
 
 IX. Rhizocarpeae . ... 203 
 
 b. Plantae thalamicae. 
 
 X., XI. Monocotyledons and Dicotyledons . . . .213 
 
 A. Radical Organs. 
 
 a. True Root (Radix) . . .217 
 
 b. Adventitious Root (Radix adventitia) . .218 
 
 B. Axial Organs. 
 
 a. The main Axis (Axis primarius) . . .221 
 
 b. Varieties of Direction .... 232 
 
 c. Of the Secondary Axis , ... 233 
 
 d. Of the Structure of Axes . . . 235 
 
 e. Review of Axial Structures and Terminology . 258 
 
 C. Foliar Organs. 
 
 a. Foliar Organs in general . . . .261 
 
 b. Structural Condition of the Foliar Organs . 276 
 
 c. Complete Review of the Foliar Organs . . 280 
 
 D. Bud-Organs (Gemmae). 
 
 a. Of the Buds in general . . . .281 
 
 b. Structure of the Bud .... 286 
 
 c. Of the particular Forms of Buds . . . 289 
 
 E. The Flowers . . . . . .296 
 
 I. The Inflorescence .... 300 
 
 II. Of the Parts of Flowers at the Time of Blooming 310 
 
 A. On the Axial Organs of the Flower . 318 
 
 B. Number, relative Position, and Duration of 
 
 the Parts of the Flower . . . 324 
 
 C. Of the true Foliar Organs of the Flower. 
 
 a. Of the Floral Envelopes . . 330 
 
 b. Of the Stamens .... 345 
 
 c. Of the Accessory Foliar Organs of the 
 
 Flower . 364 
 
 D. The Rudiments of the Fruit . . 367 
 
 a. Of the Pistil . . . .368 
 
 b. Of the Spermophore (Placenta) . . 382 
 
 d. Of the Seed-bud (Ovule) . . 389 
 
 III. Of the Transformation and Development of the 
 
 Parts of Flowers into the Fruit . . 402 
 
 A. The Change of Place and Development of 
 
 the Pollen into the Embryonal Globule . 402 
 
 B. The Development of the Embryonal Globule 
 
 into the Embryo . . .416 
 
 C. Development of the Germen and Seed-bud 
 
 to Fruit and Seed . . . 423 
 
 D. Phenomena exhibited in the remaining Part 
 
 of the Flower, during the Formation of 
 Fruit and- Seed .... 436 
 
 IV. Of the Fruit and the Seed . . . 437 
 
 I. Of the individual Parts of the Fruit . 440 
 
 II. Of the accessory Organs of the Fruit . 446 
 
 III. Enumeration of the various Forms of the Fruit 447 
 
Vlll CONTENTS. 
 
 FOURTH BOOK. 
 
 OKGANOLOGY .... 454 
 
 CHAPTER I. 
 
 GENERAL ORGANOLOGY. 183 216. 
 
 SECTION I. 
 
 General Phenomena in the Life of the entire Plant. 
 
 A. Life of the entire Plant . . . . . .458 
 
 B. Germination . . . . . . . 460 
 
 C. Of Growth . . . . ;.- . .464 
 
 D. The Process of Nutrition . . . V . . 468 
 
 I. The Food of Plants in general .... 470 
 
 II. On the Absorption of Food and Excretion . . 493 
 
 1. Of the Form of the Matter . . . .493 
 
 2. Of the Form of the Processes . . . 494 
 
 III. Assimilation of Food . . . . .504 
 
 IV. External Conditions of the Absorption and Assimilation 
 
 of Food . . . , . . 508 
 
 V. Motion of the Sap through Plants . . .515 
 
 E. Reproduction of Plants ...... 524 
 
 F. Death of the entire Plant ..... 536 
 
 SECTION II. 
 
 Special Phenomena in the Life of the entire Plant. 
 
 A. Development of Heat . .... 539 
 
 B. Development of Light ...... 542 
 
 C. Movements of the Parts of Plants .... 544 
 
 CHAPTER II. 
 
 SPECIAL ORGANOLOGY. 217 224. 
 
 A. Organs of Vegetation. 
 
 a. Angiosporse ....... 555 
 
 b. Gymnosporac ....... 555 
 
 B. Organs of Reproduction. 
 
 a. Cryptogamia ....... 557 
 
 b. Phanerogamia ....... 558 
 
 Conclusion . ... . 559 
 
 APPENDIX. 
 
 A. Analytical Papers ...... 560 
 
 B. List of Old Trees . . . .566 
 
 C. Containing the New Passages in the Third German Edition of the 
 
 First and Second Books ..... 567 
 
 D. On the Use of the Microscope ..... 575 
 
 INDEX . . .601 
 
PRINCIPLES 
 
 OF 
 
 SCIENTIFIC BOTANY, 
 
 INTRODUCTION. 
 
 BOTANY, as an inductive science, comprehends the study of the 
 laws and forms of the Vegetable Kingdom. As an experimental 
 science, it takes a very low position ; and, at present, embraces 
 but a very narrow circle of actually established facts, few indications 
 of natural laws, and no fundamental principles and ideas by which 
 it might be developed. This becomes very obvious when even the 
 answer to the question, <( What is a Plant ? " is yet a problem of 
 Botany. Hence, it must proceed with its researches upon un- 
 doubted plants, and extend itself cautiously and exclusively in the 
 path of Induction. 
 
 1. Botany is a branch of the one and entire Science of Na- 
 ture : since this embraces the laws of Physics and Chemistry, 
 these are indispensable branches of preliminary knowledge. Botany 
 is also, in itself, Science ; consequently the highest product of the 
 activity of the human understanding : but this may be led into 
 error, and follow wrong paths. If we would find truth, we must 
 know accurately what are the laws according to which the powers 
 of the mind work. Botany, therefere, requires a philosophical cul- 
 ture, that is, knowledge of a theory of the intelligent Reason, 
 founded upon an empirical Psychology; in a word, a critical 
 Philosophy. 
 
 2. The objects of Botany are actual existences natural 
 bodies. These must be examined in all possible ways ; and to this 
 many aids are necessary, for even the parts invisible to the naked 
 eye must be investigated. 
 
 B 
 
2 INTRODUCTION. 
 
 Those who wish to make solid advances in the science of Botany 
 will find the following instruments indispensably necessary : 
 
 1. A microscope.* 
 
 2. A good pocket lens. 
 
 2, Scissors, knife, needle, and pincers. 
 
 4. Certain re-agents, as Iodine dissolved separately in water 
 and in alcohol, liquid Ammonia, Sulphuric Acid, Nitric Acid, 
 Alcohol, Ether, &c. 
 
 3. In relation to other sciences, Botany has to solve the 
 following problems : 
 
 1. For Chemistry, must be resolved in the plant, as in the 
 simplest case, the question how organic combinations arise from 
 inorganic elements. 
 
 2. For Physiology to lay its simplest and most general founda- 
 tions. 
 
 Hence it is an indispensable branch of knowledge for the Che- 
 mist and the Physiologist. 
 
 In practical applications it subserves : 
 
 1. Agriculture ; as it teaches the conditions of the life of plants. 
 
 2. Pharmacy ; as it affords a knowledge of the officinal plants, 
 and gives, through the study of structural relations, the most secure 
 and often the only indications for the distinction of the drugs de- 
 rived from the vegetable kingdom. 
 
 In all these cases, it is the physiology of plants which is alone of 
 use. A knowledge of the systematic arrangement of plants is only 
 of importance to the botanist : for all others it is a pastime, if not a 
 waste of time. 
 
 4, The facts of the whole science, for the sake of study and 
 facility of comprehension, may be divided in the most intelligible 
 manner according to the following scheme : 
 
 1. Vegetable Chemistry. 
 
 2. Study of the Plant-Cell. 
 
 3. Morphology, or study of the Forms of Plants and their Organs. 
 
 4. Organology, or study of the Life of the entire Plant and its 
 Organs. 
 
 * See Preface. 
 
FIRST BOOK. 
 CHEMISTRY OF PLANTS. 
 
 CHAPTER I. 
 
 THE INORGANIC ELEMENTS. 
 
 5. THE elementary bodies found in plants are the following : 
 1. Carbon (C) ; 2. Hydrogen (H); 3. Oxygen (O); 4. Nitro- 
 gen (N); 5. Chlorine (Cl) ; 6. Iodine (I) ; 7. Bromine (Br) ; 8. 
 Sulphur (S); 9. Phosphorus (P) ; 10. Silicium (Si) ; 11. Potas- 
 sium (K); 12. Sodium (Na); 13. Calcium (Ca); 14. Magnesium 
 (Mg) ; 15. Aluminium (Al); 16. Iron (Fe) ; 17. Manganese (Ma) ; 
 18. Copper (Cu). 
 
 These substances occur in very varying proportions in plants. Car- 
 bon is of all the most important and the most abundant. It forms the 
 skeleton, the solid basis, of all plants. By careful charring, the minutest 
 parts of the texture of plants may be preserved, and almost everything 
 is consumed or driven off except the Carbon. In the spontaneous de- 
 composition of plants, it also remains longest unchanged ; and the entire 
 structure of the plant is often retained in peat and coal, so that the 
 families and genera of the plants can be recognised. Carbon is never 
 found pure in plants. 
 
 Hydrogen and Oxygen form, with Carbon, most of the proximate 
 principles of plants, and in the more important substances they occur 
 in the proportion in which they form water. Oxygen is found free 
 in plants dissolved in their juices. Hydrogen is also found free in the 
 Fungi. 
 
 Nitrogen in combination with the foregoing elements form some of 
 the most important secretions of plants. Whether it is found free in the 
 Fungi, is not yet well made out. 
 
 Chlorine, Iodine, and Bromine, are found in the form of salts. The 
 first in plants of the sea-shore ; the two last in those growing in the sea. 
 
 Sulphur and Phosphorus are found in most plants as sulphuric and 
 phosphoric acids (the last is especially abundant in the membranes of the 
 seed in grasses). They both enter into combination with protein to form 
 albumen, casein, &c. 
 
 Silicium is present in all plants as silica ; often in very large quan- 
 tities, as is shown by the following analysis of the ashes of several 
 plants : 
 
 B 2 
 
4 CHEMISTRY OF PLANTS. 
 
 The ashes of Equisetum limosum yielded 94-85 per cent of silica 
 Equisetum urvense . . 9.5.48 
 
 Equisetum hyemale . . 97 '52 ,, 
 
 Calamus Rotang . . 97*20* 
 
 Where the silica is in very large quantities, as in the bark and epi- 
 dermis of the larger grasses, the tubular palms, and the equisetums, the 
 ashes by careful burning may be made to retain the form of the plant so 
 accurately, that even microscopic organs may be readily distinguished. f 
 The silica in these plants exists in the form of small plates, grains, or 
 needles, which are often melted together by the heat ; but if the part of 
 the plant is submitted to the action of sulphuric acid, the silica retains 
 its primitive forms, This proves that the silicium is not chemically 
 united with the tissue of the plant, as is stated by ReadeJ ; or even, in- 
 deed, organised, as was formerly gratuitously maintained. 
 
 Potassium, Sodium, Calcium, Magnesium, Aluminium, Iron, Man- 
 ganese, and Copper, are present only as oxides in combination with acids. 
 The first seven exist in very varying proportions in most plants : copper 
 probably in only a few. There is an old saying among the people, 
 especially in the north of Germany, that the wood of the lime contains 
 gold. 
 
 On the origin of these substances in plants, and more particularly 
 with regard to the question as to whether plants take them up from the 
 earth, or form them by a peculiar process of vegetation out of the first 
 four elements above-named, there is but one opinion amongst chemists 
 and physiologists, and that is, that no elementary body can be present in 
 plants that has not been taken up from without the plant. The opposite 
 view, maintained by Reade||, can only be regarded at the present day as a 
 curiosity, and scarcely deserves reference but for the refutation supplied 
 by the labours of Saussure, Davy, Lassaigne, John, Jablonsky% and 
 others. It is difficult also to divine what could have induced the Berlin 
 Academy to give its prize to the single rough experiment made by 
 Schroder, and the confused reasoning of Neumann ; which, supported, 
 indeed, by Braconnot, first brought this absurd view into vogue.** If 
 we consider how small the quantity of solid matter is in most plants, and 
 the large quantity of water they take up and allow to evaporate, we 
 shall have no difficulty in accounting for the presence of substances in 
 plants, which, when diffused through the water absorbed, would resist 
 the test of the most delicate re-agents. 
 
 6. The foregoing elements form amongst themselves certain 
 binary combinations, of which the following are the most important 
 that are met with in plants : 
 
 a. Compounds with Oxygen. Of these, water (HO or H) and 
 carbonic acid come first (CO 2 or C); then oxalic acid (Oor C 2 O 3 ) 
 and the other oxygen acids ; and lastly, the oxides of the metals. 
 
 Water is the most important : without it no chemical change could 
 take place, to say nothing of vital processes. Most plants contain large 
 
 * H. A. Struve de Silica in Plantis nonnulla. Diss. inaug. Berol. 1835. f Ibid. 
 \ London and Edinburgh Phil. Mag. and Journ. 1 837. Nov. 
 See A. v. Humboldt Floras Fribergensis Specimen, Berol. 1793, p. 134. 
 || Op. cit. 
 
 ^f Jablonsky de Conditionibus Vegetationi necessariis quaedam. Diss. inaug. Berol. 
 1832. ** Tbid. p 78. 
 
THE INORGANIC ELEMENTS. 5 
 
 quantities of water in their tissues. In one hundred parts of Cerate" 
 phyllum demersum ninety were found to be water, and ten solid 
 matter. 
 
 Carbonic acid is also widely diffused with water : it forms the principal 
 source of nourishment for plants. It is found dissolved in the sap of 
 plants : at night, in almost every plant; in the day, in ripe fruits, in aerial 
 roots, &c. In consequence of the processes of respiration and combus- 
 tion on the earth, and volcanic agency, the atmosphere contains an inex- 
 haustible supply of carbonic acid for plants. 
 
 Oxalic acid is constantly produced by the decomposition of the fore- 
 going compounds, and is found apparently in all plants. It is found 
 free in most succulent plants, as the Crassulacece, Ficoidece, Cactacece*, 
 &c. ; also in the hair-glands of Cicer arietinum* 
 
 b. Compounds with Hydrogen. These are principally ammonia 
 (NH 3 ), hydrochloric, hydriodic, and hydrobromic acids* 
 
 Ammonia is probably the source of nitrogen in all plants. It occurs 
 free in the unassimilated sap, as in. the spring sap of the birch and the 
 grape vine, and perhaps also in the tissues of unnaturally succulent 
 cultivated plants, as the beet. 
 
 7. The foregoing oxides and acids unite together to form salts, 
 some of which are found dissolved in the sap of plants, and others 
 in the form of crystals. The most important are the alkalies in 
 combination with the vegetable acids, or chlorine, bromine, and iodine ; 
 then, perhaps, those with sulphuric and phosphoric acids ; whether 
 any exist with carbonic acid, is doubtful : next come the earths, 
 with vegetable acids, especially oxalic acid, then with sulphuric and 
 phosphoric acids; and, lastly, the metals mostly in combinations 
 not yet determined. The greater part of the salts are found in 
 the living, vegetating, green parts of plants, as the leaves, &c. ; 
 the least, in the wood (Saussure). A certain quantity of these 
 salts appears essential to the life of plants. Ammoniacal salts from 
 the atmosphere appear to be the source of the nitrogen in plants. 
 
 Fourcroy and Yauquelinf, long ago, proved that the greater part of 
 the carbonates found in the ashes of plants were formed, during the burn- 
 ing, from other salts of vegetable acids. They proved that almost all 
 plants contain 1. acetate and malate of lime dissolved in the sap; 
 2. citrate and tartrate of lime, which either exist as a super salt or 
 in a solid form ; 3. oxalate of lime in a solid form. All these are 
 found in the ashes of plants as carbonates ; but these latter are not to 
 be found if, before the burning, the plants are by turns treated with 
 cold and boiling water and diluted muriatic acid. 
 
 The salts of the alkalies are found dissolved in plants, but the 
 insoluble earthy salts present themselves in a crystallised form in the 
 cells. Of these, the oxalate of lime has been most accurately inves- 
 
 * Liebig (Annal. xlvi. p. 77.) says the Cactacece contain tartaric acid; but he is 
 certainly wrong with regard to most Cactacece. 
 
 f De la Metherie, Journ. de Physique et de Chim., tome Ixviii. p. 429. (1809). 
 
 B 3 
 
CHEMISTRY OF PLANTS. 
 
 3. 
 
 tigated. It appears to be present in 
 every plant, and in some in very large 
 quantities. A stem of Cereus senilis, 
 after the water was driven off, con- 
 tained eight hundred and fifty-five 
 parts oxalate of lime in the thousand. 
 The form of the crystal of oxalate of 
 lime is the quadratic octaedron (fig. 
 1.); and it presents, like almost all compounds of the earths, as its 
 primary form, the right-angled four-sided prism (in the binaxial and 
 
 unaxial systems). The following forms 
 are easily distinguished : * 1. Needle- 
 formed crystals (Raphides, DeCand.\ 
 being a combination of a very long 
 prism with an octaedron (fig. 3. b\ 
 whose surface, as in the Zircon and the 
 Hyacinth, is united with the surface 
 of the prism. These lie together in 
 bundles of from twenty to thirty in 
 a single cell, which they entirely fill 
 up; and are present in almost all 
 plants, and may be well seen in 
 Phytolacca decandra (fig. 3. c). 
 
 2. Large single crystals, either of the form of the last 
 (fig. 3. a), and then very long, as in the Agave americana, or 
 the primary forms or combinations, are octaedrons of the first 
 or second order, with two or three blunt or pointed. This 
 last form is seen very beautifully in the pollen of many species 
 of Caladium, and in the parenchyma of the old stems of 
 Tradescantia (fig. 2.). 
 
 3. Large crystals, in which the crystals have developed 
 one upon another, or grown to organic cells in such a way 
 that they constitute irregular-formed glands. They are so 
 common amongst phanerogamous plants at one season of the 
 
 year or another, that it would be difficult to give an example of a 
 
 plant in which they do not exist. They 
 are easily observed in the Cactacccc. 
 
 Next to oxalic acid with lime, car- 
 bonic acid is most frequently found, 
 and this in combination with lime. 
 The carbonate of lime assumes a va- 
 riety of forms, but most commonly that 
 of the pure rhomboedron (fig. 4.) ; as, 
 
 for instance, in the Cycadacece, in many Cactacefe, and in the leaves of 
 
 species of Costus. 
 
 Sulphate of lime is also found, in the form of single or double 
 
 octaeclrons, or in a tabular form, as octaedrons above and below, with 
 
 * Even through artificial precipitation, oxalate of lime is never amorphous, but is 
 constantly crystallised, as shown by Valentin, Repertorium, vol. ii. p. 30. 
 
 2 Oxalate of lime as a quadratic octaedron, and a combination of three octaedrons, 
 found in the pollen of a species of Caladium. 
 
 * a, Quadratic pillars combined with octaedrons. b, The same elongated. c, A 
 bundle in a cell. 
 
 4 Carbonate of lime, as seen in the epidermis of Cactncefe. 
 
THE INORGANIC ELEMENTS. 7 
 
 the end of the prism cut off (fig. 5. ) ; or, what is especially charac- 
 teristic, in a twin form, 
 like the gypsum crystals 
 of Montmartre. This last 
 form is found in the 
 Musacece and many Sci- 
 taminece. 
 
 Such crystals present 
 themselves in all phane- 
 rogamous plants, but are 
 not so frequently found in cryptogamic plants. They have been described 
 amongst the latter in ChcBtophora, Hydrurus, and Chara, where they 
 exist not in the cells but in the intercellular spaces. In Polysperma and. 
 Spirogyra they are found in the cells. In the Phanerogamia they lie 
 constantly enclosed in the cells (also in the glands of the air-passages 
 of Myriophyllum*) ; more formless crystalline masses, especially of 
 carbonate of lime, are found in the intercellular passages, and upon the 
 leaves of Lathrcea ; and in many species of Saxifraga, as S. Aizoon and 
 S. longifolia, they are seen on the edges of the leaves as true excretions. 
 
 History. The discovery of crystals in plants is due to Malpighi, who 
 first figured the glands of Opuntia (Anatome Plant, tab. xx. fig. 
 105. E.). The needle-like crystals were discovered by Jurine (Journ. de 
 Physique, 56.). Meyen and Unger have described various other forms, 
 Buchner was the first to give a chemical analysis* and thought he had 
 found phosphate of lime in them. Raspail showed that they were prin-* 
 cipally composed of oxalate of lime, which had been previously discovered 
 by Scheele in the roots of rhubarb, but forgotten. Liebig first pointed, 
 out that the vegetable acids, in all species of plants, exist combined with 
 a determinate quantity of the base, however different the base may be, 
 and that this quantity depended on the amount of oxygen combined with, 
 the base, the oxygen being always in the same proportion in the same 
 species.f The salts of ammonia were first pointed out by Saussure as 
 the source of nitrogen in plants, and afterwards further elucidated by 
 Liebig. { 
 
 * Meyen (Physiologic, vol. i. p. 241.) appears to have overlooked the fine mem-, 
 brane which encloses these glands. 
 
 f Liebig, Chemistry in its Applications to Agriculture and Physiology. 
 \ Op. cit. 
 
 5 Sulphate of lime : a, simple crystal ; b and c, twin crystals. From the petioles of 
 Musa and Strelitzia. 
 
 B 4 
 
CHEMISTRY OF PLANTS. 
 
 CHAPTER II. 
 
 ON THE ORGANIC ELEMENTS. 
 
 SECTION I. 
 
 OF THE ASSIMILATED BODIES. 
 
 8. THE four elementary bodies*, Carbon, Oxygen, Hydrogen, 
 and Nitrogen, are associated together as organic or vegetable 
 elements, but they have evidently different values for the life of 
 the plant even in its simplest forms. Next to these we find a 
 series of bodies, which are necessary for the origin and develop- 
 ment of cells, and these I call especial assimilated matters. 
 
 9. Some of these are substances of which the cell-membrane 
 is formed, or which necessarily precede the formation of it, and 
 which contain only Carbon, Hydrogen, and Oxygen. I shall 
 mention here: 1. Cellulose, or Sclerogen; 2. Amyloid; 3. Vege- 
 table Jelly; 4. Starch; 5. Gum; 6. Sugar; 7. Inulin; 8. Oil 
 of Fat. 
 
 1. Cellulose (Sclerogen, Lrignine, woody fibre) is completely formed, 
 rather tender, flexible, and elastic, perfectly clear and transparent, and 
 entirely insoluble in all known menstrua. When treated with caustic 
 potash or concentrated sulphuric acid, starch is formed. Like all 
 organic substance it is distended by moisture and contracted by drying. 
 It is permeable to all fluids and actual solutions, which, under some cir- 
 cumstances, are taken in on one side and passed out on the other. Its 
 composition, when analysed, gave the following results : 
 
 From the wood of the willow and the beech, 
 according to Prout 
 
 r c H o 
 
 1 12 8 8 
 112 11 11 
 
 Various cell-membranes, according to Payen f C H O 
 (Ann. des Sc. Nat. 1839; \ 12 10 10 
 
 These analyses differ only in the quantity of water they contain. 
 
 To me it appears most correct to use the above formula, in which the 
 carbon is reckoned at 12. Mulder, however, takes C 24, H21, O21, as 
 isomeric with soluble inulin. Crookewitt has pointed out that this does 
 
 * Vier Elemente 
 
 Innig gesellt 
 Bilden das Leben, 
 Bauen die Welt. 
 Four elements 
 Intimately mixed 
 Give form to life, 
 Build up the world. 
 
 The genius of the poet has here evidently anticipated later chemical discoveries, 
 
THE ORGANIC ELEMENTS. 9 
 
 not make it a simple substance. Combinations of Cellulose with other bodies 
 are not yet known ; there thus remains, to explain the easy transition of 
 Cellulose into Sugar, Dextrin, and Starch, only the hypothesis of Iso- 
 merism. All other formulae appear purely arbitrary, and explain nothing, 
 for the elementary analyses vary from 43*22 to 52-01 of carbon, 5-9 to 
 6*91 hydrogen, 41-57 to 50-38 oxygen, or of analyses of the same cellular 
 tissue taken into account C 43-2 447, H 6-06-5, O 49-350-59, which 
 agree perfectly with the formula given above. On the other hand, the 
 whole doctrine of an incrusting matter (Payen), although supported by 
 the profundity of Mulder (Physiol. Chem. Moleschott, p. 209.), is a mere 
 castle in the air, that must be rejected a priori. On the application of 
 the ordinary re-agents, the thickness of the cell-walls is not diminished, 
 but they become loosened and swell up. What the reagents take up are 
 the contents of the cell, and matters which the cell-wall contain, and 
 which, according to the age of the cell, would become colouring matter, 
 tannin, hurnic acid, and humates. The wood-cells are, in comparison 
 with other cells, decaying, and are constantly forming out of the cellulose 
 substances, which are more and more rich in carbon, which remain dis- 
 solved in the cell-walls, and which are taken up by means of re-agents. 
 The successive layers of the cell-wall are composed chemically out of the 
 same or an isomeric matter as the primary cell, which explains its whole 
 deportment, and even Payen's elementary analysis of the spiral fibres 
 in Musa sapientum. A knowledge of the cell-layers is especially 
 important physiologically ; a knowledge of the substances which convert 
 sap-wood into heart-wood is only technical, as here life is almost wholly 
 extinct. 
 
 Cellulose presents itself under many modifications. In its pure state 
 it appears to vary chemically, according to the quantity of water it con- 
 tains. Independently of this, it varies greatly in its physical properties, 
 such as brittleness, viscosity, density, and especially in its perviousness 
 to water, which the less it is the more it appears to approach in its 
 nature amyloid and jelly ; and there are, in fact, very many transitionary 
 bodies between these three.* 
 
 In the impure state in which it ordinarily occurs, it varies yet more 
 from the passage through it of other matters ; perhaps through some de- 
 composition which they induce. Its colour is especially various, passing 
 from perfect transparency to the darkest brown (as in ferns) ; and occa- 
 sionally all other possible colours are present, as is seen in the epidermis 
 of the seeds of Leguminosce y a golden yellow colour in the leaves of Phor- 
 mium tenax, &c. 
 
 2. Amyloid*( is, when dry, a cartilaginous, but moist, gelatinous, clear, 
 transparent body, soluble in boiling water, strong acids, and caustic 
 alkalies, but not in ether and alcohol in a concentrated state. It is 
 coloured blue by iodine, and the combination is soluble in water, giving 
 it a golden-yellow colour. It is found only in the layers of the primary 
 cell-membrane. There is no chemical analysis of this substance. It 
 has been found at present only in the cotyledon-cells of Schotia latifolia, 
 S. speciosa, Hymencea Courbaril, Mucuna urens, M. gigantea, and Tama- 
 rindus indica. Perhaps many of the observations olf Hugo Mohl belong 
 to this substance. 
 
 3. Vegetable Jelly (Vegetable Mucilage, in part, of the chemists, Bas- 
 
 * See Hugo Mohl, Some Observations upon the blue Colouring of vegetable Cell 
 Membrane, through Iodine. Flora, 1840. 
 f See Poggendorff's Annalcn, 1839. 
 
10 CHEMISTRY OF PLANTS. 
 
 sorin, Salep, Lichen carragheen (Chondrus crispus) Gelin). This sub- 
 stance, when dry, is horny, or cartilaginous ; when moist, it swells up and 
 becomes gelatinous, and diffuses itself perfectly through cold pure water. 
 When pure it is clear, and is dissolved by (perhaps only diffused in) both 
 cold and hot water, and also in caustic alkalies ; it is, perhaps, chemically 
 changed in pure acids. It is insoluble in fixed and volatile oils, ether, 
 and alcohol, and is not coloured by iodine. It passes, on the one side, 
 through various transitionary bodies into cellulose (through the cell walls 
 of the Fucoidece), and into amyloid (through some kinds of horny al- 
 bumen), and on the other side into starch (through the jelly of the orchis 
 tubers), and, in many ways, into gum and sugar. None of these bodies 
 have been analysed, so far as I know, and reduced to chemical equivalents. 
 
 Vegetable jelly forms the cell-walls of most Fucoidece, the albumen of 
 the C&salpinece, and, in part, the so-called horny albumen (Albumen 
 corneum). It is also, like gum, found in the contents of the cell. It 
 is especially abundant in the cells of the tubers of our indigenous Orchi- 
 dece and in the Cactacece, filling large individual cells, which at first often 
 exhibit upon their surface a granulated aspect : in the Cactacece they are 
 often distinguished by a vermiform twisted line. It is also seen, as a 
 secretion, in the gum-receptacles, especially in tragacanth ; and a part 
 also of the intercellular substance seems to belong to it. 
 
 In the same way as in animal chemistry, we distinguish between 
 gelatinous substances and gelatine ; so does Kiitzing (Phycologia gene- 
 ralis, p. 32.) distinguish gelin from vegetable, which last, by boiling, 
 passes into the first. Vegetable jelly will also, by long boiling, pass into 
 mucilage (schleim). These three substances appear to me to be hydrated 
 states of a common basal principle. Kutzing's horny gelin (said to 
 contain nitrogen) and his gelacin (through hydrochloric acid coloured 
 verdigris-green) appear to be only gelin contaminated by foreign bodies. 
 At any rate, the experiment of determining the nitrogen which was 
 given off in the form of ammonia, during the combustion of an entire 
 plant, to be a constituent of a particular substance, is too coarse to be 
 admitted as of any worth at the present day. 
 
 Whether pectin and pectic acid ought to be admitted under this head 
 appears, according to Mulder's experiments, doubtful.* He gives the 
 formula C 12, H 8, O 10. They appear to be more nearly related to 
 malic acid, and form, perhaps, transitionary bodies between the organic 
 acids and the indifferent secretions. The analyses, by Mulder, of the 
 carragheen moss (Chondrus crispus}, the mucilage of the quince and 
 the marshmallow, and of tragacanth gum, vary too much to allow of even 
 a common formula. The inquiry must not be disregarded, how the sepa- 
 ration of the various substances intimately mixed, as in the carragheen 
 moss and tragacanth gum, can be separated, so as to yield a pure substance 
 fitted for chemical analysis. That pectin belongs to the substances em- 
 ployed in thickening the cell-walls, is a fiction which no one microscopical 
 observation of ripe or unripe fruits, or of roots containing pectin, supports. 
 
 4. Starch ( Amylum, Amiclon, Lichen -starch). When dry, it is toler- 
 ably hard, cracking between the fingers : when moist, somewhat gela- 
 tinous : dried from its solution, at first a trembling jelly, at last as brittle 
 as glass : when pure, constantly clear (even in lichens) : when perfectly 
 pure and fresh from the plant, gradually dissolving in water. This 
 solution may, perhaps, be regarded rather as a diffusion through water, 
 
 * Poggendorf, Annalen, b. xlvi. (1838), p. 432. 
 
THE ORGANIC ELEMENTS. 11 
 
 as the so-called solution does not penetrate through cell-membranes. In 
 the plant it is ordinarily defended from this solution by the action of 
 wax, albumen, mucus, and the like. It is easily soluble (diffusible) in 
 boiling water, acids, and alkalies ; insoluble in alcohol, ether, volatile 
 and fixed oils, and is coloured blue by iodine in the most dilute solution.* 
 It appears, through modifications such as lichen-starch, to pass into amy- 
 loid, and, through the body discovered by Henry in mace, into cellulose 
 vegetable jelly, and perhaps also gum. On its chemical composition the 
 most distinguished chemists, Berzelius, Liebig, and others, are all agreed : 
 C 12, H 10, O 10. It forms the cell-wall in the asci of Lichens ; and in 
 some, as the Iceland moss (Cetraria islandica\ it is found in the external 
 layer of the thallus. It is also present, forming the contents of the cells. 
 
 A. .The Nature of Potato Starch. 
 
 The ordinary potato-starch of commerce consists of a somewhat coarse, 
 glistening, white powder, intermixed with larger pieces. On rubbing it 
 between the fingers, it pulverises more finely, but is somewhat hard to 
 the touch, and grates between the teeth. When moistened it cakes to- 
 gether in largermasses, and does not fall to pieces again on being re-dried. 
 When, however, this starch, after a long-continued extraction with cold 
 water, has been thoroughly purified with alcohol and ether, it forms an 
 extremely fine, glistening powder, which will not continue to adhere 
 together on being moistened and dried. Some considerable time is re- 
 quired to purify the starch perfectly, and the fluids used for its purifica- 
 tion continue for a long time to exhibit traces of albuminous matters and 
 of fats. The very various views that have been entertained regarding 
 the chemical relations of starch appear to me specially to arise from the 
 fact, that experiments are never made with perfectly pure, but with 
 variously adulterated, specimens. Payen and Persoz were the first who 
 seem to have thought of thoroughly purifying starch before they used it, 
 and the consequence was that the result of their experiments wholly 
 differed from those of others, and showed that starch was a perfectly 
 homogeneous vegetable substance. 
 
 When magnified 100 times, the separate granules of starch appear like 
 small, solid, invariably ovate corpuscles. Deviations from this form are, 
 comparatively speaking, very rare. In starch that has been freshly 
 extracted from the potato, we recognise most distinctly a small black spot 
 by its pointed extremity : this is Fritsche's nucleus. It is only very 
 rarely, and when very strongly magnified, that it appears as a speck in 
 the potato, filled with such a thin substance as to allow of our regarding 
 it as an indentation, or rather as a small cavity, in the denser mass. This, 
 however, is made much more clearly evident in the starch extracted from 
 the bulbs of some of the Liliacece, and is established with perfect certainty 
 on comparing it with various other kinds of starch. Around this so- 
 called nucleus there appears, sometimes paler or blacker, or sometimes 
 closer or further, a large number of lines, which at first pass circularly 
 round the nucleus : further on they describe more of an oval course, as 
 they elliptically enclose the nucleus like a focus. The space enclosed 
 by two such lines appears sometimes lighter, sometimes darker, often 
 strikingly clear at separate spots ; and an experienced microscopic 
 observer will soon recognise layers of different density, and that the 
 
 * Iodide of starch is not more soluble in water than starch, and insoluble in acids. 
 
12 CHEMISTRY OF PLANTS. 
 
 external ones are generally clearer than the internal, which, in fresii 
 starch, often appear almost gelatinous. The dark lines do not intersect the 
 line of the external circumference in any one of the granules ; and, how- 
 ever close they may lie to each other at the pointed end, every line per- 
 fectly returns to itself. On turning a single granule with deeply 
 blackened lines under the microscope, which may be easily done by the 
 addition of a drop of water, which will occasion a small current, we shall 
 see that the lines, when considered from all sides, remain equal, and 
 always encircle the nucleus in the same manner. From this it follows 
 that they cannot be mere markings upon the surface, but the surfaces of 
 contact of many hollowVvate scales laid around each other : from this the 
 whole granule is composed. Sometimes on making a fine section, with a 
 sharp razor, from a potato containing much starch, we may succeed in 
 seeing several granules of starch sharply intersected under the micro- 
 scope ; and we may thus perfectly convince ourselves that the layers to- 
 wards the interior are in general more aqueous and gelatinous, and that 
 those towards the exterior contain less water and are tougher. 
 
 Perfectly dried granules exhibit a smaller number of lines, although 
 they are frequently more strongly marked ; and we may often perceive 
 that each broad black line corresponds to a thin layer of air. On suffering 
 starch to remain for any length of time in gum water, the lines gradually 
 will disappear more and more ; and on drying it with the gum, until the 
 whole forms a perfectly tough mass that may be cut with a knife, we 
 may easily obtain a great number of sections by cutting off small chips, 
 and even have several thin discs from a single granule. In the latter we 
 discover a tolerably homogeneous substance, having in the centre a some- 
 what irregular indentation, which has naturally been occasioned by the 
 drying up of the interior aqueous layers. 
 
 On treating starch under the microscope with sulphuric acid, very dif- 
 ferent phenomena appear, according as to whether the acid is stronger or 
 weaker, and the action rapid or slow. On the rapid action of strong 
 acid, the granule is immediately affected from the point where it is 
 touched by the acid ; it becomes distended, and gradually dissolves, a pro- 
 cess that is quietly continued to the other end of the granule. We often 
 see granules which are quite dissolved at one end, while the opposite end 
 is still sharply defined, showing even a nucleus and layers. The whole 
 mass of the granule is quite uniformly affected, without the outer layers 
 being torn open, or the fluid contents escaping. In a slower action of 
 the acid, two different forms of solution occur alike frequently, depend- 
 ing probably upon the different degree of concentration of the acid. In 
 dilute acid the granule becomes gradually transparent and gelatinous ; 
 swells up, but in such a manner that it first exhibits an impression at 
 one side, and by degrees (swelling up less at the compressed side than ex- 
 ternalty) assumes a complete cup form, and is at last gradually dissolved 
 from the margins. The other form, exhibited by the slow action of the 
 very concentrated acid, consists in the nucleus passing over into a 
 decidedly recognisable air-bubble. This expands, causing one or two 
 jagged rents in the interior of the granule, which gradually inflates and 
 becomes gelatinous, whilst the lines disappear, as far as they are touched 
 by the rent, until the whole granule is rendered invisible (dissolved). 
 The first action of the sulphuric acid appears to be, that water is with- 
 drawn from the inner layers ; and this appears further confirmed by the 
 action of dry heat. 
 
 On heating potato starch upon a small plate, to such a degree that only a 
 
THE ORGANIC ELEMENTS. 13 
 
 minute portion, immediately in contact with it, assumes a yellowish colour, 
 we may easily trace, under the microscope, every possible stage of transi- 
 tion in the gradual change ; which is very remarkable, and affords the 
 best explanation of the structure of the starch granule. The first action 
 here is naturally one of drying, by which the so-called nucleus is con- 
 verted into an air-bubble, appearing so characteristic that we can thereby 
 distinguish the use of dry heat, as, for instance, in the Mandiocca fa- 
 rinha. in Sago, &c. The individual layers simultaneously separate, and, 
 in consequence of drying out, the lines of separation become sharper, 
 blacker, broader, and even recognisable broader or narrower layers of 
 air ; the layers hang closer together at some places than at others, and 
 larger or smaller spaces are formed. By degrees the separate layers peel 
 away from each other, like the scales of a bulb, whilst an actual fusion 
 (conversion into gum) takes place at individual points. 
 
 If we continue the action of water, heated gradually to the boiling 
 point, a change at first takes place, which is very similar to what has 
 been just described with reference to sulphuric acid. It is only in the 
 latter stages that the phenomenon is so far different, that the cleft in the 
 interior is gradually converted into a large cavity, when the whole 
 swollen granule looks like a compressed thick-skinned bag. 
 
 By degrees the outlines grow more indistinct ; but the paste-like 
 mass, consisting of a granule, continues clinging together; and, on 
 looking under the microscope at the thinly boiled paste mixed with 
 water, we may, by means of iodine, recognise the separate and inflated 
 granules, whilst the water added is never coloured blue. I have not 
 been able to continue the boiling during several days, but I think I may 
 venture to conclude, from my own experiments, that starch may take up 
 a large quantity of water, and thus swell to a large volume (although 
 even this seems to have its limitations), but that it never can be properly 
 dissolved either in cold or boiling water. 
 
 I will here finally mention the treatment of starch with cold water. 
 If starch be rubbed up, for the period of half an hour, in a mortar, with 
 double the volume of water, we obtain a viscid, almost stiff, salve, capable 
 of being drawn into threads. A large number of the granules then 
 appear under the microscope, to be crushed in various ways, torn and 
 broken up, partly ground into small flakes. The inner aqueous layers 
 are pressed and combined with more water by friction, as it appears, ex- 
 hibiting a finely floccular or granular, but connected, mass, which is 
 coloured blue by iodine, whilst all the actual fluid round (the water) 
 remains wholly uncoloured. 
 
 All these experiments were frequently repeated with different impure 
 specimens of starch, such as are commonly bought, but all of the same 
 kind ; and the results were, in every case, essentially the same. Iodine 
 was always used in these experiments, and there never was the most 
 remote indication of there being any part in the starch granule which 
 was not equally coloured by it. There never occurred the slightest ap- 
 pearance, in these experiments, to refute the easily tested fact, that the 
 layers of starch granules are more aqueous in proportion as they lie fur- 
 ther to the interior : nor was the unimportant point refuted, that there 
 were slight differences in the external layers, arising from the adhesion 
 or infiltration of some few traces of albumen, fat, or wax ; these differ- 
 ences merely resulting in a longer or shorter delay of the action of the 
 solvents. The same experiments were constantly repeated with purified 
 starch, in order fully to test the correctness of the last-named facts. 
 
14 CHEMISTRY OF PLANTS. 
 
 It will now be easily apparent from what has been said, that without 
 a simultaneous application of the microscope and chemical re-agents it is 
 utterly impossible to think of a true and fundamental knowledge of starch. 
 Starch is gradually dissolved in the full-grown potato, so that after three 
 months there is scarcely a trace of it to be met with in that vegetable, even 
 where it is in a perfectly sound condition. This solution is most essen- 
 tially different from all others that we are able to bring about. The 
 individual granule retains to the last moment its solidity, and is only gra- 
 dually attacked from the exterior towards the interior ; the extremities of 
 the longitudinal sections offering the greatest resistance, on which account 
 the granule after a time resembles a knotty twig, owing to the promi- 
 nent appearance of the rest of the layers. The same thing occurs in the 
 germination of the cereals, and in the solution of starch which takes place 
 through diastase, but only at a temperature of 70 C.,* which corresponds 
 entirely in form with the solution by sulphuric acid, and has been referred 
 by chemists, with an inconceivable degree of superficial carelessness, to 
 the process in living plants. 
 
 B. On the Occurrence of Starch in various Forms in the 
 Vegetable Kingdom. 
 
 We have only one treatise, and that by Fritsche (Poggend. Ann. 
 vol. xxxii.), deserving of notice, on the differences of starch in different 
 plants ; and this, with some few inconsiderable additions, has been 
 made use of by Meyen in his Vegetable Physiology. For the rest, this 
 work appears to have met with very little attention ; for when we read a 
 passage to the following effect in one of the most recent works, " Starch 
 appears in the form of small spherical corpuscles," (Endlicher und 
 linger, Grundziige derBotanik,) we may easily see that the authors have 
 neither made original observations on the subject, nor even read anything 
 regarding it. The forms of starch are exceedingly various, and often, 
 as Fritsche remarked, so characteristic, that we may easily, by means of 
 the starch, determine the plant, at any rate with reference to its genus 
 and family. I subjoin the following tabular list of the forms with which 
 I am acquainted. 
 
 I. AMORPHOUS STARCH. 
 
 Hitherto I have found amorphous starch only in two phanerogamic 
 plants, it occurring then paste-like in the cells, as in the seeds of Car- 
 damomum mimis, and in the bark of the Jamaica Sarsaparilla. In the 
 case of the latter, however, it is not improbable that the method of dry- 
 ing by the fire, common in the preparation of Sarsaparilla, may change 
 the character of the starch. The paste is most frequently found in ab- 
 normally red roots, and more seldom in the yellow ; neither of which, 
 however, have hitherto been esteemed in commerce as varieties of the 
 Jamaica Sarsaparilla. 
 
 II. SIMPLE GRANULES. 
 
 The majority of plants exhibit perfectly simple individual granules, 
 among which doublets and triplets only occur as exceptions. We may 
 further distinguish the following groups : 
 
 * A temperature that would kill every vegetable embryo. 
 
THE ORGANIC ELEMENTS. 
 
 15 
 
 1. Roundish Bodies. 
 
 A. With the central cavity, Fritsche's nucleus, apparently wanting. 
 
 1. Quite small, almost spherical, granules, occurring almost every- 
 where in the vegetable kingdom, from time to time, as cellular contents ; 
 for instance, in Carrots, in cambium, in the winter ; in leaves, as the 
 bearers of Chlorophyll, &c. 
 
 2. Large, irregular, knobby, often truncated multangular granules ; 
 as, for instance, in the bulbous buds of Saxifraga granulata, in the 
 spurious tubers of Ficaria verna. 
 
 B. With small roundish central cavities. 
 
 a. With a perceptible laminated formation. 
 
 3. Very large, rough, granules, deformed as it were, found in the pith 
 
 of the Cycadacece. There 
 
 6. are somewhat similar 
 
 granules in the subter- 
 ranean leaves of Lathrcza 
 squamaria ; in these the 
 inner layers form an ovate 
 granule, almost similar to 
 those of potato starch : the 
 few external ones, on the 
 contrary, are so irregular, 
 and generally so dispropor- 
 tionally thickened at one 
 or two sides, that the whole 
 granule assumes a broadish 
 triangular figure. 
 
 4. Ovate granules. In 
 the potato (fig. 6.). 
 
 5. Mussel-like granules. 
 In the bulbs of the larger 
 Liliacece, as in Fritillaria, 
 Lilium (fig. 7.), &c. 
 
 6. Almost triangular in 
 tulips. 
 
 b. With an indistinct or 
 deficient lamellated form- 
 ation. 
 
 7. Rounded-off polyedric granules. In the albumen (perisperm) of 
 Zea Mays. 
 
 8. Sharp-edged, polyedric, very small granules. In the albumen of 
 Oryza sativa. 
 
 C. With an elongated central cavity. 
 9. Roundish or oval granules, in a dry 
 
 condition, generally showing a star-like 
 cleft in the inner layers. In the Legu- 
 minosce, as in the seeds of Pisum, Pha- 
 seolus. 
 
 D. Perfectly hollow, apparently cup- 
 like, granules. 
 
 8 Granules of starch from the potato, the layers being copied true to nature. 
 
 7 Granules of starch from the bulb of Lilium bulbiferum. The layers are faithfully 
 delineated : a, from the surface ; and 6, a lateral view. 
 
 8 Granules taken from the rhizoma of Iris ;w//iW/i, with a large central cavity. 
 
16 
 
 CHEMISTRY OF PLANTS. 
 
 10. Very marked in the Rhizoma of Iris florentina, and in the kindred 
 species (fig. 8.). 
 
 9. 
 
 2. Flatly. compressed lenticular 
 Granules. 
 
 11. Sometimes with, sometimes with- 
 out, a decided lamellated formation ; 
 sometimes with a central, or excentric, 
 or less rounded, or more elongated, 
 or radiated torn-up cavity. In the 
 albumen of Triticum, Hordeum, Secale 
 (fig. 9.). 
 
 3. Perfectly flat Discs. 
 
 12. With more distinct layers, 
 in which it is, however, at times 
 doubtful whether they pass 
 entirely round, or are only 
 menisci laid over one another. 
 The former appears to me pro- 
 bable, owing to analogy, and the 
 phenomena presented in roast- 
 ing and on dissolving in sul- 
 phuric acid. We do not find 
 it in the rhizoma of all the 
 Scitaminece, as Meyen attests, 
 but exclusively in the Zingi- 
 beracecB Lindl. ; neither in the Cannacece, nor in the Marantacece 
 
 (fig. 10.). 
 
 4. Elongated Corpuscles. 
 
 13. With an elongated central cavity in the milk -juice of the indi- 
 genous, and a few of the tropical, EuphorbiacetB. 
 
 5. Perfectly irregular Bodies. 
 
 14. In the milky juice of many tropical Euphorbiacece. 
 
 III. COMPOUND GRANULES. 
 
 Here we only find simple granules, by way of exceptions, in the plant, 
 or part of the plant. 
 
 1. The separate Granules in the Composition without evident 
 central Cavity. 
 
 15. Compounded, according to the simplest types in 2, 3, or 4 in the 
 rhizoma of Marantacece (West Indian Arrow-root) (fig. 11.). In the 
 tubers of Aponogeton ; in the thickened vagination of the leaves of 
 Marattia ; in the root of Bryonia. 
 
 9 Granules of starch from the albumen of the seed of Secale cereale : a is seen from 
 the surface, 6 from the edge. The difference of size, without any intervening stages, is 
 striking in Secale, Triticum, Hordeum, &c. 
 
 10 Granules of starch from the rhizoma of Curcuma leucorrhiza (East Indian arrow- ^ 
 root). Very flat discs seen at a from the surface, and at b from the margin. f j? 
 
 \f 
 
THE ORGANIC ELEMENTS. 
 
 17 
 
 16. Generally regularly, seldom 
 irregularly, composed of from 2 
 to 6. In the bark of the roots 
 of the various sorts of Sarsa- 
 parilla. 
 
 2. The separate Granules in tJie 
 Composition having a distinct 
 central Cavity. 
 
 A. All the parts of the granules 
 nearly of the same size. 
 
 17. United, according to simple 
 types, from 2 to 4. The central 
 
 cavity small and roundish. In the tubers of Jatropha Manihot. 
 
 18. Combined from 2 to 4, according to simple types. The central 
 cavity large and very beautiful, opened in a star-like form. In the 
 cormus of Colchicum autumnale (fig. 12.). 
 
 19. Combined according to simple types from 2 to 4. The separate 
 
 granules quite hollow, appa- 
 rently cup-shaped. A marked 
 form occurs in Radix Ivar- 
 ancusce (Anatherum Ivaran- 
 
 CUSCB] (fig. 13.). 
 
 20. Firmly combined, from 
 2 to 12 in number, in very 
 irregular groups. In the 
 rhizoma of Arum maculatum 
 (fig. 14.). 
 
 21. A large number (often 
 as many as thirty) of small 
 roundish granules, very loosely 
 rolled together. Frequent, as, 
 
 for instance, in the stem of the Bernhardia dichotoma. 
 
 11 Granules from the rhizoma of Maranta arundinacea (West Indian arrow-root) 
 Composed of from 2 to 4 granules, the separate parti-granules always exhibit the 
 smooth connecting surfaces. 
 
 18 Starch granules from the cormus of Cokhicum autumnale. The separate granules 
 are quite similar to those in the seeds of the Leguminosce, but generally composed of 
 from 2 to 4, with very beautifully radiated opened central cavities. 
 
 13 Starch granules from the rhizoma of Anatherum Ivarancusa (Radix Ivarancusce). 
 The separate granules with large central cavities, as in Iris florentina, but composed 
 of from 2 to 3 combined. 
 
 14 Starch granules from the subterranean stem of Arum maculatum, irregularly 
 composed of many grains, each granule having an indistinctly defined central cavity. 
 
 C 
 
18 CHEMISTRY OF PLANTS. 
 
 B. Many smaller granules grown together upon one larger one. 
 
 22. In the pith of Sagus Rumphii, &c., generally in the sago. 
 
 Starch is the most generally distributed substance in the vegetable 
 kingdom. I am not acquainted with any plant which does not, at some 
 season of the year, at least at the period when vegetation is inactive, 
 contain more or less starch, frequently only in individual granules in the 
 cells, and frequently entirely filling them in grains of the most different 
 size. The starch granules adhere quite adventitiously, by means of mu- 
 cus, to the cell-walls. The umbilicus (hilum), by which the starch gra- 
 nules are said to be attached to the wall of the cell, is an error on the 
 part of Turpin. The largest granules do not appear to exceed 05 of 
 a line in their longest diameter. The starch is mostly readily obtained 
 by bursting the cellular tissue, and by washing it from the plant ; occa- 
 sionally, however, it cannot be thus obtained, as, for instance, when it 
 occurs combined with much mucus, as in Hedychium ; the starch in 
 Maranta arundinacea (Arrow-root) appears to be the purest. We 
 certainly do not say too much when we assert that starch constitutes 
 the most important, and the almost exclusive, food of two-thirds of all 
 mankind. It is certainly contained in all plants, but not always in such 
 a manner as to be sufficient and suitable for nutriment, and sometimes, 
 too, indivisible from other unpalatable admixtures, as, for instance, in 
 the horse-chestnut. Certain parts of plants contain it in the largest 
 quantity, namely, the albumen of seeds (the Cerealia), the cotyledons of 
 the embryo (Leguminosce), the medulla, or pith of the stem ( Cycadece and 
 PalmcB) * bulbs (Liliacece) f, the tubers, root-stocks, and roots of very 
 different families. J It occurs in smaller quantities in the bark and the 
 alburnum of trees in winter, whence the inhabitants of the Polar regions 
 are able to bake the bark of trees as bread. 
 
 I must not omit to make mention of an error, which is unfortunately 
 too often repeated, and which may thus lead to much confusion, especially 
 in physiology. Decandolle believed that he had proved that 100 Ibs. of 
 potatoes would yield 10 Ibs. of starch in August, 14^ Ibs. in September, 
 14^ Ibs. in October, 17 Ibs. in November, 13J Ibs. in April, and again 
 10 Ibs. in May. From this it was concluded that the quantity of the 
 starch in the potato increased and diminished again during this interval 
 of time, a most erroneous idea, which has unfortunately been too often 
 repeated in recent times. It may, however, easily be conjectured that 
 such per-centage calculations can only give relative, but no absolute, 
 quantities for any plant, or part of a plant. Granting that Decaridolle's 
 calculation is correct, it says nothing more than that the weight of starch 
 gradually comes to stand in the same relation to the weight of the 
 potato as 10, 141, 17 ? & c ., to 100 ; but whether this changed relation is 
 to be sought in the change of the quantity of the starch, or in the dimi- 
 nution of other substances, is not even indicated. It is rather obviously 
 probable that in this case starch is neither formed nor destroyed, but that 
 the aqueous contents of the potato decrease by evaporation, and again 
 augment by absorption on the revival of vegetation. 
 
 Historical Sketch. Starch was known even to the ancients. ("A/ziAoj/ 
 <Hia TO x w i' pv\ov Kara(TKvaecrdat, Dioscor.) Leeuwenhoek was the first 
 who examined it in plants, in wheat and beans ; and Stromeyer sub- 
 
 * As sago, from Cycas revoluta, Sagus Rumphii, farinif era, &c. 
 f Lilium camtchaticum, in Greenland, &c., is a source of food. 
 
 { Potatoes, from Solanum tuberosum ; Cassava, from Jatropha Manihot ; Taroo, from 
 Arum esculentum ( Colocasia macrorhiza ?), &c. 
 
THE ORGANIC ELEMENTS. 19 
 
 sequently discovered the property possessed by starch of being coloured 
 blue by iodine. 
 
 Few substances have been so comprehensively treated of as starch, 
 and few have been more imperfectly and unsatisfactorily known, this 
 arising solely in consequence of neglect or superficiality in microscopic 
 investigations. A very clear and comprehensive report of PoggendorfF 
 upon the numerous works, up to 1836, written on this substance, may be 
 found in Pogg. Annal. der Chem. und Pharm., vol. xxxvii, p. 114., &c. 
 The result of the whole is concisely summed up in these striking intro- 
 ductory words : 
 
 " No substance has been more investigated, and is yet less known, 
 than starch. It affords a striking proof of the diffuse manner in which 
 a subject may be treated if it fall into improper hands. After ten years' 
 investigations, in which the most various views have been set up on the 
 nature of starch, and when all its characteristics as a proximate vegetable 
 substance have been discussed, we are little or nothing in advance of 
 the old point of view ; and although, perhaps, we may not be wholly 
 without some extension to our knowledge in secondary points, we are 
 still entirely without fundamental grounds in proof of our having arrived 
 at the truth." 
 
 Since Poggendorff wrote these words, eight years have elapsed. In- 
 numerable works upon starch have been published by chemists and 
 vegetable physiologists ; and, on testing more exactly what has been 
 done in Endlicher's and Unger's Rudiments of Botany, we find that the 
 labours of the last eighteen years are lost, even as far as relates to the 
 more general knowledge of this substance, whilst the whole confusion in 
 the literature of those eighteen years may be found reflected in the few 
 lines of those writers, who evidently were not able by their own ele- 
 mentary investigations to avail themselves with discrimination and 
 judgment of the extensive literature opened to them. The diametrically 
 opposite views of Fritsche and Raspail are so blended together in the 
 most extraordinary manner, that the confusion is beyond all description. 
 
 There are two views upon the structure of starch granules decidedly 
 opposed to each other, on the assumption or rejection of which the 
 chemical judgment passed upon this substance must essentially depend. 
 The first, originating with Leeuwenhoek, and subsequently further de- 
 veloped by Raspail, tends to prove that the individual starch granules 
 consist of a tough sac, and semi- liquid, easily soluble contents (Dextrin), 
 and that both parts are chemically different. This view effected the 
 refutation of the diffuse works of the French chemists, who, although 
 they differed upon words and secondary points, yet agreed in the main 
 that starch was no proximate vegetable matter, and that the starch 
 granule was composed of substances differing considerably in a chemical 
 point of view. Among these may be reckoned especially the works of 
 Guibourt, those earliest written by Payen and Persoz, and those of 
 Guerin-Varry. Finally, after giving many proofs of their incapacity 
 to compose an unprejudiced and thorough analysis of organic substances, 
 Payen and Persoz came to the conclusion, " that starch purified from 
 all extraneous matter was a simple, homogenous, proximate vegetable 
 substance." Raspail's view was entirely given up, and the structural 
 relations of starch not more thoroughly pursued. Such was the state of 
 things in France. In Germany, starch was first more accurately 
 examined by Fritsche*, and by aid of the microscope, which is indis- 
 
 * PoggendorfTs Ann. vol. xxxii. p. 129. (1834). 
 c 2 
 
20 CHEMISTRY OF PLANTS. 
 
 pensable in an investigation of this kind. His results form the second 
 hypothesis upon the nature of starch, which we may oppose as the views 
 of German vegetable physiologists against those of the French chemists. 
 According to the former, starch is composed of layers ranged over one 
 another, all consisting of the same chemical substance. The external 
 layers are less easily soluble in water, owing to their saturation with 
 foreign substances. In the interior there is an extremely small nucleus, 
 which appears, by its behaviour during the action of hot water, acids, and 
 alkalies, neither to be starch, gum, nor sugar. This is more especially the 
 case with potato starch, butthe starch granules of the curcuma roots appear 
 to differ somewhat from this, exhibiting elongated flat discs, while those 
 of the cereals have lenticular bodies. Subsequent observation (especially 
 on the part of Meyen) has shown abnormally-irregular forms in the milky 
 juice of the Euphorbiacece. And here the theory rests, as far as the 
 main point is concerned. There has as yet been no thought of a more 
 exact investigation of the structural signification of the chemical rela- 
 tions, or of a comprehensive comparison of the different kinds, of starch in 
 various plants. The whole of this question has been condensed in 
 Endlicher and Unger in the following improper manner : " Amylum 
 granules consist of a more or less solid (?) nucleus, around which layers 
 of solid (!) consistency are by degrees eccentrically deposited, admitting 
 sometimes even of being peeled off. (?) On the external case(?) of the 
 ainyhum granule being burst, the interior will dissolve even in cold 
 water, and that about 0*413 of the whole granule. The chemical cha- 
 racter of the nucleus is not essentially different from that of the layers 
 which either partially or entirely invest it. (!) Iodine colours both parts 
 in like manner, blue ! Concentrated (?) mineral acids dis- 
 solve the arnylum granule, boiling water occasions only an enlargement 
 in its size by means of absorption, and this often gives rise to a cleft in 
 the external layers (!) through which the softer nucleus (!) is expressed. 
 The probable special substance of the nucleus, the so-called dextrin, 
 consists of gum and sugar." (!!!) 
 
 By way of historical references we may recommend Poggendorff, 
 Annalen, vol. xxxvii. (1836), p. 123. ; Meyen's Physiologic, p. 190. ; Mul- 
 der's Physiol. Chem. Moleschott, p. 215.* 
 
 5. Gum (Arabin, Dextrin, Vegetable Mucilage in part). In a pure 
 state it is clear; when dry, brittle like glass; easily soluble in water, and 
 also in dilute acids; not soluble in ether, alchol, and volatile and fixed 
 oils. The action of alcohol makes it horny, and it is coloured pale- 
 yellow by iodine. It passes through cerasin and some so-called varieties 
 of mucilage into vegetable jelly; it borders through dextrin on starch. 
 The analysis of gum Arabic by Berzelius gives the formula, C 12 H 11 
 Oil; of gums Arabic, Senegal, and Java, by Mulder, C 12 H 10 O 10. 
 
 It is found in a state of solution in the interior of cells, or as a secre- 
 tion in the great gum canals, and not unfrequently mixed with vegetable 
 jelly, and is frequently, through foreign substances, coloured yellow or 
 brown, a condition in which it is almost always found when collected for 
 commercial purposes. Some groups of plants are distinguished by the 
 great quantity of gum they produce, as the Mimosece and the Cycadece. 
 
 The substance called dextrin, and which can be formed through the 
 action of dilute sulphuric acid, diastase, &c., on cellulose or starch, 
 agrees with gum in many points, and especially in its elementary com- 
 position. It seems to be a substance of more importance than gum. 
 According to Mulder, the greater part of what has hitherto been called 
 
THE ORGANIC ELEMENTS. 21 
 
 gum is dextrin. Some time ago I advanced the opinion that dextrin 
 must be present in plants where so much cellulose and starch was dis- 
 solved and changed. Soon after, Mitscherlich pointed out the actual 
 presence of this substance in the sap of many plants. The principal 
 difference between gum and dextrin consists in the fact, that the latter, 
 by the action of dilute sulphuric acid or diastase, is converted into 
 grape-sugar, while the first is not. Gum apparently originates in the 
 plant from dextrin, and not as a special product of secretion ; whilst 
 dextrin is present in all the juices of the plant, and especially where 
 cells are about to be formed, and appears to be the formative matter of 
 the plant. Countless almost, however, are the modifications of dextrin, 
 through vegetable jelly, till it forms cellulose. 
 
 6. Sugar. In a solid state, and entirely pure, sugar is crystalline, 
 clear, and easily soluble in water. In some states it is unerystallisable, 
 and then, through foreign substances, coloured yellow or brown. It is 
 slightly soluble in alcohol, but not in ether, volatile and fixed oils. It 
 mixes with a solution of iodine. The analyses give, according to various 
 modifications, various results : 
 
 Anhydrous salt of sugar, with oxide of lead, 1 C H O 
 according to Berzelius and Liebig - - J 12 10 10 
 
 Crystallised cane sugar, according to Gay- \io 11 11 
 Lussac, Thenard, Berzelius, and Liebig - J 
 
 Grape sugar, from a crystallised compound 1 C H O 
 with common salt, according to Brunner - J 12 12 12 
 
 The same from grapes, honey, and starch, ac- \ , 14 14 
 cording to Saussure and Prout - J 
 
 Sugar, which is principally distinguished by its sweet taste, is by 
 various modifications, and in every case through inulin, connected with 
 the other bodies, birt of the transitionary conditions we know but little. 
 It presents itself very widely In the vegetable kingdom, and especially 
 where starch and the other substances are developing or are dissolved, 
 as in unripe peas and cereal grains ; and the early sap of trees, as of the 
 maple and beech. It is found in greater quantities, and in a more per- 
 manent form, in the stems of grasses, as the sugar-cane and maize, and 
 the Holcus saccharatus; in fleshy roots, as in the carrot and beet; and in 
 juicy fruits, as the pear and apple, gooseberry and currant. Naturally 
 it is found dissolved in the plant, but when it becomes excreted it assumes 
 the forms of crystals, as in the nectaries of plants (ex. gr. Fritillaria 
 imperialis). Mannite, the sugar of manna, does not belong to this series 
 of compounds. It is only the product of the decomposition of the sugar 
 cane. Its formula is C6 H7 O6. According to Mitscherlich, the 
 Tamarix gallica, which yields manna, contains in its tissues no mannite, 
 but cane sugar. 
 
 7. Inulin (Dahlin, Calendulin, Synantherin, Sinistrin). It is obtained 
 from the tubes of the dahlia by simply washing. It is a powder with 
 fine grains ; the grains clear, easily soluble in boiling water, from which 
 it separates, on cooling, in a granular form. It is insoluble in ether and 
 alcohol, coloured yellow by iodine. Cold water makes the grains to dis- 
 appear to the eye under the microscope, because their refracting power 
 is similar to that of water. Hence the erroneous assertion of Link and 
 Meyen, that inulin is always in solution in plants. Crookewitt found 
 that inulin, by being boiled in water fifteen hours, was converted into an 
 
22 CHEMISTRY OF PLANTS. 
 
 uncrystallisable sugar. According to the researches of Mulder and 
 Crookewitt (Liebig's Ann. Bd. 44. S. 184.), inulin from the dahlia, 
 helenium, and the dandelion, in a pure state, consists of C 12 H 10 O 10. 
 It is thus isomeric with sugar and starch. Inulin has been found in 
 many places where formerly starch was supposed to be present, as in 
 tubers and fleshy roots (ex. gr. Inula Helenium, Dahlia variabilis), 
 and is probably a very widely extended substance. 
 
 8. Fixed Oils and Wax. The great peculiarities of these physically 
 and chemically varying substances is the property of leaving upon paper 
 a transparent spot, and not adhering to water. Their colour is very 
 various ; clear, yellow, and brown. 
 
 A. Fats (Fixed Oils). They are very widely distributed, and fre- 
 quently take the place of starch, as in the cotyledons of the CrucifercB 
 (ex. gr. the species of Brassicd], of the Synantherece (as Ilelianthus 
 annuus, Madia sativa) and many other plants. They are found in the 
 juices of the fruits and roots ; and there is, perhaps, no plant, or no part 
 of a plant, that does not contain a small quantity. The most common 
 fats in the vegetable kingdom are elain and margarin, which are formed, 
 according to Mulder, of glycerin (C 3 H 2 O), and elaic acid (C 44 H 40 
 O 4 + HO), and margaric acid (C 34 H 34 O 3 4- HO). Elain 
 is fluid, margarin solid ; and the two, mixed in various proportions, 
 form the fixed oils found in plants. Besides these, there are peculiar oils, 
 such as the cocos and muscat butters, palm and bay-berry oils. They 
 form soaps with the alkalies, which are soluble in water. Alone they are 
 insoluble in water, in ether and alcohol gradually soluble, and in volatile 
 oils perfectly so. Of their changes into the other bodies mentioned, we 
 know nothing ; at the same time it cannot be doubted, from what we 
 know of the phenomena of germination in oily seeds. 
 
 B. Wax. This substance, which is distinguished from the oils and 
 fats through its perfect insolubility in cold alcohol, and its brittleness, is 
 found extensively in the vegetable kingdom, and plays an important 
 part. There are few plants that do not present traces of it upon their 
 surface. In all those plants and parts of plants called hoary, the delicate 
 bluish bloom consists of a thin layer of very small wax granules. This 
 layer is much thicker in the fruits of the order Myricece, of Croton sebi- 
 ferum, Tomex sebifcra, Rhus succedaneum, the leaves ofEncephalartos, the 
 
 bracts of Musa paradisiaca and Strelitzia farinosa, the stem of Ceroxy- 
 lon andicola. In plants generally it appears to be the basis of the 
 chlorophyll ; and in many families, as, for instance, the Balanaphored* t 
 it forms the entire contents of the cells. It is found in large quantities 
 in the milky juice of the Galactodendron utile, forming the Galactin of 
 Solly. In wax two proximate principles appear to be present, myricin 
 (C 20 H20 O), insoluble in boiling alcohol, and cerin (C 10 H 10 O), 
 soluble in boiling alcohol. AVax is decidedly formed by bees out of 
 sugar. A form of wax exists, according to Avequin (Ann. de Ch. et de 
 Phys. Oct. 1840, p. 218.), in the sugar-cane, which sometimes passes into 
 sugar, and which is sometimes formed out of sugar. The wax, which is 
 combined with chlorophyll, appears to be formed from starch, perhaps 
 from inulin (see Mulder, Physiol. Chem. Moleschott, p. 253.). The 
 composition of the last form of wax, obtained from apple-peel, accord- 
 ing to Mulder, is C 40 H 32 O 10, but in most green leaves C 15 H 15 O. 
 In every case it was found poor in oxygen. The majority, however, 
 
 * See Goppert on the structure of the Balanaphorca, in Act. Acad. Leopold. Carol. 
 Nat. Cur., vol. xviii. Supplem. pp. 236. 253. 
 
THE ORGANIC ELEMENTS. 23 
 
 of the forms of wax have not been sufficiently examined. According 
 to the first formula, 10 equivalents of starch (0120 H 100 O 100) 
 forms 3 equivalents of wax (C 120 H96 O30), with the loss of 2 HO 
 and 66 O. According to the second formula, 5 equivalents of starch 
 + 10 HO = C 60 II 60 O 60, which, by losing 56 O, is converted into 4 
 equivalents of wax, C 60 H 60 O 4. 
 
 10. Another class of substances is found in plants, which 
 neither exist in the cell-walls, nor are the cell-walls formed from 
 them, but nevertheless their presence is necessary for the simplest 
 processes of vegetation. They are composed of Carbon, Hydrogen, 
 Nitrogen, and Oxygen, to which are sometimes added Phosphorus 
 and Sulphur. I call them by the collective name Mucus ( Schleini) ; 
 the chemists give them various names, as Albumen, Gluten, Gli- 
 adin, Zymom, Gelatin, Diastase, Gluten vegetabile, Legumin, &c. 
 
 In all the vital cells of plants, besides the substances mentioned in the 
 last section, there is found a semi-fluid or liquid granular matter, of a pale 
 yellow colour, sometimes entirely fluid, sometimes solid, and which, 
 through the action of alcohol, becomes entirely granular, fibrous, or semi- 
 membranous; which is coloured dark brown by iodine; and which, ac- 
 cording to all observation, is a multiform, changeable substance. Many 
 modifications of this substance have been separated from plants by 
 chemists, to which they have given the above names, but which are 
 perhaps seldom pure, and often formed during the process of separation. 
 All of them are characterised by the possession of nitrogen, and also by 
 their action (11.) on the previous substances (9.). They are sparingly 
 present, or are absent altogether, in those parts of plants which contain 
 starch, and which do not easily pass into fermentation, as the tubers of 
 the potato, the fruit of the rye, and the rootstock of the arrow-root plant 
 (Mara?ita arundinaced) ; but in parts of plants which easily ferment 
 they are found in large quantities, as in good wheat, the juice of the 
 grape, &c. 
 
 In the youngest cells of plants, the mucus (Schleim of Schleiden ; pro- 
 tein of chemists *) presents itself as a slight covering over the whole inner 
 surface of the walls of the cells. (See this work on the Motion of the Sap 
 in Cells.) In the seeds of Legummosa, this substance is found in the 
 same cells which contain starch, but in smaller and larger quantities 
 in especial cells, and sometimes apparently filling them entirely. Thus, 
 in the grains of the Cerealia, the layer of cells immediately under the 
 coats of the seed are almost exclusively filled with the mucus, whilst the 
 remaining cells of the albumen (perisperm) contain starch, with only a 
 small quantity of mucus. In the seeds of the almond, the mucus is 
 mixed with oil; but bitter and sweet almonds, under the microscope, 
 exhibit no essential difference. 
 
 Modern chemistry, in consequence of the labours of Liebig and Mulder, 
 divided the forms of mucus into three principal groups : into Albumen 
 (vegetable albumen), Fibrin (gluten of the Cerealia), and Casein 
 (leguinin of peas and beans), and which are regarded as identical with 
 the substances of the same name found in the animal kingdom. Dumas 
 regards as a fourth group Gelatin (gelatina animalis), which should be 
 regarded as a part of the composition of gluten. Mulder has pointed out 
 that these compounds have all a common basis (H31 C 40 N 10 O 12), 
 
 * Frotoplasma of Mulder and others. TRANS. 
 c 4 
 
24 CHEMISTRY OF PLANTS. 
 
 which he calls Protein ; and that the combination of this substance 
 with sulphur (lOPr + S) forms Casein; with phosphorus and sulphur 
 (10 Pr + 1 P +1 S), Fibrin ; and with more sulphur (10 Pr + 1 P 
 + 2 S), Albumen. There is no means of distinguishing these substances 
 in the cells of plants ; and they are all so variable in their peculiarities, 
 that they can only be regarded as groups of substances. Through 
 Liebig's observation*, tliat these substances cannot be formed in the 
 animal body, but must be taken into it from without, they have obtained 
 a new and peculiar importance. According to the researches of Rochleder 
 and Hruschauer (Liebig's Ann. vol. xlv. p. 253., and vol. xlvi. p. 348.), 
 these substances, when pure, have the power of acting as weak acids. 
 Very important in this relation is their constant union with alkalies and 
 earths, especially the phosphatic salts (perhaps double salts) in the 
 vegetable and animal organism. 
 
 11. The substances mentioned in 9. constantly pass from one 
 into the other, and the presence of mucus in the cells appears 
 necessary for this object. They appear to go through, successively, 
 all the forms from sugar, the most soluble, to cellulose, the most 
 insoluble. 
 
 From the preceding remarks it will be seen, that the substances men- 
 tioned in 9. are not so well defined forms of matter as sulphuric and 
 sulphurous acids, or as the protoxide and peroxide of iron, but that a 
 pretty constant series of changes occur in the passing of one substance 
 into the other. Artificially we may produce this series of bodies by 
 mixing them with mucus, or acting upon them with sulphuric acid or 
 alkalies, or even by slighter chemical processes, as repeated solutions and 
 evaporations. The property possessed by mucus, sulphuric acid, &c., of 
 producing chemical changes without themselves becoming changed, has 
 been called by Berzelius catalysis, by Mitscherlich the action of contact 
 (Contactwirkung), and by Liebig by another name, but without any ex- 
 planation. In the first place, we ought to satisfy ourselves that it is so. 
 In those plants where the first-named bodies are in contact with mucus, a 
 constant metamorphosis seems to be going on, and only rests for a short 
 time at one point. Almost all these changeable bodies are compounded 
 according to the same chemical formula, and vary sometimes in the 
 quantity of oxygen, but mostly in the quantity of water, they contain. 
 Does it not appear very probable that they possess a common basal prin- 
 ciple, and that, through varying proportions of water, and through phy- 
 sical conditions, as cohesion, &c., they assume so many appearances ? It 
 appears to me that there is here a great field for chemical inquiry. 
 
 The mysterious property of the physical processes which is called life, 
 and which is supposed to depend on an especial vital principle, has been 
 made use of from the fact of certain chemical actions and re-actions 
 going on which have escaped observation, but which all allow to go on 
 in the commencing combinations. We know now with certainty, because 
 these changes go on out of the plant, the transition of cellulose into 
 starch, of starch into dextrin, of dextrin and cane sugar into grape sugar, 
 and of grape sugar into gum (as in the fermentation of beet-root juice). 
 All these metamorphoses, with the exception of the first, which is 
 effected only through sulphuric acid, can be produced by the agency of 
 nitrogenous substances (mucus). With great probability it may be con- 
 
 * This is not Liebig's, but Mulder's, observation. TRANS. 
 
THE ORGANIC ELEMENTS. 25 
 
 eluded, from observations on substitution in plants, and supported by 
 chemical analogy, that there is a transition from sugar into dextrin, from 
 dextrin into starch, amyloid, cellulose, and vegetable jelly, from wax into 
 sugar, from sugar and starch into wax, from starch into fixed oils, and 
 from the fixed oils into sugar and dextrin. In these changes the same 
 or very similar compound bodies, through merely taking up or depositing 
 water or oxygen, constitute the very foundations of vegetable change, 
 the formation and metamorphosis of the elementary organs, and thus 
 form an essential part of the so-called life. Any one who would wish to 
 study vegetable physiology, and every botanist must do this who attaches 
 importance to science, will not neglect a thorough investigation of the 
 subjects embraced in the sections of this work concerning Organic 
 Chemistry. 
 
 SECTION II. 
 
 ON THE REMAINING ORGANIC SUBSTANCES FORMED UNDER THE 
 INFLUENCE OF VEGETATION. 
 
 12. Amongst the numerous principles present in plants are 
 some which appear to stand in a close relation with the general 
 process of vegetation, and which are generally present : these are, 
 1. Chlorophyll ; 2. the other colouring matters of plants ; 3. 
 Malic, Citric, and Tartaric Acids ; 4. Alkaloids ; 5. Tannin ; 6. 
 Viscin and Caoutchouc ; 7. Humus. 
 
 1. Chlorophyll (Blatt-griin, fcecula viridis, Chromule, Phytochlor, 
 green vegetable wax). If any green part of a plant is bruised and sub- 
 mitted to the action of alcohol, a green tincture is formed. If this be 
 evaporated to dryness under the exhausted receiver of an air-pump, a 
 green fatty mass is left, which forms soaps with the alkalies. If this is 
 dissolved in ether and mixed with water, and the ether evaporated, small 
 greasy globules are obtained, which appear of a green colour by reflected 
 light, and of a Burgundy-red by transmitted light. Similar globules are 
 separated from the alcoholic solution by a freezing temperature. If the 
 alcoholic tincture is mixed with water and the alcohol evaporated by 
 heat, a part of the fatty substance is thrown down, the water itself is 
 coloured of a brown-yellow, and has a characteristic smell like that of 
 black tea. This is what is commonly called chlorophyll. When treated 
 with sulphuric acid it is either not changed or becomes carbonised ; it is 
 not dissolved or coloured blue, as is erroneously stated by Marquart.* 
 It is soluble in volatile and fixed oils. 
 
 This substance is found in all plants growing in the light, with the 
 exception of some of the alga?, fungi, and lichens, and the true parasites, 
 covering either conformably the cell-walls or the spiral bands, as in 
 Spirogyra, or the granular contents of the cells which are composed of 
 starch or the other similar bodies, j Only in the last sense can we speak 
 of granules of chlorophyll, as granules consisting entirely of chlorophyll 
 are unknown. It is never found in the form of vesicles. J 
 
 * See Hugo Mohl on the Winter Colouring of Leaves, Tubingen, 1837. 
 
 f Hugo, Researches upon the Anatomical Relations of Chlorophyll. Tubingen, 
 1837. 
 
 \ Smith (Elem. Thil. Bot. ed. 2.) does not state liow lie satisfied himself of chloro- 
 phyll vesicles. 
 
26 CHEMISTRY OF PLANTS. 
 
 Chlorophyll is composed of a white wax-like substance ( 9.), and a pe- 
 culiar green colouring matter. Of the first substance it contains more if 
 the first removal of the green parts is effected by ether. The fine green 
 colouring matter originates almost universally under the immediate 
 action of light, which presupposes that there must be universally diffused 
 amongst plants some substance a colourless chlorophyll, the first form 
 of the pure colouring matter, and which is easily decomposed under the 
 influence of light. To the products of this decomposition belong espe- 
 cially a yellow, a blue, and a blackish colouring matter ; and under some 
 circumstances, according to Mulder, wax (?) also appears. The yellow 
 leaves in autumn contain proportionately more wax than the green leaves 
 of summer, the rind of the yellow ripe fruits more than the green rinds 
 of unripe fruits; but in both, starch, or its equivalent, inulin, is found 
 more abundantly earlier than later. The only analysis of this substance 
 hitherto made is the unsatisfactory one of Mulder, CIS H9 N2 O8, 
 which makes it a nitrogenous body, and which could not be formed out of 
 starch alone. Meyen's defence of this view (Physiologic, bd. i. p. 193.) 
 is a mere fiction. On the other hand, we know that, simultaneously with 
 the origin of every plant-cell, protein and protein-compounds appear, 
 and that these substances, at least, never fail to be present in the parts of 
 plants about to become green. It seems, therefore, more reasonable to 
 look for the origin of chlorophyll from protein. Chlorophyll also appears 
 very closely related with the colouring matter of indigo found in the 
 green leaves of the species of Indigofera, of Polygonum tinctorium, the 
 Isatis tinctoria, &c. The formula of blue indigo is C 16 H5 N2 O2; 
 of white (deoxidized) indigo, C16 H6 N2 O2. Pure chlorophyll is 
 soluble in hydrochloric acid, sulphuric acid, and the alkalies, with a 
 green colour ; it is soluble in ether and alcohol, but insoluble in water. 
 Exposed to the action of light, or treated with hydrogen in statu nascenti, 
 it is decolorised. 
 
 The various shades of green of the organs of plants depend upon very 
 different causes : partly upon the nature of the chlorophyll, whether it is 
 pure or more or less mixed with the yellow, blue, and black products of 
 its decomposition ; partly upon the quantity of chlorophyll in individual 
 cells ; partly on the thicker or looser arrangement of these cells, which is 
 evident on the under sides of leaves, which are always of a fainter and 
 lighter green, depending on the intercellular spaces which are there 
 present, and which, reflecting the light white, mixes with and diminishes 
 the intensity of the green. Variegated leaves are produced in one of two 
 ways. First, the single groups of cells contain only the yellow product 
 of the decomposition of the chlorophyll, as in the Phalaris arundinacea 
 picta, a variety which appears on a dry soil, but disappears on a moist 
 one; or in the variegated varieties of the common holly (Ilex Aquifoliuni"). 
 Secondly, the epidermis separates itself from the cells lying under it in 
 particular places ; and the layer of air lying between them appears as a 
 bright silvery spot, as in Begonia argyrostigma, Silybum marianum, and 
 other plants. In the last place, the green colour of plants may be yet 
 considerably modified through the greater or less secretion of wax upon 
 the surface, which in some cases forms a layer of small silvery scales, 
 which appear almost snow-white, as in Elymus arenarius. 
 
 2. Vegetable Colours. Of these we know at present very little. They 
 may be generally divided into soluble and insoluble. The last are found 
 in the cells of plants in the form of globules of a yellow (Fritillaria 
 imperialist red, and seldom of a blue colour ( Strelitzia farinosa) ; they 
 
THE ORGANIC ELEMENTS. 27 
 
 are frequently soluble in ether, alcohol, volatile oils, and separated from 
 ether in a resinous, not in a fatty, form. The first, as far as I know, are 
 only of a red and blue colour ; the red caused by an acid, the blue by an 
 alkali ; and are dissolved in the fluid contents of the cell. They may be 
 found in the red parts of plants, and in the flowers of Echium vulgare. 
 They all contain nitrogen.* But there are other colouring matters 
 present in plants, as the red in Iberis umbellata, and the blue in violets, 
 which become green through the action of alkalies, and which are very 
 different from the foregoing. Chemistry has much to do in this depart- 
 ment of inquiry. 
 
 A theory was proposed in 1834, by Clamor Marquart, in a book on 
 the colours of plants, which supposed that two modifications of chlo- 
 rophyll, Anthoxanthin and Anthocyan, the one containing a little more, 
 and the other a little less, water than chlorophyll, were the cause of the 
 red and yellow series of colours, and chlorophyll of the blue. Although 
 this theory is adopted by Endlicher and linger, in their " Rudiments of 
 Botany," it is not founded on sufficiently accurate data to demand refuta- 
 tion. Berzelius (Handbuch der Chemie) and Mulder (Physiol. Chem.) 
 have both written on Chlorophyll, and I have mostly followed the latter 
 in the foregoing remarks. The remaining colouring matters important 
 in the arts, but unimportant physiologically, demand attention. 
 
 3. Tartaric Acid (Acidum tartaricum, T.), Citric Acid (Acidum ci- 
 tricum, Ci.), and Malic Acid {Acidum malicum, Ma.), are either found 
 together or alone in all sour fruits, and perhaps also in all acidulous 
 juices of plants, for malate of lime is found in the Sempervivum tectorum. 
 From the process of ripening in fruits, it has been concluded that these 
 acids stand in a peculiar relation to sugar ; that they are easily formed 
 out of it, and as easily pass into it. Liebig (Organic Chemistry) has gone 
 so far as to presume that, in the presence of alkalies, carbonic acid 
 and water are converted into hydrated oxalic acid, and this into tartaric 
 acid, malic acid, and, lastly, this into sugar and dextrin ; and that thus 
 the organic acids stand in a middle place between the organic and in- 
 organic bodies. This is one of Liebig's most genial combinations, but 
 has no observation on which to rest. The chemical composition of these 
 acids, according to Berzelius and Liebig, is as follows : 
 
 C H O 
 
 Tartaric Acid - - - 8 4 10 
 
 Citric Acid - - 12 4 12 
 
 Malic Acid - - - 8 4 8 
 
 4. The Alkaloids, like the acids, are, as far as we know at present, 
 only so far important as the remarks of Liebig (Organic Chemistry), on 
 both classes of substances, extend. Many plants appear to have a 
 facility, when it is necessary to neutralise a base by an inorganic acid, or 
 an acid by an inorganic base, and these substances fail, of substituting 
 for them organic acids and bases. Thus we find that potatoes sprouting 
 away from the soil form Solanin ; thus Quinine, Cinchonine, and Lime, 
 take the place of each other in the Cinchona barks, and Meconic acid is 
 found in opium to take the place of Sulphuric acid. 
 
 5. Tannin (Tannic Acid). In most plants, and especially the Pha- 
 nerogamia and Ferns, there is frequently found a substance which red- 
 dens litmus, tastes astringent, and changes animal gelatine into leather. 
 This substance appears to be modified in different plants. It is found 
 
 * "According to Liebig, Organic Chemistry. 
 
28 CHEMISTRY OF PLANTS. 
 
 more constantly in cells presenting a low degree of vital activity, as those 
 of the wood and bark ; and those of early decaying excrescences, as galls : 
 but still it is found in many leaves, as those of the tea-plant, and of the 
 Ericacece; but here, perhaps, it only occurs in the bundles of vessels, or 
 less actively vital cells, of the leaf. Frequently the cells of the bark 
 have few or no contents ; and I may, perhaps, hazard the opinion that 
 the tannin is only found in the cell-wall, and perhaps as a product of the 
 commencing decomposition of the cellulose. If two equivalents of 
 cellulose, C 24 H20 O 20, take up 16 O from the air, and 12 HO 
 (water), and 6 CO 2 (carbonic acid) disappears, there will be left one 
 atom of tannin (CIS H 8 O 12). The formation of tannin may be 
 conveniently regarded as the commencing process of putrefaction 
 in the cell-membrane. According to Mulder's formula of cellulose, 
 C 24 H 21 O 21, only 4 O would be taken up ; and by the 'disappearance 
 of 13 HO, an equivalent of tannin would be formed. In the living 
 cells of plants, many substances are found which cannot exist with tannin, 
 such as mucus* (Schleim). 
 
 6, Viscin (Birdlime), and Caoutchouc, have not been, up to this time, 
 sought after and examined, except in a few plants. Viscin is a clear, 
 very gelatinous, substance, and insoluble in water ; it is found in the 
 berries of the mistletoe ( Viscum album), in the fruits of Alractylis gum- 
 mifera, and in the milky juice of the green twigs of Ficus elastica. 
 Under this head we must also include the peculiar substance found in 
 the proscolla of the Orchidece, and which exists as a fibrous tissue be- 
 tween the pollen grains in the same plants ; likewise the fluid which 
 exudes from the glands on the stigma of the Asclepiadece ; and, lastly, 
 the product of the glands under the anthers of some Apocynece, as in 
 Nerium Oleander. Jf the history of the development of these parts is 
 examined, as well as the formation of the viscin in Viscum album, it will 
 be found that this substance is formed through the solution of existing 
 cells. It is well known, that in nearly all decompositions of cellulose, 
 carbon remains in excess ; and this agrees with the composition of 
 viscin, which contains, according to Macaire Prinsep, C 75*6 II 9*2 
 O15-2. 
 
 Caoutchouc, or at least an essential element of it, appears to stand in 
 the same relation to viscin as gum to pectin. It belongs to the excretory 
 substances, and is found in the milky juice of plants, especially in the 
 three Jussieuean families, Urticece, Euphorbiacece, and Apocynece. The 
 milky juices of other plants are comparatively poor in this substance, 
 although it is absent in none of them. This substance, which defies all 
 chemical agents, swells up and diffuses itself (not dissolves) in ether, and 
 on dry distillation renders some remarkable chemical products (see 
 Himly de Kaoutschouk ej usque siccae Destillationis Productis ; Gottingen, 
 1835); has many peculiarities and unexplained properties ; and its rela- 
 tion to plants, its origin, &c., are at present almost entirely unknown. 
 In the milky juice of plants, it is found diffused emulsively in the form 
 of little globules. If the juice be allowed to stand, especially if diluted 
 with a little salt water, it collects on the surface in the form of a white 
 cream, which, when dried, is of a yellowish colour, and almost perfectly 
 transparent. Schulze, who, in all his views on milky juice and milk- 
 vessels, is dreamy, regards Caoutchouc as analogous to the fibrin of 
 blood. Any one who examines the milky juice of Siphonia elastica, 
 
 * Endlicher and Unger say that the tannin is always dissolved in the cell-juice. How 
 comes it, then, that perfectly juiceless oak bark contains so much tannic acid ? 
 
THE OllGANIC ELEMENTS. 29 
 
 and still holds by Schulze's opinion, either cannot or will not see. I can 
 confirm all that Berzelius has said on this subject in his Chemistry.* 
 
 7. Humus (Humin, Humic Acid, Ulmin, Ulmic Acid, &c.). If dead 
 animal and vegetable matters are exposed to the action of moisture and 
 the atmosphere, oxygen from the air is absorbed ; the nitrogen unites 
 with hydrogen to form ammonia, which, either alone or in combina- 
 tion with carbonic acid formed at the same time, disappears if it be not 
 fixed by some acid previously present or formed at the same time. The 
 carbon forms carbonic acid ; the hydrogen, combining with the oxy- 
 gen of the air, forms water, and with its nitrogen, if the decompo- 
 sition takes place in a closed vessel, or as it does in the soil, forms am- 
 monia ; at last nothing remains but the inorganic salts of the plant 
 or animal. Between these changes, however, a number of other sub - 
 stances occur. The indifferent, insoluble, richly carbonaceous mass, 
 when it is black, is called Humin ; when brown, Ulmin. Further, 
 from these five acids present themselves, humic, ulmic, geinic, crenic, 
 and apocrenic acids. They were long regarded as substances between 
 resin and wax, and can be obtained in considerable quantities from 
 vegetable mould composed of leaves six years old, by washing with 
 ether. The acids combine with the alkalies, and even with the earths, 
 and form soluble salts which constitute the so-called humus-extract. 
 The mixture of these substances, combined with portions of the rocks 
 which form the surface of the earth, constitute the arable land or cul- 
 tivable soil, and which is the natural and most promising medium of 
 growth for the greater proportion of plants. The first-formed in time is 
 the ulmic acid, which consists of C 40 H 14 O 12. This, through ab- 
 sorption of 2 O, and the separation of 2 H O, is converted into humic 
 acid, C 40 H 12 O 12 ; and this, through the absorption of 91 O, and the 
 separation of 40 CO 2 and 24 H O, is changed into geinic acid, C 40 
 H 12 O 14. These three acids are almost insoluble in water, and are 
 precipitated by strong acids from alkaline humus-extract. There re- 
 mains in the solution crenic acid (C 24 H 12 O 16), and apocrenic acid 
 (C 48 II 12 24) : the last through acetate of copper, and the first 
 through acetate of copper and carbonate of ammonia, are precipitated as 
 crenate and apocrenate of copper. The following may be taken as an 
 example of the formation of these substances : 
 
 C H O N 
 7 Eq. of Cellulose + 80 = 84 70 78 
 
 2 Eq. Humin . . = 80 24 24 
 
 4 Carbonic acid 4 80 
 46 Water . = 46 46 
 
 84 70 78 
 1 Eq. Protein -f 4 Eq. O. = 40 31 16 10 
 
 1 Eq. Humin . . =40 15 15 
 
 1 Water . 0110 
 
 5 Ammonia . 15 10 
 
 40 31 16 10 
 
 For further information on these substances, the reader may consult 
 Mulder, Bulletin des Sciences Phys. et Nat. en Neerlande Annee, 1840, 
 liv. i., and Physiological Chemistry. 
 
 * Gutta Fercha belongs to this group of vegetable products. TKANS. 
 
30 CHEMISTRY OF PLANTS. 
 
 13. Besides the substances mentioned in the foregoing para- 
 graphs, there are a countless mass, the smaller part of which only 
 are probably at present known, and which appear generally to exert 
 but a very small influence upon the life of the plant. To these 
 belong the substances called by chemists Alkaloids and Vegetable 
 Acids, Resins, Essential Oils, Colouring Matters, &c. Many of 
 these must be regarded as mere secretions, and this would not be 
 the place even to recount them. They may be sought for in 
 manuals of Chemistry. 
 
 A great part of the vegetable acids, almost all the alkaloids, and many 
 of the resins, are found in cavities (receptacula\ or in the so-called 
 latex-vessels, but never in the plant-cells. Others, as the essential oils 
 and resins, are found in solitary cells, which they exclusively fill, and in 
 which it is impossible for any chemical change to take place, so that the 
 cell appears dead. Many amongst them, under peculiar circumstances, 
 fail to be developed, as the poisonous secretion of hemlock, which is not 
 found in the plant of the Asiatic steppes ; whilst others are substituted, 
 the one for the other, without the vegetation of the plant suffering in the 
 smallest degree. Therefore, in the contemplation of the phenomena of 
 vegetable life, I think they may, in a great measure, be disregarded as 
 unimportant substances. Upon these bodies, then, I have little or no- 
 thing to say, and especially as chemistry has scarcely begun to work 
 upon them. 
 
31 
 
 SECOND BOOK. 
 ON THE PLANT-CELL, 
 
 CHAPTER I. 
 
 FORM OF THE PLANT -CELL. 
 
 SECTION I. 
 
 THE CELL REGARDED AS AN INDIVIDUAL. 
 
 14. ONLY in a fluid (cytoblastemd] containing sugar, dextrin, 
 and mucus (protein), can cells be formed. This is effected in two 
 ways : 1st. The particles of the mucus are drawn together into 
 a more or less rounded body, a cell-kernel (cytoblastus), and change 
 the entire surface of one part of the fluid into jelly, a relatively in- 
 soluble substance. Thus originates a closed gelatinous vesicle, into 
 which penetrates the external fluid, and distends it, so that the 
 mucus-corpuscle on one side is free, and on the other remains 
 adherent to the inner wall of the vesicle or cell. It forms then a new 
 layer on its free side, and is thus enclosed in a duplicature of the 
 wall ; or it remains free, and is then mostly dissolved and disappears. 
 During the gradual extension of the vesicle the jelly of the wall is 
 commonly converted into cellulose, and the formation of the cell is 
 completed. 2d. The collective contents of a cell are divided into 
 two or more parts, and around each part there is immediately 
 formed a tender gelatinous membrane. In this way many cells 
 are formed, which fill up the cell in which they originated. 
 
 Of the nature of the fluid in and out of which the cells originate, we 
 are not yet perfectly cognisant. Thus much we know, that in some cases 
 (in the embryo-sac of the Leguminosce, for instance) a solution of sugar is 
 present ; and, as far as may be decided by the action of alcohol, this is 
 mixed with gum (dextrin ?). The constant presence of a nitrogenous 
 substance is also necessary, and which we should have anticipated from 
 previous considerations ( 11.). 
 
 In all tender hairs, almost in every growing portion of cellular tissue, 
 
32 ON THE PLANT-CELL. 
 
 and especially striking in some monocotyledonous orders, as Orchidece, 
 CommelinecB) and Asphodelece, also in many dicotyledonous orders, as the 
 Cactece, BalanophorecB, &c., in the entire leaves of Mosses, especially in 
 Sphagnum, we find in every cell, fastened to the inner wall, a small, 
 mostly plano-convex or lenticular, sharply defined body, strikingly dif- 
 ferent from all other contents of the cell. This is the cytoblast. It is 
 met with in all newly-formed cellular tissue, but later it disappears from 
 the same cells. It is seen in various stages of perfection. When per- 
 fectly formed, it is a fiat, lenticular, sharply defined, transparent, pale- 
 yellow body, in which it is easy to distinguish one or two, seldom three, 
 sharply defined and evidently hollow corpuscles, which are called nucleoli. 
 In its most imperfect form it appears merely as a flat, yellow, semi-granular 
 globule, in which there are no nucleoli, and which do not appear later. 
 It varies much in its character, according to the plant as well as its 
 age : in colour } from perfect clearness to a dark yellow grey ; by iodine it 
 is converted from a pale yellow to a dark brown : in consistence, from a 
 granular mucilage to a firm homogeneous mass : in the number of its 
 nucleoli, from one to three ; in the form of the same, from an entire 
 absence through a simple globule to one that is hollow : in its own 
 form, from the globular to the lenticular and to the egg-formed disc : in 
 its absolute size, from 0*00009 to 0-0022 of an inch in circumference : 
 in its relative size, from the cells which it fills to those in which it forms, 
 not more than the five-hundredth part of the inner surface of the cell- 
 wall ; and lastly, in its attachment to the cell-wall, from a loose adhesion 
 to a perfect union with the cell-wall and enclosure in a duplicature of the 
 same. With the exception of the nucleoli, the first statements relate 
 universally to the younger states of the cytoblast. 
 
 In those cases in which I have been able to observe completely the 
 origin of the cytoblasts, as in the albumen (perisperm) of Chamddorea 
 Schiedeana, Phormium tenax, Colchicum autumnale, Pimelea drupacea, 
 and many papilionaceous plants, I have found that they appear at first 
 amongst the little mucus-granules of the formative fluid, and that they 
 are gradually accumulated around the nucleoli ; and as they combine 
 together to a greater or less degree, a thicker or thinner disc is formed, 
 and sometimes two or three such discs lie near one another, and at last 
 the cytoblast presents itself. All this takes place before a cell can be 
 seen.* In young cells I frequently found the cytoblast convex, granular, 
 yellow, with the nucleoli simple : in older cells of the same plant, flat, 
 homogeneous, uncoloured, the nucleoli hollow (e. g. Cactece). 
 
 In the Cryptogamia the cytoblasts are not so generally seen, yet they 
 are present in the spores of Ferns, Mosses, Lichens, and some Fungi, and 
 now and then in the cellular tissue of Algae, and in the cells of Spiro- 
 gyra, free in the midst of the cell. 
 
 A chemical analysis of the nucleoli is at present impracticable. 
 
 That the cytoblast is a nitrogenous body, a protein-compound, and 
 perhaps in its simplest state pure protein, is proved by its colour, con- 
 sistence, behaviour towards liodine, alcohol, alkalies and acids, and 
 concentrated nitric acid ; and by the researches of Pay en, confirmed by 
 Mulder, on the protein-compounds in the spongioles and in the cambium, 
 compared with the microscopic analysis of those parts. 
 
 Thus far extend my own observations, but recently Niigeli has con- 
 siderably enlarged them. (Schleiden and Niigeli, Zeitschrift fur Wis- 
 
 * See Plate I. fig. 1. a, 1; 3.; 4. a, b ; 5., with the explanation. 
 
FORM OF THE PLANT- CELL. 33 
 
 sentschaftliche Botanik.) He has proved the existence of the cytoblast 
 in all the families of the Cryptogamia, especially the Algce, and shown 
 that it is necessary to distinguish between a parietal and central nu- 
 cleus.* The central nucleus subsequently becomes hollow, and may 
 be increased by division. I cannot, however, agree with Nageli when 
 he asserts that the cytoblast consists of an external membrane, with con- 
 tents. I regard this as a later stage of their development, for in the 
 young free cytoblasts there is no trace of a distinct membrane, and the 
 origin of the free cytoblast forbids such a supposition. Observation, 
 however, on this subject is not yet brought to a close ; and many things 
 will occur to modify, extend and explain our present knowledge. 
 
 Complete Observations upon the Formation of Cells. I. When the 
 cytoblasts are perfectly formed, they soon present a delicate membrane, 
 which encloses them, and which is sometimes extremely fine and soft, 
 and sometimes thicker and more compact, t This membrane soon 
 becomes elevated on one surface of the cytoblast in a vesicular form, and 
 gradually extends itself, so that the cytoblast occupies at last only a 
 small part of the wall J ; but still the cytoblast continues to enlarge, and 
 the nucleoli become more evidently defined. The membrane of the 
 vesicle, or young cell, becomes gradually stronger and thicker ; it gets a 
 round, or sometimes an elongated, form, and sometimes an irregular edge, 
 which subsequently disappears. 
 
 In the youngest state of the cell the cytoblast is generally covered on 
 all sides by a delicate membrane, which is not coloured by iodine. Mohl 
 (Botan. Zeitung, 1844) has clearly not understood my observations in 
 the paper which I published in Miiller's Archiv for 1838, and in which 
 I first made known my discoveries on this subject. As soon as this 
 primary cell membrane is removed by extension, at some distance from 
 the cyloblast, it is often found covered with a delicate layer of semifluid 
 mucus, which is sometimes seen circulating in little anastomosing streams, 
 sometimes granular, sometimes entirely homogeneous and clear, and which 
 when present may be made visible by the action of nitric acid, alcohol, and 
 iodine. This is Mohl's primordial utricle. It is directly on the bound- 
 ary between the membrane and its contents, that the most active chemical 
 processes take place ; and this goes on as long as the necessary conditions 
 are present, especially the formation of nitrogenous matters. It is, 
 therefore, not improbable that this layer is the agent in converting the 
 newly introduced constituents of the cell into cellulose, and thus of thick- 
 ening its walls (or even forming new cells). But at last these protein- 
 layers are dissolved and decomposed, and disappear. In old cells, 
 especially of wood, no trace of these layers is found, and generally only a 
 small quantity of nitrogenous matter at all. I can understand how it is 
 that Mohl may doubt the existence of a membrane free from nitrogen, for 
 I am far from asserting that my observations are complete ; but I am at 
 a loss to explain how Unger can affirm that the cytoblast is first formed 
 after the development of the cell-membrane. (Linnaea, vol. xv. part ii. 
 1841.) I have just been examining (June, 1845) the spongioles of 
 Cypripedium Calceolus and Neottia Nidus avis ; and although at first 
 I was doubtful as to whether any thing existed besides the great cyto- 
 blast, yet, when I employed nitric acid and iodine, I found surrounding 
 the cytoblasts cells which required a longer period for development in 
 
 * See Nageli on the Formation of Cells, translated by A. Henfrey for the Ray So- 
 ciety. 1845. TRANS. 
 
 f See Plate I. figs. 1. c, 4. c. \ See Plate I. figs. 1 . d, 2. 14, 15, 1G. 
 
 D 
 
34 ON THE PL ANT -CELL. 
 
 the mother cells, and which last subsequently disappeared first. I find 
 it, in fact, impossible to obtain such a section as is represented by Unger 
 (table v. op. cit.). 
 
 There often appears on the free side of the cytoblast, as, for instance, 
 in the Fritillaria imperialis and in Chamcedorea Schiedeana, a new 
 lamella, which, at the edge where it touches the cytoblast, combines 
 with the first cell wall, and thus encloses the cytoblast. Such cytoblasts 
 seldom undergo any further change. The cytoblast, after the formation 
 of the cell, sometimes becomes absorbed, and sometimes remains for the 
 entire life-time of the cell. The cell at first consists of jelly (gallerte), 
 and easily dissolves in water ; gradually it becomes changed into cellulose. 
 I have traced accurately the steps of this change in the albumen of 
 Leucojum cestivum, Phormium tenax, Colchicum autumnale, Chamce- 
 dorea Schiedeana, Pedicularis palustris, Momordica Elaterium ; in Lu- 
 pirnts, and many other Leguminosce ; in the embryo sac of Alisma 
 Plantago, Sagittaria sagittcefolia, Pedicularis palustris, CEnothera eras- 
 sipes, Tetragonia expansa ; in the germinating cotyledons of Lupinus 
 tomentosus ; in the many-celled hairs of Solatium tuberosum, and 
 many other plants ; in the sporangia of Borrera ciliaris ; and in the 
 sporocarpium of Blechnum gracile. 
 
 II. In addition to the above mode of cell-formation, Niigeli has de- 
 scribed a second, which he first observed in the formation of the primitive 
 cells of the pollen, and has more recently found to exist in a large 
 number of A/ace. Mohl imagines something of the same kind to take 
 place in the new cells of the cambium. To this mode of cell-formation 
 belong all those cases where the division of cells takes place. I have 
 not had an opportunity of making any observations on this subject, but 
 the following facts are after Nageli : 80 long as a cell is internally 
 covered with a layer of mucus, this process may go on. In the first 
 place, this mucus layer is divided into two or four parts, each of which 
 is surrounded by a delicate layer of mucus. These external mucus 
 layers are converted into cellulose, and thus two or four little sacs or 
 cells are formed, which perfectly fill up the primitive cell. In a 
 peculiar and hitherto unexplained way, the cytoblast seems to be very 
 active in this process. This increase takes place in most instances in 
 cells with a central cytoblast, and this divides itself into two or four 
 cytoblasts, each of which becomes the central point of a new cell. No 
 objection can be made to this history of cell-formation founded upon such 
 careful observations. Of the part it plays in the vegetable kingdom 
 Niigeli has given the following account. It seems to be the only mode 
 of cell-formation in the Diatomacece, Nostochinece, OscillatorietE, Ba- 
 trachospermecE, and Fucacece. In the Conferva it takes place in all the 
 cells except those of the spores. It also takes place in the special 
 mother-cells of the tetrasporous plants, as the Floridece, flepaticcc, 
 frondose Mosses, Ferns, Lycopodiacetz, and Phanerogamia. In the Fungi 
 and Lichens, in the Ulvacece, and in the formation of the spores of 
 Characece and Equisetacece, it is at present unknown. On the other 
 hand, with the exception of the special mother-cells, it is not found in 
 the cells of the Characece, Equisetacece^ Floridea, Hepaticcc, frondose 
 Mosses, Ferns, Lycopodiacete, and Phanerogamia, in all of which 
 the cell-formation takes place around a central nucleus. Probably, 
 further observations would bring this process under the same general 
 law as the preceding. 
 
 Imperfect Observations. There are some cases where the cells are very 
 small and delicate, and nearly filled with granular contents, and where a 
 
FOKM OF THE PLANT-CELL. 35 
 
 part of their layer obscures observation, and where from other causes it 
 has been found impossible to make complete observations. Nevertheless, 
 I have seen very generally, especially after the use of nitric acid, by 
 which the cells are separated from one another, sometimes two cells, with 
 their cytoblasts in a single cell in Gasteria nitida, and in the terminal 
 buds of Cypripedium Calceolus, and in the spongioles of the last plant, 
 and of Neottia Nidus avis two cytoblasts loose in a single cell, and 
 near by two cells with cytoblasts enclosed in another cell. All young 
 cellular tissue in the Phanerogamia, without exception, exhibits the 
 cytoblast. In the development of the pollen, the cells are seen filled 
 with a thick grumous fluid, which separates into four parts, around each 
 of which there is suddenly developed a tolerably thick membrane. These 
 might be regarded as four large cytoblasts, if the appearance of the 
 membrane was not attended with another characteristic cytoblast. But 
 I have observed in Passiflora Princeps and Cucurbita Pepo, at the 
 time when the dark mass in the primitive cell was yet undivided, a 
 number of clear cells, each with a little clear cytoblast enveloped in this 
 dark mass. May not these be the pollen cells, which gradually form 
 within, take up the grumous matter, and, again precipitating it gradually 
 in their cavity, grow thereby, and, suddenly dividing into four parts, 
 become visible ? I have not made any observations on the intermediate 
 stages, and Nageli (in the paper before quoted) thinks he has observed 
 another process. I have, however, found some interesting facts in 
 Rhipsalis salicornioides, which I have not had an opportunity to follow up. 
 
 Inferences from the above Facts. Up to the present time no fact 
 has occurred which is not in accordance with the complete precedence of 
 the cytoblast, as above observed. The indications of its precedence are 
 only obscure and incomplete in those cases in which accurate observa- 
 tion is surrounded by insurmountable obstacles. It is in the formation 
 of the spores, the foundation of the future plant, in Cryptogamia ; in 
 the embryo, the young plant itself, of the Phanerogamia, that the pre- 
 cedence of the cytoblast is fully made out. Both serve as points of sup- 
 port for analogous conclusions in other cases ; and it appears, until further 
 researches may necessitate modification, that we may safely conclude 
 that the precedence of the cytoblast in the formation of cells is a 
 universal fact. 
 
 If, further, we regard the easy transformation of the assimilated 
 matters, and may from artificially conducted experiments draw the con- 
 clusion that the nitrogenous matter which I have called mucus, and 
 which forms the cytoblast, is the substance whieh calls forth these 
 transformations, and if we further remark that sugar and dextrin are 
 more easily soluble than jelly, and that sugar and gum are changed into 
 jelly if the quantity of water is not increased, and which must be 
 necessarily precipitated, we must regard the whole process of cell- 
 formation as simply a chemical act. The gathering together of granules 
 of mucus to form the cytoblast we can as little explain as that, when we 
 form a solution of two salts, if we throw into the mixture a crystal of 
 one or the other salt, that salt alone crystallises around it. 
 
 Analogies. Schwann has pointed out, in an acute and profound 
 treatise*, that the animal organism also is composed of cells, and that 
 
 * Microscopic Researches on the Analogy in the Structure and Growth of Animals 
 and Plants. Berlin, 1839. Although in this work the analogies between the formation 
 of vegetable and animal tissues are pointed out, it should be borne in mind that there 
 are some tissues which are peculiarly animal, and which constitute the distinction be- 
 tween the plant and animal. Some of the animal tissues, such as the cell and nucleus 
 
 n 1 2 
 
36 ON THE PLANT-CELL. 
 
 these cells are formed in the same way as those of plants. Tf this law is 
 found essential to some plants and animals, this analogy forms a basis for 
 enunciating this mode of formation as a universal law for both kingdoms 
 of nature. 
 
 In the same work Schwann has given an interesting comparison be- 
 tween the formation of crystals and cells, and he was led to this from a 
 consideration of the nature of the substances of which the last are formed. 
 This view in future may be of the greatest importance, as it shows that 
 the apparent gulph between the organic and inorganic kingdoms may not 
 be impassable. There is one point to which I would allude, and which 
 seems to have escaped the attention of Schwann. In the formation of 
 the crystal, the matter of the same already exists, as such, dissolved in the 
 fluid, and only awaits the withdrawal of the solvent to assume its peculiar 
 form : it is otherwise in the cell of the plant. Here the organic substance 
 forming the substance of the cell is not present in the cytoblast, but is 
 formed through another necessarily present substance, and this only takes 
 place when the new-formed substance is relatively insoluble. 
 
 In the crystallisation of salts, such as the nitrate of potassa, from a 
 solution, we can observe the increase of the crystal from additions to it 
 from without. But, on the other hand, if we take a solution of two sub- 
 stances which form, when mixed, a precipitate, we shall find, on examining 
 this under the microscope, that a membrane divides the two fluids. Ac- 
 curate observation will show that this membrane consists of crystals of 
 various sizes. If the fluid remains quiet, some of the crystals are projected 
 into it on both sides ; if the fluids are mixed, the crystals are dissolved up 
 again. After many careful observations, I believe that all inorganic sub- 
 stances, if they are allowed to remain quiet, assume a crystalline form; 
 and that the so-called pulverulent precipitates consist of crystals, the form 
 of which, from their smallness, cannot be observed. 
 
 In the last place I must mention a highly interesting analogy, which, 
 when more accurately examined, may perhaps one day lead to the most 
 satisfactory explanation of the process of cell-formati on, I mean vinous 
 fermentation. We have here a fluid in which sugar and dextrin, and a 
 nitrogenous matter, as a cytoblast, are present. At a certain temperature, 
 which is perhaps necessary to the chemical activity of the mucus, there 
 originates, without, as it appears, the influence of a living plant, a process 
 of cell-formation (the origin of the so-called fermentation -fungus), and it 
 appears that it is only the vegetation of these cells which produces the 
 peculiar changes that occur in the fluid. Whether this organism is really 
 a fungus, is a matter of indifference; but whether it alone, through the 
 activity of its vital processes, determines the process of fermentation, 
 deserves to be accurately determined. 
 
 I will here add my own observations on these fermentation-cells. I 
 bruised some currants with sugar, and, having pressed the juice through 
 a cloth, diluted it with water and filtered through folded paper. The fluid 
 was bright red, quite clear and transparent, and, under the microscope, 
 showed no trace of granules, but presented a number of little drops of a 
 pure clear oil. At the end of twenty-four hours the whole fluid was 
 opalescent, and presented, under the microscope, a number of granules 
 suspended in it (fig. 9. #, Plate I.). On the second day these granules had 
 greatly increased, and there appeared amongst them perfectly-formed 
 ferment-cells (Plate I. fig. 9. a, b, c). There also appeared, now and then, 
 
 fibres (Henle, General Anatomy), have no analogues in plants. [Schwann's treatise 
 lias been translated and published by the Sydenham Society. TRANS.] 
 
FORM OF THE PLANT-CELL. 37 
 
 vesicles of carbonic acid gas. On the fourth day fermentation was very 
 active. At the bottom of the vessel, and on the surface of the fluid, yeast 
 had formed : but these yeasts consisted of single cells, or several attached 
 one to another. In the solitary cells could be observed the way in which 
 one cell was formed from another (Plate I. fig. 9. d, e, /). The ferment- 
 cells do not in this state permit of a distinction between the contents and 
 the membrane of the cell. In the midst of the cell there is a transparent 
 spot ; but whether hollow, or a solid nucleus, I could not decide. The re- 
 maining parts appeared entirely homogeneous, yellowish like a nitroge- 
 nous substance, sometimes mixed with small solitary granules (Plate I. 
 fig. 9. d, e,f). In a similar way, a solution of sugar with elder-flowers 
 was examined, and gave similar results. Other results were obtained in 
 the following way. Pure white protein (albumen), from the white of an 
 egg, was dried, and rubbed down with sugar, and left to ferment : the fluid 
 at first was perfectly clear. On the third day, the small portions of pro- 
 tein, which at the commencement exhibited a sharply angular aspect, 
 assumed partly a granular aspect, and some a more or less rounded form. 
 These globules showed an active molecular movement, and some appeared 
 strung together. On the fourth day there was seen between these granules 
 round or elongated cells, which were either solitary, or arranged together 
 in a line with a tendency to the formation of branched fibres. These cells 
 were not more than one-third of the diameter of ordinary ferment-cells 
 (Plate I. fig. 10. c, d). An active fermentation went on, and gas-bubbles 
 were given out from the protein-granules and the linear cells. Proper 
 ferment-cells did not make their appearance. Fluid albumen, mixed with 
 sugar and filtered, became thickened on the second day, and contained 
 little granules of albumen (coagulated?). The further phenomena were 
 similar to those exhibited by the preceding, except that there were deve- 
 loped a few true ferment- cells. Protein moistened with water displayed 
 the same appearances as when mixed with sugar and water ; ultimately 
 putrefaction came on, and the development of infusoria, but the vegetable 
 formation preceded. There appear to be two very different types of 
 ferment-cells, according as the fluid contains organic acids and essen- 
 tial oils or not. From the phenomena exhibited by the ferment-cells, 
 one might be inclined to regard them as similar to animal -cells, which 
 are formed through a cavity in the cytoblast, and which afford indica- 
 tions of the nucleoli in their highest development. But this analogy 
 is not tenable, and the above observations must be regarded as imperfect. 
 If we take fully developed ferment-cells, and treat them with ether, 
 alcohol, or caustic alkalies, there will be found in the fluid a number of 
 globular delicate cells, with thin but clearly distinguishable walls, which 
 contain a clear fluid, with here and there very small granules, which, 
 alone or in groups, are attached to the inner surface of the cell wall, and 
 (almost ?) always a large round flat body (a cytoblast ?). 
 
 History and Criticism. Before the discovery and scientific use of the 
 microscope, of course there could be no accurate knowledge of the cells of 
 plants. 
 
 Robert Hooke, an Englishman, was the first discoverer of the cellular 
 structure of plants. He used a microscope first brought to England by 
 Cornelius Drebbel in 1619. (Micrographia. London, 1667. Fol.) 
 
 Marcello Malpighi, professor at Bologna, gave a more accurate account 
 of the structure of plants. He sent to the Royal Society of London his 
 great work, Anatome Plantarum, in the year 1 670, and which was pub- 
 lished in two volumes folio, at the expense of the Society, in 1675 and 
 
 D 3 
 
38 ON THE PLANT-CELL. 
 
 1679. This work claims for him the title of the creator of scientific 
 botany. He is so accurate, and pursues so correct a method, that it was 
 a century before the time at which he wrote it, and at the present day 
 many so-called botanists do not know so much of plants as Malpighi. 
 He not only observed the cellular structure of plants, but maintained that 
 it was composed of separate cells, which he called Utriculi. 
 
 Nehemiah Grew was secretary to the Royal Society at the time Mal- 
 pighi's work was publishing. He published his Anatomy of Plants in 
 1682 ; is much indebted to Malpighi. He first took up the wrong view 
 that the walls of cells are composed of fibres ; he also, by comparing the 
 cells of plants to the froth of beer, would appear to have thought that 
 they were mere cavities in a homogeneous substance, a view which was 
 afterwards supported by C. Fr. Wolff in his Theoria Generations, Halle, 
 1774. These false views have in modern times found supporters: the 
 first in Meyen, in his Physiology of Plants (vol. i. p. 45.) ; the second 
 in Mirbel and Unger. Meyen founds his notion of the fibrous struc- 
 ture of the cell-wall on having observed this structure in a new species 
 of orchid from Manilla. This is, however, not a singular appearance, 
 and an inquiry into the history of the development of the cells would 
 have dispelled the delusion. 
 
 Mirbel has recently attempted * to support his view of the origin of the 
 cells as mere cavities in a homogeneous saline mass which he calls cam- 
 bium, by observations on the root of Phoenix dactylifera. This paper 
 is very incomplete, and the author has adopted a new system of nomen- 
 clature, which makes it difficult to follow him. Thus far I can say, that 
 no such division of continuity filled with a mucilaginous mass (his cam' 
 bium globuleux) between the bark (his region peripherique) and the 
 external portion of the woody bundles of the root (his region inter me* 
 diaire) exists as he describes. I have constantly found present cellular 
 tissue. Nor are the woody bundles of his region intermediaire sur- 
 rounded by this substance, but by cellular tissue. He is also deceived in 
 the nature of the contents of the cell by their intermixture with water. 
 
 Unger (Bot. Zeitung, 1844) has published some observations on the 
 growth of the stem, in which he doubts whether the cytoblast is the origin 
 of the cell. In the instances where he has not observed the cytoblast in 
 the cells they had been evidently absorbed, whilst in those in which he 
 has seen and drawn them he has represented them to meet his own views. 
 
 The views of Sprengel on the origin of cells from starch granules, the 
 similar ones of Du Petit Thouars and Raspail, and those of Turpin on the 
 nature of globuline, under which term he includes starch, mucus, colouring 
 matters, &c., do not deserve a scientific refutation. Other observations 
 on the origin of the plant-cell are unknown to me. Most botanists pass 
 the subject over in silence, although there can be no doubt that it forms 
 the introduction to a strictly scientific investigation of vegetable structure. 
 
 In conclusion, I refer to Robert Brown (Observations on Orchideae, 
 Trans. Linn. Soc. 1833), who has here, as in so many other instances, 
 opened up a new path of inquiry. He first observed the cytoblast, as a 
 body, frequently present in plants: he did not, however, know its signifi- 
 cance in relation to the life of the cell ; he called it " nucleus of the cell." 
 
 15. The free independent cells ot plants are developed in a 
 globular form. Their subsequent forms appear to depend on the 
 dissimiliar nutrition of individual parts of the cell -wall, and a con- 
 
 * " Nouvelles Notes sur le Cambium," read at the Academy of Sciences, April, 
 1839. 
 
FORM OF THE PLANT-CELL. 39 
 
 sequent irregular distension. Several forms of this nutrition may 
 be distinguished. 
 
 A. Many-sided) or a nearly uniform) nutrition. From this arises 
 globular or elliptic cells ; or, if pressed on all sides, polyedral cells ; 
 or, in a regular arrangement, dodecaedral cells. When the parts 
 deposited are unconformable, little protuberances projecting on all 
 sides in the form of rays are developed, which constitute stellate 
 cells. 
 
 B. Nutrition in the dimensions of the plane. From this arises 
 tabular cells; or, if the nutrition goes on in three dimensions of one 
 side, plano-convex cells ; but if the nutrition goes on in one direction 
 of the surface, then long small tabular cells, which may be called 
 strap-shaped. With an irregular extension this form of nutrition 
 developes rayed or stellate cells. 
 
 C. Nutrition in one direction, extension in length only. The cells 
 formed are the cylindrical, prismatic, and fibrilliform. 
 
 That an irregular nutrition is the principal cause of the variety in the 
 forms of cells is in the highest degree probable. Cells which are not 
 immediately in contact can only be nourished in those spots where they 
 are in contact with other cells ; and cell-walls in contact with air do not 
 continue to grow in that direction, but become flattened, as in the upper 
 surface of epidermis cells, and in the cells of the partition-walls of air- 
 passages on both sides. In the air-passages, when young, there are 
 globular cells which touch only at particular points : from the rapidity 
 with which the sap passes through these spaces, and is decomposed by 
 the air, these cells are only nourished at the points where they touch, 
 and the points of contact continue to grow, so as to form rays which 
 constitute the stellate cells of the partition walls, and the spongiform 
 cells of the air- passages. This irregular nutrition may also take place 
 in cells with perfect contact : in these cases the projecting rays are dis- 
 posed alternately, as is the case in many epidermis cells, whose edges 
 appear waved or toothed on the surface. 
 
 But the most decided proof that irregular nutrition of the cell-wall is 
 the cause of the various forms of cells, has been afforded by Nageli*, in 
 his researches upon Caulerpa prolifera. It consists of a little creeping 
 stem with roots below and leaves above, and sometimes forming branches 
 on the sides, and originates in the growth of a body which may be 
 regarded as an individual cell. The large size of the parts admit of an 
 easy distinction being made between the old and young cells, as well as 
 the origin of the various forms from the differing nutrition of the 
 individual parts of the cell. The diversity of growth in individual cells 
 admits of analogy between the morphological distinction of stem and leaf 
 in the higher plants, as between the leaf and stem divisions of the single 
 cell in the present case. 
 
 All the various forms of cells, with the exception of the globular, 
 elliptic, and fibrilliform, originate in the combination of many cells with 
 one another. Every free cell forms for itself an arched surface ;. polye- 
 dral cells originate from the mutual pressure of cells. If perfectly 
 formed cells of the same size are allowed to press against each other, they 
 will form rhombododecaedrons. The rhombododecacdron, although fre- 
 quently present, must not be regarded as the primitive form of the cell. 
 
 * Schleiden and Nagirli, Zcitschrift fiir wissentschafUicho Botanik, part i. p 1 34 1 G5. 
 
 D 4 
 
40 
 
 ON THE PLANT-CELL. 
 
 History and Criticism. It is usual to distinguish a number of ele- 
 mentary organs in plants, and, although mostly regarded as forms of the 
 cell, yet Link and Treviranus adhere to three, the cell, the vessel, and 
 the fibre. It is, to say the least of it, unphilosophical to assume that 
 plants have three elements, and then to prove that all three are one and 
 the same. The pretended difference of function which confirms this 
 division is of no importance, as there is not so much difference of function 
 between vessels and cells as there is between two cells, the one of which 
 secretes a volatile oil and the other granules of starch. 
 
 The milk-vessels (laticiferous tissue) which are covered with a proper 
 membrane have not, with certainty, been made out to originate in cells. 
 Their origin is obscure, and in their perfect state they resemble elon- 
 gated branched cells, and agree with these in the transition forms which 
 they exhibit in the progress of development. 
 
 16. Up to a certain time the cell- wall grows in its entire 
 extent, through intus-susception, but not often uniformly. Indi- 
 vidual spots are more freely nourished, and form warty projections 
 upon the external or internal surface of the cell. 
 
 It appears to me that the attention which this point deserves has not 
 been given to it. It has been long known that certain hairs possess 
 warts, which are clearly arranged in spiral lines. In most cases these 
 warts are small and uniform in size, as on the hairs of the families 
 Boraginece, UrticecB, Malvaceae^ &c. Sometimes, however, longer striped 
 elevations of the external surface are seen, as in the anther-hairs of Lobelia 
 cardinalis, the two-armed hairs upon the young branches of Cornus 
 mascula, &c. But the most striking thing about these warts is, that 
 they display one or two cavities in their interior, and are separated by a 
 definite line from the surface of the hair, as though they were adherent 
 cells. They are seen in the hairs of the throat of the species of Anchusa 
 (fig. 15.) and other plants. These warty excrescences are not confined 
 15 16 
 
 to the external surface of hairs, but often form projections in the interior 
 of hairs, as, for instance, in the so-called root-hairs of Marchantiacece, in 
 the fibrous cells of Peltigera canina, in the spindle-shaped cells in the 
 style of Cereus phyllanthoides (fig. 16.), in the medullary rays of Pinus 
 sylvestris, in the hairs of Malpighiacece, where they form small peduncu- 
 
 15 a, A hair from the nectary of Anchusa itaJica, covered with warts, b, c, d, Longi- 
 tudinal section of warts (e), as seen from above. 
 
 16 Hair, with warts upon it, from Cereus phyllanthoides. The cell-walls are irregularly 
 thickened. 
 
FORM OF THE PLANT-CELL. 41 
 
 lated knobs*, and in the stinging hairs of the leaves of Anchusa crassi- 
 folia, where they appear as granular warts. Of the history of the 
 development of these little knobs, especially those of the Malpighiacece, 
 we know nothing. 
 
 17. In some rare cases, as in the spores of some Conferva, there 
 are formed, sometimes upon the external surface of the cell and 
 sometimes only at a particular spot, fibrilliform processes, which 
 exhibit a vibratile motion similar to the cilia found on the mucous 
 membranes of animals. 
 
 For the observation of this highly interesting phenomenon, we are 
 indebted to the labours of Ungerf and Thuret.J I have not yet had an 
 opportunity of confirming these observations. The following is the 
 result of their researches : Thuret distinguishes four forms. In the 
 Conferva rivularis and C. glomerata the spores have at their tapering 
 ends two vibratile cilia. In Chcetopliora elegans var. pisiformis and 
 another species there are four cilia. Prolifera rivularis and P. Candollii 
 of Leon Leclerc ( OEdogonium of Klitzing ?) have in the same spot a 
 crown of vibratile cilia. In the last place, the Vaucheria Ungeri Thu- 
 ret ( V. clavata and ovata DeC.) have the entire surface of their spores 
 covered with vibratile cilia. This last fact was first ascertained by 
 linger. Upon the origin of these cilia nothing is known, and just as 
 little of the mode of their disappearance. Just as suddenly as these cilia 
 disappear when the moving spore has fixed itself, do they appear when the 
 spore leaves its spore-case. The perfectly formed spore-cells are brown 
 in all cases, according to Kiitzing, but those which have the power of 
 moving are green. According to the history of the development of the 
 cells of Algce, given by Nageli, they originally consist of a closed sac of 
 mucus, and subsequently there appears around them a membrane of 
 cellulose. It might be a matter of inquiry whether the imperfect mucus- 
 cells have not the power of forming cilia, which they lose immediately 
 the proper cell-membrane is formed. The membrane bearing the move- 
 able cilia would be then the same layer of mucus as, in the antheridia 
 of the Mosses, Hepaticce, &c., is transformed into spiral fibres, and which, 
 in the cells of the Characece, Naiadece, and many higher plants, form 
 little moving streams. Nageli has also promised shortly an account of 
 the relation between these movements and the nitrogenous contents of 
 the bodies in which they occur. 
 
 18. When the cell has reached a certain degree of development, 
 an essential change takes place in its mode of nourishment: the 
 newly formed cellulose is not taken up by intus-susception, but is 
 deposited upon its inner surface as a concrete layer. This deposi- 
 tion does not, however, take place as a continuous membrane, but 
 is formed in the direction of a spiral, as a spiral fibre or band. 
 Should the cell distend after this deposition, then the spires which 
 laid close together at first are drawn asunder. The less the cell is 
 extended, the firmer is the union of these fibres with its walls. 
 
 * Morren, Obs. sur 1'Epaississement de la Membrane vegetale dans plusieurs Or- 
 ganes de 1'Appareil pileux. (Bullet, de 1'Acad. Itoy. de Bruxelles, torn. vi. No. 9.) 
 
 f Unger, Die Pflanze in Moment der Thienverdung. Vienna, 1843. 
 
 \ Thuret, Recherches sur les Organes locomotcurs des Spores dcs Algees. (Ann 
 des Sc. Nat, Mai, 1843.) 
 
42 
 
 ON THE PLANT-CELL. 
 
 17 
 
 The individual spires of fibres, or particular spots of the spires, 
 often grow together. From these circumstances a very varied 
 configuration of the cell-wall results, which may be comprehended 
 under two divisions. First, where the fibres are clearly separable 
 (fibrous cells, cellules Jibrosce) ; and, second, where the fibres are so 
 grown together, that they appear like a continuous membrane 
 beset with little pores (porous cells, cellules porosae). 
 
 Nature and Origin of the Spiral. A spiral may be formed either 
 from left to right or from right to left. If we take the distance from the 
 
 commencement of the one spiral to 
 the commencement of another di- 
 rectly above it, and make it a, then 
 + a will be the expression of the 
 spiral winding to the right, and 
 a that of the spiral to the left, 
 and a a the expression of the 
 ring passing between them. The 
 right spiral is the most frequent, 
 but the left occurs often enough 
 to render the resulting ring as 
 indifferently the produce of either. 
 It is, however, possible for the 
 
 ring to have another origin. Each spiral may be divided into two 
 halves, which, regarded from the same point, proceed in different direc- 
 tions. If the one half of the winding be from right to left, the other 
 must be from left to right. Two spirals proceeding in the same direction 
 would run parallel, but would cross each other on a flat surface (fig. 17. c). 
 Two spirals running in opposite directions would cross each other twice 
 in the course of one entire turn (fig. 17. d). This last form has not yet been 
 observed. Link* thinks he has seen it, but his own drawing shows that 
 it belongs to the first case. The lines crossing each other in the walls 
 of the liber cells of Apocynacece, may be explained upon the supposition 
 of there being two layers, lying one upon another, turning in opposite 
 directions. 
 
 It is easy to perceive in the larger spiral fibres, when they are cut 
 transversely, that they are homogeneous. In the old fibres of Arundo 
 Donax they consist of a fibre lying on the wall, and one on each of the 
 three free sides. In a transverse section, under a good microscope, it 
 may be easily seen that the fibres are never round, but that they consist 
 of a flat, thicker or thinner, band, whose free edge or side is, perhaps, at 
 the utmost a little rounded. (Plate I. figs. 18, 19, 20.) The idea that 
 they are hollow canals arises out of defective observations. 
 
 I do not believe that the first origin of the spiral has been observed. 
 It appears to me that it exists much earlier than can be at present 
 detected by our optical instruments, as it is formed from a matter which 
 cannot be distinguished from the contents on the walls of the cell. The 
 spires are more transparent in their earliest stages, and when invisible 
 as a whole they may be observed as small projections upon the edges of 
 the cell : in this state they are contracted, and are thus more bulky. 
 
 * Elementa Philosophise Botanicee, p. 167. 
 
 17 Diagram, a, Left spiral, b, Right spiral, c, Two left spirals in one cell, d, Two 
 spirals right, and two left, in one cell. 
 
FORM OF THE PLANT-CELL. 43 
 
 Where they are perfectly invisible, the application of a little iodine will 
 frequently make traces of them evident : spiral formations are also fre- 
 quently observed, for the first time, when the vessels begin to carry air, 
 on account of the different relation of the air and the solid substance of 
 the vessel to light. 
 
 In addition, I find that in all spiral formations the spires are narrower 
 the younger they are, and also more simple and unbranched in their 
 structure : in the most abnormal forms for instance, the annular ves- 
 sels I have found most evidence of this.* From these facts, then, it is to 
 be inferred,, that the foundation of all the forms of spiral formation are 
 simple, unbranched, narrow, spiral fibres lying one upon another ; and 
 upon this simple hypothesis, combined with the undoubted fact that all 
 spiral formations become first known to us after they have been present 
 for a long time, and during this period have become considerably 
 changed, we may easily explain all the phenomena observed. 
 
 It must, however, be confessed, that we are still far from being able to 
 supply a rational induction for the phenomena of spiral formation : we 
 have, even now, scarcely any indication of the relation which exists 
 between the formation of a spiral and the nature of the plant or of the 
 cell in which it occurs. We should gain a secure point for the develop- 
 ment of the whole doctrine if we could find a single case, even a case 
 which was not connected with the formation of a spiral fibre, in which 
 we could prove, from the existence of a vegetable cell under certain cir- 
 cumstances, that a tendency to a spiral direction must necessarily follow. 
 Could we trace the spiral direction of the circulation in the central cell 
 of Chara to a peculiarity in the nature of the cell as a necessary con- 
 sequence, then we should obtain for all spiral phenomena an entirely 
 different signification. In looking at the peculiar brown-coloured spiral 
 fibres in the cells of the sporidia of the Jungermannice, the movable 
 spiral fibres in the antheridia of Charas, Mosses, Jungermannice, and 
 Ferns, it appears to be not improbable that we include under the name 
 Spiral Fibres very different things. In these instances, the one is a 
 peculiar form of the deposit layer of cell-membrane, a non-azotised sub- 
 stance (cellulose) ; and in the other, an especial form of the mucus, the 
 nitrogenous constituent of the cell. 
 
 Forms of the Spiral. After the spire has been developed in a cell, the 
 latter often becomes extended. 
 
 A. This extension produces the following modifications : 
 
 a. When the turns of a single fibre early grow to- 
 gether so as to form a ring, whilst the free fibres become 
 torn or resorbed, so that the cell exhibits either the 
 rings alone, or mixed with single turnings of the spire, 
 these rings are ordinarily little or scarcely at all con- 
 nected with the cell- wall (Cellules annuliferce) (fig. 18.). 
 
 This occurrence has been observed in its entire 
 course in the stem of many Tradescantia, in the root- 
 stock of Equisetum arvense, and in some other plants. 
 In many other plants I have failed in detecting the 
 first formation of the rings. In the Cactacece, in which 
 the rings are so large, I have not been able to observe their formation. 
 
 * Notwithstanding Mohl's objections (Flora, v, 1839, Nos. 43,44.), I still, after 
 repeating my observations, hold the view I took at first. (Ibid. Nos. 21, 22.) 
 
 18 A fibrous cell, with two single rings, from the neighbourhood of the woody bundles 
 of the Opnntid peruviana. 
 
44 
 
 ON THE PLANT-CELL. 
 
 b. When simple or compound spirals do not grow together and form 
 rino-s, but the cell continues to grow, the spirals are then found in the 
 cell more or less free (Cellulce spiriferce) (fig. 19.). 
 
 c. When many fibres grow together longitudinally, or the individual 
 turns unite at different points, and the cell grows rapidly, the free parts 
 
 19 
 
 of the fibres are drawn away from each other. The more numerous the 
 points of adhesion, the less the cell extends itself, the firmer grow the 
 fibres to the cell- wall * (Cellulce retiferce) (fig. 2023.). 
 
 20 
 
 22 
 
 B. When the cells, from the first moment at which the spiral fibres 
 are produced, cease to extend, the turns of the spire grow firmly together 
 to the original walls of the cell. In this case the fibres touch each other 
 at countless points, and grow together. It is seldom that the spires 
 unite throughout their whole length to form a homogeneous layer ; yet 
 this occurs sometimes, as seen in the cells of the liber of the Flax and the 
 Lime ( Tilia europed]. This sometimes takes place on one side of a cell, 
 whilst the other exhibits a formation of pores, as in the rows of great 
 porous cells in the vascular bundles of Monocotyledons. In most cases, 
 however, the spires grow together at particular points, leaving between 
 them smaller or larger openings in the disunited spaces (fig. 23.). Fre- 
 quently the corners of these openings become rounded by the deposition 
 of fresh matter, and the original chink appears as a little pit in the deposit- 
 layer (fig. 24.). In tolerably thick deposit-layers this pit, by a transverse 
 section, may be observed as a narrower or wider canal (fig. 24.), which 
 sometimes gradually or suddenly opens at the outside of the wall of the 
 
 * To this form belongs the branched spiral of authors. 
 
 19 A fibrous cell, with 1 3 pure spiral bands ; a seen from the side, b and c from 
 above. These cells are found under the epidermis of the leaves of Pleurothallis rusci- 
 folia. 
 
 20 Fibrous cells, with netted fibres, formed from a spiral, as seen in the veins of the 
 leaves of Gesneria latifolia. 
 
 21 Netted fibrous cells, from the back of the root of Maxillaria atropiirpurea. 
 88 The same from the root of Acropera Loddigesii. 
 
FORM OF THE PLANT-CELL. 
 
 45 
 
 23 
 
 x* 
 
 Xxx 
 XXX 
 
 24 
 
 5^ 
 
 cell (fig. 25.). In the woody tissue of the Coniferce, in the porous 
 vessels of the wood, in almost all vessels with oblong pores, the pore 
 may be seen surrounded by a double circle, an inner one easily recog- 
 nised as the pit in the deposit-layer, and an outer wider circle (fig. 26.). 
 
 26 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Sometimes three circles are seen. If we compare the transverse section 
 
 of these pits with their appearance on a flat surface, we shall see how 
 
 this takes place (fig. 27.). In the region of the 
 
 canal of the pore, the cell-walls, which at first 
 
 lay upon one another, become separated, and 
 
 leave a lenticular space between them, which is 
 
 filled with air. The edges of this space appear 
 
 from the surface as an external circle. The one 
 
 or two inner circles are produced by the canal, as 
 
 seen in fig. 27. This appearance of the external 
 
 circle admits of two explanations: 1st, its greater 
 
 83 Porous cells from the parenchyma of the stem of Arundo Donax. 
 
 24 Porous cells, from the petiole of Hoya carnosa. 
 
 25 Porous cells of the petiole of Cycas revoluta. Small pores are found where 
 the cells are xinited to each other, but large ones where the cells open into the inter- 
 cellular passages. 
 
 >6 Porous cells from the wood of Abies excelsa. The pores are surrounded by a large 
 external circle. 
 
 27 Semidiagrammatic. A single perfectly developed pore from the wood-cells ot 
 
46 
 
 ON THE PLANT-CELL. 
 
 * M 
 
 I "' 
 
 
 distance from the pore, when seen together with it from the plane sur- 
 face, is diminished (fig. 28. a, b) ; and, 2dly, the thickness of the air- 
 clefts between the cell-walls ; for 
 
 28 j if these are very flat, the bor- 
 
 dering surfaces will appear almost 
 parallel, and the edge is either 
 not at all or in a very slight 
 degree darkened, so that it cannot 
 be observed. If these cases are 
 placed in profile, as in fig. 28. 
 a, b, c, d, this explanation will be 
 understood. If we examine the pro- 
 cess of development in the large 
 and easily observed porous vessels of the cambium of the Willow, the 
 Lime, the Poplar, and the Maple, we shall find that all of them present 
 dark spots, which resemble those of the external circle of the air-clefts : 
 a clean transverse section of these spots is difficult to obtain ; but, from 
 our knowledge of optical phenomena, this dark spot may with certainty 
 be referred to the presence of a bubble of air. At this time no pore is 
 present : this is generally formed at a subsequent period. If these facts 
 are placed together, we may arrive at the conclusion that the air-cleft is 
 universally present previous to the appearance of the pore. The con- 
 sequence is, that, as the changes of matter by which the cell is nourished 
 can only take place during the contact of two cells, the cells are not 
 nourished at those points where the air exists between their walls : thus 
 the pore and its canal originate as a partial atrophy of the cell-wall. 
 Therefore, in all the transitions between porous cells through the netted 
 
 29 
 
 cells into the pure spiral, we must seek the cause of the division into 
 separate spirals not in the cell itself, but in its circumference. This 
 
 Schulertia disticha, seen from the surface and in transverse section. The dotted lines 
 explain the relation which the two aspects bear to each other. 
 
 28 Semidiagrammatic. Transverse sections of the pores, a, Pores small, in relation 
 to the spot where the neighbouring cell-walls separate from each other, b, Pores 
 large, in relation to this spot, c, The separation of the cell-walls so small that it only 
 appears as a black streak, d, The separations not observable between the cells are 
 apparently homogeneous layer rings, in which the pores terminate. 
 
 29 p orou s cells from the perispeum of the ivory nut. 
 
 !0 Transverse section of an intercellular passage, with the three portions of cell-wall 
 which forms it. The larger pores in the deposit-layer of the intercellular passages, as 
 well as the smaller ones on the double cell-walls, are seen. The corners of the inter- 
 cellular passages are rounded off by a peculiar deposit. 
 
FORM OF THE PLANT-CELL. 
 
 47 
 
 is offered as an explanation of the facts, to guide farther inquiry, rather 
 than as a true law of development. There are two cases which seem to 
 form exceptions to this view. The first is the formation of pores, which 
 open into intercellular passages independent of the neighbouring cells. 
 These are very beautifully seen in the petioles of the Cycas revoluta. In 
 this case the single wall is easily affected, and the intercellular passages, 
 filled with air, act in the same way as the air-clefts. We frequently see, 
 also, a great air-cleft, forming a large fissure-like pore on one side, and 
 many little pores on the other side, as is frequently seen present in the 
 porous vessels of the Balsaminece. In a similar manner the porous cells 
 of the medullary rays in various species of Pinus often exhibit a longitu- 
 dinal air-cleft, which resembles the pores 
 in many cells. 
 
 The last form worthy of mention is 
 when the cell-walls do not extend, and the 
 spires touch each other, but do not grow 
 together. This is the form on which 
 Meyen founded his false theory of the 
 fibrilliforin nature of all cell-membrane. 
 This phenomenon often presents itself, as 
 in the cells of the parenchyma of the 
 tubers of the Dahlia (Plate I. fig. 26.), 
 the hairs of the young leaves of Cycas re- 
 valuta, in the hairs of many Mammillarice 
 and Melocactece, the scales of the buds 
 of Pinus sylvestris, &c. Sometimes the 
 spires in these cases present fissures, as 
 is beautifully seen in the cells of the 
 rootlets of Oncidium altissimum (Plate I. 
 fig. 24.). 
 
 Individual Development of the Spiral 
 Fibres, and of Abnormal Forms. Every 
 spiral fibre at its first visible existence is 
 a fine thread, which increases both in 
 breadth and length (fig. 31. c, d.). This 
 goes on so long as the cell contains sap, 
 but ceases immediately this is absorbed, 
 and the cells fill with air. In some cases a 
 part of the spiral fibre does not increase 
 with the rest, and the fibre terminates as 
 it were with a pointed end, as is often 
 seen in the vessels of the common gourd 
 (fig. 31. e.). Occasionally, and apparently 
 from disease, the cells which had originally 
 been filled with fluid, and which had 
 given place to air, are again filled 
 with fluid when a fresh set of anasto- 
 mosing spiral fibres are formed. This 
 
 31 , Annular ducts from the stem of Canna occidentalis, with a regular distance of 
 the rings. 6, Annular ducts from the petiole of Musa sapientum, the vessel between 
 the two rings being distended, c, d, Spiral from a cactus, very young, and perfectly 
 developed, e, A spiral vessel from Cucurbita Pepo, with some of the spiral fibres ending 
 iu a point. 
 
48 ON THE PLANT-CELL. 
 
 takes place in the old stems of Scitammete, and of speces of Commelinece, 
 as in Hedychium Gardnerianum, and Tradescantia crassula. Another 
 regular formation of anastomosing fibres occurs between the spires of 
 neighbouring cells. This may be seen in the large knotted vessels of 
 many Balsaminece. In these may be seen a perfectly regular spiral fibre 
 with a slight yellow colouring, but accompanied by another short, almost 
 colourless, vertical branch, which is easily recognised by its transparency. 
 If this is traced it will be found to follow accurately the course of the 
 commissure between the two vessels, and to form a kind of bridge over 
 the commissure from one fibre to another. This clearly does not belong 
 to the original spiral formation. Its constant appearance in porous 
 vessels, with long transverse clefts, has caused it to be called scalariform 
 tissue. 
 
 In the last place the annular ducts present some striking phenomena, 
 amongst which must be reckoned the constancy of the distance between 
 the same annuli. A remarkable instance of this I have observed in 
 Canna occidentalis, where a short distance between the annuli regularly 
 alternates with one three times as long (fig. 31. .). In the annular ducts 
 of the petioles of Musa paradisiaca, I have observed the cell between 
 the two rings to be remarkably distended and swollen, so that there could 
 be no union with the rings of cells near to each other. 
 
 Historical and Critical Remarks. The spiral fibres were early dis- 
 covered by Malpighi and Grew, or perhaps even sooner by Henshaw. 
 Bernhardi (Ueber Pflanzengefiisse und cine neue Art desselben : Erfurt, 
 1805) and Moldenhauer (Beitrage zur Pflanzenanatomie : Kiel, 1822) 
 pointed out the existence of the external cell-membrane enveloping the 
 spiral fibre. The annuli or rings were discovered by Bahel, and their 
 enveloping membrane by Bernhardi. (See Link, Elementa Philosophise 
 Botanies, ed. sec. torn. i. p. 27. 169.) The porous cells were discovered 
 by Leuwenhoek (Opera omnia, tab. 462. fig. 20.); but they were first 
 correctly estimated by Mirbel (Histoire Nat. des Plantes, 1800, torn. i. 
 p. 57. ; Traite d' Anatomic et de Physiol. veget., Paris, 1802, t. i. p. 57. 
 fig. 1 4.). He was at first opposed till Hugo Mohl published his ob- 
 servations confirming Mirbel's views (Ueber den Bau der Ranken und 
 Schlingpflanzen, Tub. 1828). Mohl also discovered the membrane in- 
 vesting the porous cells (Ueber die Poren des Pflanzenzellgewebes, Tub. 
 1828). These are the most important steps in the history of our know- 
 ledge. What remains is the notice of the more or less frequent occurrence 
 of one or another modification. Meyen (Physiologic, vol. i.) has collected 
 a large mass of information on the whole of this subject. Valentin (Re- 
 pertorium, vol. i.) was the first to contend that all these formations origi- 
 nate in the spiral. Link (Elementa) maintains that the pores and clefts 
 are portions of torn spiral fibres. Mohl is of opinion that the annular 
 ducts are primary formations. Hartig (Beitrage zur Entwickelungsge- 
 schichte der Pflanzen, &c. Berlin, 1848) has announced a view of spiral 
 cell development which cannot be regarded as any thing more than an 
 ingenious fiction, it having no foundation in facts. 
 
 19. Generally, the deposit-process forms a new layer on the 
 wall of the cell of the same form ; but cases occur in which on the 
 one side of the wall it unites a spiral fibre to a homogeneous mem- 
 brane, whilst on the other it excavates a spot for a fissured pore 
 
FORM OF THE PLANT-CELL. 49 
 
 (here belong the so-called porous vessels of the wood) ; or in one 
 part of the cell it becomes changed to rings, whilst in another part 
 it becomes spiral, netted, or, what more frequently happens, it re- 
 mains entirely porous. 
 
 To this point too little attention has been given. We know in this 
 relation only the last modification, the mixed tubes (tubes mixtes) of 
 Mirbel. Here, however, belong also the so-called porous vessels of our 
 dicotyledonous woods, which, in the manner in which they are spoken of 
 in books as tubes formed of an entirely porous membrane, certainly do 
 not exist. All these so-called vessels are only so far porous as they 
 touch one another ; as, where they project on the wood-cells, these walls 
 are often almost entirely homogeneous, and exhibit scarcely a trace of 
 pores. This may be easily seen if the individual cells are isolated by 
 means of nitric acid. When these vessels are arranged in radial rows, 
 but never or very seldom when they lie laterally on one another,, if we 
 cut them directly across we shall find very evident porous walls, but 
 never or extremely seldom are they to be seen by a longitudinal section. 
 This is the case in the Coniferce, where the pores predominate (but not 
 exclusively) on the side next the medullary rays ; or in the Hibbertia 
 volubilis, where they appear, on the contrary, towards the pith and the 
 bark, seldom towards the side of the medullary rays ; so that the two 
 other sides in these cases have a homogeneous development. 
 
 20. The process of depositing layers is often repeated during 
 the life of a cell. a. Each successive layer is generally deposited 
 accurately upon the preceding, ring upon ring, spiral upon spiral, 
 porous layer upon porous layer, b. But in some less frequent 
 cases the deposit takes place according to the circumstance of the 
 cell ; so that when, through extension, the cell-fibres become sepa- 
 rated, the extension causes the deposit of a porous layer. Ordinarily, 
 also, the direction of the spiral in the following layer is the same 
 as in the foregoing, but in some cases the direction of the next 
 spiral is directly opposite that of the first. 
 
 The first condition mentioned above is very common, and rings are 
 often found so very much thickened that they have only a little hole in 
 the centre ; and as they do not increase so much in breadth, they appear, 
 when perfectly formed, like thin discs with a hole bored 
 through them. They are seen in the Cactece, as Opun- 
 tia cylindricay Melocactus, Mammillaria, &c. This 
 occurrence is also very frequent in porous cells, so that 
 the cavity of the cell is reduced to a scarcely visible 
 point. Such cells are very common in plants, and a 
 single layer may be easily seen upon a transverse section. 
 The pores of the deposit layers become gradually con- 
 verted into canals (fig. 32.). Such canals frequently 
 approach each other, and at last unite, so that the inner 
 layer is much less porous than the outer (fig. 33.). 
 With these may be compared the elegant formations in the so-called 
 
 32 Transverse section of three liber-cells and some parenchyma-cells in the China 
 reffia (Cinchona scrobiculata Humb.). The liber-cells show very clearly the deposit 
 layers and the porous canals. 
 
50 
 
 ON THE PLANT-CELL. 
 
 stones of winter pears and quinces ; 
 in the bark of the petiole and stem 
 of Roy a carnosa ; in the stem of Fraxi- 
 nus excelsior (Plate I., fig. 22.) ; and in 
 the fruit stalks of Magnolia (Plate I., 
 fig. 21.), &c. These are called, with 
 peculiar impropriety, branched porous 
 canals. Mohl* was the first who dis- 
 covered this process of growth by de- 
 posit-layers in the cells of the plants, 
 and thus explained one of the most 
 important processes in the life of the 
 plant. 
 
 Formations of the second kind have 
 been longer known, as in the wood 
 of the Yew, where separated spiral 
 fibres and rings are seen, between 
 the windings of which are also large 
 pores. In recent times many simi- 
 lar formations have been observed in the Lime, the Vine, in Primus 
 Padus, Helleborusfatidus, &c. (fig. 34.). Little 
 is at present known of their mode of formation. 
 In the Lime, in the spring, we find in the cam- 
 bium spiral cells with the fibres close together ; 
 in the course of growth these extend, the spires 
 separate from one another, and pores are formed 
 between them, so that here the porous layer is 
 the last formed. How it is formed in other 
 cases is yet a question. 
 
 In the tender spiral cells of the bark of the 
 Asclepiadece and Apocynacece y and in the deli- 
 cate spiral cellular tissue generally, there is 
 sometimes observed the appearance of a crossing 
 of the spiral fibres. This may arise from the 
 
 spires of neighbouring cells, or from the transparency of the walls of the 
 same cell ; but there can be no doubt that in some cases it is an original 
 formation (Plate I., fig. 23.), and arises probably from spires formed in 
 opposite directions. 
 
 21. In many cells the spots remaining free from the secondary 
 deposits become fluid and are resorbed. In this way cavities 
 are formed in the membrane. Upon this depends the distinc- 
 tion between cells and vessels. The last are only rows of cells 
 whose cavities have in this way been brought into union with each 
 other. 
 
 * In his work on the structure of the palm-stem, and in other places. 
 
 33 Porous cells of the petiole of Cy-cas revoluta. Small pores are found where the 
 cells are united to each other, but large ones where the cells open into the intercellular 
 passages. 
 
 34 Vessels from Helleborus faetidus. A, Longitudinal section, a, Two adhering vessels 
 with the pores cut through, and the projections of the spiral fibres, b, The wall of 
 the vessel, without pores touching the wood-cells, with the projections of the fibres. 
 , A vessel seen from without. 
 
FORM OF THE PLANT-CELL. 
 
 51 
 
 35 
 
 Hugo Mohl was the first to point out the distinction between these 
 excavations and pores ; and daily observation confirms the existence of 
 actual cavities in the membrane. The existence of a free communication 
 between the vascular cells was early recognised ; but they were regarded 
 as originally continuous tubes, and wonderful views of their structure 
 announced, because the history of their development was not studied. 
 All vessels consist originally of vertical rows of closed cells, in which are 
 gradually deposited the secondary layers, according to the 
 forms of which they are named. When these deposit- 
 layers are tolerably perfectly formed, a process commences 
 whereby the primary cell -membrane is resorbed, so that 
 the individual cells are brought into free communication. 
 This resorption generally includes all horizontal form- 
 ations of the deposit process, but in some cases a horizontal 
 wall remains with only a pore or hole in its centre (fig. 35.). 
 Such formations present themselves very decidedly in the 
 Mosses in the group Leucophanece, as in Sphagnum, in 
 the parenchyma-cells of old Cycadece, in the so-called 
 vessels and sometimes porous cells of Coniferce, where 
 they touch the medullary rays, in the green-walled cells 
 of the root-caps of Aerides odoratum, &c. 
 
 SECTION II. 
 
 OF CELLS IN COMBINATION, AND INTERCELLULAR FORMATIONS. 
 
 22. The individual cells, originating in the manner described, 
 are grouped together in various ways into great masses (called 
 tissues, tela, contextus\ which, according to their combination out 
 of various or similar elementary parts, may 
 be arranged on the following plan : 
 
 23. A. PARENCHYMA. It forms the 
 principal mass of plants and of their parts. 
 It is, 
 
 a. Incomplete Parenchyma, when the cells 
 barely touch each other by their parietes. 
 This may be again divided into, 
 
 1. Spherical or elliptical Parenchyma, 
 in which the cells are round. This pre- 
 vails in succulent plants (fig. 36.). 
 
 85 Porous vessel from Arundo Donax, in which a portion of the outer wall is removed, 
 exposing the point of union of two cells, where a horizontal wall, with a large hole in 
 it, is seen. 
 
 K Imperfect elliptical parenchyma from the leaf of Acrostichum akicorne. The ad- 
 hering surfaces are porous. 
 
 K 2 
 
52 
 
 ON THE PLANT-CELL. 
 
 2. Spongiform Pa- 
 renchyma, which con- 
 sists of cells extend- 
 ing themselves irregu- 
 larly in a stellate form, 
 and which touch only 
 at the end of each ray 
 (fig. 37.). Such tis- 
 sue frequently fills up 
 the air-passages, and oc- 
 curs in all tissue which 
 dries rapidly, and also 
 in the under half of the 
 parenchyma of most 
 
 37 
 
 leaves. 
 
 b. Complete Paren- 
 chyma, in which the 
 touching of the cells is 
 complete on every side. 
 
 1. Regular or dode- 
 caedral parenchyma, 
 consisting of almost 
 pure polyedral cells, 
 without the predomi- 
 nance of any particular dimension, 
 of plants (figs. 38, 39.). 
 
 It is found mostly in the pith 
 
 2. Longitudinal, cylindrical, or prismatic parenchyma. It occurs 
 in rapidly growing plants, sometimes in the pith of monocotyledons 
 and in the interior of species of Fucacece (fig. 40.). 
 
 3. Tabular parenchyma, consisting of four-cornered tabular 
 cells. They occur in the external bark, especially in the suberous 
 and cellular layers (fig. 41.). 
 
 87 Spongiform parenchyma from an incomplete intercellular passage of Canna occi- 
 dentalis. 
 
 83 Transverse section of the parenchyma of the stem of Balsamina hortensis. 
 39 Longitudinal section of the same. 
 
FORM OF THE PLANT-CELL. 
 
 53 
 
 42 
 
 24. B. INTEHCELLULAB SYSTEM. The contact of the sides 
 of the cells in plants is seldom or never perfect, so that there are 
 formed numerous cavities, of which the following are the most 
 important varieties : 
 
 a. Original cavities formed by the imperfect contact of the cells : 
 
 1. Intercellular passages; small three-cornered canals running 
 around the cells, and seen in almost all kinds of parenchyma. 
 
 2. Intercellular spaces ; great irregular spaces between the cells, 
 occurring especially in spongiform cellular tissue. 
 
 b. Later-formed cavities: 
 
 1. Receptacles of special secretions. These arise from the ex- 
 udation of the juices of the cells into the intercellular passages. 
 Two kinds of these may be distinguished : 
 
 a. Formed by compact cells, 
 lying close on one another, and 
 apparently not separable; as the 
 resin-cells of the bark of Coni- 
 fer &, and individual gum-cells. 
 
 /3. Formed by loose cells, with 
 their walls projecting vesicularly 
 into the cavity, and apparently 
 separable. Such cavities mostly 
 contain peculiar secretions, and 
 are seen in the latex-canals 
 of species of Mammillaria and 
 Rhus, the gum-cells of Cycadea 
 (fig. 42.), and the resin-cells of 
 the wood of Coniferce. 
 
 40 Parenchyma from the stem of Flcia Faba, In the cells are seen porous openings, 
 and in two cells cytoblasts, with granules of starch. 
 
 41 Parenchyma from the bark of Quercus Suber (cork oak), a, longitudinal section. 
 b, as seen from surface. 
 
 4a Tissue from the opening of two dextrin passages in the petiole of Cycas revolnta. 
 The compact parenchyma is clothed with a delicate vesicular tissue, projecting into the 
 
 cavitv. 
 
54 
 
 ON THE PLANT-CELL. 
 
 2. Receptacles of air, formed by the destruction of a mass of 
 parenchyma. They are : 
 
 a. Air Canals. These are formed by a portion of parenchyma 
 becoming changed first into spongiform cellular tissue, which 
 is then torn and resorbed. The walls of these canals are per- 
 fectly smooth, and the cavity is divided into 
 definite spaces by a layer of stellate cells, as 
 though interrupted by horizontal layers. Seen 
 in Canna, Nymphaa, &c. (figs. 43, 44, 45.). 
 
 43 
 
 /3. Air Cavities. In these a portion of parenchyma is inor- 
 dinately torn by the growth of a portion of the plant. Their walls 
 are rough with the remains of torn cells. Seen in the stems of 
 grasses, many Composites, and in the Umbelliferce. 
 
 25. C. VESSELS. ( Vasa, Trachea.) When a row of 
 lengthened parenchyma-cells have, through resorption, their ca- 
 vities brought into continuous communication, such a series of 
 cells are called, by an unfortunate expression, a vessel ; and it 
 is distinguished from the above tissues by different names, accord- 
 ing to the nature of its walls, as spiral vessel, annular duct, porous 
 vessel, &c. (vasa spiralia, annulata, porosa). 
 
 The nature of the vegetable vessel has been much misunderstood, from 
 the neglect of the history of its development. Various views have been 
 and are entertained ; yet nothing is easier, in the larger and more fully 
 developed parts of plants, than to observe the formation of a vessel out of 
 a row of cells. In many cases, however, it may be difficult, as the forma- 
 tion of the vessel occurs at too early a period in their history to be seen. 
 In other cases, a union of the two vessels, side to side, may prevent an 
 unskilful observer from detecting what is going on in them. Nowhere is 
 the formation of vessels out of cells, and the connexion of the spiral 
 formation with this process, more easy to be observed than in the com- 
 mon balsam (Balsamina)* 
 
 * Anatomic und Physiologic der Caeteen. 
 
 43 Stellate cellular tissue, from the horizontal layers in the air-canals of the petiole of 
 Aponogeton distachyon. The three-cornered intercellular passages are very large, and 
 the rays of the cells proportionately long. 
 
 44 The same. The three-cornered intercellular passages are somewhat rounded, and 
 rather small ; the rays of the cell proportionately short. The walls of the cells, between 
 two rays, are somewhat thickened. 
 
 45 The same from the leaves of Pilularia globulifera. The cells are somewhat length- 
 ened, with short and broad rays; the parts of the wall in contact thickened ; the inter- 
 cellular passages irregularly rounded. 
 
FORM OF THE PLANT-CELL. 55 
 
 Frequently, in the later-formed vascular cells, the septum is broken 
 down in such a manner that it remains in a circle as a small edge. This 
 septum is seldom entirely horizontal, but ordinarily somewhat inclined 
 from the axis of the plant towards the radius, very seldom towards the 
 periphery. Such cavities in the septum may be frequently seen by a 
 longitudinal section of a vessel. Treviranus * first remarked this, but 
 knew not what to make of it. Meyen f gave a very unsatisfactory expla- 
 nation of it. This breaking up of the septum only occurs where there is 
 a kind of resistance on the part of the septum itself. Where this ten- 
 dency is very strong, instead of a single cavity many are formed, and 
 the septum acquires a regular ladder-like aspect ; a fact first announced 
 by Mohl. J Examples may be seen in the Beech, in the roots of Palms, 
 in Arundo Donax, &c. Again, the tendency may be so strong, that the 
 cells may be regarded as lying on one another, and there is formed upon 
 the septum, according to the nature of the cell, spiral fibres or pores. 
 
 That the completely developed vessels contain only air, is a fact that 
 can be ascertained by the naked eye. Sometimes, in old age, abnormal 
 fluids will be found in them, and cells are developed in the vessels. Cells 
 are found in the old porous vessels of the Oak and Elm, and I have found 
 them frequently in the spiral vessels of the stems of Scitaminece, as 
 Canna and Hedychium. Such cells do not appear to me to originate in 
 the vessels, but arise from neighbouring cells being pressed into the 
 vessel between the spiral fibres. The cell thus pressed into the vessel 
 originates the new cells. The so-called monilifonn vessels are not 
 formed in a different manner from others. 
 
 26. D. VASCULAR BUNDLES. This term is applied to a mass 
 of lengthened cells, of which a part have been changed into vessels, 
 and which is more or less clearly distinguished from the parenchyma, 
 which they penetrate in longer or shorter masses. They are 
 either, 
 
 a. Simultaneous vascular bundles, when all parts of the bundle 
 originate and are developed at the same time, as seen in the 
 Cryptogamia. 
 
 b. Successive vascular bundles, when the individual parts of the 
 bundle, and especially in the stem, arise and are developed from 
 within outwards. At first they consist of a delicate cellular tissue, 
 filled with an opaque fluid (cambium), which, whilst internally it 
 forms lengthened cells and vessels, goes on increasing externally. 
 These may be divided into, 
 
 1. Definite or closed bundles. In these the growth of the bundles 
 only continues for a short time ; they then become surrounded by a 
 sharply defined cellular tissue, and are incapable of further develop- 
 ment. Ordinarily the vessels lie in a line, or are formed from 
 within outwards ; externally, or on both sides the line, are seen a 
 pair of large porous vessels, and the whole is surrounded and mixed 
 with lengthened thick-walled parenchyma, which distinguish the 
 
 * Vom inwendigen Bau der Gewiichse, Gottingen, 1806, tab. i. fig. 10. b. 
 f Phytotomie, S. 264. 
 
 J DC Palmarum Structure, tab. w. figs. 13, M, 15. 
 
 E 4 
 
56 ON THE PLANT-CELL. 
 
 bundles from the thin-walled short parenchyma around. Such arc 
 monocotyledonous vascular bundles. 
 
 2. Indefinite or unclosed bundles. In these the cambium does 
 not cease to develop, and the vessels to thicken from within outwards, 
 till the organ, or the plant to which it belongs, ceases to live. 
 Such are dicotyledonous vascular bundles, arid they may again 
 be distinguished into, 
 
 . Primary vascular Bundles, those which are produced during 
 the first period of vegetation, or first year. In the inner half it 
 consists of the same parts as the closed bundles, only that the ves- 
 sels are more numerous, and not so regularly arranged ; the outer 
 half is composed of cambium-cells, which are distinct laterally and 
 in front, but pass quickly into the surrounding parenchyma. 
 
 /3. The Wood. After the completion of the first period of vege- 
 tation, the parts of a plant generally cease to increase in length ; 
 but as the new cambium-cells must, nevertheless, extend to a certain 
 length, they necessarily interpenetrate amongst each other by 
 pointed extremities. Thus originates, in the place of parenchyma, 
 a peculiar tissue which is called proscnchyma. A part of these 
 retain their narrow lengthened form, pointed above and below 
 (wood-cells, woody fibres), but between them open individual per- 
 pendicular rows of cells, often very strongly marked, which become 
 converted into vessels. The only exceptions to this are the Coniferce, 
 Cycadacece, and some others, where all the wood-cells are tolerably 
 uniform. The portion of wood that is formed first in every year 
 is composed of broad thin-walled cells, and contains more vessels 
 than later-formed wood, which consists of smaller vessels, and the 
 cells are always narrow and thick-walled. In this way the differ- 
 ence between the growth of the earlier and later periods of the 
 year may be detected by the naked eye. It is from this cause 
 that the trunk of a tree displays, on a transverse section, as many 
 concentric rings as the tree is years old; and these are called 
 annual rings. 
 
 The cellular tissue existing between the vascular bundles and 
 their developing masses, and which ordinarily appear extended from 
 within outw.ards, are called medullary rays. Such extensions of the 
 cellular tissue are large when they reach from the pith to the bark, 
 and small when they begin or end in the wood. 
 
 The Cambium. When the growing parts of plants which form 
 and develope buds are examined, there will be found always present a 
 tissue which is only difficult of rcognition in its individuality. The 
 cells of this tissue, distended with assimilated mucilaginous granular 
 matter, contain young cells, cytoblasts, and often also superfluous nutri- 
 tionary matter, such as starch ; and are pressed by small narrow delicate 
 cells, so that it is very difficult in this tissue to distinguish its component 
 parts. Gradually, separate masses of cells, with a distinct and definite 
 outline, appear in this chaos, and they cease to partake of the process of 
 growth going on. At first the epidermis is separated, then the vascular 
 
FORM OF THE PLANT-CELL. 57 
 
 bundles, later the parenchyma, and at last there remains a portion of 
 cambium at the point of the stem (Punctum vegetationis, C. Fr. Wolff), 
 and externally to the vascular bundles. This last part has been more 
 especially characterised as cambium, but it does not differ from the other. 
 The cambium is not an unorganised mass, as was formerly supposed, but 
 in the vascular plants, at least, is always a cellular tissue containing cyto- 
 blasts, and, in a state of active vitality, forming new cells, a part of 
 which adheres in all its forms to the cellular tissue already formed, and 
 a part remains as cambium to carry on the process of growth. In this 
 cambium the following tissues originate : 
 
 The Vascular Bundles. A large series of observations prove that 
 the vessels, and to a certain extent the cells connected with them, cease 
 to exhibit the collective energy of cell-life sooner than the neighbouring 
 cells. They cease earlier to develope new cells, they pass sooner from 
 the condition of the general nutrition of the membrane into that of the 
 deposition of secondary layers, they consume quicker their assimilated 
 contents without forming new ones, and when the neighbouring cells 
 are first commencing their chemical activity they have either consumed 
 all their juices, or convey only air (the vessels) or a very homogeneous 
 indifferent sap (the young wood-cells). There are cells which pass 
 through all the stages of life quicker than the parenchyma-cells. In 
 this way all the phenomena may be easily and perfectly explained. The 
 parenchyma-cells form new cells when the vascular bundles have ceased 
 to do so. There will, therefore, be always present, in a longitudinal 
 mass, a larger number of parenchyma-cells than cells of the vascular 
 bundles ; the last are always much longer than the first. This antago- 
 nism is especially evident at the commencement of a vascular bundle, 
 at least at its sides, where its cells gradually pass into the parenchyma. 
 As the formation of the secondary layers is an important point in the 
 permanent development of cells, so the form of individual cells of the 
 vascular bundles depends on the period in which they originate. Several 
 kinds of vascular bundles are recognised. 
 
 1. In the higher Cryptogamia, the Ferns, Lycopodiacece, Equisetacece 
 (cryptogamic vascular plants), sometimes in aerial stems (less in the 
 creeping subterranean stems, and in the Equiseta generally), the entire 
 vascular bundle arises and is developed at the same time. In these 
 vascular bundles there is a great similarity of form ; and, as the stems of 
 these plants increase little in length after the formation of the vascular 
 bundles, almost the only kind of vessel seen is that with cleft-like pores.* 
 The Lycopodiacece have vessels with a very narrow spiral fibre ; the 
 Equisetacece f annular vessels, but with narrow rings.J 
 
 2. In the Phanerogamia a successive formation of vascular bundles 
 takes place. The parts next the axis are first developed from the cam- 
 bium, and the development extends gradually towards the periphery. 
 Then appear the parts belonging to the vascular bundles, but never 
 until the other portions have made considerable progress. From this 
 arises several important modifications of the vascular bundles. The 
 type of the deposit layer depends on the nature of the vessel at first. 
 Nearest the axis we find distant annular vessels ; following these, vessels 
 
 * Mohl de Structura Caudicis Filicum arborescent! um. Munich, 1833. 
 
 { They ought to he placed highest among the Cryptoyamia, according to my view. 
 
 j Bischoflf, Die kryptogamischen Gewachse. Niirub. 1828. 
 
58 
 
 ON THE PLANT-CELL. 
 
 46 
 
 with rings less distant ; then spiral vessels succeed, whose spires, al- 
 though far apart, are yet not so far apart as the rings of the annular 
 vessels ; then follow closely-wound spiral vessels ; then reticulated ; and 
 lastly, porous vessels. This course is observed although one or more of 
 these formations may be absent. So constant is this structure, that the 
 relative age of two vessels may be easily indicated by it. Thus in 
 monocotyledonous plants we often see porous vessels lying at the side, 
 or behind, the spiral and reticulated vessels, but they arise later than 
 the others, and this is shown by their configuration. 
 
 a. In Monocotyledons, a remarkable change takes place in the cam- 
 bium within a year of the first period of vegetation. At the commence- 
 ment the cells which contained cytoblasts lose them, and their place is 
 taken by a clear fluid, and all new formations cease, and the cells become 
 arranged in perpendicular rows, so that where from three to five cells 
 
 46 Simultaneous vascular bundles from the stem of Polypodium ramosum. A, Trans- 
 verse section. JB, Longitudinal section, through the smaller diameter of the vascular 
 bundle. The arrows show the direction from the centre to the periphery of the stem. 
 The thickened, somewhat lengthened, parenchyma which lies upon the vessels, surrounds 
 a thickened, very lengthened, parenchyma which represents the cambium in monoco- 
 tyledons. 
 
FORM OF THE PL ANT- CELL. 
 
 were heaped together, a row of stronger, thicker, and longer cells are 
 found (tig. 47.)-* 
 
 During this time the longitudinal parenchyma-cells belonging to the 
 vascular bundles, and which either surround them, or form a great bundle 
 both before and behind, have their walls strongly thickened, so that the 
 unchanged vascular bundles are rendered much more apparent in the 
 
 * See Mohl de Palmarum Structura, where there are many drawings of mono- 
 cotyledonous vascular bundles, but which do not express strongly enough the above 
 peculiarity. 
 
 47 Successive closed vascular bundles from the petiole of Musa sapientum, from a 
 horizontal wall between two air-passages near to the under surfaces of the petiole. 
 A, A transverse section. B, A longitudinal section of the same. The arrow denotes 
 the direction from the upper to the under surface of the petiole, a, The cambium 
 cells ( Vasa propria of Mohl). 
 
60 
 
 ON THE PLANT-CELL. 
 
 surrounding parenchyma (fig. 47.). Still, examples are very frequent in 
 which the vascular bundles pass into the surrounding parenchyma. 
 
 /3. In the earliest stages the vascular bundles of the Dicotyledons 
 cannot be distinguished from those of Monocotyledons. The difference 
 is first visible towards the close of the first period of vegetation. At 
 this period the aspect of the cambium is unchanged, its formative ac- 
 tivity continues, and new cells are deposited upon the vascular bundles. 
 The first part of the vascular bundle is formed under exactly the same 
 circumstances as in Monocotyledons, and exhibit precisely the same 
 appearances (fig. 48). From this point, however, the further development 
 
 is very different, for here it is important to observe that all longitudinal 
 extension of the parts of the plant ceases. When this takes place, the 
 new-formed cells frequently continue to extend, so that they have not 
 sufficient room ; and the consequence is, that the ends of the cells in a 
 horizontal layer press themselves between the ends of the cells which 
 lie above them and below them, and thus they all become pointed. In 
 all recently formed wood-cells it may be remarked that they are shorter 
 than the old cells, and their ends are rounded. The peculiar form of 
 the prosenchyma-cells is produced later. In the first part of the vascular 
 bundles no such cells are ever found ; the innermost are longitudinal 
 parenchyma-cells, and pass gradually outwards into the wood-cells. But 
 there are instances where no such extension of the recently formed cells 
 ever takes place, and then the entire wood consists only of parenchy- 
 matous cells, as, for instance, in Bombax pentandra, Carolinea minor, 
 and perhaps all Bombacece. In the later products of the formative acti- 
 vity of the cambium, a great difference in its growth is observed, 
 according as the cells are developed as wood-cells (prosenchyma) or as 
 they are uniformly or irregularly deposited. The simplest kinds of wood, 
 on the one side, are those in which all the cells are similarly developed, 
 and where no distinction between the cells and the so-called vessels 
 exists. Such wood is seen in the Coniferce and Cycadacece, consisting of 
 lengthened prosenchyma, like broad cells with from one to eight rows of 
 pores (fig. 49. A, B). 
 
 48 Successive unclosed vascular bundles from Vicia Faba ; a longitudinal section. 
 The arrow denotes the direction from the pith to the bark, a, Cambium cells. 
 
FORM OF THE PLANT-CELL. 
 
 A 49 
 
 61 
 
 The wood of the species ofMammillaria differs little from this. At first 
 sight it appears to consist of an entirely uniform tissue of somewhat ex- 
 tended cylindrical cells, which are distinguished by a most delicate spiral 
 band projecting far into the cell (fig. 50. B). By greater observation 
 upon longitudinal and transverse sections of the cells in which the spiral 
 
 50 
 
 fibres project less into the cells, it will be found that they are in com- 
 munication with one another, and allow air to pass through (fig. 50. A a, 
 B a). This is the simplest form of the so-called vessel. 
 
 In another way a simple kind of wood is formed in Carolinea minor. 
 It is extremely light and soft (like cork), and consists of regular paren- 
 chyma-cells, slightly elongated and somewhat porous, and of individual 
 rows of much broader and longer, cylindrical, and clearly porous cells 
 (called vessels), standing in open communication with one another. Very 
 similar to this is the wood of Bombax pentandra (figs. 51, 52.), where 
 we find, between the parenchymatous cells, individual, long, but tolerably 
 thin-walled, prosenchyma-cells (figs. 51, 52. b). From this to the ordinary 
 wood a transition is formed by some wood in my possession from the 
 
 49 A, Transverse section of the wood of Cycas revolvta. B, Longitudinal section of 
 the same, parallel to the medullary rays, a, Tn both figures, medullary ray cells. The 
 most elongated cells have upon their walls innumerable large pores. 
 
 50 A, Transverse section of the wood of Mammillaria quadrispina. B, Longitudinal 
 section of the same, parallel to the bark, a and c, Spirally formed plates inside the 
 cells : these cells contain only air. 6, Medullary ray cells. 
 
62 
 
 ON THE TLANT-CELL. 
 
 cover of a Chinese casket. At a cursory first glance the transverse sec- 
 tion (fig. 53.) appears to exhibit clearly defined annual rings. More ac- 
 curate research shows that the dark stripes which, as the most external 
 
 part of an annual ring, appear, are not connected, but form isolated 
 transverse bands between the two medullary rays. These transverse 
 
 51 Transverse section of the wood of Bombax pentandra. The entire wood consists ot 
 thin- walled but porous parenchyma (c), in which individual thick-walled wood-cells (t) 
 are scattered. Small medullary rays, consisting of individual rows of cells, pass through 
 the wood at pretty regular distances. In the under half of the section, the cell-walls 
 become imperceptibly thicker, by which the boundaries of the two annual rings are 
 clearly indicated. Single or in pairs, porous cells, lying on one another, pass through 
 the wood (c). 
 
 58 Longitudinal section of the same wood. a, Porous vessels, b, Wood-cells. 
 c, Parenchyma. 
 
 53 Transverse section of wood from a Chinese casket, with a low magnifying 
 power. At first sight, the dark transverse bands might be regarded as the boundaries 
 of the annual rings. They are not, however, connected together, and each extends 
 between the medullary rays. The small space marked at x is strongly magnified at 
 fig. 54., where it will be seen that the dark bands are formed out of small stripes of 
 wood-cells, which alternate with a thin-walled porous parenchyma (c). Between the 
 wood-cells and the medullary rays there exists also a layer of thin-walled parenchyma- 
 cells. Between the wood-cells may be observed radial rows of somewhat broader and 
 smaller thick-walled wood-cells. The thin-walled medullary ray cells (?) are also 
 porous. Fig. 55. is a longitudinal section, parallel to the medullary rays ; and the 
 letters a, b, c indicate the same parts as in fig. 54. Large porous vessels are seen in 
 fig. 53., which are not represented in the other figures. 
 
FORM OF THE PLANT-CELL. 
 
 63 
 
 bands consist exclusively of prosenchyma (figs. 54. a, 55. a), whilst the 
 wood between which they lie consists of very regular, not much ex- 
 tended, thin-walled, and porous parenchyma (figs. 54. c, 55. c). 
 
 The opposite of this is the extremely light and porous wood of the 
 various species ofAvicennia, which consists almost entirely of very broad 
 porous vessels, whose interstices are filled with small porous parenchyma- 
 cells (fig. 56.). 
 
 Lastly, the great mass of most wood consists of longitudinal, thick- 
 walled prosenchyma-cells, and, to a greater or less extent, of smaller 
 porous vessels (figs. 57, 58.). 
 
 From the foregoing remarks and observations it will be seen that what 
 are called vessels are unessential modifications of the cellular tissue, and 
 care should be taken that no erroneous impression be conveyed by the 
 once generally received term of " vascular bundles." Such bundles may 
 
 56 Transverse section of the wood of Avicennia. The wood consists entirely of very 
 broad porous vessels, together with very small thin-walled parenchymatous cells. 
 
 67 Transverse section of the very heavy and thick wood of Mahonia nepalensis. The 
 entire mass consists of very thick-walled wood-cells (c), and broad porous vessels (i). 
 The cells of the medullary rays (a) are very thick-walled, and scarcely to be distin- 
 guished from the wood-cells. 
 
 58 Longitudinal section of the same, a, b, c, correspond with fig. 55. d, the cut 
 cells of a large medullary ray. 
 
64 ON THE PLANT- CELL. 
 
 be seen without vessels in the longitudinal tissue of many Cryptogamia, 
 as in the Mosses, also amongst the P/ianerogamia, in Mayaca fluvia- 
 tilis, some species of Potamogeton, in jVajas, Caulinia, and Cerato- 
 phyllum ; in short, in all plants growing under water, or which are 
 nourished from their surface and not their roots. The term " vessel" has 
 misled botanists, and it is time that we should be apprised of the fact 
 that there is as much difference between the so-called vegetable vessels 
 and those of animals, as there is between vegetable and animal wings and 
 reproductive germs. The vessels of plants play but a very subordinate part 
 in the functions of vegetable life, and, so far from being special organs for 
 the circulation of the fluids of plants, they are themselves the last pro- 
 duced results of such movements of the sap, and the first parts to become 
 filled up and impervious to the admission of the juices circulating in the 
 plant. Vessels are often found wanting in entire plants, and the most 
 important parts of plants, as in the gemmules and filaments, whilst in 
 other plants closely related to these they are found present. These views 
 of the doctrine of the vascular bundles I first propounded in Wiegmann's 
 Archiv for 1839 (Bd. I. S. 220.).* 
 
 27. E. TISSUE OF THE LIBER ( Tela Jibrosa, Bastgewebe). 
 This is formed of cells so long that they cannot be regarded as cells 
 superimposed upon one another, but as fibres lying close to one 
 another. The walls of these cells are strong, often thickened so as to 
 exclude the transmission of light, without exhibiting a clear confi- 
 guration of the deposit layers. They are mostly soft and flexible. 
 These cells seldom present themselves individually in the pith and 
 the bark : they are more frequently seen in bundles (liber-bundles), 
 in the visible nerves (veins) of flat small leaves, in the projecting 
 angles of stems, and very frequently in the neighbourhood of the 
 vascular bundles on the external side of the cambium ; in the last 
 it is especially called liber. 
 
 F. LIBER CELLS of Apocynacea* and Asclepiadacece. These are 
 peculiarly long, seldom branched cells, with thickened walls, which 
 often exhibit very delicate spiral fibres crossing each other. In 
 some spots their cavity is entirely obliterated, whilst in others they 
 are swollen and vesicular, and contain a true milky juice. 
 
 G. MILK VESSELS ( Vasa lactescentiu), are longitudinal cells, 
 frequently branched in all directions. Sometimes their walls are 
 thin and homogeneous ; at other times, especially from age, they 
 are thickened by layers, and marked in a spiral manner (as in the 
 leafless JZuphorbiacece). They contain a colourless or variously 
 coloured milky juice. 
 
 There are few departments of botany that offer more unanswered 
 questions, and that demand greater research, than the subjects of the 
 three preceding paragraphs. 
 
 The fibres of the liber in the youngest parts of the bud in which they 
 can be seen are very short, almost spindle-shaped, cells, which lie with 
 their sharp ends pushed between each other, so that as the part to which 
 they belong increases in length, so do they increase also, but are brought 
 
 * This paper is also printed in Schleiden's Botanische Beitrage, vol. i. p. 29. ; and has 
 been translated in Taylor's Scientific Memoirs, and by the Sydenham Society. TRANS. 
 
FORM OF THE PLANT-CELL. 
 
 65 
 
 into closer contact, always pressing more and more upon each other, 
 until they are quite parallel. They probably originate in parenchyma- 
 tous cells, in the same way as prosenchyma. Between them and the 
 longitudinal parenchymatous cells, there are a number of transition 
 forms, and in many cases it is difficult to say to which form a particular 
 tissue may belong. Such intermediate forms are very frequent in mono- 
 cotyledons in the neighbourhood of vessels ; they are also seen in dico- 
 
 60 
 
 tyledons, as in some of the Cactacece (fig. 59.). As they approach the 
 character of shorter cells, the configuration of the walls, with pores or 
 sharply defined layers, is evident (figs. 60, 61.). 
 
 If we regard the pointing at both ends and the thickness of the de- 
 posit layers as essential characters of liber-cells, then the branched cells 
 discovered by me* in the ovary of some Aroidece (in Monstera and 
 Scindapsus), and in the pith of Rhizophora Mangle (fig. 63.), belong 
 to them. 
 
 Ordinarily the liber-cells are so long, that the whole of them cannot be 
 seen by a strong magnifying power (fig. 62.), and, next to the cells of 
 some species of C/iara and the pollen tubes of some plants, are the longest 
 cells which present themselves in the vegetable kingdom. I have mea- 
 sured liber-cells from 4 to 5" in length, but these are probably not the 
 
 * Wiegmann's Archiv, 1839, vol. i. p. 231.; Schleiden, Botanisehe Beitrage, vol. i. 
 p. 42. 
 
 59 An intermediate form between liber- and parenchyma-cells (a), from the bark of 
 the root of Maxillaria atropurpnrea. 
 
 50 A liber-fibre, short, thick, and porous, from the China regia. 
 
 61 Transverse section of three liber-fibres and some parenchyma-cells from the China 
 regia (Cinchona scrobiculata Humb. Yellow Bark.) The liber-cells show beautifully 
 the deposit-layers and the porous canals. 
 
 52 Upper end of a liber-fibre from the Tilia europcca. 
 
 83 A branched liber-cell from the pith of Rhizophora Mangle. 
 
66 
 
 ON THE PLANT-CELL. 
 
 longest. The branched liber-cells (fig. 63.), on account of their branch- 
 ing, are included in the following forms. 
 
 Upon the origin of the liber -cells of Apocynacece and Asclepiadacece no 
 observations have been made : only thus much is certain, that they fre- 
 quently contain milky juice. They are found singly, or in little bundles, 
 near to, or in the place of, the liber-bundles ; and are sometimes branched, 
 ex. gr., in Hoya carnosa (according to Meyen), and very beautiful in Sar- 
 costemma viminale. The configuration of their walls is entirely the same 
 as in old milk-vessels. 
 
 The Milk-vessels, in relation to their origin, have been at present but 
 little examined. They appear at first as enlarged intercellular passages, 
 
 64 
 
 65 
 
 and without any visible membrane (fig. 65.) to form them. Nor does any 
 membrane appear to exist over the furrow formed by two neighbouring 
 cells, as it does in all true cells, In old vessels, also, we often find impres- 
 sions and projecting angles, showing that they must have fitted accurately 
 into the surrounding cells (66. A, B). They are mostly branched in so 
 compound a manner, that it is not often possible to examine a cell in its 
 entire length (fig. 67.), yet it is easy to separate it into its parts if the tissue 
 is treated with nitric acid. "Without this means it is easily seen that they 
 
 64 Intermediate formation between liber-cells and milk-vessels from the bark of Cero- 
 pegia dichotoma. The spiral stripes are drawn only in one half. 
 
 65 Milk-vessels from the leaves of Limnocharis Humboldti. The walls of the upper 
 part of the vessel at a are fallen together. The arrows show the direction of the cur- 
 rents. Every milk-vessel is enclosed by two rows of smaller and longer cells of 
 parenchyma. 
 
FORM OF THE PLANT-CELL, 
 
 67 
 
 66 
 
 extend through the entire length of a plant, and often end in a cul de sac. 
 This is so obvious in some forms of leafless Euphorbiacece, that it is 
 wonderful how any difference of opinion could have existed on the point. 
 In the older vessels, also seen well in the leafless EuphorbiacecB, the 
 spiral bands and the deposit-layers on the walls are easily distinguished, 
 so that the lateral development of these organs agrees entirely with that 
 of cells. 
 
 In their relation to one another, these three forms of tissue, as well as 
 the receptacles of milk without proper walls, seem mutually to represent 
 each other. They are seen before the vascular bundles of the stem, as 
 receptacles of milk in Mammillaria, as liber in Cereus, as transitionary 
 forms in the Apocynacece and Asclepiadacece, which in some species 
 resemble liber-cells, whilst in others, as in Sarcostemma viminale, they 
 are not to be distinguished from milk-vessels. 
 
 History and Criticism. The liber and the milk vessels were known 
 to the earliest observers. The proper walls of the last were first seen 
 by Mirbel, but more accurately observed by Schultz, whose observa- 
 tions, overloaded by false theory and hasty inferences, have led to this 
 principal result, that a large proportion of the milk -vessels do really 
 possess a peculiar covering.* His theory of their origin, founded on 
 insufficient observation, has become now quite antiquated. linger 
 
 Natur der lebenden 
 
 * Ueber Circulation des Saftes im Schollkraut. Berlin, 1821. 
 Pflanze. Berlin, 1832. 
 
 66 A, A transverse section of a thickened milk -vessel from the bark of the stem of 
 Euphorbia ccerulescens, with the walls of the same lying upon the cells. B, A longi- 
 tudinal section of the same, isolated through maceration. The sides of the vessel are 
 irregular, from being pressed into the surrounding cells. 
 
 67 Longitudinal section from the rind of Euphorbia trigona, parallel to the medullary 
 rays. Many of the vessels branch arid anastomose, whilst others end in blind extremi- 
 ties. Irregularly formed starch granules are seen in their interior. 
 
 F 2 
 
68 ON THE PLANT-CELL. 
 
 thinks they originate from the union of rows of cells, but accurate ob- 
 servations do not support this view. Mirbel was the first to discover the 
 liber-cells.* Meyen, in his Physiology of Plants (vol. i. p. 107.), appro- 
 priates to himself their discovery, but does not say where his observations 
 on that subject are to be found. Mohl f first examined the liber-cells 
 with care. Upon the origin of the liber-cells Meyen has set forth a 
 peculiar view.J He believes them to originate in the union of rows of 
 parenchymatous cells. This view is founded upon erroneous observations 
 on the appearance of the liber-cells in the buds of dEsculus. 
 
 28. H. FIBROUS TISSUE (Tela 68 
 
 contexta) consists of very long, thin, 
 fibrilliform cells, intimately woven 
 and variously mixed with each other. 
 It is of two kinds. 
 
 a. It exists in the Fungi as a soft, 
 almost sebaceous, and easily destruc- 
 tible cellular tissue. 
 
 b. In Lichens as a dry, tender, 
 fibrous tissue, formed out of forked 
 and branched cells (fig. 68.). 
 
 29. /. EPIDERMAL TISSUE ( Tela epidermoidea), is univer- 
 sally the most external layer of cells of a plant, so far as they can 
 be distinguished from the cells they cover, by their form and con- 
 tents. They only exist in the higher Cryptogamic and in nearly all 
 the Phanerogamic plants. 
 
 It may be distinguished into, 
 
 a. The Epidermis, a continuous layer of cells, which may be 
 again divided into three kinds, according to the medium in which 
 it is developed. 
 
 1. Epithelium. Exceedingly delicate, homogeneous, transparent 
 cells, filled with colourless juices, and covering the surface without 
 forming intercellular passages. It is always present in the growing 
 parts of plants, and remains longest in closed cavities, as in the 
 ovary, but changes mostly into one or other of the following 
 forms : 
 
 2. Epiblema, consisting of compact cells flattened outwards, though 
 not so at first, and without intercellular passages opening exter- 
 nally. They are developed in the water and in the earth. 
 
 3. True Epidermis. It consists of very flat tabular cells, whose 
 walls laterally and outwardly are usually very compact. They are 
 generally placed close to each other; but in most plants there 
 
 * Annales des Sciences Naturelles, 1835. 
 
 f Erliiuterung meiner Ansicht iiber Structur der Pflanzcnsubstanz. Tubingen, 
 1836. 
 
 | Wiegmann's Archiv, 1839. 
 
 The English reader must not confound this with woody fibre, as this term has been 
 sometimes thus used by British botanists TRANS. 
 
 68 Fibrous tissue from the inner portion of Cetraria islandica, from a section parallel 
 to its surface. 
 
FORM OF THE PLANT-CELL. 69 
 
 exists, at particular points, an intercellular passage, which, through 
 the other intercellular passages and spaces, enables the subjacent 
 parenchyma to communicate freely with the external air. At the 
 inner opening of these intercellular passages, are placed (except in 
 Salvinia and Marchantia) two semi-lunar parenchyma-cells, with 
 their concave edges turned towards each other, which, according to 
 the amount of their turgescence, allow a greater or less space to 
 exist between them, or close the intercellular passage up alto- 
 gether. These two cells, with the intercellular openings, are called 
 stomates (stoma). 
 
 b. Appendicular Organs. They are all found upon the surface 
 of plants, and are formed from cells. They are : 
 
 1. Papilla, which are mere extensions of the external cell-wall, 
 in the form of little elevations, as upon the petals of flowers; or -as 
 vesicles, as in Mesembryanthemum crystallinum; or as apparent 
 hairs, as the so-called root-hairs. 
 
 2. Hairs (Pili) consist of one or more thin- walled cells, varied 
 in their form and arrangement, and planted upon the epidermis. 
 They are simple (pili simplices), branched (p. ramosi), stellate (p. 
 stellati), scales (lepides), knobbed (p. capitati), glandular (jp.glandu- 
 liferi) if the upper cells secrete a peculiar fluid. 
 
 3. Setce, stiff, thick- walled, pricking cells. 
 
 4. Stings (Pili urentes) are stiff, thick-walled cells, terminating 
 either in a point or a little head turned on one side, and mostly 
 containing an irritating secretion. The cells at the base are often 
 thin-walled, club-shaped, and swollen, and the whole enclosed by a 
 number of wart -like cells produced from the epidermis. 
 
 5. Thorns (Aculei) consist of numerous rigid, thick-walled cells, 
 firmly bound together, and terminating in a sharp point. 
 
 6. Warts ( Verrucce), formed out of many compact semicircular 
 and variously formed cells. 
 
 c. Cork (Suber). In the cells of the epidermis there is often 
 collected a grumous substance, from which are developed flat 
 tabular cells. The epidermis bursts, and thus is formed what is 
 popularly called " bark," or, where it is strongly developed and 
 elastic, " cork," as in juicy fruits, but especially in the second year's 
 stems of the Quercus Suber. 
 
 d. Root Sheath ( Velamen radicum). In most tropical Orchi- 
 y and some Aroidecs, there exists upon the epidermis of the 
 
 roots (the adventitious roots) a layer which is ordinarily composed 
 of the most delicate cellular tissue, whose contents are entirely air. 
 
 The controversy about the nature of the epidermis was only possible 
 at a time when the conception of the elementary structure of plants was 
 of a very imperfect kind, and a false analogy with the epidermis of ani- 
 mals led to erroneous conclusions. 
 
 "When a part is about to be formed from the cambium in phaneroga- 
 mic plants, the first thing that meets our view is a layer of one or more 
 series of delicate cells, which are homogeneous and contain a clear fluid, 
 
 F 3 
 
70 
 
 ON THE PLANT-CELL. 
 
 and which form the external boundary and cover over the developing part. 
 These cells of various signification I call Epithelium (fig. 69. a). The 
 
 69 
 
 70 
 
 same thing may be observed in the so-called vascular cryptogamic plants 
 (Ferns, Lycopodiacece, Equisetacece, Rhizocarpeai). It is also seen in 
 the MarchantiacecB. This epithelium differs according to the external 
 
 influences which act upon it. It is 
 71 only in a few cases that the epithelium 
 
 retains its true character for any length 
 of time, as in the cavities of the ovary. 
 In the air, in water, or in the earth, it 
 becomes changed more or less, the cells 
 become more compact, and their ex- 
 ternal surface flattened (fig. 70. a) in the 
 air, so that most epidermis-cells have 
 a tabular or ligulate form (fig. 71. a). 
 The forms which these tissues assume are very numerous. In the 
 more delicate forms of these external coverings, as seen in the petals of 
 some plants, individual cells elevate themselves above the surface (fig. 
 72. a), and thus form a transition to the simple forms of hairs. 
 
 7:* 
 
 72 
 
 In other petals they are much more compact, and very much elongated 
 from within outwards (fig. 73. a). The extreme of these two conditions 
 occurs in the epidermis of some seeds, especially in those of the Legumi- 
 nosce. Here the cells are often long, cylindrical, extended from within 
 outwards, and often entirely filled up at particular points (fig. 74. a). 
 
 69 Epithelium (a) from the gemmules of Tradescantia crassula, with a layer of 
 parenchyma-cells lying under it. 
 
 70 Epiblema (a) from the root of Spirodela polyrrhiza, lying over a layer of paren- 
 chyma-cells. 
 
 71 Epidermis (a) from the upper surface of the leaf of Tradescantia discolor, with the 
 parenchyma beneath. 
 
 " Papillary epidermis (a) from the under surface of the petals of Iris variegata, 
 accompanying the underlying parenchyma. 
 
 73 Epidermis (a) of the under surface of the petals of the white rose. The external 
 surface is beset with delicate furrows (aciculatus). Loose parenchyma underneath the 
 epidermis. 
 
FORM OF THE PLANT-CELL. 
 
 71 
 
 The gradual development of these external cells is attended with an 
 irregular nourishment of their lateral walls, whereby round or pointed 
 projections are formed, which are received into the concavities of the 
 surrounding cells, so that a waving line appears. This causes a great 
 variety in the appearance of the cells, according to the number of the 
 individual cells, the size of the wavy bulgings, and the roundness or 
 sharpness of their projections (fig. 75.). These cells are distinguished from 
 those lying under them, by the presence of a transparent colourless or 
 coloured fluid, but never, as has been erroneously stated, by containing 
 air. The configuration of the cell-walls of the epidermis is very varied. 
 A common phenomenon is, that their walls are, above and laterally, 
 thicker than they are at the lower part, where they lie upon the paren- 
 chyma (figs. 68, 69.), as seen in the seeds of the Asparagus offlcinalis. 
 Spiral formations abound in it, both with jelly in the seeds of Hydrocharis 
 Morsus ranee, and without jelly in the peri cap of Salvia verticillata.* The 
 epidermis-cells are frequently porous, sometimes on the side where 
 they touch each other, as in the leaves of Epidendrum elongatum ; or 
 where they touch the parenchyma-cells, as in the stem of Melocactus; 
 they are least frequent externally, but this form presents itself in the 
 
 leaves of Abies. In these leaves 
 every one of the thick-walled ex- 
 ternal cells possesses three or four 
 rows of porous canals, which run 
 externally, and terminate in a small 
 round cavity. The same thing is 
 seen in Cycas (fig. 76.). The cells 
 of the epithelium are placed so 
 close to one another, that no inter- 
 cellular passages are found opening 
 between them. When epithelium is converted into epidermis in the 
 air, it happens that the cells soften at their margins, and thus form inter- 
 
 * Schleiden, Beitrage zur Phylogenesis, Miiller's Archiv, 1838. See Taylor's 
 Scientific Memoirs. 
 
 74 Epidermis (a) of the seed of Lupinus rivularis, composed of long, very much 
 thickened, cells. Under these is a layer of entirely separate cells, and beneath them 
 parenchyma. 
 
 75 Epidermis of the nectary of Goldfussia anisophylla. The cells are exceedingly 
 flat and irregular. Section parallel with surface. 
 
 r6 Perpendicular section of the surface of a leaf of Cycas revoluta. The epidermis- 
 cells (6) are laterally and externally porous. They are covered above by a layer of 
 secreted matter (a). 
 
72 
 
 ON THE PLANT-CELL. 
 
 77 
 
 cellular passages, either generally, as in 
 Salvinia (fig. 77.), or in particular spots, 
 as in other plants (fig. 78.). Sometimes 
 they occur in groups, whilst the re- 
 maining epidermis is free from inter- 
 cellular passages, as in Saxifraga sar- 
 mentosa ; and sometimes, in special, ex- 
 cavated pits, surrounded and concealed 
 
 by hairs, as in Nerium Oleander, and species of Bariksia and Dryandra 
 (figs. 79, 80.). This intercellular passage during its growth is entirely 
 
 79 
 
 
 a 
 
 closed towards the inner part of the leaf by a simple cell. In the course of 
 further development two new cells are formed in this cell, which is 
 subsequently absorbed, and the two new cells gradually assume a semi- 
 lunar form, the concave sides of which, being presented to each other, 
 form an opening between them, through which a communication is 
 
 77 Epidermis of the upper surface of the leaf of Salvinia natans. Here may be 
 seen the simplest form of stomates, as intercellular passages between the epidermal 
 cells. 
 
 !S Epidermis peeled off from an AJlium, with four stomates. 
 
 r9 Transverse section through the leaf of a Banksia. a, a, Epidermis, under which 
 lies, on both sides, a layer of transparent cells, c, Spongy cellular tissue, d, Stretched 
 cellular tissue of the upper half of the leaf; to the right and left, bundles of liber trans- 
 versely cut through, b, A transverse section through one of the little pits of the 
 under part of the leaf, which are clothed with hairs, and at whose base peculiar stomates 
 (e) are found. 
 
FORM OF THE PLANT- CELL. 
 
 8) 
 
 73 
 
 formed with the intercellular passage in the parenchyma. These semi- 
 lunar cells are not found in Salvinia, nor in Marchantiacece*, but are 
 found doubled and trebled in some Proteacece.\ 
 
 In the arrangement of the parts of these organs many varieties are 
 found, especially in the relation of the stomatic cells with the intercellular 
 passage, and the arrangement of the epidermal cells forming the inter- 
 
 cellular passage ; these peculiarities distinguish families and genera, as 
 in the Cactacece, the Grasses, Aloe, Tradescantia, &c. The stomatic 
 cells may be pushed somewhat outwards with their edges above the 
 epidermal cells, or they may lie upon the same plane (fig. 81.), or they 
 may lie entirely under the edge of the cells of the epidermis (fig. 82.). 
 With regard to the second form here mentioned, we frequently see the 
 cells lying next to the intercellular passage coloured differently, and 
 
 * In these plants the intercellular space ordinarily found under the stomates is beset 
 with peculiar flask-shaped papillary cells. 
 
 f See Mohl, Ueber die Spaltoffhungen der Proteacese, in N. A. A. L. C. N. C. 
 t. xvi. p. 2. 
 
 80 A parallel section of the under surface of the leaf of a Banksia, from which 
 the epidermis is removed, x, The vascular bundles forming the network of the leaf. 
 a, b b, Three little pits, which vary in appearance according as the section by which the 
 epidermis was removed, cut deeply or superficially. The lower b, A pit with the hairs 
 and stomates at the base : a exhibits the base of the pit, with the stomates ; b exhibits 
 the same, but the spongy cellular tissue is seen below, o, The epidermis clothing the 
 base of the pit is removed, leaving nothing but the spongy cellular tissue. 
 
 81 Perpendicular section through the epidermal tissue of the leaf of a Stock, c, The 
 epidermal cells covered with a layer of secretion (6), which, at the most external parts, is 
 formed out of a more compact layer, a, Entrance to the stomate through the secreted 
 layer. 
 
74 
 
 ON THE PLANT-CELL. 
 
 flatter, and the intercellular passage itself formed of a larger or smaller 
 number of cells. In the Marchantia four cells are usually found ; in 
 
 83 
 
 8-1 
 
 Cycas, and at the base of the leaves of Nelumbium (fig. 85.), a much 
 greater number. In most cases the epidermal cells lie on the same plane 
 with the others, but in Cycas and Marchantia they are elevated so as 
 to form a semicircular wart open at the point. In some instances a 
 kind of stunting takes place, which, in the leaves of Opuntice, is almost 
 normal. In this case, from three to five semi -lunar cells are pressed irre- 
 gularly one upon another. 
 
 The contents of the stomatic cells, without exception, resemble those 
 of the adjacent parenchyma, seldom or never those of the epidermal cells 
 (figs. 83, 84.). I know of only a few cases, as Agave lurida, Aloe nigri- 
 
 83 Perpendicular section of the surface of the leaf of Hakea amplexifolia. The 
 stomate forms a large cavity, the bottom of which is closed on every side by two cells, 
 which embrace between them the two special stomatic cells. The loose parenchyma 
 contains many oddly-formed cells. 
 
 83 Epidermis from the under surface of the leaves of Tradescantia discolor. The 
 hatched cells contain a dark-red fluid. The two stomatic cells are surrounded by four 
 regular cells, with perfectly clear contents. 
 
 84 A perpendicular section of the surface of the above, in the direction a- b. The 
 epidermal cells, filled with red sap, present a vacant space, which is closed externally by 
 the flat clear cells, and the stomatic cells filled with chlorophyll. 
 
FORM OF THE PLANT-CELL. 
 
 75 
 
 cans (fig. 86.), and some others, where remarkable substances, such as 
 oil or resin, are present. 
 
 The epidermis of the roots of tropical Orchidece and Aroidece exhibit 
 some very anomalous phenomena. In these cases the stomates lie upon 
 the epidermis, and do not belong to the parenchyma of the bark, but to 
 the root-sheath. The most regular and ordinary form of these internal 
 stomates are seen in Pathos crassinervis, the most complicated and 
 irregular in Aerides odoratum, and in various others they are more or less 
 evident. 
 
 History and Criticism. A knowledge of the functions and structure 
 of the epidermal tissues depends upon accurate observation, which the 
 author of this work was almost the only one to make during the present 
 century. Much misunderstanding has, however, prevailed, and many bad 
 observations have been made. The most important co-workers on this 
 subject have been Krocker, father* and sonf, TreviranusJ, Meyen, 
 Brongniart||, linger.)., and Mohl^f. The view of Brongniart, that the 
 epidermis is a delicate structureless membrane, will be mentioned pre- 
 sently ( 69.). Recently, some botanists instead of using the term stomates 
 have employed the expression skin-glands (Haut-driisen), thus unneces- 
 
 * De Plantarum Epidermide. Halae, 1800. 
 
 f De Plantarum Epidermide. Breslau, 1833. 
 
 { Beitrage zur Pflanzenphysiologie. Gottingen, 1811. 
 
 Phytotomie, s. 67. || Annales des Sciences Nat. vol. xxi. 
 
 | Die Exantheme der Pflanzen. Wien, 1 833. 
 
 f Ueber die Spaltoffnungen der Proteacea?, N. A. A. L. C. N. C. t. xvi. p. 2. 
 
 85 Epidermis from the midst of the upper leaves of Nelumbium speciosiim, with a 
 stomate. The cells of the epidermis are elevated in the midst into a papilla, which, 
 seen from the surface, appears like a ring. The stomate itself is formed of nine cells 
 of epidermis, and under it lie two stomatic cells of the usual semilunar form. B is a 
 perpendicular section of the same. 
 
 86 A perpendicular section of the surface of the leaf of Aloe nigricans. a, Canal of 
 the stomate, filled with orange-coloured granules of resin, b, Cavity under the stomate 
 lined with cells, which contain granules of chlorophyll and resin. The papillose epi- 
 dermal cells are filled with clear or dark-red sap, and rose-coloured granules of resin. 
 Of the two stomatic cells, one contains chlorophyll, the other a large bright-yellow 
 granule of resin, c, Secretion of the epidermis. 
 
76 
 
 ON THE PLANT-CELL. 
 
 
 sarilj playing with words. From a long series of researches I have 
 come to the conclusion, that in at least two thirds of the whole vegetable 
 kingdom the function of the two semi-lunar cells of stomates is no 
 way different from the ordinary cells of the leaf. That in the other 
 cases these cells act as glands, I do not at all believe. 
 
 Appendicular Organs. Although the epidermal cells are universally 
 the first in which the process of growth ceases, yet it often continues in 
 particular spots. The most simple form 
 is the mere extension of the external 
 cell-wall into longer or shorter papillae, 
 which give to petals their peculiar as- 
 pect, and roots their hairy appearance 
 (fig 87.). Frequently these papillary 
 growths exist only at particular spots, 
 and the papillaa develop from two to five cells, which at first are round, 
 but afterwards become extended, and thus form a cellular upright hair 
 of the epidermis (fig. 88.). This is the general way in which hairs are 
 
 
 87 Papillary epidermis from the under surface of the petals of Iris variegata, with 
 underlying cells of parenchyma. 
 
 88 c, Epidermis, with simple hairs, from the stem of an (Enothera. a, Club-shaped 
 hair, b, Pointed hair. 
 
 89 Part of the epidermis of the leaf of Helleborus faetidus, with two hairs. Every hair (a) 
 is swollen and club-shaped above, and appears to contain a poisonous secretion. The hair 
 becomes gradually empty, and falls in, as seen at b. 
 
 90 Stellate hair of Alyssnm rostratum. a, Its point of attachment. 
 
 91 c, Epidermis, and d, the parenchyma, of Alte.rnantlie.ra axillaris, with a single hair. 
 This consists of a series of flat cells at the base (6), and a multiform thick-walled coll 
 above, a, Spot where a branch of the cell has been removed. 
 
FORM OF THE PLANT-CELL. 
 
 77 
 
 developed, but further special researches are needed. Frequently a hair 
 consisting of a single cell is developed into manifold forms, sometimes 
 swelling into a knot (figs. 88, 89.); at other times forming numerous 
 branches (fig. 90.), as, for instance, in the hairs of some species of 
 Malpighia and Rhamnus, in which the branches of the hair extend in 
 two opposite directions, and are pressed flat upon the surface of the 
 epidermis ; and also in the remarkable four-armed pair of cells in 
 the vessels of Utricularia. These at first consist of two round cells 
 lying close to one another; they then form two short pedicels, which 
 swell and form a little head, each of which sends out two arms, a long 
 one and a short one. 
 
 In most cases, several cells go to form a hair. In this case the 
 branches often consist of cells (fig. 91.). Amongst compound hairs those 
 bearing knobs are very frequent. The pedicel either consists of a 
 single cell, or a row of cells (fig. 92. b\ or several cells. The same 
 
 thing occurs in the structure of the knob, which is often green, or 
 coloured, or contains a peculiar secretion.* Sometimes hairs exhibit 
 in the interior spiral vessels, as in Drosera. The most remarkable 
 
 * I cannot entertain the notion of a gland in the vegetable kingdom ; so that here, as 
 elsewhere, I make no distinction. 
 
 9i Lateral view of a portion of the epidermis of the Wigandia wrens, with two hairs : 
 a is a stinging hair, with a knob, and circulating fluid in the interior ; 6, a club-shaped 
 glandular hair. Every one of the simple cylindrical cells, which, placed one upon the 
 other, form the stalk, exhibit a cytoblast and circulation. The knob, formed out of 
 many little cells, is covered with secreted resin. The arrows show the direction of the 
 streams. 
 
 93 A prickle-hair from the leaf of Dipsacut fullonum. It consists of a long, some- 
 what bent cell, thickened by layers (a), which is embraced at the base by an elevated 
 mass of porous epidermis-cells. 
 
78 ON THE PLANT-CELL. 
 
 of the epidermal processes are the stinging hairs. They constitute 
 the type of a very common form of the epidermal tissue, in which a 
 few wart-like cells are elevated above the surface, and embrace the base 
 of a single elongated cell (figs. 92, 93. a). 
 
 Such hairs, very much thickened and distinguished by the porosity 
 of the epidermal cells, are seen in Dipsacus (fig. 93.); ordinarily 
 the lower cells of such hairs are swollen, with thin walls, whilst those 
 above are pointed and thick-walled. They are frequently marked on 
 the upper surface with little warts spirally arranged, and with elevated 
 stripes. This form characterises the Urticacece, the Boraginacece, the 
 Cucurbitacece, and the Loasacece. The mechanism also of the stinging 
 hairs in Urtica, Wigandia urens, and the Loasacece, is very interesting. 
 Almost all stinging hairs end in a little knob-shaped swelling, which 
 is exceedingly brittle, and easily knocked off by a touch. The opened 
 point, on being pressed against, exudes the secretions contained in the 
 cells at the base of the hair, and will produce poisonous effects when 
 introduced into animal tissues. Our indigenous nettles are the least 
 injurious. The stings of the Loasacece are much more so, while the Urtica 
 crenata and crenulata of the East Indies produce wounds in which 
 pain is felt for weeks and months after touching them. The most dan- 
 gerous of all is the Urtica urentissima of Blume, called in Timor Daoun 
 setan, and by the English " Devil's leaf." The wounds of this plant give 
 pain for years after, especially in damp weather, and occasionally death 
 from tetanus is the result. Could we separate this poison, it would be 
 the most powerful vegetable poison known. 
 
 In the early stages of growth these hairs, all of them, possess an active 
 circulation of the sap. Some hairs have their contents absorbed at a 
 special time, so that the hair is, as it were, absorbed into its own proper 
 cavity. This remarkable phenomenon 
 takes place in the hairs of the style in 
 Campanulacece* (fig. 94.). Also in the 
 globular cells of knob-shaped hairs, which 
 then look as if half had been cut through, 
 or as if a cover had been removed.f 
 Meyen has published a work on hairs, 
 distinguished by a host of peculiarities.^ 
 
 Cork. A peculiar change goes on in 
 the epidermal cells of particular parts, 
 
 more especially the stem and fruits of Jf&l x^nJJ 15""") 
 
 certain trees. A quantity of yellow slimy 
 matter collects in the cells and gradually 
 increases in quantity, so that the external 
 cell-wall is torn by the under one and lifted 
 above the surface. Cells are formed in 
 a hitherto undiscovered manner in the 
 
 yellow substance, which assume the form of four- cornered tables, and are 
 arranged in connected concentric layers. When perfectly formed, this 
 
 * See Brongniart, Ann. de Sc. Nat., 1839, p. 244. 
 
 f According to Meyen; but it is erroneous. 
 
 j Ueber die Secretionsorgane der Pflanzen. Berlin, 1837. 
 
 94 Longitudinal section through the style of a Campanula, with two hairs : a, a hair 
 exhibiting a circulation ; its point is enclosed in a layer of mucus : b has lost its con- 
 tents, and is in consequence contracted. 
 
FORM OF THE PLANT-CELL. 79 
 
 tissue exhibits great elasticity, and the tissue known by the name of cork 
 belongs to this form. It exists, however, in countless other forms, and 
 its existence seems detetermined by the presence of an epidermis which 
 vegetates for a longer period than is usual. When the process of cork- 
 formation once commences, it goes on ; but should the layer be thrown off 
 the tree at any particular stage of its growth, it is not again engendered, 
 as, for instance, in the vine and the Clematis Vitalba. Mohl * was the 
 first who accurately examined this subject, and I have sought to explain 
 its origin, f 
 
 Root-sheaths. If the organs of Pathos crassinervis, called aerial-roots, 
 are examined, there will be found a distinct epidermis, with stomates whose 
 semilunar cells, filled with a brown granular matter, are elevated above 
 the surface of the epidermis, and form a special tissue whose walls exhibit 
 the most delicate spiral fibres. These cells are filled with air, and thus 
 give the brilliant white appearance to these roots. How this layer origi- 
 nates is not very clear, but it is formed in the same way at the points of 
 the roots as in the other parts. The same layer is found on the roots of 
 most tropical Orchidacece, and the cell-walls exhibit in them the most 
 striking modifications. It is very remarkable in Aerides odoratum. I have 
 seen it in Epidendrum elongatum, Cattleya Forbesii, Brassavola cordafa, 
 Maxillaria atropurpurea, M* Harrisonii, Acropera Loddigesii, Cyrto- 
 podium speciosissimum, Oncidiunt altissimum, and other species. I also 
 found it, but without spiral fibres, in Pothos reflexa, acaulis, violacea, 
 cordata, longifolia, and digitata. In other families I have not seen it. 
 The roots have ordinarily a fresh green point ; in these the cells are full 
 of sap, and the green cortical parenchyma is seen through them. The 
 relations of this layer differ so much from those of the epidermal cells, 
 that it has been regarded as a peculiar tissue. Link J first discovered 
 this layer, Meyen examined it more accurately, but no one has correctly 
 appreciated it. 
 
 * Ueber die Entwickelung des Korkes und der Borke. Tub. 1836. 
 f Beitrage zur Anatomie und Physiologie der Cacteen. 
 \ Elem. Phil. Bot. Ed. i. p. 393. 
 
 Physiologie, i. p. 47. Meyen, copying Link, says that Dutrochet has examined 
 this tissue ; but this is a mistake. 
 
80 ON THE PLANT-CELL. 
 
 CHAPTEE II. 
 
 ON THE LIFE OF THE PLANT-CELL. 
 
 SECTION I. 
 
 FUNCTIONS OF THE INDIVIDUAL CELL. 
 
 30. ALL the chemical and physical powers of the earth naturally 
 act upon the plant-cell. Inasmuch as these striking phenomena are 
 called forth, and especially as they exhibit, in and through the cell 
 itself, an especial form of action, I call all such action the life (vita) 
 of the cell. Most of the physical powers of nature are too little 
 known for us to be able to comprehend the peculiarities which they 
 exhibit under especial relations. We can only say generally that 
 the various chemical processes which take place in the cell must 
 be accompanied by changes of temperature, electricity, absolute 
 and specific gravity, &c., without being able to count or measure 
 the same. There are, therefore, only a few relations which permit 
 of a more accurate estimation, as the absorption of foreign agents 
 (endosmosis), the decomposition and recomposition of the same (as- 
 similation and secretion), the getting rid of superfluous matter 
 (exhalation and excretion), the working up of the assimilated 
 matter (organisation), the movements of the contents of the cell 
 (circulation), the movement of the whole cell (locomotion), the 
 formation of new cells within the old ones (propagation), and the 
 cessation of all these processes (death). 
 
 I. On the Absorption of Foreign Agents. 
 
 31. The cell-membrane (in its young state) is perfectly closed, 
 but permeable to all fluids. It thus takes up all perfect solutions 
 through its walls into its cavity. In consequence of the chemical 
 change going on in its interior, the cell constantly contains a fluid 
 thicker than water, or dilute solutions of saline substances, and 
 mostly one which, like a solution of sugar or gum, has so great an 
 affinity for water, that they draw water into the cavity with a cer- 
 tain degree of force, and, on the other hand, a small quantity of the 
 concentrated fluid passes out of the cell. The passing in of the 
 fluid into the cell has been called by Dutrochet endosmose, and its 
 passing out exosmose. 
 
 The property which cellulose possesses of allowing fluids to pass 
 through it has already been mentioned. It is an entirely superfluous 
 
LIFE OF THE PLANT-CELL. 81 
 
 and gratuitous hypothesis to suppose that it possesses invisible pores, or 
 that the membrane stands in the same relation to fluid as salts to water. 
 In the latter case, the water is supposed to dissolve up a little of the mem- 
 brane, which, in passing through, it yields up again. The passing of the 
 fluid through the membrane is produced by the relation of water to certain 
 other substances contained in the cell. If gum or sugar is dissolved in 
 a small quantity of water, and pure water is poured carefully over the 
 solution, the two liquids remain apparently for a short time unmixed, but 
 at the edges where the fluids meet a process goes on, in which the two 
 fluids pass one into the other until the whole is completely mixed. If the 
 two fluids are separated by a vegetable or animal membrane, the attraction 
 is not diminished, because both fluids penetrate the membrane and thus 
 come in contact, but the thicker fluid passes through the membrane with 
 more difficulty than the thinner. Thus a larger quantity of the thin fluid, 
 in the same time, is found present with the thicker than of the thicker with 
 the thinner. The experiment may be performed in glass tubes, wh<.>n the 
 relative height to which the fluids will rise in a given time will be in pro- 
 portion to their relative thickness. The same results take place when 
 fluids, not thickened, but varying in specific gravity, as alcohol and water, 
 are employed, the lighter passing into the heavier most rapidly. Dutrochet 
 called the passing in of the thinner fluid endosmose, and the passing out 
 of the thicker exosmose, and measured the endosmotic power of the fluids 
 by the difference of height which they reached in tubes. By means of a 
 graduated apparatus, Dutrochet estimated the relative power of the fol- 
 lowing substances as compared with water : 
 
 Animal albumen . . at 12 
 Sugar .... 1J 
 
 Gum .... 5-17. 
 
 Vegetable albumen belongs to the nitrogenous vegetable substances, and 
 is similar in many points to animal albumen. In its physical properties 
 it is difficult, if not impossible, to separate it from the vegetable substance 
 described above as mucus (protein). It appears to me not too much to 
 assume that this vegetable albumen (mucus), out of which the cytoblast is 
 formed, possesses the same endosmotic power as animal albumen. We can 
 thus easily explain how it is that, immediately after the cytoblast is sur- 
 rounded by a membrane, endosmose begins, and thus takes up those sub- 
 stances upon which the cytoblast exercises a changing influence. In this 
 ( way sugar and gum are formed, and the cell is thus filled with substances 
 which increase the process of endosmose. Scarcely any further explana- 
 tion of the process of absorption is needed, as this simple process suffices 
 for the understanding the most complicated phenomena of vegetable life. 
 It is to be regretted that so few experiments have been made on the 
 relations exhibited by this process. There are two points of especial im- 
 portance. The first is, the great variety in the nature of the various sub- 
 stances within and without the cells of plants, and the great difference in 
 the power with which they are attracted: on the relation of numerous 
 solutions to one another, we have no experiments. In the second place, 
 the nature of the separating membrane demands attention. Water and 
 alcohol, for instance, exhibit a very powerful reciprocal attraction ; but in 
 an endosmotic apparatus, when bladder or caoutchouc is used as a means 
 of separation, the result is very different. With the bladder the water 
 passes to the alcohol, but not vice versa, as alcohol does not easily per- 
 meate animal membrane. With the caoutchouc the result is exactly the 
 
 G 
 
82 ON THE PLANT-CELL. 
 
 reverse, the alcohol readily passing through this substance. Similar 
 modifications in the simplest processes of cell-life must take place, on 
 account of the countless varieties of cell-membrane. In all experiments, 
 however, it is necessary to avoid the the hypothesis of the porosity of the 
 organic membrane, which can only be attended with the same bad results 
 as the notion of the existence of atoms in chemistry.* 
 
 32. The most universally distributed medium of solution in 
 nature, water, is also the fluid which is absorbed by the plant- 
 cell, and conveys all other matters into its interior. The most 
 essential of these matters are carbonic acid and ammonia, both of 
 which are contained in water which either falls from the air or haa 
 been a long time in contact with it. Water, carbonic acid, and 
 ammonia contain carbon, hydrogen, oxygen, and nitrogen, all of 
 which are essential to the formation of the assimilated substances 
 and to the especial nourishment of the cell. But the water occa- 
 sionally conveys to the cell, in small quantities, all substances which 
 are capable of solution in water. 
 
 In spite of the almost endless works upon the nourishment of plants, 
 nothing is in a more uncertain state than our knowledge of the food 
 necessary for plants. This has arisen from the facts having been selected 
 from, and the experiments made upon, the higher and more complicated 
 forms of plants instead of the lowest. The simplest and most natural 
 object for such researches is the Protococcus viridis, or some other simple 
 Conferva., which consists of one or only a few cells, and which floats free 
 in water, and contains the substances universally necessary for the life of 
 the cell. These plants require nothing more for their vegetation than 
 pure water, which has taken up from the atmosphere carbonic acid and 
 ammonia, and perhaps a very small quantity of inorganic salts ; the 
 necessity for which last has not been proved, but is supposed to be 
 necessary from analogy with the higher plants. The experiment is 
 easily made of supplying these plants with water containing a large 
 quantity of carbonic acid, when they will be found to grow more rapidly, 
 and thrive more luxuriously, than when placed in water to which 
 humus, humic acid, or humic acid salts have been added. This is 
 sufficient proof that these last substances are not essential to the life of 
 the cell. 
 
 It is worthy of remark, that just as Carices, and other so-called moor- 
 plants, flourish with a certain quantity of humic acid, which is generally 
 unfavourable to vegetation, so also other plants, as the little Conferva 
 which requires tannin and grows in infusions of galls, require other 
 substances. The Mycoderma aceti grows under the influence of the 
 decomposition of vinegar. In these cases, probably, the free acid is as 
 little necessary to nutrition as in other plants, but the mode and manner 
 of the decomposition of the acid is a favouring moment for the vegetation 
 of the above-named plants. 
 
 Few researches have been made on the nature of the nitrogenous 
 substances in the simplest plants. I have hitherto supposed that the 
 nitrogenous compounds of plants are pure protein. But if we regard 
 
 * See Dutrochet, L' Agent immediat du Mouvement vital devoile, &c. Paris, 1826. 
 Also Poggendorff's Annalen, vol. xi. p. 138., vol. xxviii. p. 134. ; and Schweigger's 
 Journal, Iviii. p. 1. 20. [Also Draper on the Chemistry of Plants, and Matteucci on 
 the Physical Phenomena of Living Beings. TRANS.] 
 
LIFE OF THE PLANT-CELL. 83 
 
 them as albumen, fibrin, and casein, we must allow for the absorption 
 of sulphur and phosphorus, as well as salts of sulphuric and phosphoric 
 acids : through this the phenomena become much more complicated. 
 The reduction of the phosphates and sulphates to phosphoric and sul- 
 phuric acids, and the separation of the sulphur or phosphorus and the 
 oxygen, indicate complicated chemical processes, which are not, however, 
 performed without the presence of nitrogenous substances, and thus they 
 appear to be the simplest additions to the plant-cell next the formation 
 of protein. The notion of such changes is justified by Mulder's re- 
 searches upon the mother of vinegar (Mycoderma Pers.), which is 
 formed out of hydrated acetic acid and the albumen contained in the 
 vinegar. It is composed of cellulose and protein, which always exist in 
 the proportion of one equivalent of protein with four of cellulose.* A 
 similar accurate examination of the fermentation-cells would be of the 
 highest interest. 
 
 The plant-cell takes up all substances that are in solution in water, 
 both mineral and vegetable poisons and tannin, which, by producing an 
 interruption of the chemical processes, are capable of destroying its life. 
 The cell in this view has no choice beyond the endosmotic power of the 
 various substances which are presented to it. \ On the other hand, every 
 fluid is unfit for the nutrition of the cell, which, on account of its specific 
 nature as alcohol, or its density as concentrated solutions of sugar and 
 gum:}:, renders endosmose impossible, should it even contain all the 
 elements necessary for the growth of the cell. 
 
 In the last place we may observe, that in the changes which are 
 undergone in the cell of the plant there is no individual element, with 
 the exception of oxygen, which takes part alone in those chemical pro- 
 cesses. Nitrogen is taken in with water, but passes out again without 
 undergoing any change. Hence all calculations with regard to the 
 composition and metamorphoses of organic bodies, in which the pure 
 elements, and not their combinations, are supposed to play a part, must 
 be rejected as hypothetical. 
 
 II. On the Assimilation of the absorbed Matters, and Secretion. 
 
 33. The assimilated substances consist of carbon, hydrogen, oxy- 
 gen, and nitrogen (sometimes with sulphur and phosphorus) ; and these 
 are only assimilated from the definite combinations, carbonic acid, 
 water, and ammonia. As soon as these substances are conducted 
 into the interior of the cell, in the before-mentioned manner, che- 
 mical processes originate which first commence in the destruction 
 of the ammoniacal compounds and (perhaps as a result) the decom- 
 position of the water, and whose progress is distinguished by the 
 action of the assimilated nitrogenous matter (mucus) upon non- 
 nitrogenous substances. Thus are formed at the same time both 
 mucus and non-nitrogenous substances. 
 
 * Liebig's Annalen, vol. xlvi. p. 207. 
 
 f See the experiments of Saussure, Chemische Untersuchungen iiber die Vegeta- 
 tion, Leipzig, 1805, p. 228. 
 
 \ De Saussure and Davy found that plants flourished on dilute solutions of gum and 
 sugar. 
 
 Davy, Elements of Agriculture. 
 
84 ON THE PLANT-CELL. 
 
 I call those assimilated matters which have been mentioned above in 
 the chapter on the substances contained in plants. We can only place 
 in this class those substances which are produced and exist in the 
 simplest cells, and which are necessary universally for the growth of 
 the plant- cell. I do not say that those mentioned above are all, as 
 subsequent researches may add to their number by the discovery of 
 unsuspected relations. There is, for instance, resin, which, though fre- 
 quently present, is excluded because we cannot detect its transitions to 
 the assimilated matters as we can in the fixed oils. In this way we may 
 draw a permanent and useful distinction between assimilated substances 
 and secretions. I would, however, disclaim here any analogy that may 
 be supposed to exist between these substances and those of the animal 
 kingdom, and must insist on regarding these terms as connected with 
 ideas belonging to the vegetable kingdom alone. 
 
 There can be little doubt that all the foregoing processes of decom- 
 position and recomposition of the substances of which the plant-cell is 
 composed have their foundation in well-known chemical powers and laws. 
 That the elements of which the plant-cell is composed obey the same 
 laws in the cell as out of it, seems warranted by the strongest presump- 
 tions of inductive inquiry. All the elements of which plants are com- 
 posed are derived from the inorganic world, and the combinations which 
 carbon, hydrogen, oxygen, nitrogen, &c. enter into in the plant take 
 place under the influence of the properties or powers which they possess 
 independent of the plant-cell. It is for those who suppose that these 
 substances undergo some change in passing into the organism to bring 
 forward some proof of such a change. So long us this proof is wanting 
 (and it ever will be), we must regard it as true that all the chemical laws 
 find uncontrolled exercise in the organism. The activity of the modern 
 school of chemists, Liebig and his followers, Dumas, Mulder, &c., lead 
 us from another point of view to the same result*. Their labours have 
 placed the perfect identity of the elements and processes which go on in 
 and out of the body upon the most satisfactory inductive basis. Liebig 
 and Mulder especially have shown that, if we analyse the course of 
 changes which occur in the elements composing an organism according 
 to the laws of inorganic chemistry, we come to the same results as 
 though they were independent of the organic body. 
 
 The questions to be solved in this department of vegetable physiology 
 are, first, what are the compounds, and what the chemical processes, by 
 which the simplest plant-cells are formed ; and, secondly, what are the 
 compounds, and in what way are formed the substances, which are con- 
 tained in every plant-cell. For a knowledge of the compounds, am- 
 monia, carbonic acid gas, and water, which are every where and 
 universally required for the formation of the assimilated matters, we 
 are indebted to the chemists, De Saussure, Liebig, and others. Liebig * 
 has rightly exposed the absurdity of those who attempt to explain all 
 organic phenomena by what takes place in the elements, away from an 
 organism. There is, however, one fact which occurs in inorganic bodies 
 which exercises the most important influence in organic combinations. 
 It is, that bodies will enter much more freely into union with each other 
 at the moment they are released from other combinations than at any 
 other time. A body in this condition is said to be in statu nascenti, in 
 a nascent state. Of the substances which constitute the food of plants, 
 
 * Chemistry in its relation to Physiology and Pathology. 
 
LIFE OF THE PLANT-CELL. 85 
 
 two, water and the salts of ammonia, easily enter into a state of decom- 
 position. Water on coming in contact with zinc gives off its hydrogen, 
 and the weakest galvanic current serves to separate its oxygen and hy- 
 drogen ; whilst an alteration of temperature or solution is sufficient to 
 decompose or produce important alterations in the salts of ammonia. 
 Thus, through the destruction of a single equivalent of water, an impulse 
 would be given to an endless chain of chemical processes, which would 
 result in the development of those substances which are found in the 
 plant-cell. The question is, however, still unanswered as to what 
 change is the first that takes place in the series. Liebig has observed, 
 very correctly, that, as far as the ultimate results are concerned, it 
 signifies little whether carbonic acid or water is first decomposed. Al- 
 though, as before stated, we must not explain the changes which take 
 place in the cell on the supposition that the elements, as such, unite 
 together, yet, on the other hand, we are not in a position to say that the 
 formation of starch, &c. is dependent on the decomposition of carbonic 
 acid and water. Where plants grow, and where cells are formed, there 
 we have present at the same time water, carbonic acid, and the com- 
 pounds of ammonia. We also see that nitrogenous and non-nitrogenous 
 substances are developed at the same time, and apparently by the same 
 process. In this point of view, the analogy between the composition of 
 vinegar and the mother of vinegar, which last, according to Mulder, 
 consists of one equivalent of protein and four equivalents of cellulose, 
 is a matter of some interest. Thus : 
 
 C H O N 
 
 74 Water (H O) = . . 74 74 
 
 94 Carbonic acid (C O 2 ) = .94 188 
 2 Carbonate of ammonia 1 , 
 
 (H 2 N 6 CO 2 ) 2 J 
 
 96 76 266 12 
 Forms 
 
 1 Protein = . .48 36 14 12 
 
 4 Cellulose (C 12 H 10 O 10 ) = 48 40 40 
 
 212 Oxygen = . . 212 
 
 96 76 266 12 
 
 The 212 of oxygen would suffice to convert 53 equivalents of alcohol 
 into acetic acid. 
 
 But if we leave out of the question the nitrogenous substances, the 
 following scheme will give us the changes that occur in carbonic acid 
 and water : 
 
 C H O 
 
 12 Carbonic acid = . . 12 24 
 
 24 Water = 24 24 
 
 12 24 48 
 
 24 O = . . 24 
 
 X = . . 12 24 24 
 
 X= 1 Grape Sugar + 12 Water = 12 12 12 -h 12 H O 
 
 {Cellulose ~J 
 Dextrin 1 , 14 }9 1O 
 
 Cane Sugar f + ] 
 Inulin 
 
 1 Wood(Prout)+ 16 =12 8 8 4- 16 HO 
 
86 ON THE tL ANT-CELL. 
 
 These changes require no further explanation than the decomposition 
 of water, the setting free of oxygen, and the separation of a smaller or 
 larger number of equivalents of water ; processes which we know con- 
 stantly present themselves in the decomposition of organic substances. 
 
 One of the most important of the proximate principles is undoubtedly 
 dextrin. In all formative fluids, according to Mitscherlich and Mulder, 
 dextrin presents itself as the primary substance out of which all the 
 other assimilated matters are formed. In the various changes which 
 these matters undergo, the nitrogenous bodies seem to be the means of 
 effecting changes in the other bodies, whilst they themselves remain 
 unchanged. This phenomenon has got various names without any ex- 
 planation of it being given. Berzelius calls the process catalysis; 
 Mitscherlich, the contact of substances ; and Liebig the activity of ap- 
 prehending bodies. A number of such chemical facts are known ; thus 
 sulphuric acid, with heat, converts starch into dextrin and sugar and 
 alcohol into ether ; diastase changes starch into dextrin and sugar ; albu- 
 men, protein, &c. convert sugar into alcohol. Liebig's explanation of 
 the phenomenon as a communication of motion is founded on the notion 
 of the existence of ultimate atoms, and is otherwise untenable. Could 
 we explain better this phenomenon of one of the assimilated substances 
 facilitating the changes which go on in the others, we should have yet 
 to explain the changes which produced the nitrogenous substances. 
 
 The most important of these changes appears to be the decomposition 
 of water, but we are at a loss to know whose calculations to adopt. 
 Almost all plants need for their growth the influence of light. Here 
 also we have a need of experiments to determine the action of the par- 
 ticular rays of the sun-light, as of the coloured, the calorific, and the 
 chemical. Only thus much is known from De Saussure's experiments : 
 that under the influence of light the carbonic acid of the air is fixed in 
 the cells, and combines also with hydrogen ; a process which will not go 
 on when light is excluded. That in this case light can be supplied 
 through hydrogen, appears to be proved by an interesting experiment of 
 Humboldt's.* 
 
 34. In the formation of the assimilated matters, many sub- 
 stances become free, which, either through their natural affinities, 
 or the effect of contact, or predisposing affinity, form new com- 
 binations either amongst themselves, or with the non-assimilable 
 substances which may have been absorbed at the same time. All 
 substances formed in this way I call secretions (materia secreta) of 
 the cells. Some of these are universally present, as free oxygen, 
 or at least when they have vegetated under definite circumstances, 
 as the green colouring matter (chlorophyll). There are others 
 whose formation depends on especial circumstances, as conia, so- 
 lania, and the like. The chemical changes by which such sub- 
 stances are produced are for the most part concealed. Two points 
 remain to be noticed here: 1. That these secretions would be 
 frequently injurious to the cells were they not neutralised by in- 
 organic substances taken up- from without or by newly formed 
 organic matters: thus, oxalic acid combines with lime, and the 
 
 * Floras Fribergensis Specimen, p. 180. [See also, on this subject, Hunt's Reports 
 in the Transactions of the British Association, 1847 ; and Draper on the Chemistry of 
 Plants TRANS.] 
 
LIFE OF THE PL ANT -CELL. 87 
 
 alkaloids are found united to the organic acids. 2. Bodies such as 
 tannin, resin, &c., are frequently formed which have a great affinity 
 for oxygen, and thus from the vicinity of the cell absorb a con- 
 siderable quantity of this gas. 
 
 There is more need perhaps of research on these subjects than those 
 of preceding paragraphs, but yet sufficient is known to impress us with 
 the fact that all depend on physico-chemical processes. The great in- 
 security here arises from the deficient knowledge we possess of the rela- 
 tion of these substances to the so-called indifferent bodies. We know 
 that starch, sugar, &c. are composed of so many atoms of carbon and 
 water, but not how they are actually formed, or how they originate from 
 their elements. 
 
 Above I have divided the secretions from the assimilated matters ; and 
 though some of the former should ultimately be placed among the latter, 
 it will not affect the propriety of this division. We might here classify 
 these secretions according to their greater or less extension throughout 
 the vegetable kingdom ; but such an arrangement would have no relation 
 to the processes of life in the plant-cell, and therefore would be super- 
 fluous in this place. 
 
 Two points must be noticed here. The cells take up with the water 
 various salts. A part of them are inorganic, a part organic. Of the first 
 a part, perhaps, remain in the cell from the evaporation of the water. 
 Another part are decomposed in manifold ways through the chemical 
 processes which go on in the inside of the cell. From these are pro- 
 duced new bodies, which again decompose each other, and act upon those 
 bodies already formed ; and thus the whole of the processes become more 
 complicated. A part of the salts seem also destined for the neutralisation 
 and removal of the acids produced by necessary processes. The pre- 
 sence of a large quantity of oxalate of lime in the Cactacece is thus 
 explained, the injurious oxalic acid which is formed in the cell being 
 united to lime, which is taken up from without in the form of a soluble 
 carbonate of lime, and an insoluble and innocuous salt is thus formed. 
 Liebig* has given an opinion that a certain quantity of bases appear to 
 be constant, in every plant, in every locality. Perhaps, they are those 
 which the plant cannot do without to bring its chemical processes into 
 equilibrium. A similar equilibrium may be found between some of the 
 substances which are injurious, and formed in the cell, and which united 
 together form perfectly harmless bodies. 
 
 The substances which are formed in the cell, and which have a great 
 affinity for oxygen gas, will take up this substance from without the cell, 
 provided it is not supplied them from within. This is easily effected, as 
 the experiments of Dalton and Graham show that a moist membrane is 
 no hindrance to the penetration of a gas. In this way an absorption of 
 foreign substances originates which is entirely independent of the pe- 
 culiar nutrition of the cell. It may be a question as to whether other 
 gases, as, for instance, carbonic acid, are not taken up into the cell in this 
 manner. It is very certain that through this oxidation the substances 
 are thus brought into a new relation with each other, and a new play of 
 chemical activities is introduced. 
 
 * Organische Chemie, p. 85. 
 G 4 
 
88 ON THE PLANT-CELL. 
 
 III. Of the Excretion of Substances from the Plant-Cell 
 
 35. The endosmose whereby fluids are introduced into cells 
 necessitates an exosmose, consequently a small quantity of the 
 contents of the cell pass out. In this case there is no elective 
 power of the cell to be assumed, but all that is dissolved in the 
 cell, with the secreted matters, are exposed to a modification which, 
 as in endosmose, is regulated by the relation of the substances in 
 the inside to those on the outside of the cell. 
 
 In this place we must speak of "the theory of excretion by the roots. 
 But, first, we must regard this process as it takes place in the individual 
 cell, for of such is the external part of the root composed. In this case 
 we find that where endosmose takes place there also exosmose must 
 exist ; and the denial of excretion by the one process whilst absorption is 
 admitted by the other, as is done by Meyen*, is highly unphilosophical. 
 This, however, is a different question from that as to whether the plant 
 has the power of rejecting those substances which are injurious to its 
 life. We cannot conceive of an endosmose without an exosmose ; but 
 there is no sense in which we can say that the plant has the power of 
 getting rid exclusively of that which is injurious to it, because the 
 assumption of injurious and non-injurious substances is altogether gra- 
 tuitous. 
 
 The substances which are thrown out from the cell during exosmose 
 may become changed at the moment of their exit by contact with the 
 substances passing inwards, so that in many cases it is not improbable 
 that it is impossible to learn what is truly the product of exosmose. 
 With this case we have one remarkable analogy. During the process of 
 germination, starch, by virtue of the gluten (diastase), is converted into 
 dextrin, and this again into sugar, and the sugar is ultimately converted 
 into other substances, during which changes carbonic acid is fixed, and 
 acetic acid is set free (according to Becquerel) ; at the same time acetic 
 acid is never found free in germination. In fermentation the gluten 
 changes the starch into gum and sugar, and separates this into carbonic 
 acid and alcohol, which is easily (as, for instance, with soft platinum) con- 
 verted, in contact with oxygen, into acetic acid. The analogy is so strik- 
 ing in this case, that we cannot avoid supplying by hypothesis the failing 
 link, and supposing that alcohol also is formed during germination, and is 
 immediately converted by union with oxygen into acetic acid, which is 
 then separated. 
 
 Two points demand attention here, which modify the process of exos- 
 mose considerably. The one is the decided affinity between substances 
 without the cell, and which are free to follow this attraction ; and, secondly, 
 the attraction which similar substances have for each other. In a fluid 
 in which two salts are dissolved, we may produce a crystallisation of either 
 one or the other, according as we throw into the solution a crystal of one 
 or the other. In this way a cell appears to give out especially the mat- 
 ters which are found surrounding it in greatest quantity. At least, in 
 this way we may explain the fact that the cells surrounding the gum- 
 passages secrete the largest quantity of gum. These points will be recon- 
 sidered when we speak of the root. 
 
 * Physiologie, vol. ii. pp. 27. 524. 
 
LIFE OF THE PLANT-CELL. 89 
 
 36. When free gases are present in the cell in larger quantities 
 than can be held in solution in the fluid, they naturally pass through 
 the cell-wall, which presents no hindrance to their escape. When 
 the fluid is saturated with gas, the nature of the gases in the neigh- 
 bourhood of the cell determines whether, according to the law of 
 equilibrium of gases, a partial interchange takes place or not. The 
 gases which are combined in this way are principally oxygen, car- 
 bonic acid, and hydrogen. 
 
 The most universally present processes in the cells of plants are the 
 decomposition of water, with the fixation of hydrogen, and the decom- 
 position of the assimilated matters by the formation of carbonic acid.* 
 Sometimes, as in the Fungi, the decomposition of water is attended with 
 the liberation of hydrogen, f From hence it arises that, with the water of 
 the plant-cell, the gases which are dissolved in it are also taken up. Thus 
 we constantly find free gases which do not unite as in other chemical 
 combinations, but which must also pass out free. This process occurs in 
 its simplest form in the vegetating cells of the Conferva, where carbonic 
 acid gas is taken up, and oxygen gas is given out as the consequence. $ 
 In this case, the Daltonian law of the interchange of gases cannot be 
 taken into consideration, because the quantities do not correspond with 
 the law. 
 
 A fluid consisting of a solution of equal parts of gum and sugar, when 
 saturated, would contain about 70 per cent, of carbonic acid. When this 
 becomes fixed, about sixty-three volumes must be set free in the form of 
 oxygen gas, so that the carbonic acid is diminished nine-tenths of its bulk 
 by the loss of oxygen. De Saussure's experiments prove that this is 
 about the relation which the carbonic acid and oxygen bear to each other. 
 There are, however, many circumstances which may modify this process 
 to some extent, and especially the interchange of gases according to the 
 law of Dalton. This process is sometimes called, with great impropriety, 
 respiration, and is supposed to resemble the same process in animals. The 
 phenomena become much more complicated when, in addition to the 
 simple process of decomposition which goes on in the cell, some of the 
 contained substances, as, for instance, resin and the like, absorb gases, as 
 oxygen, from without, and unite with them. 
 
 IV. Disposition of the assimilated Matters. 
 
 37. The plant-membrane grows through the assimilated matters 
 in such a way that it is extended equally on every side, so that a 
 still larger space is surrounded, and its walls become thickened. 
 
 The cause of growth in this case is apparently from the attraction of 
 similar substances for each other, as seen in the increase in size of crystals 
 when placed in solutions of the same salt. The absorbed matters do not, 
 however, arrange themselves in regular layers upon the surface of the 
 membrane, but permeate all parts of the absorbent membrane in a semi- 
 fluid state ; but still the increase of surface is greater than of thickness. 
 In this way a cell continues to grow without its walls becoming thicker. 
 We have no grounds to suppose that isolated cells grow through apposi- 
 
 * See Germination. 
 
 t Humboldt, Floras Fribergensis Specimen, p. 179. 
 
 I First observed by Priestley, in the year 1773. See Priestley, Observations and 
 Experiments on various Kinds of Air. 
 
90 ON THE PLANT-CELL. 
 
 tion, but much more evidence to prove that this process takes place by a 
 true intus-susception. Schwann has made some highly ingenious re- 
 searches on this subject.* 
 
 38. At a definite period, the cell-membrane ceases for the most 
 part, or entirely, to grow ; and the assimilated matters, which are so 
 formed that they pass readily into a solid form, distribute themselves 
 in a special layer upon the inner surface of the membrane, in the 
 various forms we have already spoken of ( 16.). This process goes 
 on as long as new matters are formed. 
 
 In the formation of crystals, we find that the constantly increasing 
 layers are deposited only of a definite thickness, and when this thickness 
 is reached the formation of a new layer begins. We find the same taking 
 place in the plant-cell ; only with this difference, that in the cell the solu- 
 tion is in the interior, and the newer layers are deposited from within. 
 Of the cause which gives to these deposits a spiral form we know little or 
 nothing ; only this much we can say, that neither in round nor longitudinal 
 isolated cells are either deposit-layers or a spiral arrangement exhibited. 
 The first indication of a spiral direction of parts is seen in the species of 
 Spirogyra ; but here the spirally deposited matter is not the formative 
 matter of the cell, but chlorophyll. 
 
 It often happens that the primary cell-membrane continues to grow 
 after the second layer is deposited, which results in a division of the last 
 layer if it has not grown equally with the first. When a new layer con- 
 sists of another modification of the assimilated matter, or the first layer 
 becomes dry and firm before the second is deposited, a greater or less 
 evident separation between them is visible. 
 
 39. The matters contained in the cell serve not only for the 
 completion of the cell itself, or for the formation of new cells 
 ( 13.), but also constitute, in various conditions of aggregation, 
 and under multifarious forms, the contents of the cells. In the 
 organic substances the fluid portion is very gradually transformed 
 into a relatively speaking firm, but not completely solid, matter. 
 The unazotised compounds, gum, dextrin, jelly, amyloid, starch, 
 &c., are rendered firm by the gradual abstraction of the solvent 
 (water), and, in a similar way, from the azotised compounds, is 
 formed the mucus. In consequence of this process of change, 
 many of these substances appear in remarkably defined forms, 
 requiring especial notice. Besides crystals of inorganic salts, we 
 observe, in the cells, starch-, inulin-, and mucus-granules, larger 
 globules of gum, resin, and oil. But the most remarkable of these 
 forms is one of a peculiar character, assumed by the mucus in cer- 
 tain cells of the antheridia in the Characece, Mosses, Lichens, and 
 Ferns, in which it presents the aspect of a spiral filament, with from 
 one to two turns and a half. 
 
 The contents of the individual cells exhibit an endless variety, from a 
 mixture of many very different fluid and solid constituents to a single 
 nearly uniform material, either liquid or solid, occupying the whole cell. 
 
 * Mikroskopisehe Untersuchungen, p. 229. 
 
LIFE OF THE PLANT-CELL. 91 
 
 Individual cells are frequently entirely filled with essential oil or with 
 resin, or with a substance not yet chemically determined, of a red or 
 brownish colour, which is found in the cells of many Algce (the hologo- 
 nimic cells of Kutzing). In the green cells in a state of active vegetation, 
 the following appearances are usually observed : the internal surface is 
 invested with a continuous and very delicate layer of semifluid mucus 
 (" amylid-cell" of Kutzing, " primordial utricle" of Mohl), to which the 
 more solid mucus and starch granules adhere ; these granules are usually 
 covered by chlorophyll in a semifluid state, or that substance is attached 
 to the mucous layer, occasionally, as in the species of Spirogyrce, in 
 spiral bands jagged at the edges.* The chlorophyll may be merely 
 deposited upon the starch, or it may be, perhaps, that starch is formed 
 into chlorophyll, but never from it. Chemistry is wholly opposed to 
 the latter being the case ( 12. 1.). The rest of the space in the cell is 
 usually filled with a thin, tolerably clear fluid a mixture of dextrin, 
 sugar, and albumen in solution, in the most varying proportions ; and not 
 unfrequently also containing more minute, semifluid, mucus-granules, 
 inulin, extremely minute oil-globules, and chlorophyll, distributed in 
 various ways : inorganic crystals, on the other hand, are rarely met with 
 in cells in a full state of vitality (as is sometimes the case in Spirogyra). 
 Of these matters, however, one or the other is occasionally wanting, or 
 exists in greater or less proportion. Crystals, especially when in great 
 numbers, usually occur only in an aqueous fluid containing few organic 
 compounds, as, for instance, dextrin : oil and resin are frequently found 
 alone. As to the forms exhibited by these substances, all that is 
 necessary has been already said ( 7. 9, 10.) : I will here merely notice, 
 in addition, two very remarkable conditions. 
 
 a. Upon examining the fibres of the root of Neottia Nidus avis (in 
 flower), three layers of cells will usually be observed immediately 
 beneath the epidermis ; the first consisting of cells about three times as 
 long as the epidermis cells, and of the same breadth ; the second and 
 third, of cells of the same length as the former, but as broad as long. 
 Immediately on the inside of these succeed cells of the same breadth, but 
 three or four times longer, containing starch. Each cell of the outermost 
 of these three layers contains an elongated irregular mass of a semi-solid 
 yellowish substance (coagulated mucus?), which occupies nearly the 
 whole of the cell. Each cell of the internal layer is filled in the same 
 way, but in them the contents are intermixed with distinct fibres. The 
 cells of the intermediate layer, lastly, contain a globular mass of a 
 material of a browner colour which almost fills them ; this globular mass 
 is not composed of an amorphous substance, but, on the contrary, is con- 
 stituted almost entirely of interlaced fibres, very similar to those which 
 occur in the internal layer of cells. These fibres, which at first sight 
 might be taken for spiral fibres, are seen, on stricter examination, to be, 
 in the first place, all confusedly entangled, and, secondly, to be not solid 
 but to constitute tubes with unyielding walls and of moderately wide 
 calibre. They frequently present irregular dilatations and short lateral 
 coecal branches, and they not unfrequently subdivide into longitudinal 
 branches. They also exhibit dissepiments at regular distances, especially 
 towards their extremities, which are rather dilated ; these dissepiments 
 
 * Kiitzing's notion that the amylid-cell is contracted into these spiral bands (Phy- 
 cologia generalis, p. 49.) is to he attributed to the want of precise observation. The 
 soft mucus investment co-exists in a perfect state together with the spiral bands. 
 
92 ON THE PLANT-CELL. 
 
 are composed of a bright yellow substance (mucus ?), so that the fibres 
 do not altogether appear unlike some Confervce. With respect to the 
 real character of these peculiar formations I have nothing at all to 
 observe. The system of vessels discovered by Gottsche, in Preissia 
 commutata, may be adduced as the only thing at all analogous to them, 
 but just as isolated and mysterious. In this case the individual cells are 
 traversed by similar tubes, which appear to perforate the cell-wall itself. 
 In either case, an elucidation of the mystery can be expected only from 
 tracing the course of development. 
 
 b. In the antheridia of the Characece, Mosses, and Lichens, as well as 
 of the Ferns, the layer of mucus is apparently transformed, in the 
 tender cell, into a spiral filament ; the history of which has, as yet, been 
 by no means rendered clear. Its relation to the soft mucous layer 
 especially, still requires more particular investigation ; and it might also 
 probably be a question for determination, whether the cells in which 
 these spiral filaments are developed are in reality perfect cells or only 
 the nuclei of cells, that is to say, hollow cytoblasts. The best recent 
 researches on the subject are those of Nageli.* 
 
 V. Motion of the Cell Contents. 
 
 40. The fluid contents of vegetable cells exhibit two kinds of 
 motion, as to the causes of which we are still wholly in the dark. 
 In most plants in the families of the Characea, Najadacce, and 
 Hydrocharidacea, there is observable in each cell a single current 
 ascending on the one side and descending on the other, the fluid 
 constituting which, differs in colour, consistence (mucosity), and 
 insolubility in aqueous fluids, from the remainder of the transparent 
 cell-juice. The current is rendered more evident, in some cases, 
 from its carrying along with it the spherical bodies contained in 
 the fluid (starch, chlorophyll, mucus, &c.) ; but for the most part it 
 is sufficiently evident of itself. 
 
 The motion is best seen in the species of Nitella, in the hairs on the 
 roots of Hydrocharis morsus ranee, and in Vallisneria spiralis. Each, 
 however, has its peculiarities. In Nitella the moving stream is very 
 considerable, so that only a narrow streak remains at comparative rest 
 between the ascending and descending currents. The stream is strong 
 and rapid, and carries along with it starch -granules of considerable size. 
 Its course is not exactly parallel to the axis of the cell, but forms a small 
 angle with it. In two contiguous cells the currents flowing on the par- 
 tition between them run in opposite directions, consequently throughout 
 the whole plant the ascending streams are on one side, and, in fact, 
 owing to their oblique direction, form a spiral ; this is the case also with 
 the descending streams. When very young, the cells are perfectly trans- 
 parent, a condition which they subsequently lose, in consequence of 
 numerous granules, covered with chlorophyll, arranging themselves in 
 slender parallel rows upon the walls exactly in the course of the streams, 
 and leaving on each side only the narrow interspace between the streams 
 
 * Schleiden und Nageli, Zeitschrift fiir wissenschaftliche Botanik, Bd. I. Heft. I. 
 S. 168. et seq. This paper is translated by the Ray Society in " Reports and Papers 
 on Botany," 1845. 
 
LIFE OF THE PLANT-CELL. 
 
 93 
 
 uncovered. If the cell be carefully tied across, the current is in a short 
 time re-established in each subdivision. If the cell be cut through, the 
 circulating fluid escapes only on one side from the stream which is directed 
 towards the opening, the remainder of the fluid completing its entire 
 circuit through the cell before it also comes to escape. Any influence 
 detrimental to the life of the plant also affects the motion of the sap, and 
 whatever favours the former also promotes the latter. The same thing, 
 in all respects, takes place in Chara, only that in this plant the observa- 
 tion is not so readily made. In no plant in which the circulation is in 
 any way exhibited are the currents found to be so associated as to 
 constitute an ascending and a descending spiral. In Hydrocharis, 
 owing to the perfect transparency of the naturally isolated cells of the 
 hairs of the roots, the observation is exceedingly easy. In Vallisneria 
 (figs. 95, 96.), although the leaf must first be cut parallel to the surface, 
 in order to render it sufficiently transparent for convenient observation, 
 this proceeding is not detrimental to the motion, which, after a few 
 minutes, is again exhibited in its pristine activity. In this plant the 
 circulating mucous fluid is very scanty, and constitutes merely a very 
 thin covering on two opposite walls ; but it has sufficient power to carry 
 on the usually flattened lenticular granules covered with chlorophyll, 
 and which are of tolerable size. 
 
 95 A, Section parallel to the surface from the leaf of Vallisneria spiralis. In the cells 
 from a to e is seen the current of sap, the direction of which, as observed in each cell, 
 is indicated by the arrow. In the cells marked 6, which form the lateral boundaries of 
 the air-passage opened by the section, the anterior half only of the current is seen in 
 its whole width. The very gelatinous cytoblast circulates with the stream. B exempli- 
 fies the same section on a ground plan. 
 
 96 A portion from the section shown in fig. 95. more highly magnified. The thick- 
 ness of the stream exceeds that of the double cell-wall : the elongated, roughened 
 corpuscles are the lenticular granules of chlorophyll carried along with the current ; 
 at the same time their varying figure and various positions in the circulating fluid 
 are exhibited. 
 
94 ON THE PLANT- CELL. 
 
 In Najas major and Caulinia fragilis, in the fruit-stalk of the Junger- 
 manniacce (according toMeyen), the motions are precisely of the same kind. 
 The observation is of extreme difficulty in Stratiotes aloides; and after 
 frequently repeated examination of every species of Potamogeton, I have 
 only twice succeeded in actually seeing the motion : I have, unfortunately, 
 forgotten to note the species. 
 
 After the most careful research with the best instruments, I have 
 been unable to perceive a trace of the presence of vibratile cilia as a 
 cause of the motion, and it is very improbable that such should exist. 
 Whenever these cilia are found in animals and plants, they always 
 appear as processes on the exterior, never in the interior, of cells. 
 
 This kind of circulation, taken as a whole, seems to be, for the most 
 part, a phenomenon wholly peculiar to the vegetable-cell, and to be con- 
 nected with its perfect individuality. All the plants above mentioned, 
 in which the circulation is observed with certainty, are aquatic, or else 
 very fond of water, belonging to families very low in the scale of 
 organisation, in which the cells exhibit a great degree of independence, 
 so that separated portions of the plant (for instance, of the leaves of 
 Vallisneria) often retain their vitality for months. The supposed circu- 
 lation of the same kind in higher terrestrial plants I must for the present 
 leave undetermined, as I have never been successful in making even a 
 single observation with regard to it. 
 
 Historical and Critical In the year 1772, Bonaventura Corti dis- 
 covered the circulation of the sap in certain Characece and in Caulinia 
 fragilis (" mia pianta," as he constantly terms it), and also extended his 
 observations to many land and water plants, the determination of which 
 is, at the present time, for the most part impossible. Fontana confirmed 
 these discoveries, and at the same time cleared up some errors into which 
 Corti had at first fallen. Both these inquirers had observed so accu- 
 rately, and made such numerous experiments, that their successors were 
 not able to add anything essential. Their discoveries, however, in 
 the times of the Linnaean school of compilers, were so totally forgotten, 
 that C. L. Treviranus, first in 1807, rediscovered the motion of the sap 
 in the Charce, and Amici in 1819 in Caulinia; to which instances Meyen 
 subsequently added the other plants enumerated, after Horkel had again 
 fallen upon the writings of Corti, and drawn attention to their contents. 
 
 Corti's observations, above alluded to, upon land plants, as has been 
 said, do not admit of repetition. Meyen* formerly said a good deal 
 about these observations, that he had confirmed them all, without at the 
 same time entering into particulars, with reference to which I would 
 remark, that at the time he wrote his " Phytotomie " he was unac- 
 quainted with the kind of motion described in the following section, or, 
 at all events, did not distinguish it from the other. In his last work f he 
 passes it over in, as it appears, prudent silence. In his "Prize Essay" 
 he states that he has also observed the motion in Pistia Stratiotes. He 
 and others have repeatedly confounded the circulation here described 
 with the following. 
 
 Corti's notion, which was opposed even by Fontana, that the ascending 
 and descending streams are separated by a septum in the cell, has been 
 repeatedly broached since his time, but it is easily shown to be false. 
 
 * Meyen, Phytotomie, S. 182. Ueber die neuesten Fortschritte der Anatomie und 
 Physiologic. Harlemer Preisschrift, 1836, p. 165, and elsewhere, 
 f Physiologic, vol. ii. p. 206, et seq. 
 
LIFE OF THE PLANT-CELL. 
 
 95 
 
 The fanciful opinion propounded by Amici, Dutrochet, and others, of the 
 motion being caused by a galvanic influence, in which the rows of 
 chlorophyll globules in the Charts represent the connecting chain, is an 
 unscientific sporting with lame analogies. It is at once refuted by the 
 fact, that in the germinating Chara the circulation is evident previous 
 to the existence of the globules and their serial arrangement. 
 
 41. In almost all cells which, according to their position or 
 degree of completion, enjoy a high degree of independence, a 
 peculiar system of minute currents, with numerous anastomosing 
 branches, is exhibited. The fluid of which these currents are 
 constituted is of a mucous nature, mixed with minute opaque 
 granules ; and the streams proceed from, and return to, the cyto- 
 blast, which is invariably present at the same time : they cover the in- 
 ternal surface of the cell- wall (fig. 97.), 
 or traverse the cavity of the cell from 
 one wall to the other, without ming- 
 ling with the rest of the cell-fluid, 
 which is for the most part as clear as 
 water. 
 
 Up to the present time, I have found 
 this peculiar form of circulation in nume- 
 rous cryptogamous plants, for instance, in 
 Achlya prolifera, Spirogyra, and other 
 Hyphomycetes and Conferva; in almost 
 ail the forms of hair in the Phanero- 
 gamia (Plate I., fig. 13.) that I have as 
 yet examined, for instance, in Solanum 
 tuberosum ; in many spores, such as of 
 Equisetum arvense, and pollen granules, 
 for instance, of (Enothera grandiflora in 
 
 the immature state ; in almost all immature endosperm-cells, as in Nuphar 
 luteum, and especially in such as are subsequently, reabsorbed as 
 in Ceratophyllum demersum, in almost all stigma-papillae, 
 as in Tulipa Gesneriana, in the loose cells of juicy 
 fruits in the young state, as in Prunus domestica ; in the 
 pulp which is constituted by the placental cords (Plate I., 
 fig. 7), as in Mammillaria ; less frequently in the loose 
 juicy parenchyma of many plants in the young state, | 
 as in Tradescantia rosea. I believe it exists, however, in | 
 all vegetable-cells as long as the cytoblast retains its vital 
 activity. Upon the whole, I have, up to the present time, 
 collected several hundred examples from the most various 
 families. 
 
 As instances admitting of easy verification, I would 
 mention the fruit of Symphoricarpos racemosa (snow- 
 berry) (fig. 98.), which may be procured anywhere, or of 
 a Mammillaria. Each cell in these instances is entirely 
 
 07 Longitudinal section through the style of a Campanula, with two hairs : a, a hair 
 exhibiting a circulation ; its point is enclosed in a layer of mucus : b has lost its con- 
 tents, and is in consequence contracted. 
 
 99 A single cell from the fruit of the Snowberry : the arrows give the direction of the 
 currents. 
 
96 ON THE PLANT-CELL. 
 
 isolated, and filled with a colourless clear fluid. At one part of the wall is 
 affixed a sharply defined, faintly granular cytoblast, presenting a well- 
 marked nucleolar corpuscle. The cytoblast is always surrounded by a 
 narrow areola of a yellowish mucous fluid, thickly crowded with minute 
 opaque granules, and from it proceed currents of various width and 
 depth. At the margin, and consequently where the cell is viewed from 
 the side, these currents are often seen to advance with distinct minute 
 undulations: the direction of some of the currents is from the cytoblast, 
 of others towards it. In their course they exhibit numerous branches, 
 and anastomose with each other : in these plants only rarely, but in others 
 more frequently, separate currents traverse the cell, in order to unite 
 with other currents on the opposite side. Many of the streams are so 
 minute, that under the highest magnifying power they exhibit the 
 appearance of a line without any breadth, merely rendered to a slight 
 extent irregular by the individual granules. Occasionally a current is 
 suddenly interrupted, the leading portion continuing its course; a minute 
 drop of the fluid is then formed at the extremity of the remaining portion, 
 from which, after some time, the current is continued in the former or 
 in a new direction, or else two or more currents proceed in a new direc- 
 tion. In this respect, all other cells present merely unessential differ- 
 ences, of which, however, the most interesting is exhibited in Cerato- 
 phyllum* There are certain facts that must be borne in mind, in future 
 attempts at explaining the nature of the motion described in the two 
 preceding paragraphs, and which may probably lead to the explanation 
 of them : these are the endosmosis and exosmosis, which must neces- 
 sarily, in some way or other, give existence to a motion of the cell 
 contents; the continuous formative agency of the cytoblast, the pecu- 
 liar nature of the circulating fluid, its immiscibility with the watery 
 sap, its great adhesion to the cell-walls, as well as its great intrinsic 
 cohesion. At present it must be confessed, however, that we are not in 
 a condition to construct any useful theory out of these elements. 
 
 As far as it can be determined with certainty, the circulating fluid 
 appears invariably to be mucus (albumen?). When cells, in which is 
 exhibited the circulation described in this and the preceding section, are 
 submitted to the action of alcohol or nitric acid, the mucus contracts on 
 its coagulation, and may be observed to invest the whole surface of the 
 walls with a thin layer, and the currents will be seen to constitute merely 
 thicker streaks of mucus. The same thing takes place in every cell as 
 yet immature. Both in the latter, and in those cells which exhibit a 
 circulation, the cell-contents frequently coagulate of themselves, in con- 
 sequence of chemical processes in the cell, and then retract spontaneously 
 from the walls. In cells undergoing lignification the mucus gradually 
 disappears. In all young cells the mucous investment may be de- 
 monstrated also by the use of iodine. Might not its existence be 
 said always to indicate motion ? What phytotomist can have over- 
 looked the innumerable instances of cells in which mucous filaments 
 radiate from the cytoblast ? Whenever I have examined these cells in 
 the earlier condition, I have never failed, with due perseverance, to ob- 
 serve the circulation in these mucous filaments, or rather streams. The 
 mucous layer in question is frequently so little granular, that its motion 
 
 * See my " Beitrage zur Kenntniss der Ceratophylleen in the Linnaea," vol. ii. 
 (1837), p. 527, et seq. Botanische Beitrage, vol. i p. 213, et seq. 
 
LIFE OF THE PLANT-CELL. 97 
 
 is scarcely at all observable. May not this motion be regarded as a 
 universal phenomenon, and as most intimately connected with the assi- 
 milation of the azotized matters ? 
 
 Historical and Critical. This form of sap-motion was discovered 
 by Robert Brown in 1831, in the hairs of the filaments of Tradescantia 
 virginica* Slack, Meyen, and myself, have contributed the principal 
 additions to the number of instances. Meyen thinks that, besides these 
 sap-currents, air is contained in the hair- cells in T. virginica; but 
 this is altogether erroneous. His attributing an assertion to the same 
 effect to Robert Brown f, arises simply from a mistranslation of the 
 English : Robert Brown refers merely to the air which is adherent to 
 the hairs. Slack \ supposed that the hair-cells of T. virginica contain 
 a second utricle, and that the currents flow between its wall and that of 
 the cell. Accurate observation easily shows this view to be a mere 
 fiction. The most superficial observation only, or the most defective 
 microscope, could have led Schultz to misplace these currents on the 
 outside of the cell, in a special system of vessels (his " vasa laticis con- 
 tracta"). A single attentive observation is sufficient to refutet his notion, 
 and to demonstrate the phenomena as I have described them, as well as 
 the impossibility of the existence of such a system of vessels. Meyen 
 ascribes the motion not to the fluid, but to a self-motive power inherent 
 in the granules that are carried round with it ; an idea which, in some 
 cases, has led to his overlooking the fluid. But views of this kind I regard 
 as being without any foundation whatever. 
 
 I make no reference to the dispute as to the existence of either this or 
 the previously described motion, any question upon the subject being 
 altogether out of date. Whoever, at the present day, entertains a doubt 
 about it, is quite unfit to make any physiological observation. 
 
 42. The spiral filaments in the antheridia of the Characece, 
 Mosses, Hepaticce, and Ferns, mentioned at the end of 39., ex- 
 hibit, at least when in contact with water, a peculiar motion, con- 
 sisting principally in a rotation around the axis of the spiral, and 
 which motion in the free filaments is shortly changed (according 
 to the law of the Archimedean screw) into a progressive movement ; 
 but the motion is modified in divers ways, according to the varying 
 width and diameter of the spirals. 
 
 The motion referred to in the section is as yet, together Avith the 
 existence of vibratile cilia, one of the most remarkable and mysterious 
 phenomena in the vegetable world. Phenomena of this kind afford but 
 too ready a ground for the unbridled fancy to fill up the defective gaps 
 in our knowledge, with what are termed clever notions; the divine 
 maxim of St. Paul, " that we know in part," being disregarded. Many 
 fabulous statements consequently have, in former times, been made 
 on this subject. Too much caution, therefore, cannot be employed 
 when apparent analogies are indicated, lest they should be received 
 as views having a scientific foundation, and used in the erection of a 
 
 * On the Sexual Organs, &c. in the Orchides-e and Asclepiadeae (1831), p. 172. 
 
 f Physiologic, Bd. II. S. 244, et seq. 
 
 \ Transactions of the Society of Arts, &c., vol. xix. (1833). 
 
 Flora, 1834, p 120., and his Paris prize essay upon " Cyclosis." 
 
 H 
 
98 ON THE PLANT-CELL. 
 
 farther superstructure. I myself always prefer as much as possible 
 to refrain from this play of an active fancy, rather acknowledging my 
 ignorance, and endeavouring to show that it arises inevitably from the 
 nature of the thing itself. As in every thing else, however, theoretical 
 views of one sort or another have abounded respecting the phenomena in 
 question. 
 
 In the first place, we are not even acquainted with the morphological 
 significance of the organs in which the delicate cells, with spiral fila- 
 ments, are developed. We know just as little about the development of 
 the cells; are just as, or perhaps more, ignorant regarding the formation 
 of the spiral filaments ; and with respect to their chemical nature, we are 
 able to arrive at only a very imperfect probability. As to the mechanism 
 of the motion, we know just as little as we do of that of the moving cilia : 
 of the cause of motion, of the motive power, just as much as that of 
 the contraction of the primitive muscular fibre, of the motion of animal 
 spermatic filaments, and of the vibratile cilia on animal and vegetable 
 cells ; that is to say, absolutely nothing. A comparison of this motion 
 with that of the heavenly bodies, is, however, wholly inadmissible, be- 
 cause the commencement of the motion in the organisms in question has 
 relation to time, but not so that of the heavenly bodies ; on which ac- 
 count, with respect to the latter, the question after the first impulse 
 (tangential force) does not concern us at all, but it does very materially 
 with respect to the organic structures. All these motions fall into the 
 same category, in every respect, with those which will be described in 
 the following section. Ignorance and stupidity term them " primitive 
 phenomena." The discreet and profound investigator of nature recog- 
 nises their temporary limitation in this respect, as well as their destined 
 application to purposes of further activity. 
 
 43. When a multitude of very minute corpuscles of either an 
 organic or inorganic nature, for instance, minute starch-granules, 
 small crystals, c., are contained in a cell in a fluid of sufficient 
 tenuity, they usually exhibit a quivering motion (termed " mole- 
 cular motion "), the cause of which is still unknown to us ; but in 
 any case it has no necessary or exclusive connexion with the life of 
 the cell. 
 
 Some observations relative to this subject had been made at an earlier 
 period, but had been either disregarded or at least not followed up, and 
 it was not till 1827 that R. Brown* first took up this phenomenon in a 
 connected point of view, and at the same time completed the inquiry so 
 fully, that scarcely any thing remained to be added ; and it required the 
 subjection of a Meyen to preconceived notions to speak of it as a vital 
 phenomenon. 
 
 All bodies sufficiently minute, organic or inorganic, and suspended in a 
 fluid not too thick, present a peculiar oscillatory motion, unattended with 
 any perceptible change of place. Instances of this phenomenon are to 
 be found in almost all plants, in the mucus- and starch -granules, crystals, 
 &c., whether inclosed in a cell or free ; but only when the fluid can 
 retain them in suspension, so that they cannot sink to the bottom. The 
 milky juice, and that contained in the pollen grains, are fluids eminently 
 of this nature, and in these, consequently, the motion in question is most 
 
 * Vermischte Schriften herausg. von Nees v. Esenbcck, vol. iv. p. 143. 
 
LIFE OF THE PLANT-CELL. 99 
 
 frequently and most readily observed. As it happened accidentally that 
 these motions were first observed in the latter organs, as being more fre- 
 quently and more particularly examined than the common cells, fancy was 
 at once busied in erecting therefrom all sorts of wonderful systems. It is 
 to these motions that those amongst us who are gifted with speculative 
 heads are indebted for the vegetable Spermatozoa. But it is to be 
 hoped that we shall soon be delivered from them, as such true and sober 
 observers as Fritsche* and Nagelif for plants, and KollikerJ for ani- 
 mals, have declared war on good grounds against the animality of 
 the Spermatozoa. That the supposed change of form of the minute, 
 elongated, crescentic starch-granules in the Onagraacece depends upon 
 optical illusion, is easily ascertained by the attentive and unprejudiced 
 observer. There can be no question as to its not being a vital phe- 
 nomenon, because the motions continue even in the alcoholic tincture of 
 iodine (an absolute poison for all vegetable and animal life), of which 
 any one may readily convince himself, and which Fritsche has, with his 
 well-known accuracy, shown to be the case in a great number of plants. 
 No person but one blinded by preconceived notions, and looking every 
 where for prodigies, and especially not under the cautious guidance and 
 support of a sound philosophy of nature, can find anything extraordinary 
 in the perfectly natural occurrence of this universal physical phenomenon 
 in the contents of the pollen-cell, or endeavour, with empty fancies, to 
 supply the gap which he imagines nature to have left. 
 
 Respecting the ultimate cause of this phenomenon we know nothing at 
 all ; electrical tensions and the balancing of electrical forces, consequent 
 upon chemical processes, have been provisionally proposed as an ex- 
 planation. It is better to wait and direct our activity to something else, 
 than to waste our own and others' time with premature views and untenable 
 fictions. 
 
 VI. Motions of the Vegetable- Cells. 
 
 44. In the spore-cells of certain of the lower aquatic plants, there 
 is exhibited, for some time after their quitting the mother-cell, 
 occasionally also some time before their doing so, a locomotion 
 resembling the molecular movement ; but with the difference, that 
 in this case the motions are more considerable, and effected by 
 means of vibratile cilia. 
 
 Perhaps in no case has the want of sound philosophical principles led 
 to greater phantasies than in the above phenomenon. The subject has 
 become still more involved by the statement in former times of a multi- 
 tude of supposed facts, the immediate offspring of imperfect observation, 
 and which had no actual existence. Meyen, to whom we are indebted 
 for a very industrious compilation of all that has been said on the subject, 
 (Physiologic, vol. iii.) says that he found himself compelled to make a 
 
 * Ueber den Pollen. St. Petersburg, 1837. From the Mem. de 1'Acad. Imp. des 
 Sc. de St. Petersburg, printed separately, p. 24, et seq. 
 
 f Zur Entwicklungsgeschichte des Pollens bei den Phanerogamen. Zurich, 1842. 
 
 \ Beitrage zur Kenntniss der Geschlechtsverhaltnisse und der Saatnenflussigkeit 
 wirbelloser Thiere, u. s. w. Berlin, 1841, p. 49. 
 
 L. c. 
 
 H 2 
 
100 ON THE PLANT-CELL. 
 
 critical selection of the facts, but afterwards goes to work as uncritically 
 as possible. Two circumstances conduce to render the earlier observa- 
 tions of Ingenhousz, Agardh, Wrangel, Wilke, Girod- Chantrans, and 
 others, entirely useless, or, at all events, very suspicious; in the first 
 place, because the above-named observers were not sufficiently assured of 
 the identity of the motionless and moving corpuscles, and secondly 
 because, owing to the then state of science, and the nature of their instru- 
 ments, they were not at all in a condition to distinguish between true 
 Infusoria and the minute spores of the Confervce, &c. To which, also, 
 may be added that, as regards the Confervcz, many things have been 
 looked upon as spores which were merely cell-contents, as starch, chloro- 
 phyll-granules, &c., and which consequently, very naturally, occasionally 
 exhibited the molecular motion. 
 
 As a proof of the good grounds I have for this scepticism, I would 
 merely remark, that an observer like Kiitzing, who has devoted thirteen 
 years, with the most unwearied industry, to the observation of the Algce, 
 ventures to state in his whole work but three instances in which he him- 
 self had an opportunity of observing the phenomenon in question. 
 
 As facts of a more certain and useful nature, only a few observations 
 remain, in which it was noticed that the spore-cells were liberated and 
 exhibited spontaneous motion, but afterwards became motionless and 
 germinated. The latter circumstance especially must necessarily be 
 inquired into in referring to the older observations, because we also know 
 as a fact that true Infusoria are actually met with in the interior of the 
 cells of Confervce. Acting in an earnest spirit of criticism, which 
 alone will suffice to secure us from being misled by the dreams of 
 fancy, I can admit but very few of the facts adduced by Meyen 
 in his " Physiologic " and Annual Reports, all of which have re- 
 ference to spore-cells, partly of the Conferva and partly in the fila- 
 mentous Fungi. To these, also, are to be added some later observations 
 by linger *, Kiitzing f, and Thuret J . I have succeeded in observing a 
 phenomenon of the kind in question in two plants only, viz., in Achlya 
 prolifera and Vaucheria clavata DeC. This observation is quite suffi- 
 cient, however, to place the fact itself beyond doubt. Achlya prolifera 
 presents two kinds of spores : larger ones, which are formed in smaller 
 number in spherical sporangia ; and smaller ones, which are developed in 
 greater numbers in the unchanged filiform terminal joints, from which, 
 when the spores are mature, a minute operculum is detached. Shortly 
 before this, the spores assume a vibrating motion, which is accompanied 
 with change of place, often considerable. This motion lasts for some time 
 after the spores have escaped, and finally ceases, whereupon the spores 
 frequently, even after a few hours, begin to germinate. When a terminal 
 joint of this kind is emptied, a new similar joint usually grows within it, 
 arising from the next septum, and frequently not wholly filling the 
 remaining former one. In this new joint, also, spores are again formed, 
 which have then, in making their escape, to pass two openings, and 
 occasionally move about for a long time between the two cell- walls before 
 they reach the second opening. But it also happens, that they never 
 arrive at this second opening at all, and germinate, or at least begin to 
 germinate, within the older utricle. 
 
 * Unger, Die Pflanze ittt Momente der Thierwerdung, 
 
 f Kiitzing, Phycologia generalis. 
 
 I Thuret, Les Organes Locomoteurs. 
 
LIFE OF THE PLANT-CELL. 101 
 
 In Achlya pronyera, no observation has yet been published serving to 
 throw light upon the mechanism of this motion ; my own observations 
 date at a period in which I first began the pursuit of Botany. In Vau- 
 cheria clavata I have only once observed a liberated and spontaneously 
 moving spore, and immediately noticed currents on each side of it, rendered 
 manifest by the rapid transit of minute corpuscles. I thereupon concluded 
 that these currents were produced by cilia, but in trying to fix the spore 
 and observe it more closely it was unfortunately destroyed. linger, and, 
 after him, Thuret, have communicated more particular observations on 
 this subject, and shown that the whole exterior of the cell is covered with 
 vibratile cilia. Thuret has also observed motion and vibratile cilia as the 
 cause of it in Conferva rivularis and C. glomerata, in two species of Ch<z- 
 tophora, and two of Prolifera. (?) Kiitzing simply noticed the motion in 
 Achlya prolifera, Tetraspora gelatinosa, and Ulothrix zonata, without 
 making any observation on its cause. Excepting in those of Achlya 
 prolifera, Vaucheria clavata, and Tetraspora gelatinosa, Kiitzing and 
 Thuret found in the self-moving spores a reddish spot, like that in the 
 green monads, and termed by Ehrenberg " eye-points." Kiitzing observed 
 this spot in the spores, not only whilst yet in the sporangium, but also 
 even in the first or second cell of the spore when becoming developed into 
 a Conferva. All these spores, except those of Achlya prolifera, are 
 green ; whilst Kiitzing states it as a law, that in all the lower Algce 
 (his Isocarpece) the true and mature spores are brown. More pre- 
 cise and comprehensive observations on this phenomenon are still indis- 
 pensable before any conclusive result can be drawn from them. Are there 
 not probably spores whose completion is not yet effected, in which the 
 formation of the cell-membrane from the tender mucus-layer has not been 
 as yet perfected, which lose their cilia (mucus ?) and become capable of 
 development as soon as the formation of the cell-membrane is quite 
 completed ? 
 
 The lower Conferva, filamentous Fungi, &c., have at all times af- 
 forded the most fertile field for the mystical dreams of fancy, because in 
 no part of Botany are researches so difficult to make, and so much out of 
 our power to control. Here, more than any where else, it is necessary, in 
 order to escape all unscientific, fanciful delusions, to be guided by the 
 maxims of a sound philosophy. Particularly is it necessary in this case, 
 if we do not wish to deprive scientific research of all certainty, at once to 
 dismiss from consideration every observation that has not been made 
 upon indubitable plants. I have consequently, in considering this question, 
 as elsewhere, left entirely out of the field the Diatomacecs, Bacillarice, &c. ; 
 in short, all those forms the animal nature of which has been asserted by 
 Ehrenberg, upon grounds at all events worthy of consideration. Whoever 
 is interested in this subject, will find in the masterly works of Ehrenberg, 
 especially in his great one on the Infusoria, as well as in the diligent 
 labours of Kiitzing, a great mass of historical matter, collected with the 
 most extraordinary industry, together with abundance of remarkable 
 original observations. As a basis, however, for the foundation of botanical 
 laws, these materials should not be employed. 
 
 Only a science crazy with fantastical mysticism, and far removed from 
 a clear, self-intelligible Natural Philosophy, could entertain the dreamy 
 notion that creatures may be at one time animals and at another plants. 
 Were this possible, it would necessarily much more readily happen that 
 a being should be now a fish and now a bird ; or at one time a conferva, 
 at another a rose ; and then what would all our natural science be but 
 
 H 3 
 
102 ON THE PLANT-CELL. 
 
 folly ! This perplexity of ideas, correctly and most happily designated 
 by Valentin (Repert. Bd. 8. S. 4.) as Anachronism, has latterly been 
 carried to a great length by linger (Die Pflanze im Momente der Thier- 
 werdung) and Kiitzing ( Phycologia generalis). It can only be regretted 
 that such able inquirers should be so entirely without any philosophical 
 insight. 
 
 Lastly, when, in the mention of facts of the nature in question, we 
 meet with the expressions " the cells move spontaneously here and 
 there," &c., it shows us how obscure and perplexed so many men even 
 of the greatest scientific acquirements may be. We discover spontaneity 
 only in our minds by self -observation. In animals, analogy leads us to 
 conclude its existence, from our observing actions having a definite 
 object ; and yet in this case the subject is attended with a sort of 
 mystery, for there is nothing by which we can know that the object was 
 really aimed at by the animal itself. No reasonable man, however, 
 believes that the planets designedly pursue exactly this or that course, 
 and with exactly the proper degree of rapidity or slowness, to prevent the 
 possibility of mishap; and yet an object is attained by their motion 
 the maintenance of the solar system. But, with reference to motions 
 by which in no case can any intelligible object be attained, to speak 
 of " will " is a mere playing upon words. 
 
 VII. Reproduction of the Cell. 
 
 45. When a large quantity of soluble assimilated matter, 
 together with the needful quantity of mucus, have been formed in a 
 cell, the processes described 23. necessarily recommence. One 
 or several new cells (filial cells, blastidia) are formed within the 
 cell (mother-cell, matrix), which is destroyed when the new cells 
 have attained a sufficient expansion. Since it is a matter of 
 course that a figure should depend upon the material from which 
 it is constructed, and the conditions of its formation, and as both 
 these are derived from the mother-cell, it necessarily follows that 
 the filial cells are repetitions of, or resemble, the mother-cell. 
 
 If anywhere, it may certainly be here asserted that it is of essential 
 importance in the treatment of a science to set each individual point in 
 its appropriate place and in its proper light, to allow of the whole being 
 correctly understood. As the scientific problem has never been put 
 plainly and rigorously, nor the questions requiring answer deduced from 
 it, the point referred to in the section has remained even up to the 
 most recent period wholly untouched, and has in fact but just received 
 some cursory notices ; and yet in the whole vegetable kingdom there is 
 nothing of more importance. With few exceptions, every plant consists 
 of numerous cells ; the beginning, however, of every plant is in a single 
 cell, in the Cryptogamia the spore, in the Phanerogamia the embryonic 
 cell. The question respecting the multiplication of the cells consequently 
 includes the origin and the life of the whole plant, which remains alto- 
 gether obscure to us previous to the elucidation of this relation. The 
 mode in which one cell forms many, and how these, dependent on the 
 
 * See C. v. Siebold de Finibus inter lleguum Animale et Vegetabile constituendis. 
 Erlangen, 1844. 
 
LIFE OF THE PLANT-CELL. 103 
 
 influence of the former, assume their proper figure and arrangement, is 
 exactly the point upon which the whole knowledge of plants turns ; and 
 whosoever does not propose this question to himself, or does not reply 
 to it, can never connect a clear scientific idea with plants and their 
 life. From the total neglect of this point it is no wonder that most of 
 the notions in Botany are enveloped in a dark and formless mysticism. 
 
 The Protococcus-cell here again suggests the natural standard by 
 which to judge of the most simple conditions. In it we may observe 
 that two new cells are formed within the cell, which lie for a time 
 loose in the mother-cell, and at last destroy it, and then become new, 
 free organisms. The same thing takes place, according to Nageli, in 
 almost all the Algce : a similar process is exhibited in the double spores 
 of the Lichens. In the Pezizce we may notice eight new cells originate 
 in a cell. In the Ferns and Equiseta the spore-cells are formed in the 
 mother-cell. In the Phanerogamia it is easy to observe the formation of 
 cell within cell : in the embryo-sac (a large cell), in the embryonic cell, 
 in which the production of new cells within the first-formed ones may 
 also be traced. In the pollen of most plants there is no doubt that free 
 cells are formed in other cells ; in the apex of the bud, and in the cambium, 
 it not unfrequently happens that new-formed cells are seen in the 
 mother-cell : almost all forms of hair entirely corroborate this view of 
 the process. Examples of this sort are exhibited in nearly every group 
 of plants, and almost in every part ; and consequently I believe that 
 the proposition based upon induction may be thus provisionally de- 
 fined : " The process of the reproduction of cells by the formation of 
 new cells in their interior is a general law in the vegetable kingdom, and 
 is the foundation of the production of cell-tissue" Respecting the way 
 in which new cells are produced, all that is necessary has been pre- 
 viously stated ( 13.). 
 
 The figure of the incipient crystal depends upon the material of which 
 it is formed, and the physical conditions under which it originates. This 
 might, perhaps, be thus expressed in general terms : the figure depends 
 upon the nature of the material and the nature of the formative processes. 
 To apply it to the cell, as the matter and form of the originating formative 
 process are derived from the mother-cell, the latter must exert an es- 
 sential influence upon the filial-cell. The formation of the latter, how- 
 ever, is not completed in the mother-cell, but is continued after its 
 liberation therefrom, and consequently the figure of the filial-cell is 
 modified in many ways by after influences and relations. This explains 
 both the constancy of the specific figure, and the multiplicity of the 
 individual varieties. Here, consequently, we require nothing but the 
 complete analysis of the process of cell-formation in its separate elements, 
 and of the information to be derived from crystallisation (as, from a definite 
 material and determinate physical condition, a determinate figure must 
 inevitably arise), in order to subject to a scientific solution, and under 
 the simplest form, the great mystery of organic generation, upon which 
 the constancy of species, and together with it the normal conditions of 
 the whole of organic life upon the earth, depend : clearly a goal within 
 the possible attainment of the human faculties. 
 
 The primary elements of this doctrine I gave in Muller's Archiv, 
 for the year 1 838.* It was further developed by Nageli. | Mirbel \ dis- 
 
 * Schleiden, Botanische Beitriige, vol. i. p. 121. 
 f Schleiden und Nageli, Zeitsch. f. w. B., vol. i. part 1. 
 } Sur la Marchantia polymorpha, Paris, 1831 et 1S32, p. 32. 
 ii 4 
 
104 ON THE PLANT-CELL. 
 
 tinguishes three modes in which vegetable cells originate, which he terms 
 "intra-utriculaire" (the process above descrived), " supra-utriculaire," 
 and " inter-utriculaire." The first only of these modes is proved to exist 
 by actual observation ; the two latter have not been observed, and are gra- 
 tuitous assumptions. 
 
 46. According to Hugo Mohl*, another mode of increase ob- 
 tains in the cells of the Cryptogamia (Conferva), consisting in a 
 circular constriction of the cell, which gradually advancing inwards 
 divides the cell in the middle into two, so that a complete division 
 of the cell into two new ones is effected. 
 
 These researches of Mohl contain the first and (except those of Niigeli 
 and myself) the only actual observations on the multiplication of vege- 
 table cells, f I have never been so fortunate as to observe a complete 
 series of cells in this course of development, although I have frequently 
 examined Potysperma glomerata, the plant which formed the principal 
 subject of Mohl's researches. This has been the case also with Nasgeli, 
 who has explained the error in Mohl's supposition. J 
 
 After Mohl, Meyen has been the principal advocate of this view, be- 
 lieving that he has in numerous instances recognised this process of 
 spontaneous scission, and regarding it as almost a general law in plants. 
 In most of the cases adduced by him, the fact has simply been invented, 
 not observed. In the instance in which he refers to direct observation 
 on the origin of four pollen -cells in the matrix, the fact is exactly the 
 reverse ; with reference to which, compare what is said on the subject 
 of pollen in a subsequent part of this work. 
 
 linger, also, has again propounded the multiplication of cells by scission 
 as a general law in plants ||, but with as little truth as Meyen. Neither 
 has he adduced a single instance in which he had actually observed the 
 process of division. The fact that, in a particular instance, at first but 
 one and afterwards in the same place two cells exist, that near one large 
 cell two others occur which together perhaps have the same circum- 
 ference as the first, does not throw the least light upon the process of 
 multiplication : he has, however, no other facts to rest upon, or at least 
 has not communicated them. 
 
 Whether cell-division occurs generally in plants is still to be deter- 
 mined. Certainly, the condition mentioned in the preceding section is 
 the more frequent one. 
 
 VIII. Of the Termination of Cell-Life. 
 
 47. As soon as the play of chemical affinities has become im- 
 possible in a cell, the latter must be regarded as individually dead. 
 So far, all cells must be considered to have died as individuals which 
 
 * Ueber Vermehrung der Pflanzenzelle durch Theilung. Tub., 1835. 
 
 f To these names must be added that of Mr. A. Henfrey, whose original and in- 
 teresting observations respecting the multiplication of vegetable-cells were first made 
 known at the meeting of the British Association at Cambridge, in 1845, and have 
 subsequently been incorporated in his work entitled " Outlines of Structural and 
 Physiological Botany," Lond. 1847. Mr. Henfrey adopts Mohl's views with some 
 modifications. TRANS. 
 
 \ L. c. Physiologic, vol. iii. p. 123, et seq. 
 
 |[ Bau und Wachsthura des Dicotyledonenstammes, Petersburg, 1840, p. 86, et seq. 
 
LIFE OF THE PLANT-CELL. 105 
 
 have entirely consumed their contents, and contain nothing but 
 air : the so-termed vascular, medullary, and liber cells ; or those 
 the contents of which have become converted into an isolated ho- 
 mogeneous matter, as the cells containing nothing but essential 
 oil, resin, &c. The latter, however, are proportionately few in 
 number. 
 
 Here we have another point, which has been either entirely neglected, 
 or only superficially and cursorily treated of in books which for the most 
 part do not even teach us any thing respecting the death of the whole 
 plant. If we place the life of the cell wholly, or at all events for the 
 greatest part, in the chemico-physical processes going on in the cell, we 
 must term the cell dead in which these processes have entirely and for 
 ever ceased. This is the case particularly in all cells which convey only 
 air, which, being themselves dead, are saved from decomposition only by 
 the living cells surrounding them, but which are instantly destroyed 
 when exposed to the decomposing action of the atmosphere ; as, for in- 
 stance, the pith and heart- wood in trees becoming hollow, and cork and 
 bark always at a certain time. There are, however, cells of this kind 
 which gradually convert their whole contents into an isolated secretion, 
 as into essential oil, as happens in the rhizomes of the Scitaminece, in 
 the leaves and stem of the Aloes, &c. In these cases the cell must be 
 regarded as dead from that moment. The after-process is neither de- 
 termined nor modified by the cell ; it is a chemical process, and consists 
 in the gradual oxidation of the essential oil, with the completion of which 
 all farther change is at an end. It is in this way that the termination 
 of the individual cell-life, even in the very interior of the most perfect 
 plants, is indicated. 
 
 48. Only the completely formed cellulose resists the usual 
 solvent reagents ; all the other substances of which cell-walls can 
 consist, are still within the domain of the solvent or transmuting 
 chemical forces which are active in the cell. All cells, therefore, 
 whose formation is not completed admit of being again rendered 
 fluid and becoming absorbed. This is the case in all mother-cells, 
 in the spongy cellular tissue which originally fills the air-canals, 
 in the nucleus of the ovule, &c. 
 
 It is undoubtedly a proof of superficial observation when a botanist, 
 as has been the case, denies the resorption of organised structures in 
 plants, an event which is observed with less facility in animals than in 
 plants. The enormous number of mother-cells alone affords the most 
 irresistible proof that this process does take place. But in what way 
 it is effected is as yet unknown. Probably there takes place in this case 
 a chemical change of the assimilated matter opposed to the formation of 
 cellulose ; that the former is first changed into jelly, then into gum 
 (dextrin), and finally into sugar, and as such is absorbed. I would 
 hereupon remark, that it has sometimes appeared to me as if, in the 
 nucleus of the ovule, the cytoblasts reassumed a more sharply defined 
 and younger aspect when their cells approached the period of solution. 
 A peculiar transformation of already formed cells into an amorphous 
 substance, " viscin," has been before adverted to ( 12. 6). 
 
 49. The life of the vegetable- cell continues only so long as 
 the chemico-physical processes go on within it, and these become 
 
106 ON THE PLANT-CELL. 
 
 impossible immediately that endosmosis is in any way arrested. 
 The cell is then gradually destroyed by the action of the atmo- 
 sphere, and decays, though in different ways as it is exposed occa- 
 sionally or constantly to the action of water. The causes of 
 this death may be various laceration (as in the sporangia of the 
 Cryptogamia on the escape of the spores), complete dryness, removal 
 from the situation in which alone endosmosis is maintained (as in 
 the fall of the leaf), &c. 
 
 The process of dissolution of a dead cell does not belong to Botany ; 
 we willingly commit the inquiry jnto it to Chemistry, and refer to the 
 latest and best works on the subject, byBerzelius*, Liebigf, and Mulder J. 
 The causes, however, which expose vegetable-cells to these destructive 
 influences are of interest to us ; and we may name among them, as a 
 very general one, the impossibility of endosmosis. Every vegetable-cell 
 which can no longer take up fluid, in order to maintain the chemical 
 processes within it, necessarily dies. Complete desiccation acts in the 
 same way ; and also the disruption of the cell, in consequence of which 
 isolation of the materials contained takes place, and the processes going 
 on within it cease. A peculiar state connected with this, is exhibited in 
 most of the cells which are separated from a plant in the form of leaves. 
 At the time of separation they are evidently not yet dead, for, under a 
 very favourable though extremely rare conjunction of circumstances, a 
 new process of vegetation may commence in one cell or another, in such 
 a way that an entirely new plant is thence produced. Commonly, how- 
 ever, they die altogether, it being no longer possible for them to take 
 up fluids, which had previously been brought to them in consequence of 
 their connection with the entire plant. 
 
 SECTION II. 
 
 LIFE OF THE CELL IN CONNECTION WITH OTHERS. 
 
 50. As soon as the cells are associated so as to constitute 
 tissues, they exhibit certain modifications in their vital processes, 
 and these modifications are especially worthy of consideration. 
 Much of what relates to this part of the subject has necessarily 
 been touched upon in former sections, as we are not yet sufficiently 
 advanced to be able to comprehend with absolute precision the 
 individual cell-life, and thus in many things that occur do not 
 know how much or how little is due to the influence of the con- 
 tiguous cells : much, also, that is undoubtedly referable to the 
 combined action of several cells has necessarily been adduced, as 
 serving to explain the nature of the individual cells. What we 
 have now to consider are, first, the modifications which universally 
 take place in the life of cells in consequence of their being asso- 
 ciated ; and afterwards, the special peculiarities incidental to the 
 different tissues. 
 
 * Lehrbuch der Chemie, latest edition, vol. viii. f Organic Chemistry. 
 
 \ Physiologische Chem. (Moleschott), p. 146, et seq. Translated into English, by 
 Fromberg. 
 
LIFE OF THE PLANT-CELL. 107 
 
 I. General Modifications of the Life of Cells in consequence of the 
 Association of several Cells. 
 
 51. As soon as a large number of cells are united into a cel- 
 lular tissue, part of them at least are shut out from immediate 
 contact with the nutritive fluid ; consequently, they receive nutri- 
 ment by endosmosis only from the contiguous cells, in which, 
 however, the fluid has always already undergone a change. 
 
 When all the cells of a tissue contain a fluid of equal density, en- 
 dosmosis takes place in those which are in immediate contact with water, 
 in consequence of which the fluid contained in them is diluted, and there 
 is established between them and the next cells a condition of the fluids fa- 
 vourable to endosmosis, and so on. This is the most important relation in 
 which cell-life can be viewed, because the sole, universal motion of the 
 fluids, upon which the nutrition of the whole plant is contingent, arises 
 therefrom. There are absolutely no vessels for the distribution of the 
 nutritive fluid in the body of plants ; and no person would take the 
 trouble of looking for them, or would imagine he saw them anywhere, 
 but one who goes to the investigation of plants labouring under the 
 false and pernicious prejudice in favour of the supposed unhappy ana- 
 logy between them and animals ( 63 146.). The sound sense of 
 all botanists has been much confused on this subject ; who have ad- 
 vanced every possible perversion of physics and logic, rather than part 
 with this fixed idea.* Every living cell, however, which obtains fluid by 
 endosmosis immediately induces in such fluid a chemical change and con- 
 verts it into assimilated matter, so that the cells which are remote 
 from the source of the raw nutritive fluid do not receive it in this state. 
 In them, consequently, there is no occasion for the process of assimilation 
 to go on, as far as relates to the decomposition of water and the fixation 
 of carbonic acid ; they enjoy, however, an active life, are nourished, form 
 new cells, &c., as in the woody bundles of dicotyledons. This is suffi- 
 cient to show how untenable is the law instituted by Liebig/f 
 
 52. By the arrangement of a great mass of the cells in a 
 plant, some of them are partially brought into contact with the 
 atmospheric air. From this, two important conditions result : first, 
 that the water evaporates constantly from the surface of the cell 
 in proportion to the warmth, dryness, and motion of the air, un- 
 less the cells are protected in some special manner ( 69.); in 
 consequence of this evaporation the fluid in the interior of the 
 cell is continually lessened in bulk and concentrated, and thus the 
 endosmosis towards the other cells is strengthened and sustained : 
 secondly, that the fluid contained in the cells is enabled to absorb 
 gases from the air, viz. carbonic acid and ammonia, and occasionally 
 oxygen. 
 
 * See Knight, in Treviranus's Beitrage zur Pflanzenphysiologie, Gottingen, 1811, 
 p. 162. Sennebier, Physiologic vegetale, vol. ii. cap. iv. p. 332. ; and others. 
 
 f " No material can be regarded as the nutriment of plants whose composition is/ 
 identical with or similar to their own, and consequently the assimilation of which can 
 ensue without the separation of oxygen." Lieb. Org. Chem. p. 26. The law is at 
 once simply contradicted by the great number of Fungi and true parasites. 
 
108 ON THE PLANT-CELL. 
 
 The conditions mentioned are of the highest importance as regards 
 the life of the entire plant. Carbonic acid, ammonia, and water, con- 
 stitute the chief nutritive matter of the cell, which, however, takes it up 
 in various ways. Those cells which are in contact with fluid receive all 
 the three substances at once. In this, consequently, must the most active 
 assimilating process take place. Those cells which are partially in con- 
 tact with the air obtain, it is true, on the one side, all necessary elements 
 dissolved in water, but they can also receive, on the other side, carbonic 
 acid and ammonia from the atmosphere. At the same time they give 
 out into the atmosphere a larger or less quantity of water, by the loss of 
 which their juices are concentrated, and this concentration again main- 
 tains the endosmosis. This enables us to explain how it is that after the 
 bursting forth of their leaves plants no longer abound with such very 
 watery sap, and yet continue the process of assimilation with greater 
 energy. The perfect solution is conveyed farther by the endosmosis. 
 The salts held in solution by the water and the inorganic constituents in 
 general, upon which the chemical forces of the cell have little influence 
 or none at all, are carried with the water unchanged through all the 
 cells until they reach the surface of the cells at which evaporation takes 
 place. At this point, they of necessity gradually accumulate in larger 
 quantity, which accounts for the greater residue after incineration left 
 by the leaves, green bark, &c. The water evaporated from the cell, 
 like all water when evaporating, carries away with it a small quantity 
 of non-volatile substances, on which account the water perspired by 
 plants is never quite pure *, but is impregnated more with organic than 
 with inorganic (less volatile) matter. 
 
 53. By the association of many cells, and the reciprocal in- 
 fluence thence set up, certain modifications are produced in the 
 life of the individual cells which have been in part previously 
 considered. To these modifications is probably to be referred, 
 in part, the formation of new distinct layers, and the spiral arrange- 
 ment of the material constituting these layers connected therewith. 
 This part of the subject also embraces the peculiar construction of 
 air-vesicles between two contiguous cells, upon which the forma- 
 tion of the pores appears to depend. 
 
 What refers to this subject has been already discussed ( 17.). In no 
 isolated cell, in no cell previous to its association with others into a 
 tissue, do we find spiral deposit-layers ; nor, moreover, do we observe in 
 any such the air-vesicles on the outer wall to which the canals of the 
 pores correspond internally. It appears that the canals of the pores of 
 two contiguous cells always correspond in sucli a way that they com- 
 mence from an air-vesicle of this kind, or from a space in the common 
 wall corresponding to it. We are acquainted with but few exceptions 
 to this, which, however, demand further investigation. In Juniperus 
 Sabina there occur in the bark thick-walled, four-sided, prismatic cells, 
 the pore-canals of which regularly run only towards the four inter- 
 cellular passages, which in this instance, and in a tissue which elsewhere 
 presents no intercellular passages, appear to represent the air-vesicles 
 above described. The same thing is seen in the parenchyma of the 
 petiole in Cycas (vide p. 45.). In the epidermis-cells of several plants, 
 
 * Sennebier, Phys. veg. t. i. p. 79., and many others. 
 
LIFE OF TIIE PLANT-CELL. 109 
 
 as, for instance, in Cycas and Abies, pore-canals also find their way 
 towards the free surface (vide pp. 45 50.). 
 
 54. Peculiar changes also take place in the secretions, the 
 more solid secretions assuming definite forms. To these may be 
 referred the gelatinous envelop of many Alga; the intercellular 
 substance, the peculiar matter, which invests the spores and pollen- 
 grains ; and the matters secreted from the epidermis. 
 
 Most Conferva, several Ulvce, &c., secrete a large quantity of gela- 
 tinous matter, which assumes a definite form, and thus frequently deter- 
 mines the figure of the whole plant, as in Chcetophora and Undina. In 
 most Confervce it constitutes a delicate uniform membrane investing the 
 whole plant ; in Rivularia, Chcetophora, Nostoc, &c., larger masses. It 
 is always wanting, however, in the spore, and is not formed except by 
 the vital activity of the self-multiplying cells.* 
 
 In the same way a solid substance is secreted in the intercellular 
 passages : a similar secretion, of determinate form, is also found on the 
 epidermis. The subject of both these secretions will be entered upon 
 more fully hereafter ( 59. 63.). 
 
 The most interesting and most complicated phenomenon, however, 
 still remains that of the peculiar investment of the spores and pollen- 
 grains. All spores (except those of the Algce, many Fungi, and some 
 Lichens), all pollen-grains (with the exception of those of plants which 
 flower under water), are constituted of the proper, essential cell, which 
 is formed as such, and a peculiar material investing it, which is simply 
 uniform or is furnished with warts, protuberances, spines, bands, or the 
 most extraordinary abnormal formations, disposed irregularly or with 
 the utmost mathematical regularity. The nature of this material differs 
 from all known assimilated vegetable substances in this respect : that it 
 is affected, according to Fritsche, not at all, according to others but 
 very slowly, by concentrated sulphuric acid, but is always rendered 
 more opaque, and sometimes of a purple-red colour. The matter itself 
 presents various colours, mostly yellow, though also blue, red, green, 
 brown, &c. It is a pure product of secretion of the spore, or pollen -cell. 
 I shall be obliged to say more about it afterwards, when speaking of the 
 pollen. For our best information respecting its chemical nature, but 
 especially with respect to its extraordinary forms, we are indebted to the 
 indefatigable and astonishing researches of Fritsche. f MohFs J opinion 
 upon this point that the external pollen-membrane is intercellular 
 substance, in which perfect cells or their beginnings (as granules) are 
 formed appears to be completely contradicted by Fritsche's, Meyen's , 
 my own, and Nageli's || investigations. The peculiar chemical nature 
 of the material appears at once to be opposed to any comparison of it 
 with the substances of which cells are formed. 
 
 55. The peculiar relation in which the sap-currents stand 
 
 * This condition has not been quite correctly comprehended by Mohl, Erlauterung 
 und Vertheidigung meiner Ansicht von der Structur der Pflanzensubstanz. Tubingen, 
 1836. In other respects he shows, as usual, distinguished powers of observation, 
 f Fritsche, Ueber den Pollen. Petersburg, 1837. 
 
 \ Hugo Mohl, Beitriige zur Anatomic und Physiologic der Gewachse, Part I. ; und 
 Erlauterung und Vertheidigung, &c., p. 18. and elsewhere. 
 Physiologic, vol. iii. p. 146, et seq. 
 Zur Entwicklungsgesuhichte des Pollens, &c. 
 
110 ON THE PLANT-CELL. 
 
 towards each other in their direction, in two contiguous cells, 
 manifestly depends upon the association of the cells, since in the 
 Charce, without exception, the current in the one cell corresponds 
 to a current in an opposite direction in the other. 
 
 The fact itself is indubitable, and is readily observed in Chara, and 
 partially also in Vallisneria, &c. : the reason of it is wholly unknown. 
 It shows, however, pretty distinctly, that the necessary conditions of 
 the sap-motion lie altogether or in part external to the cell, and that 
 endosmosis probably has a great share in producing them. We never 
 observe, also, in cells which are in contact with others on all sides, as in 
 Najas and Vallisneria, that the currents cover the whole of the walls, but 
 exist only on two opposite sides, which lie, throughout all the cells, in 
 parallel planes, by which the possibility of the contiguous streams being 
 frequently in opposite directions throughout the plant is explained. The 
 second kind of sap-motion in a network of minute currents is probably 
 connected with a greater degree of independence and disconnection of 
 the individual cells among themselves ; and it is also but very rarely 
 observed in the closed cellular tissue. 
 
 56. The individual cell may, as regards its own vital processes, 
 be already dead, but yet retain its connection with other living 
 cells, and probably also conduce to their vitality, and consequently 
 to that of the whole plant, for some time longer. In this way, 
 probably, the so-called vessels, at the period of the ascent of the 
 sap in spring, are reservoirs for the reception (quite passive) of the 
 superabundant sap, which is not yet fit for assimilation ; but at 
 other times they are receptacles for secreted air: the same with 
 the cells which contain special secretions, &c. 
 
 It is a peculiar condition, and one proceeding only from the high degree 
 of individualisation of the cell, and its association with others into a plant 
 without complete abolition of its own individuality, that it may be so cir- 
 cumstanced as relatively (to itself) to be dead, but, as regards the whole 
 plant, still to be deemed alive. This condition also shows how futile and 
 inapplicable all analogies between animals and plants are, two creations, 
 whose most intimate nature is so entirely different, that almost every 
 comparison proceeding upon the constitution of the elementary organ is 
 a mere delusion of the fancy, without any scientific value. 
 
 II. Peculiarities in the Life of entire Tissues. 
 
 57, It may be stated generally, that the vital processes in 
 each individual cell in the same tissue are identical, or at all events 
 very much alike : thus, similar elements frequently compose the 
 greater mass of the parenchyma ; the alburnum-bundles, the milk- 
 vessels, &c. of a plant, contain the same substances. Important 
 exceptions, however, are also met with ; and we find in the par- 
 enchyma, and in closely contiguous cells of the same form, contents 
 of very different nature ; and in the vascular bundles and elsewhere 
 
LIFE OF THE PLANT-CELL. Ill 
 
 the different vital properties of the individual cells are exhibited 
 in the varying mode and rapidity with which the cells themselves 
 are perfected. 
 
 It can only be regarded as a law having an average or general appli- 
 cation, that the cells of an entire tissue have identical functions ; and 
 such important exceptions exist in this respect, that the classification of 
 the tissues, according to supposed differences in their functions, appears 
 to be at least wholly untenable ; the morphology of the cell alone afford- 
 ing a sufficient principle to go upon. In the same parenchyma we find 
 a cell crammed full of starch, next to a similar one containing nothing 
 but essential oil ; and both, probably, contiguous to a third, filled with a 
 clear, watery, red or blue coloured matter ; whilst a fourth, together with 
 various assimilated substances, contains a large quantity of chlorophyll. 
 In the midst of the thin-walled parenchyma we observe scattered, or 
 forming groups with the others, cells of the same size and form, but 
 filled up almost to the closure of their cavity by deposit-layers, as in 
 the so-called stony concretions in the quince and pear, in the bark and 
 pith of Hoja carnosa, and of many trees, in the aerial roots of the 
 Maxillarice, and in a hundred other situations. All this indicates the 
 great independence of the individual cells, and the possibility of each 
 cell, in any situation, on occasion, going through all the phases of cell- 
 life, and becoming developed in any way that the circumstances under 
 which it is placed render necessary. The cell-life is modified only to 
 a slight degree by the mode of disposition of the cells, and consequent 
 dependence on the contiguous cells. Leaving this independence out of 
 the question, the tissues, as a whole, present certain phenomena which 
 must be regarded as peculiar to each. 
 
 58. The cells of the parenchyma enjoy the greatest degree of 
 independence, and it is, consequently, in that tissue that we find, 
 in the greatest number and disposed with the least regularity, cells 
 with the greatest variety of contents, and having the most various con- 
 figuration of their walls, next to each other. Larger masses of the 
 parenchyma present, in preponderating quantity, starch (potato), or 
 fixed oil (cotyledons of the species of Brassica), or gum (roots of 
 Althcea), or emulsin (oil and vegetable albumen in the cotyledons 
 of the almond), or assimilated substances and chlorophyll (in all 
 green leaves), or colouring matters of the same kind (in the petals 
 of flowers), or air (in the pith), &c. 
 
 59. The various formations in the system of intercellular spaces 
 comprehend a very great variety of substances. The peculiarity in 
 this case consists in the circumstance, as I believe, that all the cells 
 forming the boundaries of these intercellular spaces, without excep- 
 tion, exhibit equal vital activity ; they either exert no influence at all 
 upon the contents of the intercellular spaces, or all secrete into it 
 the same material. To this system are to be referred all the various 
 reservoirs of special secretions, resin- and gum-passages, as well as 
 the receptacles of the milk-sap ; and, besides these, the solid inter- 
 cellular substance (substantia inter 'cellularis), which frequently pre- 
 sents a determinate form, dependent on the neighbouring cells. 
 
112 
 
 ON THE PLANT-CELL. 
 
 Respecting the process by which the reservoirs of proper juices are 
 filled with the matters contained in them, the preparation of this matter 
 by the neighbouring cells, and the power through which these materials 
 are secreted within the reservoirs, we as yet know nothing. All these 
 particulars being left out of consideration, the only differences pre- 
 sented by the intercellular spaces, which are filled with a solid substance, 
 arise from the nature of the secreted substance. These spaces present 
 two varieties of form. In the wood of dicotyledons, and in other instances, 
 the narrow intercellular passages are frequently occupied by a substance 
 homogeneous in appearance, its colour and tenacity differing in some 
 degree from those of the cell-wall. 
 
 On the other hand, the constitution of the intercellular substance be- 
 tween the cells of the external cortical layer in the Chenopodiacce, Ama- 
 ranthacece, Umbelliferce, Malvaceae, &c., is more remarkable. 
 
 If we examine these cells in a 
 transverse section of Abutilen 
 graveolens (fig. 99.), we observe 
 large intercellular spaces formed 
 by from three to six cells (b). From 
 each of the cell-walls, forming 
 the boundaries of the space, there 
 projects into it a semi-solid, semi- 
 gelatinous mass (a); the aggre- l^J^1/~Xi/ V V/ JLt 
 gate, however, of these masses 
 is not sufficient to fill up the 
 whole intercellular space. 
 
 In Amaranthus viridis (fig. 100.), three cells on a transverse section 
 present a stellate form (b\ and in this way constitute very spacious, 
 
 100 
 
 rounded, intercellular passages, which also are partially filled with a 
 secreted substance (a), exhibiting concentric laminse, which run parallel 
 
 99 Transverse section from the outer cortical layer of Abutilon graveolens. a, The 
 intercellular substance secreted by the cell-walls. 6, Cells. 
 
 100 Transverse section of the outer cortical layer of Amaranthus viridis. a, The inter- 
 cellular substance secreted in lamina? by the cells. 
 
LIFE OF THE PLANT-CELL. 
 
 113 
 
 to the cell-walls from which they are secreted. The 
 latter circumstance appears to me to be decisive of 
 their nature as a product of secretion. 
 
 Lastly, upon examining the same formations in 
 Justicia carnea, in a longitudinal section (fig. 101.), 
 the secreted substance is seen to be continuous 
 throughout the whole length, between the rows of 
 cells, and presenting only indistinct traces of divi- 
 sion. 
 
 The history of the development of these forma- 
 tions is at present deficient. Mohl's * earlier opi- 
 nion, according to which the intercellular substance 
 is said to be the remains of the primordial ma- 
 terial in and from which the cells are formed, I 
 consider decidedly incorrect, and to be contra- 
 dicted by Meyen'sf discovery of the division into 
 portions of the intercellular substance. He has 
 himself also, perhaps, since then relinquished this 
 notion. 
 
 It appears, however, to me that, to the above de- 
 scribed formations in the external cortical layer in 
 the families mentioned, and some others, other dif- 
 ferent but analogous forms must be referred, par- 
 ticularly the cells of the cotyledons in Scholia 
 speciosa and latifolia, Tamarindus indica, and some other Leguminosce, 
 as well as the very similar formations between the angles of the epider- 
 mal cells in many species of Begonia, and of the leaf-cells in several 
 Junyermannice. In these instances, also, a triangular intercellular space 
 appears to be filled with a substance secreted from the three cells form- 
 ing its boundaries, as has been also observed by Meyen J in Begonia. 
 Of some formations (particularly those in Schotia and Jungermannice), 
 Mohl has now offered an explanation similar to that which he gives of 
 the secreted layer in the epidermis, viz., that the cells are thickened by 
 a laminated deposit on the internal surface, in consequence of which the 
 outer layers must necessarily constantly undergo a change in their 
 chemical nature, for in all these formations the apparently perfectly 
 continuous cell-membrane bounds the cavity of the cell. How far Mohl 
 is inclined to extend this view of his to other conditions, I know not. I 
 must confess, that the view propounded by Meyen at present appears to 
 me to be inadmissible. As yet, however, a complete history of the de- 
 velopment of these structures is wanting, to enable us to arrive at a more 
 certain conclusion. 
 
 The semi-fluid gelatinous matter which occurs in the intercellular 
 spaces of the albumen of the Cassice and other Leguminosce, between 
 the cells of the Lichens, especially of the utricular layer, but, above 
 all, in the intercellular spaces of the Fucoidece, which latter very 
 nearly approaches dextrin (?), presents a manifest transition from the 
 
 * Erlauterung und Vertheidigung meiner Ansichten uber Pflanzensubstanz, &c. 
 f Physiologic, vol. i. p. 170. J L. c. 
 
 101 Longitudinal section through the outer cortical layer of Justicia carnea; perpendi- 
 cular rows of cells with chlorophyll granules, intercellular substance, secreted on both 
 sides of the intercellular passages. 
 
114 ON THE PLANT-CELL. 
 
 intercellular substance to gum. The cells are occasionally observed 
 to exist previous to the formation of these matters ; and the latter are 
 found to increase,, instead of diminish, on the completion of the cellular 
 tissue ; consequently they are in all probability secreted by the cells. 
 
 60. All the cells of the vascular bundles exhibit nearly iden- 
 tical vital processes, and differ for the most part only in their age 
 and the configuration of the walls dependent upon their age. The 
 vessels, when completed, convey air, and perhaps admit juices, but 
 these only occasionally for a short time, and in any case passively. 
 The other elongated cells of the .prosenchyma exhibit, as long as the 
 tissue is living, a rapid change of matter in their interior, and, con- 
 sequently, in general contain a homogeneous watery fluid. They 
 subsequently lose their vitality, and then convey nothing but air. 
 
 That the vessels convey only air, and no juices, may be seen by 
 any one, possessing the least physical knowledge, on the most cursory 
 glance at a longitudinal section of a plant. That any dispute should have 
 arisen on this point, only shows how exceedingly confused most observers 
 are by prejudices and supposed analogies : it is not worth while, however, 
 to waste words about it. It has been already remarked (pp. 57, 64.), that 
 the cells of the vascular bundles probably owe their elongated form itself 
 to a rapid current through them of the sap in a determinate direction, by 
 which means their extremities are more vigorously nourished than their 
 sides. This rapid change explains the circumstance of the chemical 
 processes carried on in them being very simple. We very seldom find 
 peculiar substances formed in them as long as they retain their vitality : 
 even the more solid assimilated matters, as starch, occur in them but 
 seldom, and in small quantity. When they have begun to lose their 
 vitality, however, (to constitute heart -wood,) they for the most part cease 
 altogether to convey sap ; and where they are not completely protected 
 against the external air and moisture, a process of chemical decomposition 
 (decay) is set up, in consequence of which, although retaining their 
 form, they are gradually converted into substances rich in carbon. The 
 peculiar products of the wood, tannin, extractive matter, colouring 
 matter, probably for the most part owe their origin to this process ; less 
 frequently to the sap-channels, bounded by parenchymatous cells, which 
 penetrate the wood, as is the case with the resinous products in the 
 Conifer CB. This subject, however, still presents an extensive field for 
 further investigations. 
 
 61. With regard to the peculiar vital properties of the liber- 
 cells, of the usual form, as seen in the Apocynacea and of the 
 milk- vessels, our knowledge is equivalent to nothing at all. Every 
 thing with respect to these remains to be investigated. 
 
 On the subject of these structures, and especially on the milk- ves- 
 sels, I am rather afraid of saying too much than too little, for, owing 
 to the total neglect of a correct, scientific method, and the puerile sporting 
 with hypotheses, without any foundation or guiding principle, the 
 question respecting them is loaded with such a heap of nonsense, that the 
 best way in beginning upon it is, in the first place, to throw overboard 
 all that has hitherto been done and commence entirely de novo, instead 
 of undertaking the thankless task of cleansing this true Augean stable. 
 
LIFE OF THE PLANT-CELL. 115 
 
 In the works of our first botanists we meet with such propositions as 
 this : " The vessels of the stem which belong to this system are the 
 expressions of the two foci of the ideal ellipse of the true peripheric cir- 
 culating system. The one abside conducts towards the light, .... the other 
 abside carries the diagonal of the former in an opposite direction into the 
 
 darkness " Words like these are so entirely without meaning, that 
 
 one scarcely knows what to say to them. But when once the reins of a 
 sound method are broken, there is no stopping short of the most absolute 
 nonsense, the writer not even having the least suspicion of it. Almost 
 every page that has been written on the milk-vessels exhibits proofs 
 of superficial observation, unbridled fancy, unscientific physical notions, 
 &c. The whole idea of a universal intercommunicating system of vessels 
 throughout the plant (" a cell with multifarious ramifications through the 
 plant, but closed in itself," Meyen) is purely visionary (how could the 
 few little sections, taken from a plant upon which observations are made, 
 afford foundation for a notion of this kind ?) ; but writers have been sa 
 deeply smitten with it, as to have adduced it as the fruit of observation 
 with the utmost coolness. Up to the present time, a motion of the milk- 
 sap has been noticed in only two or three uninjured plants ; and even in 
 these instances only by the direct light of the sun, observations made with 
 which are so open to optical illusion : from them, however, a universal 
 circulation is boldly deduced, and its direction, even through the entire 
 plant, described with the utmost precision. The escape of the sap from 
 cut portions is viewed as a decisive proof of its motion in the uninjured 
 part. Does not the wine in a cask also move as it runs out, when the tap 
 is turned and the equilibrium which had hitherto existed is destroyed ? 
 " The sap is expelled only by a vital action, otherwise it would be 
 retained by capillary attraction," say others. But do those who make this 
 assertion know what capillary attraction is ? Unyielding walls are essen- 
 tial to it, but not thin membranes in a turgescent tissue. Do they know 
 how capillarity acts? that it exhibits a determinate relation to the size 
 of the tube, the nature of the material of which the tube is composed, and 
 the mutual relations of the fluid and tube towards each other; and also 
 that it exists as capillary elevation or capillary depression ? Have they 
 measured the diameter of the latex-vessels, and determined the capillary 
 force of the substance composing the tubes and of the fluid, and from 
 these data calculated their capillarity ? Oh! no, it is much easier to 
 weave vain fancies than to make accurate measurements and precise cal- 
 culations ? What is the amount of the flow, then, from a stem when 
 cut across ? Very little ; and it is necessary to make a fresh section to 
 procure another flow of sap, and so on. In this case it would not be 
 wholly improbable that the capillarity should actually retain some of the 
 sap after the escape of that portion of it which could not be thus retained. 
 But in every case, however the escape is effected, leaving out of view 
 the actual motion of the sap in uninjured plants, by the turgescence of 
 the contiguous cellular tissue; and this cause must always be first taken 
 into account. It explains, for instance, very readily, the reason why more 
 sap escapes from the upper end of a cut stem than from the] lower ; 
 because the younger cells, with more yielding walls and more distended 
 with fluid, must necessarily enlarge more than the more closely united, 
 older, and thick-walled cells in the lower portion of the plant. Argu- 
 ments of this kind might be multiplied to a great length, but what I have 
 observed is sufficient to show how very superficially this subject has been 
 treated. It is by no means my intention in this way to prove the non- 
 
 l 2 
 
116 
 
 ON THE PLANT-CELL. 
 
 J02 
 
 existence of the motion of the latex, but merely to show that the mode in 
 which this subject has hitherto been treated cannot lead to any useful 
 scientific result. 
 
 When the facts themselves are consulted we must accurately divide 
 them into two sets ; those which are derived from the prepared, and those 
 from the uninjured, plant. It must, moreover, here be remarked that in 
 the very young condition only a clear watery fluid is contained in the 
 latex-vessels, and consequently that it is impossible to observe any 
 
 motion in it ; and that in ves- 
 sels of a certain age, and with 
 thick walls, the latex coagu- 
 lates in many ways, and is 
 transformed into a solid mass, 
 as, for instance, in the Eu- 
 phorbiacce. The question re- 
 specting a motion can only 
 arise principally with respect 
 to vessels of an intermediate 
 age. Under these circum- 
 stances, when a section is 
 placed under the microscope, 
 a rapid motion is noticed in 
 the, for the most part granu- 
 lar, sap *, frequently in oppo- 
 site directions. Upon looking 
 at the extremities of the cut 
 vessels, a protruded and coa- 
 gulated mass will be found at 
 each end of the same vessel, 
 and at the same time an outward current will be remarked at each side 
 or the commencement of such a current at one side ; and when the 
 escape of the fluid is stayed at this point by the coagulum, immediately 
 after its cessation, an outward current will be established on the other 
 side : so that it is impossible, without a preconceived notion, to regard 
 this motion as it appears in these observations as one having a deter- 
 minate direction. 
 
 In uninjured plants, the motion of the latex can very seldom be suc- 
 cessfully shown : even in Chelidonum ma jus it is only occasionally pos- 
 sible, and then presents great optical difficulties. It is easy, on the other 
 hand, to observe it in Alisma Plantago. In this case a motion is un- 
 doubtedly visible, viz. a current sometimes more rapid, sometimes slower, 
 and, in the same vessel, sometimes in one direction, sometimes in the 
 other, but frequently alternating with very long periods of quiet. Of a 
 regular motion in a determinate direction, I have never been able to ob- 
 serve any indication. What I have just stated, then, may in general 
 terms be said to include all that I have been able to arrive at as a certain 
 result, from the most careful observations made on the most different 
 
 * Meyen, who at one time saw cells everywhere as Muscos volitantes, also regarded 
 these granules in the same light. They are, however, decidedly consistent, solid 
 granules. 
 
 102 Latex-vessel from the leaf of Limnocharis Humboldti. At the commencement cf 
 the observation, the upper end (a) emptied itself and collapsed. The arrows indicate 
 the observed direction of the outward current. Every latex-vessel is bordered by two 
 rows of narrow, somewhat elongated, parenchymatous cells (&). 
 
LIFE OF THE PLANT-CELL. 117 
 
 plants, and under the most varied circumstances. Every one having 
 the slightest idea of what experiments, hypothesis, induction, and theory 
 really signify in the natural sciences, will certainly agree with me, that, 
 in the generally defective state of our knowledge respecting the physical 
 and chemical processes going on in plants, it would be altogether a 
 childish undertaking to attempt to weave a theory out of elements such 
 as these ; and any others are, as yet at least, in dispute. Let any one 
 that will have recourse to the convenient scape-goat of a universal vital 
 power amuse himself with it, but he must not imagine that in doing so 
 he is proposing any thing profound or really scientific. It is also clear 
 that we have no certain facts sufficient to afford foundation for an ana- 
 logy with the motion of the blood in animals, even allowing that this 
 analogy is any thing more than an idle and fanciful notion. 
 
 Respecting the contents of the latex-vessels and of the other two forms 
 we know just as little. They differ specifically in almost every plant, 
 and frequently in different individuals of the same species, at least in 
 the quantity of the separate constituents. It would appear that the latex 
 pretty generally contains caoutchouc in granules, in greater or less quan- 
 tity according to the age and the manner of vegetation of the plant. 
 It also presents a great number of peculiar substances, for the most part 
 of a poisonous, at all events of a highly suspicious, nature. Of the 
 contents of the liber-cells we know nothing at all. "With regard to 
 the importance of the latex, in respect to the life of the plant, if we 
 disregard Schultz's wholly unfounded fancies, we are also entirely in 
 ignorance. Meyen*, after collecting all the cases in which the latex is 
 innoxious, and showing that, in many instances where it is poisonous, 
 innoxious substances are also found in it, concludes " that the latex 
 may be a thoroughly elaborated nutritive juice, at least as regards man 
 and animals, and therefore the assumption that it also plays the part of 
 a nutritious sap in the plant is certainly not inadmissible." It is cer- 
 tainly impossible to arrive at a conclusion more illogically. Commencing 
 with the absolutely poisonous latex of Antiaris toxicaria, Hippomane, 
 ami Exccecaria, when it is shown how frequently an innoxious latex, 
 as, for instance, that of the young lettuce, becomes poisonous as soon 
 as the plant is only in some degree perfected, how the poppy can be 
 poisoned with opium, and the lettuce with lactucarium, there would 
 appear to be much better reason for arriving at an exactly opposite con- 
 clusion. But, on this subject, the question is not at all as to inferences 
 and conclusions ; we have here to deal only with suppositions and asser- 
 tions. 
 
 Probably all these organs, like the latex receptacles by which they 
 are frequently replaced, are for the purpose of receiving matters, and 
 preventing their reaction upon the living cells, which would otherwise 
 be detrimental to the life of the plant. This is at all events indicated 
 by the circumstance that almost all vegetable poisons, and which act as 
 such on the very plants by which they are yielded, are found in the 
 latex ; but, as yet, nothing but the most vague suppositions can be 
 broached. Liebig'sj* notion, that in plants with a milky sap the water is 
 surrounded by an impervious case of caoutchouc, and that plants in a hot 
 climate are thus secured against desiccation, arises from a complete ig- 
 norance of vegetable structure. 
 
 * Pflanzenphysiologie, vol. ii. p. 410. 
 f Organische CbcMiiie, p. 57. 
 i 3 
 
118 ON THE PLANT-CELL. 
 
 62. Of the filamentous tissue of Fungi and Lichens we know 
 at present next to nothing. The cells usually contain a clear co- 
 lourless juice ; in the Lichens, occasionally, air. 
 
 63. The epidermal cells contain a clear aqueous or coloured 
 fluid, rarely here and there peculiar substances, as resin (in Aloe 
 nigricans). Externally the true epidermis affords peculiar secre- 
 tions, at first a waxy material, usually in the form of a delicate 
 layer, which renders the surface smooth or shining, more rarely 
 in that of minute granules (the so-called bloom, pruina), in 
 either case protecting the epidermis against being wetted or pene- 
 trated by water, thus rendering all interchange of gases and va- 
 pours impossible excepting only through the stomates. A second 
 layer (cuticula) is subsequently formed beneath this first secretion, 
 which is composed of an assimilated material not yet precisely 
 investigated. This layer is in many cases of great thickness, and 
 constitutes tubercles, warts, and such-like productions, especially 
 in the neighbourhood of the stomates. In their vital properties 
 these epidermoidal appendages exhibit numerous varieties, and in 
 them again we meet with very various contents and peculiar 
 secretions. With respect to cork, we only know that it soon dies 
 and decays bit by bit. 
 
 The epithelium differs from the parencliymatous cells only in its clear 
 aqueous juice : the epiblema has not as yet been sufficiently investigated. 
 But as soon as the epithelium is converted in the air into epidermis, it 
 becomes covered with a delicate layer of a material which can be re- 
 moved by absolute alcohol or ether, and which always gives the epi- 
 dermis a certain brilliancy, and affords a perfect protection against its 
 being wetted by water : the latter is the most important point. We 
 well know that a membrane penetrated by moisture offers no impediment 
 to the evaporation of the water enclosed by it, and to the absorption and 
 transmission of gases, but that the contrary is the case with a dry mem- 
 brane. In this way the epidermis isolates the cells of the parenchyma 
 from all action of the atmosphere, as, owing to the intervention of the 
 epidermis, they cannot receive anything from it nor give out anything 
 to it. The whole reaction, therefore, is limited to the stomates, through 
 which alone is evaporation or interchange of gases possible. This pe- 
 culiar investment of the epidermis has been hitherto wholly unnoticed, 
 and has been recognised only in those cases where it is presented in 
 greater quantity, in the form of minute granules, as the " bloom : " 
 it exists, however, on every epidermis, and may be removed by ether, 
 when the cells of that membrane, like all others, become permeable to 
 water. 
 
 In a section perpendicular to the surface this waxy secretion can be 
 demonstrated only in those cases in which, as in Elymus arenarius, 
 Strelitzia farinosa, &c., it attains a considerable thickness : conse- 
 quently it is not shown in all the woodcuts appended to this Section. 
 
 The object of preventing, by this layer, all evaporation, &c. on the 
 surface of plants is probably still further promoted by the secondary 
 secretion. 
 
 Upon examining a fine transverse section of the epidermis of Aloe 
 
LIFE OF THE PLANT-CELL. 
 
 119 
 
 103 
 
 nicjricans (fig. 103.), epidermis- 
 cells enlarged outwardly into 
 papilla? will be observed, al- 
 though the surface of the leaf 
 is very nearly smooth, the 
 spaces between the epidermis- 
 cells being filled up by a 
 material which extends out- 
 wardly far beyond them, is 
 readily distinguishable from 
 the cell-membrane by its op- 
 tical properties (fig. 103. c). 
 
 When a very young leaf of 
 Hyacinthus orientalis is in- 
 spected, it will be seen to be 
 enveloped merely by a de- 
 licate epithelium, the cells of 
 
 which are slightly elevated on the external surface in a vesicular manner- 
 During the further development of this epithelium a gelatinous matter 
 appears first in the depressions between the cells, which soon hardens, 
 and thus represents a network, the meshes of which indicate the limits 
 of the cells. In a short time the cells are wholly covered with a similar 
 layer, which is firmly united with the network above described, and 
 which, also, rapidly hardens. The epidermis-cells now secrete on their 
 external surface a material of less 
 consistence and density, which raises 
 the former layer, together with the 
 fibrous network, and gradually attains 
 considerable thickness. 
 
 These distinct portions may be 
 observed even in the completely- 
 formed cuticle of Dipsacus fullonum 
 (fig. 104.) But in this instance the 
 epidermis- cells (c) secrete this layer, 
 not only on their external aspect (a), 
 but also secrete an intercellular sub- 
 stance on their internal aspect (b) ; 
 and in this respect the same condition 
 obtains in the layer of cells imme- 
 diately subjacent to the epidermis. 
 
 103 A section perpendicular to the surface of the leaf of Aloe nigricans. a, Canal of 
 the stomate, filled with orange-coloured granules of resin. b, Cavity beneath the 
 stomate, surrounded by cells, containing in part chlorophyll granules (black in the 
 figure), and in part rose-red or orange-coloured resin granules. The papillary cuticu- 
 lar cells are filled with fluid of a brighter or darker red, and in part with rose-red 
 resin granules. Of the two cells forming the stomate, the one contains chlorophyll, 
 the other a single large bright-yellow granule of resin, c is the secreted layer of the 
 epidermis-cells. 
 
 104 A section perpendicular to the surface of the leaf of Dipsacus fullonum. c, The 
 epidermis-cells, with their granular contents. , The secreted layer of the epidermis 
 cells, on their external surface. The most external portion of this secreted layer is 
 more dense, and readily distinguishable ; beneath it, and corresponding to the furrows 
 between the cuticular cells, is a fibrous network, also composed of a more dense ma- 
 terial. The epidermis-cells also secrete from their internal surface an inteicellular 
 substance, which, in this situation, joins that which is secreted by the subcuticular layer 
 of cells, which cells are again covered, on their internal aspect, with an intercellular 
 substance, resting upon the more lax green parenchyma. 
 
 i 4 
 
120 
 
 ON THE PLANT-CELL. 
 
 The cuticula (6) is remarkably thick in the Tree Carnation 
 (baumnelke) (fig. 105.), in which the first and firmer secretion can also 
 be clearly distinguished from the subsequent and softer deposit. 
 
 105 
 
 105 
 
 In Cycas revoluta (fig. 106.) the entire secreted layer is homogeneous ; 
 but in this plant an interesting condition is presented, the epidermis- 
 cells exhibiting pores on the external wall, in consequence of which it 
 is more easy to distinguish the membrane of the epidermis-cells from 
 the secreted layer. 
 
 Hugo Mohl * has furnished a whole series of other peculiar modes in 
 which this secreted layer is formed. 
 
 Sometimes the first secretion is formed more prominently in definite 
 situations ; for instance, .on the middle of the cell (P/tormium tenax~), 
 or at two or three points, or at the margins of the stomates (Agave 
 americana), constituting warty and other similar productions. It 
 is frequently deposited so irregularly that it appears as if scratched 
 with needles, as in Epidendrum elongatum. In most cases the secretion 
 manifestly differs in aspect from the outer wall of the epidermis-cells. 
 Frequently the wall of the cells merely appears to be thickened ; but, 
 even in this case, careful maceration will render the secreted layer 
 evident, which is elsewhere readily seen. It is in this way that the 
 membrane termed cuticula by Brongniart is obtained, f Along with 
 this secretion, that of the waxy substance is also probably developed ; 
 for the more brilliant and less pervious to water, and the less readily 
 deprived of that property by means of alcohol, do we find the epidermis 
 cells to be in proportion to the greater thickness of the last-described 
 layer. 
 
 I must here, however, mention two different views that have been 
 more lately advocated respecting the layer of secretion on the epidermis. 
 The former has been developed by H. Mohl in the Linnsea (1842). He 
 is of opinion that the secreted layer is wholly formed from the outer 
 walls of the eprdermis-cells, which become thickened in the usual lami- 
 nated manner, and, in fact, in such a way that normally the innermost 
 last-formed lamina acquires the nature of the original membrane, whilst 
 the exterior older lamince become gelatinous, or otherwise variously 
 modified by the common membrane. This view is based upon very pre- 
 cise and comprehensive investigations of the perfect epidermis, to which 
 
 * Linnaea, 1842. 
 
 f Annales des Sciences natur. torn. xxi. 
 
 105 Perpendicular section through the epidermis of the leaf of a Tree Carnation, 
 e, Epidermis-cells covered with the secreted layer (fe), which, externally, is constituted 
 of a more dense deposit, cr, Passage through the secreted layer to the stomate. 
 
 106 Section perpendicular to the surface of the leaf of Cycas revoluta. The epidermis- 
 cells (6) are porous on the lateral and external aspects, and, on the latter, covered with 
 the secreted layer. 
 
LIFE OF THE PLANT-CELL. 121 
 
 Mohl very briefly adds the remark, that the development is also in 
 accordance with it. I believe that a thoroughly complete history of the 
 development of this structure would have been on all accounts of greater 
 importance than the most comprehensive observation of it in its com- 
 pleted state. I believe that H. Mohl will be obliged to admit with me 
 that all the completed forms may, in the absence of any preconceived 
 opinion, be explained at least as well according to my view. I believe, 
 however, that his mode of explaining this formation is met by insuper- 
 able difficulties in certain conditions, as, for instance, in Cycas revoluta 
 on account of the formation of the pores, which elsewhere universally 
 proceeds from the original cell-membrane. By far the most simple and 
 most natural explanation of this formation in Cycas appears to be the fol- 
 lowing : that on the one side (externally) a secretion has been deposited, 
 and on the other side (internally) a thickening of the original cell-mem- 
 brane has been effected by the formation of lamina, up to the commence- 
 ment of the pore-canals. In this case, also, the observation of earlier 
 conditions shows that the pores become visible at least simultaneously 
 with the commencement of the formation of the " cuticula," and probably 
 even somewhat earlier ; a fact that is totally irreconcilable with the view 
 advocated by Mohl. I must continue, for the present, to consider my 
 view as supported by the observation of the course of development of 
 the secreted layer. Especially do the observations on Oryza sativa, the 
 Hyacinth, and on Dipsacus fullonum, appear to me to afford sufficient 
 assurance of its being well founded. 
 
 The second view has been proposed by Hartig (Beitrage zur Entwick- 
 lungsgeschichte der Pflanzen, 1843). He assumes that the first cell, the 
 foundation of the whole plant (primary cell), remains persistent, and 
 envelopes the entire plant, continuing to grow during the whole life of 
 the latter ; that it is sometimes drawn through the stomata into the 
 intercellular spaces, and is sometimes continuous over the stomata, 
 closing them up. * This primary cell subsequently acts like all other 
 cells ; that is, it secretes, as " ptychode," an " astathe," and " eustathe," 
 which would appear to be my " secreted layer," the history of the de- 
 velopment of which is given with perfect correctness, and accords with 
 mine. With respect to this it is to be remarked, that, in direct opposi- 
 tion to his entire view of the mode of formation of cells, Hartig in this 
 case assumes that the " eustathe" is formed before the " astathe ;" more- 
 over, although a secretion may be allowed to take place in the case- of 
 cells with amorphous contents, in which chemical changes are proceeding, 
 it cannot be admitted to occur in Hartig's imaginary primary cell, which 
 has no proper contents at all, but merely encloses the cells of which the 
 plant is constituted. Consequently, in this case the epidermis-cells must 
 have secreted exteriorly their proper " eustathe" and " astathe," and 
 then, by means of these and the ' ptychode" of the primary cell through- 
 out, also the "eustathe" and "astathe" of the primary cell. It will, 
 from what precedes, be already evident that this view is very obscurely 
 worked out, and consequently cannot in any way be derived from direct 
 observation. Moreover, it is again to be remarked that the existence of 
 the primary cell in the form of a membrane immediately superjacent 
 
 * This double relation of the cuticula to the stomate is of itself in the highest 
 degree improbable, and is evidently only imagined in order to bring into accordance 
 \\-i.h the notion set up by him of the primary cell the incontrovertible fact that the 
 stomate, for the most part indubitably open, leads into the subjacent intercellular 
 space. 
 
122 ON THE PLANT-CELL. 
 
 upon the epidermis-cells is not proved by Hartig in a single actual in- 
 stance ; and proof is also wholly wanting, that the delicate " cuticula," 
 rendered evident on the embryo by sulphuric acid, is identical with the 
 presumed "ptychode" of the primary cell lying immediately upon the 
 epidermis-cells, and much less with the outermost secreted layer (the 
 "eustathe") of the epidermis-cells. I consequently consider the view 
 which I have developed, and which is not, as Hartig says, the general 
 one, but peculiar to myself, to be, as yet, the better founded and more 
 correct of the two. 
 
 The two cells of the stomate do not differ, as has been previously re- 
 marked, in their contents and vital properties from those of the subjacent 
 parenchyma. The width of opening of the fissure left between them 
 varies at different times, and in different parts in the same plant ; and 
 it is thence evident that the degree of admission of atmospheric air to 
 the parenchyma is variously modified. Our knowledge with respect to 
 these cells is, as yet, very imperfect, and we do not even know whether 
 the contraction of the fissure be effected by the turgescence or by the 
 collapse of the cells. The latter appears to me to be the more probable 
 supposition, because when the evaporation is too rapid, in which case 
 these cells are evidently the first affected, it would by this means be 
 checked. 
 
 The appendicular organs, again, consist of cells, which, like the paren- 
 chyma, have necessarily relinquished less of their individuality, owing 
 to which innumerable peculiar processes continue to be exhibited in 
 them, the production of special substances, some of which 
 are secreted, particularly viscous, saccharine, resinous matters, 
 and essential oils. The conditions exhibited in these organs 
 are endlessly multifarious, and what is necessary regarding 
 them has already been partly referred to. 
 
 To one phenomenon, however, I must here direct attention. 
 The stinging hairs of the Boraginacece (Borago officinalis, 
 fig. 107.) and Urticacece become filled, when old, from the point 
 towards the base, with an assimilated material deposited in 
 laminae, and differing from the wall. In the Urticacece (in the 
 BoraginacecB I have not as yet been able to observe any thing 
 similar), this deposit, when it has extented to the dilated base 
 of the hair (fig. 108. c), constitutes a globular mass projecting 
 into the base of the hair, the peduncle of which is sometimes 
 longer and sometimes shorter (Ficus, Broussonetia), and 
 which is occasionally beset with minute crystals of carbonate 
 of lime (fig. 109.). In Cannabis a minute point only of 
 these hairs projects above the epidermis ; in Urtica cana- 
 densis there is merely a large globular cell, level with the sur- 
 face of the epidermis ; in Parietaria judaica, Humulus, Forskcehlia tenacis- 
 sima, a similar cell (a) is placed beneath the epidermis (&). I believe 
 the latter might be regarded as stinging hairs, normally undeveloped in 
 accordance with a specific law. * 
 
 * Meyen (Miiller's Archiv, Jahrg. 1839, p. 257.) discovered these concretions in Ficus. 
 Payen (Froriep's Notizen, Vol. xvi. No. 335.) found them in several plants, and there- 
 upon has woven a prolix soi-disant theory a la mode Frangaise, which, to a physiologist 
 with more precise notions, carries its own refutation with it. 
 
 K7 Upper part of a hair of Borago afficinalis, at first thickened by a laminated de- 
 posit, and afterwards gradually filled up from above downwards by a solid material. 
 
 107 
 
LIFE OF THE PLANT-CELL 
 
 123 
 
 
 109 
 
 64. The cells of the root sheath contain only air, and probably 
 serve for the condensation of the aqueous vapour, and the con- 
 veying of it to the parenchyma of the root. 
 
 Here we have again an unsolved mystery of which I can give no other 
 explanation, although the consideration of the conditions under which 
 these roots occur in plants, growing for the most part without earth in 
 an atmosphere saturated with moisture, may throw some light upon the 
 subject. I do not allow much importance to the supposed great hy- 
 groscopicity of the spiral fibres, which is always put prominently forward 
 by Meyen ; but attribute more to the extreme porosity of this layer, which 
 probably acts in the same way as freshly burned charcoal. 
 
 los Perpendicular section through the epidermis (e?) of the leaf of Fiats Carica, by 
 which two hairs (a and &), with dilated basal portion, are laid open. In the figure, the 
 point of b is left. Both hairs are filled towards the upper part by gradual deposits, 
 and these concretions (c) hang down into the basal dilatation of the hair-cell. In the 
 hair marked b, this concretion consists of three united portions. 
 
 !09 Section perpendicular to the surface of the leaf of Humulus Lupulus, through 
 the epidermis (b), and some of the subjacent parenchymatous cells, a, An epidermis- 
 coll dilated inwardly into a vesicle, analogous to the hairs of Ficus. The narrower 
 extremity is filled up, and from this part depends by a sort of peduncle a concre- 
 tionary mass into the dilated portion of the cclL 
 
124 
 
 THIRD BOOK. 
 MORPHOLOGY, 
 
 65. MORPHOLOGY is the study of the forms of plants, and of their 
 several parts. It is divisible into a general branch, which elucidates 
 all that has reference to plants and their organs in general; and a 
 special branch, which treats of plants according to their principal 
 groups, as well as their individual organs : and this latter branch, 
 again, is separable into two parallel sections, namely, the delineation 
 of external form, and the delineation of internal structure, or of 
 the peculiar composition of plants and their parts from various 
 tissues. 
 
 In my methodological introduction I have endeavoured to show that 
 the external morphology of plants is really the most important sec- 
 tion of Botany. A mere glance at the history of the science will con- 
 vince any one of the truth of this view, for it is truly wonderful to observe 
 how far it has succeeded, to the almost entire neglect of all other 
 scientific knowledge, in taking possession of the material by merely 
 examining its exterior, and arranging it in such a manner that the 
 systems which, in recent times, have taken another path I allude to the 
 anatomico-physiological have scarcely effected more than the introduc- 
 tion of extremely trifling changes, in some instances clearly untenable, 
 and others at best of very doubtful validity. The morphological method 
 of observation has certainly, from the origin of the science, been the 
 basis of all treatises on Botany ; but those who have thus pursued it have 
 been far from taking a strictly scientific view of the question, or seeking 
 in this way for the solution of its difficulties. This task is two-fold, at 
 once empirical and theoretical. In its first character, the study requires 
 us to examine into and characterise the fundamental forms which, us 
 types, or conceptions of generic and specific shapes, constitute the basis 
 of individual forms. In its second character, this study has to unfold 
 the natural laws according to which these types are formed, and which 
 control and explain the deviations that occur in individual forms from 
 their prototypes. For the first, or empirical part of our researches, we 
 may congratulate ourselves on having some little information, although of 
 a very fragmentary nature ; but in the second, or theoretical department, 
 we have scarcely even an indication to guide us. That the solution of the 
 difficulties must be sought by beginning from the simplest case is evident, 
 and here Schwann has certainly shown eminent acuteness in establishing 
 the analogy between the formation of crystals and that of cells ; but 
 unfortunately we have not yet brought the law of crystalline formation 
 into the dominion of science. Thus at the present time we can do no 
 more than specify the problem presented to Botany, the solution of which 
 
MOKPHOLOGY. 125 
 
 is alone to be expected when the mathematical construction of the 
 formation of crystals lies perfectly complete before us. If, however, this 
 is ever to be effected, we must enter upon all possible construction in a 
 very different way from what has hitherto been done. For this purpose, 
 we must consider somewhat more exactly the characteristics of organic 
 form, especially the vegetable, as opposed to the inorganic. The 
 inorganic form, the crystal, is permanent when once formed ; it is un- 
 changeable ; the individual (the individual existence) is the form itself, 
 and by its solution and change of form a new individual arises. In the 
 plant, on the other hand, the form is not stable, or permanent, but an 
 ever-changing one. The analogies between the two hold good only in 
 the simplest cases. The nucleus of a crystal originates in a definite form, 
 and then passes through a series of forms, until it reaches the deduced 
 crystalline form. As such it then remains unchangeable until the 
 individual is destroyed with the form. Thus, certainly, it has a very 
 simple history of development, but this continues merely so long as 
 something is still being added to that which is already present until 
 the whole is completed. The cell is formed in a manner somewhat 
 analogous to this, originating in a "definite form, and passing through a 
 series of changes, which, as it appears, only contribute new matter 
 until the form is complete ; this then remains stationary until its solution 
 and the consequent destruction of its individuality. It is, however, 
 wholly different in combined forms, and these it is which, with few 
 exceptions, compose what we term plants. Here a number of cells com- 
 bine together within definite external limits ; but these cells themselves 
 do not enter into the form as dead particles of the mass ; they continue 
 to develop new cells, whilst the old ones are partially destroyed : the 
 newly originated cells change, by their arrangement, the form of the 
 whole, and, since formation of new parts and destruction of the old are 
 continually going on, the general boundary of the whole never appears as 
 anything definitely fixed. As, however, this metamorphosis is constant 
 in its nature, and only occurs in individual parts, we cannot regard each 
 one of the forms resulting from this process as a new one, but merely as 
 a slight modification of the one immediately preceding it ; and this 
 peculiar connection brings the whole to us as one individual, which, at 
 its first appearance, may be entirely different in all its parts, both in 
 shape and material, from what it is at last ; but in the conception of 
 which we must comprehend the whole series of changing forms, wherein 
 the widely distant members have perhaps no element identical, if we 
 would attain to scientific knowledge, if we would understand the object, 
 and not merely acquire a disjointed, uncomprehended, and incomprehen- 
 sible impression. From these considerations it follows, granting the 
 paramount importance of the morphological method of observation, that 
 we gain nothing by the comprehension of the forms complete at any one 
 moment, but that we must trace out the law of morphological develop- 
 ment, and direct our scientific inquiries, not to an individual complete 
 at any one period, but to the comprehension of the collective constant 
 series of normally changing forms. The conception of genera and species 
 in Botany is consequently, therefore, not merely the result of a compari- 
 son, but also of a connection of the various individual characteristics 
 with each other. In this manner we should lay a firm foundation for the 
 inductions to lead us to a theory of organic morphology, if we could but 
 succeed in completing the theory of the formation of inorganic forms. 
 As yet we are far from this point, and simply because it is only in the 
 
126 MORPHOLOGY. 
 
 most recent times, and yet very imperfectly, that the importance oi the 
 study of the history of development has been acknowledged ; although, 
 without this, Botany would be wholly divested of all scientific principle. 
 This deficiency renders it impossible as yet to treat morphology with 
 scientific logical development, or in accordance with a perfectly systema- 
 tic mode of arrangement, as will but too obviously appear in my manner 
 of treating this subject, although the blame of this is only partially to be 
 imputed to me. It seems, however, practicable perfectly to state the 
 problem, and to this end I subjoin the following remarks. 
 
 We have to construct the laws of morphological formation, and to 
 delineate the forms themselves. The first remains for the present a mere 
 problem, the solution of which must be reserved for succeeding times. 
 The second may be accomplished, although imperfectly. I say imper- 
 fectly, because, instead of those complete series of development of which 
 we ought alone to treat, we only know a few individual conditions ; and, 
 therefore, the greatest portion of the task still lies unperformed before 
 us. Here we must again distinguish between 1. Series of forms which 
 occur in all or in very many plants of a very different nature, and may, 
 therefore, especially serve as the foundation of the study of vegetable 
 forms ; that is, " general morphology." 2. Series of forms which are only 
 peculiar to definite groups of plants : " special or comparative mor- 
 phology." These two would further branch off into the consideration of 
 form without reference to its composition from the different forms of the 
 elementary organs, " external morphology ;" and into the consideration 
 of the manner in which forms are composed from individual tissues, 
 " internal morphology " (the theory of structure " comparative 
 anatomy"). This last part falls, however, away from general mor- 
 phology ; for all that we can, for the present at least, say is, that every 
 plant is composed of the different forms of the elementary organs which 
 have already been treated of. Even with respect to the second part, 
 in regard to comparative morphology, it appears to me unadvisable 
 to divide the two sections, on account of our deficiency of material ; 
 I shall, therefore, in the examination of the individual groups and parts 
 of plants, subjoin all that is known concerning their structure. 
 
 CHAPTER I. 
 
 GENERAL MORPHOLOGY. 
 
 66. THE forms of individuals and their parts are the special 
 objects to be considered by Morphology. 
 
 I. In scientific Botany we have to consider the separate cells, 
 and, according to the empirical conception, plants, as individual 
 organisms. In the latter relation we find individuals of different 
 orders. The elementary organs combine to constitute definite 
 forms (a simple plant, planta simplex). New and like individuals 
 (buds, gcmmcB) are formed by development upon the plant, and 
 
GENERAL MORPHOLOGY. 127 
 
 frequently remain in connection with the parent plant, offering for 
 our consideration one collective individual (a compound plant, 
 plaitta composita). If only organs of propagation, or blossoms, 
 proceed from the buds, we still term the plant simple. This com- 
 position is repeated in innumerable gradations. 
 
 Much has been written and disputed concerning the conception of 
 the individual, without, however, elucidating the subject, principally 
 owing to the misconception that still exists as to the origin of the con- 
 ception. Now the individual is no conception, but the mere subjective com- 
 prehension of an actual object, presented to us under some given specific 
 conception, and on this latter it alone depends whether the object is or 
 is not an individual. Under the specific conception of the solar system, 
 ours is an individual: in relation to the specific conception of a planetary 
 body, it is an aggregate of many individuals. There is, therefore, no 
 sense in contending as to whether a certain object is or is not an indi- 
 vidual in the vegetable world, until the conception of the species, the 
 plant, be perfectly defined. Now I have already shown in the intro- 
 duction that we have hitherto been unable to comprehend plants col- 
 lectively, with any degree of scientific perspicuity in a definite con- 
 ception, but have merely given them in rough outline. The manner 
 in which we take up the materials we have become acquainted with, 
 and apply them as temporary scientific aids in defining the conceptions 
 of the species of plants, is purely arbitrary, and can at most only give 
 rise to a contest upon the applicability of this or that definition. I 
 think, however, that, looking at the indubitable facts already mentioned, 
 and the relations treated of in the course of these considerations, it will 
 appear most advantageous and most useful, in a scientific point of view, 
 to consider the vegetable cell as the general type of the plant (simple 
 plant of the first order). Under this conception, Protococcus and other 
 plants consisting of only one cell, and the spore and pollen-granule, will 
 appear as individuals. Such individuals may, however, again, with a 
 partial renunciation of their individual independence, combine under 
 definite laws into definite forms (somewhat as the individual animals 
 do in the globe of the Volvox globator). These again appear empirically 
 as individual beings, under a conception of a species (simple plants of 
 the second order) derived from the form of the normal connection of the 
 elementary individuals. But we cannot stop here, since Nature herself 
 combines these individuals, under a definite form*, into larger associa- 
 tions, whence we draw the third conception of the plant, from a con- 
 nection, as it were, of the second power (compound plants plants of 
 the third order). The simple plant proceeding from the combination of 
 the elementary individuals is then termed a bud (gemma), in the compo- 
 sition of plants of the third order. This last conception, however, admits 
 only of strict application where the form of the connection of the ele- 
 mentary individuals is quite regularly defined ; and this we first meet with 
 from Mosses upward ; the connection being so loose in the AIg<z, Lichens, 
 and Fungi, that we cannot well distinguish between an individual 
 development of the plant, and a repeated composition of the same ; or, in 
 other words, between growth and the formation of buds (gemmation . 
 We regard them provisionally as simple plants (of the second order). 
 
 * " Gcmmze totidem hcrba?," Linnc. Phil. Bot. 132. We find this relation already 
 correctly conceived hero. 
 
128 MORPHOLOGY. 
 
 As, however, the formation of reproductive organs, or blossoms, in every 
 case completely hinders the further development of the simple plant in 
 the same direction, we still apply this term of simple plants to those in 
 which the buds are solely reproductive organs, or blossoms, and which, 
 consequently, are individuals incapable of growth. 
 
 67. II. Under the parts of the plants whose forms have to be 
 considered, I understand the constant subdivisions of the total 
 form which present themselves as subjectively perceptible within 
 the sphere of a group of plants, and these parts I name the organs 
 of plants. 
 
 Among the deplorable confusions which a false analogy with animals 
 has introduced into Botany, we must reckon the attempt that is commonly 
 made to define the organs of plants by their physiological characteris- 
 tics, with a thorough disregard of the fact that we know of no organ in 
 which the individual cells have not a perfectly independent life, only occa- 
 sionally so far modified as to cause one definite phenomenon of this life to 
 appear especially prominent (as we shall subsequently show under the head 
 of Organology), without the others becoming, on that account, completely 
 suppressed. Through what vital part can the plant not imbibe nutri- 
 ment, form secretions, and develop itself? If even these most important 
 functions are not apportioned to a definite organ, how can we still 
 universally talk of the physiological differences of organs? It appears 
 to me that everything regarding this subject has to be based upon mor- 
 phology. It must be left to Special Morphology to determine whether, 
 and what, organs are thus formed; while it belongs to Organology to dis- 
 cover how far, in these organs, particular definite phenomena of cell-life 
 are developed for the production of one remarkable collective effect. 
 
 68. The condition of all morphological development is exten- 
 sion in space. Every plant, every part of a plant, may therefore 
 appear in the form of a line Conferva, Usnea, Cuscuta, most 
 stems, the leaves of Juncns, Triylochin, &c. ; in the form of a sur- 
 face, as Ulva, Parmelia, Lads, Marathrum, the stem of Opuntia, 
 Phyllanthus, Ruscus, ordinary leaves, &c., or be expanded into a 
 solid, as Protococcus, Undiiia, Mammillaria, Melocactus, and the 
 leaves of the species of Sedum, or Mesembryanihemum. 
 
 The mere prevalence of one dimension must never be received as a 
 characteristic in our conception of a group of plants, or of a part of a 
 plant, since herein experience leads to no definite laws ; a priori, how- 
 ever, expansions in all three dimensions of space are equally possible. 
 It is certainly very important to hold firmly the general validity of this 
 proposition, for, simple as it is, it has frequently been contested, in 
 deciding upon the nature of individual organs according to mere relations 
 of dimension. 
 
 69. Linear structures (fig. 110.) are still more exactly defined 
 according to a sectional figure, as teres (a), anceps (b), triqueter (c), 
 
 ... t 110 c. 9. t. / 
 
GENERAL MORPHOLOGY. 129 
 
 quandrangularis (d\ &c. The forms of surfaces are never enclosed 
 by exactly straight lines, but are mostly bounded by curves, and, 
 in accordance with these, are either rotundus (e), ovalus (f), &c. 
 Lastly, the forms of solids are designated according to their resem- 
 
 blance to stereometric figures (fig. 1 1 1 . ), as 
 
 conicus (z), &c. ; or according to incidental resemblances to known 
 
 objects, as acinaciforme (Ji), dolabriforme (/), mammillaris, &c. 
 
 It cannot be my object to give here the whole of this terminology, 
 which is in. part so very superfluously diffuse, and yet in many respects 
 most inappropriate. I would merely indicate the method in which these 
 expressions have been sought for, and the point of view from which they 
 must be explained. No one can deny that it is absolutely disgusting to 
 read in botanical works, for instance, that a leaf may be flat and oval, 
 or lanceolate or linear, and likewise thick and fleshy ; and then again 
 with reference to the stem, that it may also be thick and fleshy, or flat 
 and oval, or lanceolate, or linear ; and, finally, the same rigmarole 
 repeated about the petals, anthers, and a hundred other parts, by which 
 the time of the scholar is most lamentably wasted. These general 
 adjective technical expressions are not peculiar to Botany, but belong to 
 the natural sciences in general ; they properly constitute a special study, 
 the scientific theory of observation, which Illiger* made an attempt, 
 although an unsuccessful one, to systematise.. Since then the subject has 
 remained untouched. The more recent theories of the schools have, 
 however, seriously endeavoured to educate boys gradually into sensible 
 beings, with open eyes and senses ; whilst philology seemed in former 
 days to have trained men to little better than mere bock-worms, and spoiled 
 them for all sound and clear comprehension by observation ; whence have 
 come into our science so many useless wildernesses of words, and so little 
 simplicity and correctness of observation. By way of reference for all 
 these useless, and in some degree foolish, designations, I would recom- 
 mend Bischoif's t little hand-book of botanical technical terms, as the- 
 simplest and most concise. I shall here, and in my subsequent descrip- 
 tions, only indicate the correct arrangement of the technical terms 
 according to the roots of their meanings, and limit myself as much as 
 possible to the use of such as designate something peculiarly botanical. 
 I would here remark, however, that we soon find our stock of accurately- 
 defining mathematical expressions exhausted, and that we have then no 
 alternative left but to use figurative terms; and here the fate of the art 
 of scientific description depends upon the greater or lesser skill of the 
 individual. The main cause of the great deficiency that characterises 
 our terminology for the natural sciences, has arisen from heedlessness in 
 
 * J. K. W. Illiger's Versucli einer systematischen, vollstandigen Terminologie fiir 
 das Thier- und Pflanzenreich. Helmstadt, 1808. 
 
 f Bischoff, Lehrbuch der Botanik. Appendix. Stuttgart, 1839. 
 
130 MORPHOLOGY. 
 
 the choice of words, it having appeared sufficient in most instances that 
 these terms applied to the case immediately in point, whilst an incidental 
 accessory signification of the word often rendered it wholly inapplicable 
 in its general interpretation. 
 
 70. As the comparison with geometrical figures cannot be carried 
 out very far, and as the designations of resemblance with other 
 known objects may easily become too vague and uncertain, we must 
 have recourse to some artifices to aid us in the description of forms. 
 They are partly described as follows : 
 
 I. In the first place the general outlines must be defined, and 
 this is done by supposing all the external points in a superficies to 
 be united by a line, and those of a corporeal form by a surface, 
 and then applying some term to this line or surface. We thus 
 obtain the following designations (fig. 112.): - 
 
 
 A. The greatest transversal diameter in the centre. 
 
 1. About twice as long as it is broad, oval (a). 
 
 2. Three or more times as long as it is broad, oblong (Z>). 
 
 B. The greatest transversal diameter in the lower third. 
 
 1. Twice as long as it is broad, ovate (c), or if the greatest 
 diameter lie in the upper third it is conversely ovate (obovafus). 
 
 2. Three and more times longer than it is broad, lance-shaped 
 (lanceolatus) (d). 
 
 C. Broader than it is long; rounded off at the one extremity, 
 and excavated at the other, kidney-shaped (reniformis) (e). 
 
 D. The upper part broader than the lower, which ends in a 
 decidedly narrower portion: in bodies this form is club-shaped 
 (clavatus)', in surfaces it is spatula- shaped (spathulatus) (f). 
 
 II. The main division of these forms is further given according 
 to the following gradations : for instance, we draw the divisions 
 upon an imaginary medial line, or around a central point (fig. 1 13.), 
 and divide the distance between this line or point to the circum- 
 ference into two parts. 
 
GENEKAL MOHPHOLOGY. 
 
 131 
 
 A. Divided to about half-way, cleft (fissus) (g, K)\ the indi- 
 vidual parts are lobes (lobi). 
 
 B. Divided beyond the middle, divided (partitus) (h); the 
 individual portions, parts (partes). 
 
 C. Divided to the assumed line or point, cut up (sectus) (i) ; and 
 the individual portions, segments (segmenta). 
 
 III. We have a series of tolerably definite expressions for the out- 
 lines of hollow forms, in which we make no special reference 
 to the division. The expressions are comparisons, and explain 
 themselves (fig. 114.). 
 
 Bell-shaped (campanulatus) (/), funnel-shaped (infundibuliformis) 
 (m), salver-shaped (hypocrateriformis)* (n), pitcher-shaped (urceo- 
 latus) (o\ flask-shaped (lagenceformis) (p), tube-shaped (tubuliformis) 
 (q\ cup-shaped (cupuliformis) (s), plate-shaped (patell&formis) (r). 
 In all these forms where the distinction is applicable, the lower and 
 more cylindrical part is termed the tube (tubus), and the upper and 
 more expanded the limb (limbus), and the point of junction the 
 throat (faux). 
 
 71. In the further description of forms we especially examine 
 the base and the apex. The region of a form by which it is 
 attached, as, for instance, a leaf on a stalk, is termed the base 
 (basis), and the opposite free end the point or summit (apex). There 
 are special designations for both (fig. 115.). 
 
 I. A. Apex with a notch, where this is 1 . acute, excised (excisus) 
 (a); 2. where the angle is rounded oif, it is emarginate (emar- 
 ginatus) (b). 
 
 B. Where the apex is abrupt, either truncate (truncatus) (c\ 
 or when rounded offj rounded (rotundatus) (d). 
 
 C. Where the apex terminates in an angle with convex sides, 1. 
 in a right or larger angle, the form is obtuse (obtums) (e) ; 2. less than 
 a right angle it is acute (acutus) (f). 
 
 D. Where the apex terminating in an angle with concave sides is 
 1. suddenly and sharply acute, the form is mucronate (mucronatus} 
 (g) ; 2. gradually and long pointed it is peaked (acuminatus) (h). 
 
 II. A. A base with a penetrating angle: 1. where the angle is 
 
 * This expression will be best understood by those who are familiar with the form 
 of the plate or salver on which glasses were placed in the middle ages, as we find it in 
 old collections, or delineated by the old masters. 
 
132 
 
 acute, the form is heart-shaped (cordatus) (i) ; 2. where the angle is 
 rounded, it is kidney-shaped (reniformis). 
 
 B. A base roundly truncated is rounded (rotundatd) (k). 
 
 C. A base continued down into an angle with convex sides, 1. in 
 a right and larger angle, is obtuse (pbtusa) (I) ; 2. in less than a right 
 angle, is acute (acuta) (TTZ). 
 
 D. A. base terminating in an angle with concave sides is attenu- 
 ated (attenuata) (n). 
 
 All these expressions apply equally to solid and to superficial 
 forms ; but as the latter only can have a margin (margd), the fol- 
 lowing terms are applicable to them alone, being derived from 
 slighter marginal irregularities of figure (fig. 116.), 
 
 A. With acute angles, either projecting or penetrating: 1. 
 where the sides are unequal, the margins are said to be serrate 
 (serratus) (o) ; 2. the sides equal, toothed (dentatus) (p\ The sepa- 
 rate projections in either case are termed teeth (denies). 
 
 B. Where the projecting points are rounded, and the penetrating 
 angle acute, the outline is notched (crenatus) (q), and the separate 
 projections are crenatures (crenaturce). 
 
 C. Where the projecting angle is acute, and the penetrating one 
 rounded, the outline is scooped out (repandus), and the separate 
 projections are teeth (denies). 
 
 D. Where the projecting and penetrating angles are rounded, the 
 margin is sinuate (sinuatus) (s), and the separate parts are termed 
 lobes (lobuli). 
 
 E. Where the projecting and penetrating angles are very acute, 
 and the sections very narrow and long, the outline is ciliate (ciliatus) 
 (i), and the separate parts are termed cilia (cilice). 
 
GENERAL MORPHOLOGY. 
 
 133 
 
 F. Where the projecting and the penetrating angle and the lobes 
 are very irregular, and small and close, the margins are said to be 
 bitten out (erosus) (u). 
 
 72. The simple fundamental forms may combine again by 
 uniting together according to the three dimensions of space, whence 
 an endless variety of compound structures is produced, for a very 
 few of which only we have designations which give clear impressions, 
 as, for instance, spherical forms connected in a linear series are 
 termed (moniliformes) necklace-shaped or beaded. A spherical or 
 flat part, the base of which is connected by a linear part (stipes) 
 with another, is said to be stalked (pars stipitata) (fig. 117. , 1.); 
 if it be immediately connected with some other part, it is sessile 
 (sessilis) (a, 2.). 
 
 The most important relations have been comprised under the 
 following method of consideration : A simple form is regarded as 
 the main part, the supporter of the others, the axis on which they 
 are attached as limbs or accessories of the whole (articuli, paries ap- 
 pendiculares vel laterales). In the first place, a distinction is made 
 according to the form of the axis, whether it be elongated or not ; 
 and next, according to the form of the lateral parts, whether they 
 are stalked; further, according to the arrangement of the lateral parts 
 on the axis ; and, finally, according to their different relative size. 
 We thus obtain the following distinctions : 
 
 A. The axis spherical or short. 
 
 A. When all the lateral parts lie on one plane (b, c), they are hand- 
 or finger-shaped (partes palmatce, digitatce). 
 
 B. When they surround the axis on all sides : 
 
 1. Sessile lateral parts are in heads (p. capitatce) (/>>) ; * 
 
 2. Stalked lateral parts are in umbels (. umbellatce) (c). 
 
 B. The axis elongated. 
 
 A. Lateral parts of equal length, from below upward. 
 
 * Or at the end of an elongated axis, also tufted (p. comosce). 
 K 3 
 
134 MORPHOLOGY. 
 
 1. When pointing in all directions. 
 
 a. Many arising nearly at one point. 
 
 . Repeated at intervals along the axis, whorled (p. verticillatxB) 
 (d). 
 
 /3. On the base of the axis, rosette-shaped parts (p. rosulatce). 
 
 b. Arising at different heights, scattered, spirally arranged parts 
 {p. sparsce, spiraliter posita) (e). 
 
 a. Sessile lateral parts, spiked (p. spicatce) (f). 
 
 /3. Stalked lateral parts, clustered or racemose (p. racemosce) (g). 
 
 2. When lying in one plane. 
 
 a. Only on one side of the axis, unilateral or secund (p. secundd). 
 
 b. On both sides of the axis. 
 
 . All equally long, pinnate (p. pinnatce) (A). 
 
 /3. Alternately long and short, interruptedly pinnate (p. inter- 
 rupte pinnat&) (i). 
 
 B. Where the lateral parts decrease gradually in length from 
 below upward, so that the points lie in one plane, pyramidal parts, 
 corymbs (p. fastigiata, corymbi) (A).* 
 
 Here, as we have already remarked, perfect completeness is not aimed 
 at; nor, indeed, is it attainable. As in every other instance, our termin- 
 ology is here an unscientific chaos. Expressions have been constantly 
 adopted for mere individual cases; and as observation becomes more 
 extended, the expressions admit either but imperfectly or not at all of 
 being further applied to the general characteristics which the individual 
 -cases present, while these, after all, are precisely what we want to name. 
 But we can scarcely expect to attain to a strictly scientific morphological 
 terminology before we have fully succeeded in the mathematical con- 
 struction of forms. In the mean time we may, in some degree, prepare 
 for this by abstaining from using expressions which indicate nothing pe- 
 culiarly relating to plants, but merely conditions of simple combinations 
 of forms, in accidental application to wholly special cases, without, at the 
 same time, explaining their generality. We might, with equal correct- 
 ness, talk of head-shaped, united, pinnate, palmate, &c., crystals. What 
 distinguishes ears and heads in blossoms is precisely similar to that which 
 marks the difference of folia sparsa from foliis rosulatis. We com- 
 prehend under these terms nothing peculiarly characteristic of blossoms, 
 leaves, or, indeed, any part of the plant, but merely a combination of 
 forms, wholly independent of the nature of the forms themselves. 
 
 73. As soon as we meet with more intricate combinations, or 
 less definite forms, nothing remains for us but to combine these 
 expressions, or choose wholly indefinite comparisons ; thus we say 
 palmatifid parts (p. palmatifidce), bipinnate parts (p. bipinnattB), &c. ; 
 or we designate forms as helmets, hoods, spurs, &c., which are 
 almost all expressions which are intelligible merely within a definite 
 sphere of forms, and consequently relate only to special botany. 
 
 Finally, to express small inequalities on the surface, a large 
 number of terms have been made use of, which in like manner are 
 for the most part figurative, and admit of no scientific strictness of 
 
 * Several corymbs combined form a cyme 
 
GENERAL MORPHOLOGY. 135 
 
 applications : as, for instance, aciculatus, as if torn by a needle ; 
 rimosus, with fissures or chinks ; sulcatus, punctatus, scrobiculatus, 
 granulosus, verrucosus, &c. ; and to these we may add the designa- 
 tions in use for a hairy surface, as, for instance, arachnoideus, lanu- 
 ginosus, tomentosus, pubescens, pilosus, setosus, strigosus, &c. Scien- 
 tific exactness can only be attained here by a more accurate 
 description of the parts in question, and especially by the charac- 
 terisation of their morphological or anatomical signification. 
 
 74. In all plants, with the exception of the few which consist 
 only of one cell, the form depends upon the manner in which the 
 cells are combined together. The development of forms is here 
 dependent on two essential points, namely, the arrangement of the 
 newly formed cells, and the different expansion of those already 
 existing. These two determining causes are normally definite for 
 every individual species of plant and for each separate organ, but 
 are entirely incidental for plants in general. The expansion of a 
 plant, or the part of a plant, in one, two, or three dimensions of 
 space, may depend as well upon the arrangement of the developing 
 cells as upon the expansion of those already developed, or as upon 
 the two causes combined. 
 
 This subject has hitherto been wholly neglected, although it must form 
 the foundation of the whole science of morphology, since on this alone 
 depends the development of forms in plants. The whole question will be 
 understood in all its relations if we only remember that when four new 
 cells arise in one cell (fig. 118.), they may be within the parent-cell, either 
 
 118 c. 
 
 oooo 
 
 in a row, linearly ( C), or two and two beside each other (B\ forming a 
 plane, or, finally, may lie within the parent-cell, like the corners of the te- 
 traedron (^4), forming a solid body. Owing to the great difficulty, in most 
 cases, of observing the first origin of cells, a long time must elapse before 
 we shall be able to account for the origin of different forms. All future in- 
 vestigations into the history of development must, however, necessarily be 
 directed to this essential point, and it is here, therefore, that we have to 
 expect the most interesting laws for the science of morphology. We are 
 unable, at present, to express any general statements, and it must, there- 
 fore, suffice here to have drawn attention to the paramount importance of 
 this point. A few more special amplifications will be met with in a sub- 
 sequent part of our work, especially with reference to the stem and 
 the foliar organs. As the foundation of every plant is in all cases one 
 individual cell (spore or embryonary vesicle), within or out of which the 
 new cells which gradually form the whole plant are developed, in each 
 primary cell must lie the conditions according to which the subsequently 
 developed cells are arranged : since, however, the expansion of the indi- 
 vidual cell in the three dimensions of space depends essentially upon 
 
 K 4 
 
136 
 
 MORPHOLOGY. 
 
 the nutrition of its membrane, and the latter upon the presence of a 
 nutrient fluid, that second cause of form will almost always be a conse- 
 quence of the first, so soon as the cells are removed from an immediate 
 contact with the nutrient fluid. A linear arrangement of the cells may, 
 therefore, easily produce a greater expansion lengthwise, &c. By way of 
 illustration of the regular arrangement of newly developed cells, I will 
 .only cite the case of two cells of the stomate. Here two young cells arise 
 in a parent-eel), formed, without exception, exactly in such a manner that 
 they lie in a plane with the epidermis, and never so as to lie one upon 
 another, as seen from the exterior of this membrane. 
 
 75. Regular mathematical forms never occur in plants, with 
 the exception of the spherical form of individual cells. We term 
 those forms in plants regular which admit of being divided into 
 .two equal parts by many sections passing through an imaginary 
 
 119 
 
 axis (); and symmetrical, ,those that can only be divided by one 
 single section into two equal parts, standing in the relation of right 
 and left to each other 
 
 As each separate cell is a wholly independent individual, and as only a 
 few simple individuals of the second order are formed by the mere col- 
 lection of cells, while most plants acquire their whole form from the 
 combination of these latter; and since each individual of the first and 
 second order may be considered per se, owing to the independence of 
 external influences possessed by its existence, without, at the same time, 
 its being on that account exempt from a connection with the whole, it will 
 easily be understood how very indefinite the form of most plants must be. 
 We consequently meet with regularity, or even symmetry, in the sense 
 above applied to the terms, in but a very small number of entire plants, 
 as, for instance, in Protococcus, Phascum, Equisetum, Wolffia, Melo- 
 cactus. We more frequently meet with both in the individual parts of 
 plants, especially in the reproductive apparatus of the higher plants 
 which have the closest morphological and physiological connection ; for 
 instance, in the capsule of mosses, in blossoms and fruits ; we also often 
 find .only symmetry, at least in the leaves, and in whole individuals of the 
 
GENERAL MORPHOLOGY. 137 
 
 second order, as in young shoots. Hugo Mohl* has collected many in- 
 teresting facts with reference to this, but as yet we have not been able 
 to deduce any results from them. 
 
 76. A form that frequently occurs in the plant, and which 
 appears to be especially characteristic, is the spiral, most constantly 
 and normally appearing as a thickening layer, in the vital processes 
 of the individual cell (see above, 18.); also in the arrangement of 
 the chlorophyll in Spirogyra, Chara ; again in the spiral position 
 of the nodose thickening of the cell-wall (see 17.), in the very 
 frequently evident spiral arrangement of appendicular parts rounii 
 an axis; and, finally, in the spiral twistings of elongated parts, 
 as tendrils and twining plants. 
 
 The facts adduced in the above paragraph are indisputable, and 
 decidedly indicate a certain connection between a spiral direction and 
 some peculiarity inherent in the nature of plants ; but we must beware of 
 overrating the importance of these facts, since they present much that is 
 but vague and uncertain. In tendrils and twining plants, the phenomenon 
 admits of a different explanation, for every filiform part, when wound 
 round a stick, must form a spiral, which no one would seek to explain 
 from the nature of an iron wire or a hemp cord. With respect to the 
 spiral position of appendicular organs, appearance, or even strict mathe- 
 matical measurement, may in many cases confirm the view of the existence 
 of this peculiarity, as, for instance, in the cones of Coniferce, in the warts of 
 Mammillarice, and in the fruits of the sun-flower; but it cannot be denied, 
 at the same time, that in most of these cases the leaves decidedly do not 
 form any mathematical spiral, and that it can only be proved that the law 
 discovered for the spiral may be tolerably well applied to the arrange- 
 ment of leaves, when only we bring the leaves a little into order. It 
 seems to be entirely forgotten here, that all the points scattered upon a 
 cylinder (and a stem is seldom or never a mathematical cylinder) may be 
 united by a spiral, if we consider the distances of all the points from the 
 base as fractional parts of the length of the cylinder, and assume that the 
 common measure of these fractional parts is the distance between every 
 two windings of the spiral. We ought, however, only to assume that there is 
 the spiral indicated in the arrangement of the points when the distance 
 between the two points is everywhere equal. But this requirement is only to 
 be fulfilled by an arbitrary pushing aside of the points (the places at which 
 the leaves are inserted), or by the assumption of an abortion, which we 
 cannot find in nature. This view will acquire a true significance in the 
 observation of the vegetable organism when we are able to show from 
 what property of the plant a spiral arrangement must necessarily result, 
 and the laws on which the individual irregularities depend. The two 
 opposite views of Schimper and the brothers Bravais plainly demonstrate 
 how arbitrary every thing is that has reference to the subject. I shall 
 have occasion to revert to this when I come to speak of the leaves of the 
 Phanerogamia. The spiral arrangement of the thickening layer in the 
 cell seems evidently the most certain, but even in this we have the mere 
 naked fact, and not a single idea how it maybe methodically derived from 
 the nature of the cell of the plant. It is manifest that the comparisons 
 
 * Hugo Mohl, Ueber die Symmetric der Pflanzen. Tiibingen, 1838. 
 
138 MORPHOLOGY. 
 
 made with a magneto-electric spiral* are a mere jest, and a very superfi- 
 cial one, since we have not as yet obtained any proof, based upon the most 
 remote appearance of probability, of the presence of a galvanic current, 
 for which there is not even a semblance of possibility when we consider 
 the damp, and consequently universally conducting, condition of the cell- 
 membranes. 
 
 77. We have, as yet, no general numerical laws for plants. 
 Indications of such admit, perhaps, of being traced from the fact 
 that, in the far greater majority of cases, two, four, or eight young 
 cells are formed within the parent-cell, as in Tetraspora, in the 
 spores of the Octosporidia, Mosses, and the pollen of Phanerogamic^ 
 To these we may probably also add the frequently regular occur- 
 rence of definite numbers in whorls, as the recurrence of the number 
 three in the parts of the flower of the monocotyledons, and the 
 number five in the dicotyledons. 
 
 All these specified relations have already often been used in mere 
 childish numerical jugglery ; individual cases having been arbitrarily 
 selected to confirm a preconceived theory, the exceptions being disre- 
 garded, fashioned by means of just as arbitrarily imagined fictions into a 
 form adapted to the pretended theory. We cannot as yet decide, even 
 with the most remote approximation to probability, if, for instance, the 
 three petals of a monocotyledonous plant are to be regarded as a triple 
 whorl or as a three-limbed spiral. These two must, however, be very 
 differently derived from the nature of the plant, and, in the latter view, 
 the contest originating in the hitherto equally balanced hypotheses of 
 Schimper and Bravais would still remain to be decided. Before we can 
 give any probability to such a deduction drawn from the nature of the 
 vegetable organism, it is at any rate but just, amid the large number of 
 exceptions present before us, to consider the more frequent occurrence of 
 one or other number as purely accidental to plants in general. This 
 occurrence of the numbers 2, 4, 8 in the young cells seems to possess 
 more the appearance of systematic arrangement, but here we are utterly 
 unable to discover any connection with the nature of the vegetable cell. 
 We shall probably have to wait long before we meet with even indications 
 more definite. 
 
 CHAPTER II. 
 
 SPECIAL MORPHOLOGY. 
 
 78. THE history of development forms the groundwork for 
 all special botanical morphology, and we must, therefore, have 
 reference to it in choosing our general modes of classification. 
 Every plant originates from a cell ; and the first difference among 
 
 * As, for instance, in Link's Element. Phil. Bot. ed. 2. t. i. p. 1^7. 
 
SPECIAL MORPHOLOGY. 139 
 
 cells capable of affecting the form of their development is, whether 
 these cells become at an early period, isolated and independent, 
 whether they remain for a longer period of time, till their sub- 
 sequent development, merely as parts of the parent organism, as 
 secondary cells within the parent cell. In the latter case the pro- 
 pagating cells are enclosed within a parent cell (sporangium), 
 while in the former they are contained free in a cavity of certain 
 portions of cellular tissue (sporocarp, anther cell) ; and, grounding 
 my division on these points, I divide plants into covered-spored 
 (Ajigiosporce) and naked-spored (GymnosporcB). 
 
 The next difference to be considered affects the manner in which 
 the spores are developed, whether under the influence of other cells of 
 the parent plant or not. We find that this affords us another ground 
 of division for the Gymnosporce, for the propagating cell either 
 develops itself freely to a new asexual plant (Plant agamicce), 
 which, together with the Angiosporce, have been termed, since the 
 time of Linnasus, Cryptogams ; or it requires for its development to 
 be previously encased by, and brought under the material influence 
 of, certain cells of the parent plant (sexual plants (PL gamicce). 
 Finally, under this last head, we may admit another difference 
 between plants having no definite point of union for the sexes (PL 
 athalamiccs), where the two different kinds of cells, or cellular 
 masses, only combine subsequently to their separation from the 
 parent plant, and plants having a definite point of union for the 
 sexes (PL thalamica or Phanerogamce), where the propagating cell 
 is taken up at a definite part of the parent plant, and there deve- 
 loped for a time previous to its separation from it. 
 
 My words would be most erroneously construed, were it supposed for 
 a moment that I was arbitrarily constructing a form of division, and 
 then arranging the plants in accordance with it. So far from this, it 
 has been my endeavour first to form the groups by a comparison of the 
 whole history of development, and then seek for a characteristic by 
 which to designate the groups thus found, On taking a general survey 
 of the whole vegetable kingdom, unbiassed by previously conceived 
 views, we should be inevitably led to separate the Alga, Lichens, and 
 Fungi from all other plants, and arrange them in one common group, but 
 it must be left to a subsequently acquired and a more extended know- 
 ledge of all plants to determine the strict confines and the combination 
 of characteristics appertaining to this group. It cannot, however, be 
 denied that an essential difference is manifested in the formative prin- 
 ciples of the already named lower groups, and the higher plants, which, 
 although apparent to every observer, science is not always able to cha- 
 racterise. Granting even that in the form of separate lateral parts, as, 
 for instance, in the so-called fronds of the Floridetz, an analogy may 
 really be found with the leaf-formation of higher plants, this would 
 only be an evidence of the deficient condition of our knowledge, but 
 could not efface the line of demarcation which has here evidently been 
 drawn by Nature. Nageli, in opposing my mode of division, has afforded 
 a most signal proof of the difficulty, to those who have once been led 
 astray in dogmatising, of extricating themselves, although with the best 
 
140 MORPHOLOGY. 
 
 will to do so, or even of comprehending the more correct views of 
 others. Nageli might have spared himself the trouble of contesting 
 against my system, as I have expressly protested against any such mis- 
 conception. No one possessed of a capacity for classification will ever 
 concur in drawing a main line of demarcation between Floridece and the 
 other Alga (as Nageli does), so that the former are not made to find 
 the most proximate affinity to the latter ; and the mere subtilty of 
 dogmatism selects a character, or a mode of division, and then sepa- 
 rates the groups in accordance with it. According to my views, it would 
 form a more natural classification if one were to insert the three lowest 
 groups of plants as a special kingdom between the animal and the 
 vegetable, rather than to divide a portion from this department and 
 subjoin it to the higher orders of plants. No ground for such a division, 
 no systematic principle, justifies us in adopting this mode of separation; 
 simply the judgment from appearances, if I may so express myself, which 
 requires that science should corroborate it ; the expression of the same 
 sound sense that has named the heads of the Composites a flower, and 
 which, indeed, may demand the assistance of science, but may never 
 be slighted by her. The task of science is to refine and cultivate 
 the sense of perceptive comprehension, to render the appreciation of the 
 true and natural more acutely sensitive, and, finally, to ground the 
 dictum of the senses upon the scientific basis derived from the study of 
 comparative development. As the principal groups are adopted espe- 
 cially from observation, their designations may naturally be derived from 
 various characters, since it is only by degrees that we are enabled to 
 substitute in the place of these the only correct ground of division 
 namely, that founded upon the history of development. This demand 
 for uniformity of division carries us away from the purely inductive 
 method, which, while it always follows a definite course, is conscious of 
 being still far removed from the aim it strives to attain. 
 
 Notwithstanding Niigeli's opposition to them, my provisional designa- 
 tions of the two principal groups, as Angiosporce and Gymnosporce, seem 
 to me perfectly applicable. This difference still remains, that in all 
 Angiosporce the propagating cells remain firmly enclosed in the paren- 
 chyma of the parent plant, forming one continuous tissue, until their 
 separation from it, while in all other plants the propagating cells remain 
 perfectly free, unconnected with the tissue of the parent plant, and 
 merely enclosed within its cavities. As yet, we are deficient in the 
 investigations necessary for substituting any term derived from the 
 history of development in the place of this character. As far as I am 
 able to judge, the following difference seems to be indicated: In the 
 Angiosporce the whole propagating cell is converted into the new plant, 
 and in the Gymnosporce the propagating cell extends into a pouch-like 
 cavity varying in length, one protruded cellular extremity only being 
 developed into a new plant, while the other dies off*. This characteristic 
 is only lost, but its truth at the same time confirmed, in the Liverwort, 
 which evidently forms the transition in the relation already designated. 
 But here we are deficient in our knowledge of the more minute phe- 
 nomena of development of the Lichens and the Lycopodiacece. The same 
 difficulty meets us in the classification into asexual* and sexual plants. 
 
 * It will of course be understood that the word " sex " means nothing beyond a mere 
 indication, it being at any rate at present incorrect to attach to the term the meaning 
 current with respect to animal life. It would be highly desirable wholly to banish the 
 use of this equivocal term, as many misconceptions might thus be avoided. 
 
SPECIAL MORPHOLOGY. 141 
 
 The law of development might perhaps aid us in finding the distinguish- 
 ing differences in the development of the proembryo in the first named, 
 since between the first development of the propagating cell and the 
 actual development of the perfect plant a passing stage of transition is to 
 be met with, which manifests a certain analogy with the formations of 
 the groups of the Angiosporce. The further subdivision of the sexual 
 plants is, however, wholly based upon the law of development. The 
 Rhizocarpece, as the Athalamicce, constitute an admirable medial stage 
 between the Agamce and the Phanerogamce ; agreeing with the former 
 in this, that the propagating cell is developed to a new plant, without 
 any intermediate interruption*, and with the latter in their development 
 not being free, but being effected at first in the interior of a cellular 
 mass engendered by the parent plant. 
 
 There are other characteristics denoting the internal and external 
 form of developed plants, which coincide in a remarkable manner with 
 those above given, and derived from the law of development ; these have 
 been already partially, but very imperfectly, treated of. The Angiosporce 
 may also be termed cellular plants (PL cellulares), since they afford no 
 indication of a current of sap passing through definitely arranged elon- 
 gated cells (vascular bundles). In like manner, their external form may 
 be defined as stemless (PL acaules, Thallophytce Endl.), as we have 
 not hitherto been able to detect any sharply defined morphological con- 
 trast between a lateral parenchymatic extension (leaves) and a body 
 uniting these (stem). In contradistinction the Angiosporce are designated 
 as vascular plants (PL vasculares), and as plants having stems (PL can- 
 lince, Cormophytce Endl.). The divisions of the Gymnosporce would 
 correspond to plants having simultaneous and progressive vascular bun- 
 dles ( 26.), and plants with or without an apparatus for propagation, and 
 finally characteristics drawn from the nature of the vascular bundles and 
 the morphology of the flowering portions of the plant might perhaps be 
 added to the Athalamic and Thalamic orders, but unfortunately we are 
 still deficient, especially with respect to the Rhizocarpecc, in the more 
 accurate investigations necessary to guide us. We cannot too frequently 
 repeat, that all our subdivisions are, and must be, regarded as merely 
 provisional, and as extremely deficient, as a correct classification can 
 only be derived from a complete knowledge of the law of comparative 
 development, from the attainment of which we are still infinitely far 
 removed. All that we can say is, that all divisions grounded upon cha- 
 racteristics which appertain in their nature only to a definite stage of 
 development, and do not stand in the most immediate connection with 
 the developing process, must either be decidedly false, or, at best, simply 
 accidental, and do not by their own value constitute the natural groups. 
 On the other hand, every classification must remain permanent that has 
 been derived from characteristics depending upon the law of develop- 
 ment. Thus the line of demarcation which has been laid down between 
 the Cryptogamia and the Phanerogamia will ever continue, even though 
 these divisions may not always be regarded as those possessing the 
 highest importance. The recent attempts to range the Cycadacece under 
 the head of the Ferns rests on such erroneous conceptions of vegetable 
 nature, and are based upon observations of so inessential a kind, that 
 they cannot be long maintained. In the same way, Monocotyledons and 
 Dicotyledons will always remain separated, and notwithstanding all the 
 
 * They do not pass through a stage of seminal maturity, or slumber in embryonic 
 life. 
 
142 MORPHOLOGY. 
 
 substitutes that have been proposed, tried like some new article of 
 fashion, and then rejected, as Endogenes and Exogenes, Amphibryce and 
 Acramphibryce, Loxince and Orthoince, Exorhizce and Endorhizce, &c., 
 we shall still have to return to the old division, as being the best and 
 most applicable of all, because it rests upon what is most essential in the 
 morphological law of development. It is only to be lamented that so 
 much valuable time and such fine powers, which might be devoted to 
 well-grounded observations on the law of development, and consequently 
 to the special furtherance of science, should have been wasted in this 
 utterly useless game of system-making. 
 
 I must, however, be permitted to remark, that, with very few excep- 
 tions, all our classifications of plants into individual larger or smaller 
 groups are still so unstable, that we are obliged almost in every case to 
 designate certain forms as mere transitions from one group to another. 
 In order to avoid misconception on this head, we must, however, consider 
 more attentively what is meant by the term Transition. We may inter- 
 pret it in three different ways. In the first place, it may mean an 
 individual transition of the nature that occurs when one and the same 
 being passes through different phases of its existence at different times, 
 and may therefore at various periods fall under various specific heads. 
 We have already pointed out the absurdity of such an idea ; it has never- 
 theless met with supporters among persons who have given evidence, by 
 the maintenance of such views, of their own ignorance and thorough 
 want of philosophical clearness of understanding. In the present highly 
 deficient state of our knowledge regarding simple vegetable organisms, 
 a transitional stage of development must often be mistaken, for a time, to 
 be an independent species ; but as soon as further observations have 
 shown the course of its development to another species, the transiently 
 established classification falls to the ground, and we are as little disposed 
 to regard the plant as a separate species as we should be thus to de- 
 signate the pollen -granule and the seed or the ovum in animals. The 
 matter appears so simple, that we should be struck with astonishment that 
 any one could even have arrived at the conclusions embraced by Agardh*, 
 Hornschucht, Meyen J, and others, but that we know that Schelling's 
 so-called Philosophy of Nature has misled so many into the belief that there 
 is something scientific in the subtleties of comparison and analogy. The 
 proembryo of Mosses is as little a Conferva as the pollen-granule of the 
 Zostera marina. Both are dependent structures, which only acquire their 
 full signification in the complete connection of the law of development. 
 Thus the whole of what Agardh and others have enlarged so much upon 
 simply amounts to this, that Mosses as well as all other plants consist of 
 differently formed cells at various periods of their existence. 
 
 The second interpretation that may be given to the expression 
 transition, does designate actually different species, the characters of 
 which are so similar in the two most immediately allied species, or ap- 
 proach so nearly through the individual variations, that it is impossible 
 to lay hold of any one individual character which may separate the 
 whole into two groups, although their extremes seem to indicate or 
 demand some such division. Here we must in the first place remember 
 
 * Allgemeine Biologie der Pflanzen, from the Swedish by Creplin. Greifswald, 
 1832, 42. 
 
 f Act. Acad. Leojj. Car. x. 
 
 j: Robert Brown's Miscellaneous Writings. [German edition, in 5 vols. For the 
 purpose of illustration, it contains the papers and remarks of other botanists TRANS.] 
 
SPECIAL MORPHOLOGY. 143 
 
 that Nature presents no system for our scientific considerations, but 
 simply individual beings, between which no middle form can be imagined, 
 since the character of individuality precludes the possibility of varia- 
 tions. It is we ourselves who introduce into the number of individual 
 beings an arrangement and classification into larger or smaller groups, 
 species, races, or families. On finding a greater degree of uniformity 
 among a certain number of individuals, we arrange these together, and 
 then proceed to seek for an expression by which to characterise this 
 group. And it is only when we have learnt to know all the individuals 
 perfectly according to all their characters, and have made ourselves 
 thoroughly acquainted with ea.ch character in all its relations, that 
 we are enabled to find an expression that shall fully mark and distin- 
 guish the individuals of the group from those in that immediately suc- 
 ceeding it. As long, however, as this perfect knowledge is nothing 
 more than a mere desideratum, we content ourselves for the time with 
 the choice of any character that may seem most applicable for the 
 purposes of classification, although it may not be perfectly correct, and 
 may not draw the line as clearly as should be. Thus there will present 
 themselves many individuals which the provisionally adopted character 
 will not aid us in defining, and such we term Transition forms. These 
 exist, therefore, only as the creations of our ignorance ; and it is merely 
 owing to our own inefficient knowledge that we are unable to define 
 clearly the different boundaries, the occurrence of these transitions 
 affording us a criterion by which to judge of the great deficiency of our 
 information regarding any one particular point, and thus stimulating us 
 to further and more exact observations. 
 
 There still remains a third signification of the word transition for 
 us to notice. We have not as yet found any expression for the nature 
 of the plant in general, which might enable us in doubtful cases to de- 
 cide upon the vegetable or animal nature of an object. On passing 
 from one certain group of plants to another, we must have common 
 parts of both by which the two groups may be connected together 
 under one general conception of plants, that we may know with 
 certainty that we are not encroaching upon the department of animal 
 life. This occurs everywhere, where we combine two or more subor- 
 dinate groups within the sphere of a higher conception ; and here, con- 
 sequently, the links necessary to convince us that we are correctly 
 embracing the lower groups under the idea of a higher one must be re- 
 garded as transitions from one group to another, although in a totally 
 different sense from the one already alluded to. Instead of the term 
 transition, I shall in the latter signification use the words " intervening 
 stage," limiting the application of transition merely to those cases where 
 the line of demarcation cannot be sharply defined, owing to the deficiency 
 of our knowledge on the subject. 
 
 SECTION I. 
 
 THE ANGIOSPORJS. 
 
 79. Plants develope either from a naked cell, or, in the case of 
 Lichens and Fungi, from an enclosed and double cell, into such 
 multifarious and indefinite forms that no general character can be 
 
144 MORPHOLOGY. 
 
 applied to their parts. They have, therefore, no distinct organs. 
 In the less simple plants, merely certain cells or portions of cells, or 
 else cellular groups with a clearly characteristic constant form and 
 arrangement, especially officiate in the formation of new propa- 
 gating cells, and, therefore, can alone be regarded as organs. The 
 single or complex cell out of which the new individual is deve- 
 loped, I name spore (spora) ; the parent cell forming and enclosing 
 the former, the spore case (sporangium) ; and a number of these 
 combined together in a definite form with the special parts of the 
 plant which enclose them, a sporocarp (sporocarpium). Some- 
 times, also, individual cells or groups of cells assume the form of 
 fibres or Iamina3, in order to fasten the plants to the body which 
 supports them (organs of attachment, rhizinci). These plants have 
 been provisionally divided into three groups, the limits of which 
 are still very ill defined. The best characteristic may perhaps be 
 derived from the habitation and the formation of the spores, and 
 we may thus distinguish those growing in the water (PL aquaticce) 
 (Algcs), from those growing upon any kind of support in the air 
 (PL aerece) ; and these latter may again be designated as Fungi and 
 Lichens, according as their spores are formed separately in pro- 
 tuberances of the sporangia, and thrown off with the latter, or 
 numbers of spores are developed in one sporangium which subse- 
 quently bursts to discharge them. 
 
 The same useless playing with fictions to explain what is perfectly 
 simple and clear in itself, which meets us at every step in the science of 
 Botany, is not absent here. Most botanists have not deemed it suffi- 
 ciently abstruse to suppose that cells combine in simple plants to produce 
 simple undefined changeable forms, and much senseless matter has been 
 advanced not only concerning the fusing of leaves and stalks, but also 
 about the formation of buds and all appertaining thereto. In the case 
 of the Marchantitf, which belong to a group of plants in which the form- 
 ation of the stalk and frond is normal, such views, by way of analogy 
 at any rate, might have some reasonable grounds. In the three groups 
 of plants in question, it is, however, a mere childish play of words to 
 speak of stalks and leaves, if we do not understand under the term de- 
 finite products of the formative force, and prove the actual existence of 
 such : things created by imagination exist, however, only in confused 
 heads, and not in nature, which embraces nothing beyond the actual in 
 space and time. 
 
 The expressions already made use of, and which were first proposed 
 by Link (Elem. Phil. Bot. ed. 2.), fully suffice for the description of the 
 Angiosporece, although they are not clearly defined, and therefore still 
 loosely applied, and we may thus entirely dispense with the diffuse and 
 in part irrational terminology, and that confusion of words which has 
 originated in vanity and a love of innovation. 
 
 It is extremely difficult to characterise the three above-named divi- 
 sions in such a manner as to decide at once in individual cases ; and 
 wholly impossible to do so at present, when we are only able to compare 
 individual conditions instead of complete series of development. For 
 instance, it is wholly impossible to distinguish Undina (Algce) and Col- 
 lema (Lichens); Sphceria, Sporocybe (Fungi) ; and Verrucaria, Calycium 
 
SPECIAL MORPHOLOGY: ALG^E. 145 
 
 (Lichens), or Mycoderma (Fungi ?) from Protococcus (Algae), by 
 characters belonging to groups, and scarcely even generically. We may 
 separate them more safely by looking at the whole series of development ; 
 but even here the boundaries, as especially between Algce and Fungi, 
 when the latter grow in water, are confused, and between Fungi and 
 Lichens there are at least transitional forms which it is difficult to bring 
 into a definite position. 
 
 If we look, on the one hand, at the often naked fruits of the gelatinous 
 Lichens and the species of Peziza, and on the other at the Sphcerice, 
 whicn agree with many of the Lichens, we soon see that no very marked 
 difference can be established between Lichens and Fungi from their con- 
 ditions of consistence or structure. If we join the Pyrenomycetes and 
 the Discomycetes to the Lichens, which, as far as regards the former of 
 the two, appears in conformity with a natural arrangement, and is not 
 very extravagant with respect to the latter, if we look upon a Peziza, 
 for instance, as an Apothecium with the thallus (the mycelium) obli- 
 terated the formation of the spores within the sporangium ( Thecce) 
 would in that case be characteristic of Lichens. For the sake of the 
 facility which jt affords in the treatment of the subject, I shall adopt 
 this mode of subdivision, without, however, laying any peculiar stress 
 upon its importance. To me it appears evident that whoever has ac- 
 curately observed both groups must see the little value that is to be 
 attached to the difference of the thallus (in the Lichenes) and the stroma 
 (Fungi), (owing to a few green cells in the former,) as characteristic of 
 the two groups. One is disposed to assert that all botanists have ab- 
 stained from placing most Sphcerice and Hysterics under the head of 
 Lichens solely because their teachers had told them that they were Fungi. 
 
 We obtain the following divisions from the form of the spores: Spores 
 which develop themselves (from 1 to 4) in the sporangium according to 
 the second form of cell formation Algce; spores which to the number of 
 eight to ten are formed in the sporangium according to the first form of 
 cellular formation Lichenes; and lastly, spores developed individually in 
 smaller lateral expansions of the sporangium, separating themselves with 
 it Fungi* 
 
 L ALG^E. 
 
 80. The propagating cell (the spore) constitutes, in some rare 
 cases, the whole plant (Protococcus, &c.). More generally, however, 
 it expands itself during its development to a long, thread-like, often 
 ramifying cell ( Vaucheria) ; or it forms, in a manner with which we 
 are as yet unacquainted, many other cells, variously and multi- 
 fariously arranged, and thus constitutes the plant (frons Auctor). 
 
 The simplest forms exhibit waving ( Undind) or straight rows of 
 spherical cells interspersed here and there with whorls of lateral 
 branches (Batrachospermuni) : in other cases the cells acquire the 
 form of cylinders attached together so as to compose longer or 
 shorter filaments. These threads are either simple, or are them- 
 selves ramified in various ways so as to constitute a closed net 
 ( Confervacece). These plants generally secrete a definitely formed 
 gelatinous layer, which in the case of the Nostochinece determines 
 the form of the whole plant, while in that of the Confervacece it 
 constitutes only a membranous investment of the individual threads. 
 
 L 
 
146 MORPHOLOGY. 
 
 (See Plate II. fig. 7.) The majority swim freely in water, while 
 in a few the spores form in the course of their development a 
 thread-like prolongation, terminated at the extremity in a little 
 disc which adheres to some foreign body (organs of attachment, 
 rhizince), as in the instance of the Potysperma glomerata. In 
 others, again, the cells developed from the spores arrange themselves 
 so as to produce a greater surface ( Ulvacece), which at times ex- 
 pands at one extremity into a small adhering disc, and occasionally 
 appears as a hollow cylinder (Solenia Ag,). 
 
 Finally, in the most complicated forms the cellular process 
 developed by the propagating cell gives rise to solid structures 
 composed of cells ranged one upon the other ; these are either 
 thread-shaped (Scitosiphon Ag.), band-shaped (Laminaria Lam.), 
 leaf-like (Delesseria Lam.), simple, or divided in many ways, or 
 developed alternately in an apparently regular order into thread- 
 like and leaf-like forms (Sargassum). The plants are for the most 
 part attached to some place by a disc-like organ of attachment. 
 At times we meet with bladder-like inflations (Fucus nodosus) or 
 pedicled bladders (Sargassum). 
 
 I believe that no system is destined to be so thoroughly overthrown 
 as the one at present established for the Afgce, especially with reference 
 to the lower divisions ; and it appears to me that at least one third of 
 the species will probably be set aside. Certain it is, that many species 
 are described three or four times according to the different appearance 
 they have presented under magnifying powers of varying strength. 
 Hence it comes that most writers have had little or no conception of 
 the actual structure of plants in general*, and of the Alga in particular, 
 and that consequently a certain distinction between the stages and kinds 
 of formation is impossible. It is at any rate certain that mere stages of 
 development, which have very frequently been described as peculiar 
 species of plants, must fall to the ground as soon as their true character 
 has been recognised. My views on this subject are fully concurred in 
 by Kiitzing f, who, after thirteen years' laborious study, declares that 
 there are no species, but merely forms, of Algce ; and these he has fol- 
 lowed throughout the whole course of their development, showing, in 
 many cases by careful observation, although in a confused manner, that 
 they are devoid of an independent existence. 
 
 The terminology in use at the present time with respect to the Alga 
 is a mere confusion of words ; and as my purpose is simply to throw a 
 
 * Phycomater ; Gelatina inorganica (?), effusa, granulis (but surely cellulis) nuttis : 
 or Byssi meteoric! : formationes aerece, vegetatione nulla (?). What this is I cannot 
 decide ; but that it can be no race of plant, must, I should think, be evident to every 
 one who has acquired any fundamental knowledge of the nature of vegetable life. And 
 it will, at all events, be acknowledged by every man, even if he be no botanist, that it 
 is a flagrant absurdity to reckon among plants that which is defined as inorganic, and 
 to which is denied the first and indispensable character of plants. " There is a great 
 confusion in synonymy, which can only be cleared up by the careful examination of 
 original specimens. All delineations hitherto made only allow of a partial idea of the 
 real form and species, owing to their being copied from specimens which were not 
 sufficiently magnified, and also owing to their being drawn without the requisite exact- 
 ness," Kiitzing, Phycologia generalis, p. 249. 
 
 J" Phycologia generalis. 
 
SPECIAL MORPHOLOGY : 
 
 147 
 
 120 
 
 glance over the forms as far as may be necessary for the clear compre- 
 hension of the whole, and not to furnish my readers with a monography, 
 I may wholly dispense with all these empty terms. Kiitzing, who has 
 carried this fabrication of words beyond all limits, makes use of seventy 
 terms for the different forms of the family of the Algae. 
 
 We have already spoken at large, in the first part of this work (p. 36), 
 of a very interesting specimen of Algce, namely, the Fermentation 
 Fungus. Much has been written of late years upon this subject, but 
 I will here only enumerate some of the principal works : as, for in- 
 stance, Schwann (Poggendorff's Ann. vol. xli. p. 184.) ; Cagniard-La- 
 tour (L'Institut, 1836, Nov. 23.) ; Meyen (Wiegmann's Archiv, 1838, 
 vol. ii. p. 99.); Querenne (Journal de Pharmacie, 1838, June) ; Turpin 
 (Comptes rendus de 1'Academ. 1838, July ; and L'Institut, 1838, August). 
 We are still very much in the dark respecting the law of development 
 of the Algce. I am not acquainted with any complete exposition of the 
 subject.* There are many Algce of which we do not even know the 
 spores ; for where, in the case of the Confervce, the author speaks of a 
 Massa sporacea (chlorophyll, starch, &c.), he neither understands 
 himself or nature. Kiitzing certainly maintains that the granular cel- 
 lular contents are developed into new plants, but his representations to 
 that effect are far from furnishing us with the requisite proofs ; besides, 
 the whole thing is so contrary to all analogy in the vegetable kingdom 
 
 that it seems best to receive the fact only 
 as provisionally true. The process exhi- 
 bited in the Protococcus viridis is the 
 simplest. Here a spherical cell is slightly 
 expanded, soon after which we perceive 
 two young cells, which become isolated as 
 the parent cell gradually disappears. I 
 have not, however, been able to observe 
 how these young cells are developed. In 
 Mougeotia genuflexa (fig, 120,), the cell 
 of the spore extends at one extremity into 
 a tube, whose end bulges out into a spherical 
 form, flattening out on reaching any sup- 
 port in order to attach itself to it (/*). 
 From the other extremity of the spore, cells 
 proceed, which expand cylindrically and ar- 
 range in a thread-like form. I have been 
 unable to trace them in their earliest deve- 
 lopment ; and have hitherto been unsuc- 
 cessful in my attempts to observe the ger- 
 mination of Spirogyra. Since Vaucher f 
 observed the young Confervce issuing from 
 the burst spore J, nothing more exact has been noticed with regard to 
 
 * Meyen, Physiologic, vol. iii. p. 411., gives the heading of his subject as the Pro- 
 pagation of the Alyae, but in the text speaks almost entirely of Diatomece, part of which 
 are undoubtedly animals, and of a few Conferva:. The most important, as the Fucoidece 
 and Floridea;, are not even mentioned : and this is called a system of physiology. 
 
 f Vaucher, Histoire des Conferves d'Eau douce. Geneve, 1809. 
 
 | Meyen, Physiologie, vol. iii. p. 423., offers only conjectures on the subject. 
 
 l '' Mougeotia genuflexa. Development of the plant from the spore (a) in four stages 
 (b e). The last stage shows the adhesion of the plant by an adhering disc (/), which 
 is already indicated at d by the spherical enlargement (#). 
 
 L 2 
 
148 MORPHOLOGY. 
 
 them. In a few instances germination has been observed in more deve- 
 loped Algae, as, for instance, by Martius *, Agardh, and Kutzing, with- 
 out, however, their having had regard to the most essential points, viz. 
 the origin of new cells. The self-division so much insisted upon by 
 Meyen f has not been established by observation, excepting in the case 
 of Diatomece, and other doubtful organisms, but has merely been as- 
 sumed. In Hydrodictyon utriculatum a young plant is developed within 
 a cell in an unknown manner.^ Mohl thinks he has seen a multipli- 
 cation of cells by division in Conferva glomerata. We are, however, 
 indebted to Nageli for elucidating this relation, as well as the whole cel- 
 lular formation, of the Algce, by showing that all increase of cells in 
 the AlgcB depends upon the second type of cellular formation ( 14). 
 
 81. In the simplest forms of Alga, the plant itself is the parent 
 cell (sporangium) of the spores (Protococcus). In the thread-like 
 Vauclierice, a portion of the cell expands spherically into a spo- 
 rangium. In those composed of many cells the sporangium is 
 formed from one individual cell which, at times swelling into a 
 spherical form, furnishes the sporangium (CEdogonium vesicatum). 
 In the case of the greater part, however, we know but little of 
 the formation of the spores. In the more complex Floridea there 
 are apparently two kinds of spores in the different individuals. 
 Some enclosed in large numbers in a sporocarp (Kiitzing's Kapsel- 
 fruchte) are developed in a manner with which we are still unac- 
 quainted : the others (Kiitzing's Vier ling sf rue lite) are formed, accord- 
 ing to Nageli, exactly like the pollen-granules of the higher plants, 
 in a parent cell (sporangium), which sometimes becomes subse- 
 quently absorbed and disappears. |] The different forms of fruits 
 are either scattered, heaped together, or again frequently united 
 upon peculiarly formed lobes of the plants (receptaculum). 
 
 Here, again, we have every thing shrouded in the greatest darkness. 
 Not that the water contains marvels, as Link declares, but that it has 
 been examined with the most unsatisfactory observation, combined in 
 some degree with an unrestrained fancy. In such a state of things there 
 cannot of course exist any thorough well-grounded study of the law of 
 development. I have myself unfortunately been unable hitherto to make 
 any more comprehensive observations. 
 
 In certain respects, Kiitzing's Phycologia generalis forms a new epocli 
 in the study of the Algce, and, notwithstanding the constant and reiter- 
 ated changes and enlargements which he superfluously makes in the 
 terminology, and the deficiency which is throughout observable of accu- 
 rate observations upon the law of development, his work furnishes us 
 with the first attempt at arrangement of the greater part of the mate- 
 
 * Martius, Nov. Act. Leopold. Carol, ix. p. 217. 
 
 f Meyen, Physiologie, vol. iii. p. 440, &c. 
 
 J Vaucher, Hist, de Conf. 
 
 " Vermehrung der Pflanzenzelle durch Theilung." Multiplication of the vegetable 
 cell by division. Tub. 1 836. 
 
 || This Nageli maintains at any rate (loc. c/.), whilst Deeaisne (Archives du Mus. 
 d'Hist. Nat. vol. ii. ; Plantes de PArabie heureuse, p. 112.) positively maintains the 
 
SPECIAL MORPHOLOGY: ALG.E. 
 
 149 
 
 rials, which he handles according to a principle of unity, by which we 
 are enabled to compare separate observations with each other, and trace 
 their mutual relations. And we must not conceal that it is extremely 
 difficult, owing to the external relations, to make comprehensive obser- 
 vations upon the law of development, and that consequently the re- 
 proaches which we must make against the state of the science in regard 
 to the Algce in our day, only apply to a certain extent to the individual 
 investigations. In some degree, certainly, the cause lies in the artificial, 
 senseless methods of research that infect the whole science of Botany, 
 which has hitherto directed its attention far more to herbaria than to 
 living plants ; and hence, those who live far inland become Algologists, 
 whilst botanists residing near the sea-side busy themselves in describing 
 some little dried Jungermannia brought from Java ; and European in- 
 vestigators thus too often devote more attention to tropical plants than 
 to those that are indigenous to their own country, and are in their own 
 immediate neighbourhood. 
 
 The so-called copulation of Spirogyra and a few other Conferva 
 (fig. 121.) are generally represented as especially remarkable. They consist 
 
 121 
 
 of thread-like cylindrical cells arranged in a linear series. At a definite 
 time one side of each cell expands into a papilla, which combines with 
 any papilla of another cell of the same or another filament with 
 which it may come in contact, and then the partition is absorbed, the 
 contents of the one cell pass over into those of the other cell, and out of 
 the total mass a spore is formed (fig. 121. a a). I have observed the 
 following cases, which prove how inessential this process really is. Two 
 cells were combined with the papilla of a third cell ; and thus arose four 
 spores, one in each of the first-named cells, and two in the third. Three 
 cells were combined, and the result was the formation of one spore in 
 the space formed by the three papilla. Again : two cells were combined, 
 in the one of which there appeared two spores, and a third spore in the 
 cavity of the papilla. Two cells combined together, and here a spore 
 was formed in each one (fig. 121. c). Another instance very frequently 
 occurred in which one cell, that had a papilla which did not combine 
 with another, exhibited a spore formed within the cell (fig. 121. b b). 
 Finally, it sometimes happens, although but rarely, that a spore is formed 
 without the cell having borne any papilla. 
 
 The Algce certainly merit the most thorough examination, as we are 
 
 181 Zygnema quininum. Phenomena of the so-called copulation. At a a, the con- 
 nexion is effected, and the contents, being transferred from one thread to another, form a 
 spore. At b b, the projections are formed, without, however, their being able to com- 
 bine with another cell ; notwithstanding which, a spore is formed. At c, a spore is 
 formed, and here another prolongation effected, which is connected with another cell, in 
 which the contents begin at the same time to concentrate themselves into a spore. 
 
 t 3 
 
150 MORPHOLOGY. 
 
 justified in expecting important results to science from them on account 
 of the simplicity of their structure and life. To effect this, however, it 
 will be necessary, if we would avoid thorough confusion, entirely to 
 exclude the Diatomece and the true Oscillatorice, which, according to my 
 view, are equally dubious. 
 
 82. The Alga, consist generally of cells in a low condition of 
 development, having for the most part gelatinous walls; in the 
 FucoidecR and Floridecs we find, in the interior, more elongated or 
 broader cells, which, by their distinct porous canals, indicate the 
 presence of thickening layers, so that the cavity of the cell has fre- 
 quently a beautifully ramified appearance. These cells are very 
 often found to be arranged with the greatest regularity. In 
 most of the Algce, the tender mucous integument of the inner 
 surface of the cell-wall is especially developed, and here motions of 
 currents of fluid may frequently be traced, as, for instance, in the 
 species of Spirogyra. The chlorophyll often appears as an in- 
 vestment of the cell-wall, in the form of spiral bands with jagged 
 edges ; the granular contents of the cells (the starch) are generally 
 very coarse-grained. In the more complex species, we may distin- 
 guish a smaller, more closely packed cellular tissue, as rind (cor- 
 tex) from the larger-celled porous pith (medulla). The vesicles 
 contain very porous, spongy cellular tissue. All the Algae exhibit 
 a more or less distinctly apparent secreted layer of gelatinous, 
 amorphous substance, covering the whole external surface. 
 
 The structure of the Algce. is, on the whole, very simple, if we do not 
 include amongst them the dubious Diatomece, &c. with their siliceous 
 shields ; and which, as has been already stated, are quite out of place 
 here. I give an exact representation (Plate II. figs. 1 to 6.) of the sili- 
 ceous shield of Navicula viridis, one of the commonest of the Diatomece, 
 of which I have not hitherto met with so minute, nor indeed any accu- 
 rate, representation. It will show that this curious structure is wholly 
 without analogy in the vegetable kingdom*, and cannot be derived from 
 laws of vegetation with which we are at present acquainted. One of the 
 most striking phenomena is the deposition of chlorophyll in the spiral 
 jagged bands observed in the species of Spirogyra. The formation of a 
 secreted layer upon the surface of the Alga appears to throw consider- 
 able light upon the nature of the cuticula in the higher plants. Ca- 
 bomba aquatica shows great affinity to these formations, by its very 
 gelatinous cuticula. It has, however, been shown by the observations of 
 Kutzingf, that this layer in the Algce must certainly be a secreted sub- 
 stance, as, when removed or injured, it is replaced by a liquid mucus, 
 that gradually hardens. On the other hand, the clothing of the inte- 
 rior of the actively vegetating cell, with a semi fluid layer of a nitrogenous 
 substance, frequently circulating in currents (inappropriately termed 
 an amylid cell by Kiitzing), is most remarkably conspicuous in the 
 Algce. Compare, with reference to the above, the Plate II. fig. 7. with 
 the accompanying explanation. 
 
 * Meyen passes this by as a matter of common occurrence because silica is found in 
 other plants, and thus entirely overlooks the essential difference. 
 ) Kiitzing, Phycologia generalis, p. 87. 
 
SPECIAL MORPHOLOGY: FUNGI. 151 
 
 II. FUNGI. 
 
 83. The spore expands in many directions into an interwoven 
 tissue (rnycelium, stroma, Jlocci, thallus) composed of thread-like, 
 mostly transitory, cells, forming the actual plant, which exhibits 
 no other organs excepting those of propagation. We are wont to 
 make the transitory nature of this part a means of judging of the 
 more strikingly apparent, and frequently more lasting propagating 
 organs of the whole plant. 
 
 A Fungus, as I believe, very seldom consists solely of roundish cells. 
 I cannot regard the true Uredines, &c. ( Coniomycetes) as independent 
 plants. Meyen observed the formation of Uredo Maidis* as an abnormal 
 process of cell-formation in the interior of the cells of the parent plant ; 
 and, in this respect, my own observations on Elymus arenarius coincide 
 with his : on the other hand, the views of Leveille f appear but little 
 entitled to be opposed to the investigations of Meyen, being evidently 
 more superficial and incomplete. An advanced stage of knowledge re- 
 garding the Fungus tribes will no doubt lead to the general conviction 
 that all Fungi consist of a few thread-like cells, forming spores in a 
 similar manner ; and that the classification into groups, tribes, and spe- 
 cies, must depend upon the modification of the process of the formation 
 of spores, upon the aggregation of individual fungus-cells to more com- 
 plex plants, and upon the types of the forms of these compound Fungi. 
 I must, also, regard many other supposed species of plants, as Cceoma, 
 Puccinia, &c., as devoid of individuality, and simply as diseases of plants. 
 On the other hand, such Fungi as are formed in the intercellular pas- 
 sages, and grow from the openings of the stomates, I consider as real 
 parasitical plants (Epiphytes}. The whole tribe of the Leptomitece Ag. 
 do not appertain as independent structures to the Algce, but to the 
 Fungi\) as being species of mould germinating in water. The confu- 
 sion that existed regarding these most imperfect plants was, up to the 
 most recent time, beyond all description, and will not be very speedily 
 removed, since only a few botanists deserving of credit, as Leveille, 
 Montagne, and Berkeley, have devoted themselves to the general study 
 of these groups ; and, in spite of the best observations on the subject, 
 the old errors are for ever revived in systematic works. It may be said 
 of such systematisers, as of the French emigrants, " They forget nothing, 
 and learn nothing." 
 
 We still know but little of the law of development of Fungi. Thus, 
 although the origin of new cells from the spore may have been observed, 
 we yet have no delineation of any one single kind. J. Schmitz has 
 made a very successful introduction, in recent times, to accurate observ- 
 ations of the law of development. (See Beitriige zur Anatomic and Phy- 
 siologic der Schwamme, Linnaea 1843, p. 417.) 
 
 We have certainly recently acquired many very complete series of 
 
 * Wiegmann's Arcbiv, Jahrg. 1837, vol. i. p. 419. 
 
 f Annales des Sc. N., ser. ii. vol. xi. p. 5. 
 
 \ Compare, amongst others, Meyen, in Wiegmann's Archiv, 1838, vol. ii. p. 100. ; 
 and Montague's Skizzen zur Organogr. und Physiol. der Schwamme, Prag. 1844, 
 p. 15. 
 
 Thus we find in Kiitzing's Phycolog. gen, all the species of Leptomitus and Hygro- 
 crocis received as Alga. 
 
 L 4 
 
152 MORPHOLOGY. 
 
 observations on several of the more interesting species, but even these are 
 deficient, in a botanical point of view, in that completeness which can 
 alone be obtained by the acquirement of a more perfect knowledge of the 
 origin of the individual cells. I will here especially mention the follow- 
 ing works : 
 
 1. The Ergot (Sphacelia segetum), on which observations have been 
 contributed by Meyen (Miiller's Archiv, 1838, p. 357.); Leveille (Ann. 
 des Sciences Nat. 1837, Dec.) ; Phoebus (Description of German Poison- 
 ous Plants, Part 2, p. 97.); Fee (Flora, 1839, p. 293.) ; Spiering (De 
 Secali cornuto Diss. inaug., Berlin, 1839) ; E. J. Quekett (Ann. of Nat. 
 History, 1839, p. 54.). 
 
 2. The Muscardine (Calcino, Botrytis Bassiana); a Fungus growing 
 upon the Caterpillar of the Silkworm, observed by Bassi (Wiegmann's 
 Archiv, 1837, vol. ii. p. 107.); Balsamo Crivelli (Linnsea, 1836. p. 609.); 
 Audouin and Montagne (Comptes rendus de 1'Acad. 1838, p. 86.). 
 
 84. The development of the organs of propagation varies very 
 much, and has only been perfectly observed in a very few instances. 
 
 The most simple (Hyphomycetes, filamentous Fungi) form, at 
 the end of the thread-like cells, narrower protuberances, in each of 
 which a spore is developed ; this at length separates, having con- 
 sequently a double membrane, the cell of the spore itself and the 
 covering (sporangium) arising from the parent cell, as, for instance, 
 Penicillium, Botrytis. In others the thread-like cells form a sphe- 
 rical swelling at the extremity, from which project a number of 
 such prolongations, each of which contains a spore, while the 
 whole forms a divided sporangium, &s, for instance, Mucor, Penicil- 
 lium ? 
 
 In others (Crasteromycetces, the ventricular Funy'i) the thread- 
 like cells combine into pointed, or non-pointed, variously-shaped 
 sporocarps; in or upon which are spores, of the development of 
 which we know nothing. After the scattering of the spores, 
 the thread-like cells often remain as tender wool (in the Trichi- 
 acece), or as a delicate network (capillitium), as, for instance, in 
 Stemonitis, Cribraria; and the external capsule (uterus, peridiuni) 
 generally composed of fine filamentous cells, is then dissolved, or 
 bursts in different regular ways, as in Arcyria, Geastrum. 
 
 In the most highly developed Fungi (Hymenomycetes, membrane 
 Fungi\ elongated pouch-like cells (probably only the ends of the 
 interwoven filiform fungus-cells, developed into the sporocarps, or 
 cells formed at the ends of these cells) combine by arrangement 
 side by side so closely as to form a membrane (hymeniuni). Some 
 of the cells of tins membrane enlarge considerably (sporangia)) and 
 send out from one to six points at their free extremity, in each of 
 which a spore is developed. The filiform cells of the Fungus then 
 either form round masses, closed in all round (sporocarps), with 
 cavities in their interior, the walls of which are clothed by the 
 hymenium, or they form definitely arranged columns (in Merisma), 
 tubes (in Pofyporus), or lamellae (in Dcedalea, Agaricus), which 
 are clothed by the hymenium (the Hymenomycetes). Of the latter 
 we only know, with any amount of accuracy, the law of develop- 
 
SPECIAL MORPHOLOGY I FUNGI. 
 
 153 
 
 ment relating to the Toadstools, and more especially that of the 
 Agaricinea. In these latter there are formed, at definite parts of 
 the floculent mycelium, small hollow heads (yolvce) ; at the bottom of 
 the cavity there grows a corpuscle, shortly pedunculated below, and 
 enlarged into spherical form at the top. In the lower part of this 
 protuberance, a horizontal circular cavity is formed, to the upper 
 surface of which are attached the tubes, lamella, &c., which bear 
 the hymenium. The bottom of the cavity is only formed by a 
 membrane (indusium), which is either separated from the pedicle 
 on its further development, or, loosening itself from it and the 
 upper part at the same time, remains as a membranous ring (annu- 
 lus) upon the stalk. The upper part, which supports the hyme- 
 nium on its lower surface, dilates subsequently, and appears as an 
 umbrella-like expansion, called the hat (pileus). The whole then 
 breaks through the volva, which is very soon dissolved. 
 
 Almost all the works that have hitherto appeared on the lower Fungi 
 are wholly useless, and may, without farther consideration, be cast aside, 
 since the work must again be commenced from the beginning. Investi- 
 gations are of no value where they do not trace the composition of the 
 forms from the individual cells. Even by the aid of delineations (as, for 
 instance, in Nees von Esen- 
 beck's System of the Fungi 
 and of Flocculent Plants. 
 Schwamme}, we do not learn 
 whether we have to do with 
 individual cells, or structures 
 composed of such cells ; and 
 yet on this depends every- 
 thing. I must confess that 
 I find it quite impossible to 
 determine one of the lower 
 Fungi from the ordinary 
 descriptions, as they do not 
 express what nature exhi- 
 bits. Even delineations are 
 not often of much avail. This 
 arises from the fact that in 
 many cases the specific dif- 
 ference does not certainly 
 rest in the plant, but in the 
 observers, their instruments, 
 and the magnifying power 
 used. My own limited ob- 
 servations yield the following 
 results : on the Allium fistu- 
 losum there is, on the yel- 
 low leaves, a small epiphyte 
 (Botrytis?) (fig. 122.), con- 
 sisting of one single multi- 
 fariously ramifying cell. It 
 germinates in the intercel- 
 
 128 JBotrytis (parasitica ?). A, Grown out from the stomate of a leaf of Allium jistu. 
 
154 
 
 MORPHOLOGY. 
 
 lular passages, and grows as a little stem from the stomate, branching 
 externally in a tree-like form. I observed it in all its stages of develop- 
 ment from the germ. At the points of the branches, and distinctly en- 
 closed by the membrane, a small cell is seen, which gradually swells to a 
 considerable size, and then separates itself from the branch with the in- 
 tegument it has derived from the parent cell. This is the mode of forma- 
 tion of the spore. According to Meyen's delineations*, the same pro- 
 cess goes on in Penicillium. I found upon damp linen a colourless mould 
 (Mucor ?) (fig. 123.), consisting of one cylindrical cell (seldom more), 
 much ramified upon the surface ; it had one stem, the end of which was 
 
 123 
 
 spherically enlarged, and furnished with small pear-shaped processes, 
 projecting in all directions. An individual cell was distinctly visible in 
 the interior and at the point of each process, which, gradually enlarging, 
 separated itself from its support. On the withering leaves of the Passi- 
 flora alata, I found a mould that was almost as black as pitch, consist- 
 ing of one simple thread, formed below of shorter and thicker, and 
 above of longer and narrower cells, of which the uppermost, which was 
 spherically expanded, exhibited the same process of spore- development. 
 I found upon the withered stalks of the same plant another whitish-gray 
 mould, composed of short and thick cells at the bottom, and longer and 
 thinner ones at the top, forming ramified threads. The two or three last 
 joints of the stalks and the branches contained a turbid, mucous, granu- 
 lar fluid, which sometimes exhibited very small but sharply-defined 
 globules, or discs (cytoblasts). Very minute delicate cells were fre- 
 quently to be observed, closely applied upon the wall of the cell, 
 which was often arched outward over the cells. I met with all 
 possible stages of transition from this condition to a longer wart -like 
 projection of the wall, at the point of which lay a young cell, free and 
 
 * Pflanzenphysiologie, vol. iii. pi. x. figs. 22. 20, and 21. 
 
 losum. A section of the latter is given. P, A portion of the fungus, with spores in 
 different conditions of development (a d), and a barren branch (e). 
 
 lk3 Mucor (sphcerocephalits ?). a, The whole plant, b, The head of the spore-case, 
 in a longitudinal section, the greater part of the processes with the spores being omitted 
 in the delineation, c, Earlier condition of such a protuberance, with the spore originat- 
 ing from it. d, Protuberance, with the ripe spore. 
 
SPECIAL MORPHOLOGY : FUNGI. 
 
 155 
 
 again from this condition to that of a riper spore, connected by a short 
 pedicle with the cellular wall. (Compare Plate II., fig. 8.) In both of the 
 above-described species of mould, the lowest cell was short, almost 
 barrel-shaped, and immediately attached to the still distinctly recog- 
 nisable cells of the epidermis of the plant, which, although they were 
 withered, were otherwise wholly uninjured, while not a trace of adhering 
 discs or fibres was to be perceived. I likewise observed upon the hyme- 
 nium of Agaricus campestris (figs. 124, 125.) and A. Oreades, and Amanita 
 
 125 
 
 124 
 
 muscaria, the perfect formation of these processes from the large cells of 
 the hymenium, and the origin of the spores as little globules within the 
 points of these projections. On comparing this representation with 
 what follows, it will become very evident that the external membrane 
 of the Fungus-spores cannot be compared with that of the Moss-spores, or 
 the pollen granules ; but that it represents a spore-case. This membrane 
 does not prevent the spore from expanding irregularly, in the act of 
 germination, into many thread- like prolongations, and that at any point 
 indiscriminately. The above-mentioned development of the pileus of 
 the pileate Fungi has been thoroughly observed, and frequently deline- 
 ated.* Of the development of all other Fungi, with the exception of the 
 
 * By Bischoff, among others, Handb. der Botanik, pi. vii. fig. 163. of Agaricus vol- 
 vaceus. 
 
 m Agaricus campestris, shown in a longitudinal section, a, Substance of the pileus. 
 fe, The lamellae, covered by the hymenium. c, The stipe of the pileus. d, The 
 actual plant (mycelium). The dotted line indicates the direction of the section 
 125. a. 
 
 185 a, A section through the lamellae of the pileus of the Agaricus campestris (fig. 
 124.). The lamellae are covered by the hymenium, on which appear the spores, b is 
 a portion of the hymenium, with the spore -cases in three different stages of formation ; 
 the middle one shows already the four processes, c, A spore somewhat more deve- 
 loped. In the process to the right is a spore in the first stage ; to the left, one some- 
 what more developed. d shows a spore-case with four processes and many half- 
 developed spores. e, The upper part of a spore-case, with a process, and a fully 
 developed spore. 
 
156 MORPHOLOGY. 
 
 parasitical*, we know scarcely anything. In the Fungi, too, we observe 
 a formation of the spores very similar to the copulation in Spirogyra ; 
 with this exception, that here the spore is developed quite regularly in the 
 middle of the tube formed by the fusion of the two papillae, f 
 
 In more recent times, much has been said on the subject of the an- 
 theridia of the Fungi\ ; and Meyen has even discovered them in^Eci- 
 dium. What is to be thought of all this scientific juggling with the 
 word anther, will be subsequently discussed. The case is as follows in 
 the Hymenomycetes. Beside the sporiferous cells, between the sterile, 
 cells upon the hymenium, there are a few projecting, wider tubes, filled 
 with a turbid, mucous fluid (cystides, Leveille ; utricles, Berkeley ; para- 
 physes, Auctor) ; and this is all that we know of the matter. Klotsch, 
 according to his own statement, has observed that the spores coming in 
 contact with these tubes germinate more certainly than those in which 
 he w r as not positive of the same condition existing. || At present this 
 seems to be a very vague supposition, and proves nothing for the nature 
 of the anthers. As to the JEcidium anthers, an exanthema described by 
 Unger, and frequently occurring, together with the external eruption of 
 jEcidium it is asserted by Meyen, that a more accurate investigation of 
 its formation, as well as its relations in time and space, compel him to re- 
 gard it as a male JEcidium plant, although it may be proved by observa- 
 tion that there can be no question here of actual impregnation. Anthers 
 must really have become a fixed idea in the mind of Meyen, since, in 
 spite of everything, he can declare these structures to be such. The 
 facts furnish not only no compulsory arguments in favour of it, but 
 not even a shadow of possibility, that ^Ecidiolum cxanthematum (Ung.), 
 which develops alone previously, frequently upon leaves, on the other 
 side of which the JEcidia are formed, while sometimes no such con- 
 sequence follows, stand in any other relation to the JEcidium than 
 the Acne punctata does to the Acne rosacea, in the human subject, or 
 any one disease of the skin to another. Those imaginative physicians 
 who declare disease to be an independent organism, have, according to 
 this analogy, a wide field for the flights of their fancy, in seeking for 
 males and females among the different pocka, pustules, and vesicles. 
 
 85. Filiform cells and the interwoven tissue are almost the 
 sole element of the Fungi. The nature of the cells, however, 
 varies from a readily deliquescent softness, fatty or greasy, as it 
 were, to the touch, to the most compact wood-like hardness, as in 
 German tinder. Spiral formations do not appear to occur. A few 
 Agarics contain a milky juice, which, in the case of the Ag. deli- 
 ciosus at least, is contained in definite small groups of parenchy- 
 matous cells. 
 
 The hair-like cells in the sporocarp of the Trichia and the Arcyria 
 appear almost like spiral fibrous cells ; but I think that I have reason to 
 assert that they are merely flat band-like cells spirally twisted. In the 
 
 * See Unger's excellent treatise, Die Exantheme der Pflanze, Vienna, ] 833. 
 
 j- See Ehrenberg, in Transactions of the Ges. naturforschender Freunde, Berlin, 
 1820, vol. i. page ii. 
 
 J See Wiegmann's Archiv, 1839, vol. ii. p. 51. 
 
 Pflanzpathologie, p. 41. 
 
 || Dietrich's Flora of the Kingdom of Prussia, vol. vi., under the head Agarieut deli- 
 quescens. 
 
SPECIAL MORPHOLOGY: LICHENES. 157 
 
 Ag. deliciosus the milky juice is certainly present, as I have indicated; but 
 some have insisted that they also found true lacteals in Fungi, a state- 
 ment that for the present I must leave undisputed. The most remarkable 
 thing in the Fungi is at all events the great difference in the nature of 
 the cell-membrane, which, at least, according to Payen's investigations, 
 consists of common cellulose. The state of decomposition into which 
 the various species of Coprinus pass in the course of a few hours, 
 becoming converted into a black, highly carbonaceous fluid, is very 
 striking indeed. But we are still deficient here in accurate observations. 
 Telephora hirsuta contains, according to Schmitz (Linnsea, 1834, p. 438.), 
 beautiful octoedric crystals (oxalate of lime ?) 
 
 III. LICHENES (LICHENS). 
 
 86. Whilst the Fungi form their spores in a thread-like pro- 
 longation of the parent cell, and separate by constriction across 
 the neck, the Lichens develope many spores simultaneously (many 
 of them double spores) in the interior of a larger parent cell. We 
 thus have a clearly defined limit drawn between the two groups. 
 
 Many nuclear Fungi (Pyrenomycetes) cannot, or at least not easily, 
 be distinguished, without previous acquaintance with them, from many 
 Lichens (as, for instance, of the groups Idiothalami and Gasterothalami). 
 They correspond so closely with Lichens, with respect to the law of the 
 development of their spores, that I, at least, for my part am unable 
 to separate them. But the same may be said of the discoid Fungi 
 (Discomycetes). Most of the smaller species of Peziza are altogether 
 deficient in any characteristic by which they may be distinguished from 
 the apothecia of Lichens as a peculiar order, especially if we compare 
 with them the soft gelatinous substance of the fruits of the Col/ema, 
 which so frequently occur without any thallus. I therefore combine 
 them with the Lichens, as I thus gain from the peculiar, essentially- 
 distinct history of their development a well-marked characteristic to 
 separate the two groups. After the admirable observations and inves- 
 tigations of Camille Montagne*, we can no longer doubt that Lichina 
 (Ag.) belongs to the true Lichens. 
 
 87. The spores of Lichens develope, in a way of which we are 
 ignorant, cells mostly of roundish form, which spread out flat upon 
 the subjacent surface (protothallus) : by degrees larger globular 
 cells are formed upon this, which the upper and under surfaces, be- 
 coming more closely connected, and the lower face a little elongated 
 in a vertical direction, form a plant (thallus Aut.) of crustaceous 
 aspect (thallus crustaceus), the outline of which appears usually very 
 irregular and dependent upon accident. 
 
 In other forms the Lichen tissue is developed between the upper 
 and lower layer, and then the plant assumes more definite and 
 independent lobed forms (tliallus foliaceus), the outline of which is 
 generally circular. Irregular bundles of interwoven tissue often 
 separate themselves from the lower surface, serving as organs of 
 
 * Ann. de Sc. Nat. 1841, xv. (Mars), p. 146. 
 
158 MORPHOLOGY. 
 
 attachment (rhizince). For the most part the thallus foliaceus is 
 more or less closely appressed to the supporting surface, sometimes 
 only fastened at the middle point by a small adhering disc (as, for 
 instance, in Urnbilicaria) ; at others it rises freely, and then appears 
 in flat ramifying forms, which always admit of being distinguished 
 from the succeeding form by the inequality of their two surfaces. 
 
 Finally, in the highest forms the cellular mass rises and forms 
 multifariously ramifying bands or threads of greater or lesser thick- 
 ness (thallus fruticulosus). 
 
 We know but little as yet of the law of development of Lichens. 
 Hitherto, Meyer* and Wallroth| are the only ones who have given us 
 any information on the subject ; yet both were as deficient in funda- 
 mental physiological information to know what was requisite, as in good 
 microscopes, &c., to see things worthy of being noticed. Meyer has 
 clearly and fully explained all that could be seen with the naked eye, 
 whilst "Wallroth has rendered his work wholly unendurable by the use 
 of a terminology as superfluous as it is disgustingly barbarous. 
 
 The structure of the forms in Lichens is on the whole very simple. As 
 they almost all grow uniformly from one point of the spore in all direc- 
 tions, and are besides generally attached to the supporting surface, the 
 most general is the round outline, modified by the form of the surface on 
 which they grow, and by the specific structure of the lobes. In some, as, 
 for instance, in those nuclear Fungi which I include under the same head 
 and Helvellacece, and also in many true Lichens, especially in the pul- 
 verulent Lichens, or as, for instance, in Coniot/ialami, and some columel- 
 lar Lichens, the plant is so perishable that we scarcely find anything 
 beyond naked sporocarps. In some^ as in the Graphidece, &c., the plant, 
 similarly to what is the case in most Pyrenomycetes, expands itself 
 within those parts of plants (mostly bark) which serve as a basis to 
 it, and subsequently, after the destruction of the covering, nothing 
 appears but the naked sporocarp, or sometimes, but rarely, also the 
 plant itself. It is only in a very few cases that the plant rises stem-like 
 and free from the base, either by the erection of the lobes, as inEvernia, 
 Borrera, &c., or by some real difference of development, where the plant 
 developes linearly upwards instead of laterally and superficially ; thus, 
 consequently, exhibiting the same surface as it had previously done 
 while recumbent. The word thallus is superfluous in the case of such 
 a plant. 
 
 88. The development of the spores is very uniform for all cases 
 included within the limits of this family. At wholly indefinite 
 parts of the surface of the plant, there is formed a semi-circular 
 channel-shaped, or more or less spherical or cylindrically closed 
 layer of delicate walled, closely packed, roundish cells, which 
 sometimes appear coloured, as in Lecidea sanguined (when form- 
 ing a rim round the developed sporocarp, named excipulum pro- 
 priwni) ; and on the inner surface of this layer is a second, composed 
 of thin filiform cells (paraphyses, Saftfaden), placed vertically 
 upon the preceding layer (Lamina proligera Auct.). By degrees, 
 
 * The Development, Metamorphosis, and Propagation of Lichens. Gottingen, 1825. 
 j- Natural History of Lichens. Frankfort, 1825-27. 
 
SPECIAL MORPHOLOGY: LICHENES. 159 
 
 single, broader, elliptical, tender-walled cells (sporangia, thecce, 
 asci, Auct.), grow up between them, and soon become filled with 
 a viscid matter. Within these, cell- nuclei are developed, and from 
 them cells which form simple spores ; or, again, two or more cell- 
 nuclei appear, from which cells, and then double-spores, are deve- 
 loped. During this process, the whole sporocarp approaches by 
 degrees nearer to the surface of the plant, being always covered 
 by a substance the tissue of which it is difficult to determine, but 
 which appears to be partly the product of the paraphyses, fre- 
 quently occurring as a black, finely granular, mass, as is especially 
 the case in Pyrenomycetes and Pyrenothalami ; and partly, in the 
 subsequently expanded fruits, composed of a thin lamella of the 
 cortical layer of the thallus, and is sooner or later destroyed. 
 Remaining in this closed condition as a nucleus, it forms the fruit 
 of Pyrenomycetes and Pyrenothalami (sporangia angiospora nu- 
 cleo pradita, Meyer). In others it bursts through the upper 
 surface, spreads itself more or less into a linear cup, or disc- shaped 
 (apotheciuni) patella, when circular ; lirella, when linear ; (sporo- 
 carpia angiospora laminam gerentia, Meyer). It sometimes raises 
 a part of the upper surface of the plant, which then appears as 
 a margin (margo thallodes, excipulum thallodes) ; at others, again, 
 this portion grows more decidedly out, and raises the sporocarp 
 upon a pedicle (podetiurri) varying in height. In most Lichens the 
 sporangia remain long closed ; in some, however, they open early, 
 and the spores then lie free upon the sporocarp (sporocarpia gym- 
 nospora, Meyer ; coniothalami). 
 
 The history of the development of the fruit of the Lichens is still 
 very incomplete. Meyer has furnished us with much valuable informa- 
 tion concerning all that may be seen by the naked eye, or an ordinary 
 lens ; as, for instance, his valuable account of the development of the cup- 
 shaped fruits of the species of the Cladonia, appearing either on the 
 margin in new fruits, or expanding into cups. I have sketched the 
 process from my own observations on Borrera ciliaris, Lecidea san- 
 guinea, Sphcerophoron coralloides, Calycium trachelinum, Parmelia 
 subfusca, &c. By way of illustration I will here give the development of 
 the sporocarp of Borrera ciliaris (figs. 126. 127.), and at Plate II. fig. 9. 
 
 a j27 
 
 fe^N 
 126 
 
 86 Borrera ciliaris ; a portion of the plant. a, First beginning of a sporocarp 
 6, The same more fully developed, c, Quite developed. 
 
 87 Section through the sporocarp of the Borrera ciliaris, in three different conditions 
 
160 MORPHOLOGY. 
 
 the development of the spores of the same plant. It is certain that 
 there is no difference perceptible between the development of the pul- 
 verulent and that of other Lichens ; and equally certain, that the so- 
 called paraphyses appear earlier than the sporangia, and that the latter 
 grow between the former, differing in their volume from the very begin- 
 ning, which proves that these paraphyses cannot be regarded as abortive 
 sporangia. Finally, it is evident that nothing appears in the whole 
 sporocarp but the paraphyses and the sporangia in different stages of 
 development. We cannot, for want of the necessary details, determine 
 what is meant by the so-called antheridia purporting to be discovered 
 by Link (indeed the statement rests only on an announcement in the 
 Prussian newspaper, Die preuss. Staatszeitung). The development 
 of the spores is very interesting in Lecidea sanguined. The young 
 sporangia have a very thick gelatinous wall, and the narrow cavity is 
 filled by a mucous mass (appearing in all Lichens), resembling intestinal 
 convolutions, in which from eight to twelve young spores are formed ; 
 of which only one, or occasionally two, are perfectly developed. In 
 time there appears upon the gelatinous wall of the sporangium a thicker, 
 more internal, lamella, formed probably by the pressure of the expanding 
 contents, which is gradually pressed outwards, and at length becomes 
 so blended with the outer bounding surface, that it alone encloses the 
 ripe spore. The ripening spore has likewise a gelatinous cellular mem- 
 brane, thickened in layers. The abortive, or more or less developed 
 spores often adhere to the perfectly formed spores, imparting to them 
 horns, points, or other strange excrescences. A few Lichen spores have 
 distinctly an outer coating of a hardened mucous substance. In Par- 
 melia parietina, for instance, this covering forms hollow hemispheres, 
 covering both ends of the spores, connected by a narrow strip of the 
 same substance (similar to the pollen-granules in Pinus). In Borrera 
 ciliaris the spores are of a dark, blackish-green colour, and it is dif- 
 ficult to determine whether this is produced by a similar coating, or is 
 due to the cellular contents. Owing to the almost general unanimity 
 that exists as to the use of the terminology, which is, to a great extent, 
 superfluous, I have given the most commonly used expressions in 
 parentheses. 
 
 89. The anatomical structure of the Lichens is, generally 
 speaking, very simple. The most complicated, as, for instance, 
 Borrera ciliaris, consist of a three-fold layer. The principal mass 
 is formed of lichen tissue ; long, thin, dry, mostly forked, ramified, 
 and rather loosely interwoven cells (medullary layer), which curve 
 outward on the external surface, and, by degrees, pass into shorter 
 cells more closely packed together, and firmly connected by much 
 intercellular substance, and often into detached cells, the character 
 of which is with difficulty to be recognised as that of cells at all 
 (cortical layer). On the limit between the two lie larger or smaller 
 groups of roundish, cells, containing chlorophyll, and exhibiting, in 
 
 (or, b, c), which correspond with the parts delineated in fig. 126. at a, I, c. We may 
 distinguish the layers of medullary and cortical layers of the plant in the sporocarp, 
 the layer of spore-cases at a still as the nucleus, and as a disc at b and c. Around the 
 nucleus at a there is a delicate layer of formative cells, which at b forms a base below 
 the tubular layer. At a the whole is enclosed in the layers of medulla and cortex ; at 
 b the latter layer only covers the disc ; at c this has also disappeared. 
 
SPECIAL MORPHOLOGY: LICHENES. 161 
 
 most cases, a distinct cytoblast. The colour of the plant, in a 
 moist condition, depends upon whether the colour of the chloro- 
 phyll be yellow (as in the Parmelia parietina), brownish (in P. 
 stygia), or of a pure green colour (in the Borrera ciliaris), &c. 
 since the gelatinous cortical layer is then transparent. In a dry 
 state the colour is more or less blended with gray, according to the 
 different thickness of the cortex. If we suppose two Lichens of the 
 above-described structure laid together by their under surfaces, we 
 have the structure of the flat upright Lichens, as the Cetraria, of 
 which the filiform Usnece and Alectorice are the thinnest forms. 
 The sporangia of all Lichens, with the exception of those plants I 
 have added to them from the Fungi, are formed of a substance 
 (starch ?) which is rendered blue by iodine. In the Cetraria 
 islandica, the cells and the intercellular substance of the cortical 
 layer are coloured blue by iodine (moss starch). In Lichens with 
 a crustaceous thallus, the Lichen tissue is more or less frequently 
 wanting, being replaced by more gelatinous cells, but slightly 
 elongated, and mostly placed vertically upon the base. In the 
 Pyrenomycetes we find thin-walled, closely compressed, polygonal 
 cells, as in the Sphceria fragiformis ; in the Helvellacece a loose, 
 soft, interwoven tissue. Finally, the gelatinous Lichens consist of 
 convoluted filaments, composed of spherical cells containing chloro- 
 phyll, and imbedded in a softish gelatinous intercellular substance, 
 so that it is not possible to distinguish them anatomically from the 
 species of Undina. 
 
 Lichens offer little worthy of notice. No trace has as yet been dis- 
 covered of a spiral deposit layer. The thickened walls of the spores 
 of the Lecidea sanguined give, however, indications of this arrange- 
 ment. Knotty deposits, projecting irregularly into the cavity, are 
 exhibited by the long cells of the Peltidea canina. We have a special 
 treatise by Korber * on the green, round, cells ; and our only regret is, 
 that the author should have adopted, and even enlarged upon, the ter- 
 minological waste of words introduced by Wallroth. Special stress is 
 laid upon the conditions under which these cells increase, become some- 
 what altered, break through the cortical layer, and then appear as 
 masses of dust (soredia Auct.) upon the surface, whence the individual 
 cells are distributed and grow into new plants. This is no peculiar 
 property of Lichens, and not a process to be compared with the forma- 
 tion of buds in the higher plants, but simply an evidence that, under 
 favourable circumstances, every vital vegetating cell of a plant may grow 
 into a plant ; and of this we shall have occasion, as we proceed, to ob- 
 serve many cases in point. There, as here, a strict individualisation of 
 each cell is at variance with the regular formation of organic fructifica- 
 tion, since, in the latter, the individuality of the separate cells appears 
 most circumscribed and checked. 
 
 * DC Gonidiis Liclicnum. Berlin, 1839. 
 
 M 
 
1 62 MORPHOLOGY. 
 
 APPENDIX. 
 CHARGE 
 
 90. The small group of the Characeos, consisting of the two 
 species Chara and Nitella, which are separated merely on anato- 
 mical grounds, have hitherto presented great difficulties in the way 
 of its classification. It is not improbable that subsequent inves- 
 tigations or discoveries may throw some light upon its proper 
 affinity with other classes. According to our present knowledge, 
 we must, at all events, place it as far from the sexual plants as 
 from the Algae, while we are as yet unable to decide whether it 
 belongs to the Gymnosporee or the Angiosporce. 
 
 Here, again, we suffer from the absence of the necessary investigations, 
 especially with regard to the structural formation of the spores. The 
 inexplicable organs, termed anthers, which it presents, afford an ana- 
 logy, although but a faint one, with structures called antheridias in the 
 Mosses and Liverworts. The differences are, however, numerous and 
 important, and we are, as yet, unacquainted with anything analogous to 
 the structure of the sporocarp. 
 
 91. The spore-cell, which is enclosed by other cells, expands 
 at a certain definite point, issues from its case, and developes in 
 two directions, terminating downward in one or more thread-like 
 adhering fibres, by which it attaches itself, and upward in an 
 utricle of variable length ; from the extremity of this new cells are 
 developed, and there arrange themselves to form the plant.* In 
 Nitella the plant consists of separate cylindrical filamentous cells, 
 arranged end to end ; at the points of union a whorl of similarly 
 united cells is produced, forming lateral branches, which, on the 
 side turned towards the axil, bears small cells, frequently occur- 
 ring in pairs, which are likewise inserted at the junction of two 
 cells of the branch. The same arrangement occurs in the case of 
 Chara, excepting that here a simple layer of elongated cells is 
 spirally wound round the cells of the axis and the lateral branches, 
 forming a kind of cortical layer. In the cells of Nitella and the 
 cortical cells of Chara, the chlorophyll granules are ranged in rows, 
 running spirally round the axis of the cells. 
 
 The structure of the Characece is, as has been described, extremely 
 simple. Much, however, is still wanting in regard to our knowledge of 
 individual points. Meyen's account of the development of the cell of 
 the Charace<B\ scarcely furnishes us with the most superficial informa- 
 tion on the subject ; and, for an investigation of the kind, it would have 
 been far better had he made choice of a germinating Nitella, instead of 
 
 * See the admirable treatise of Kaulfuss upon the germination of the Characece. 
 Leipzig, 1725. [See also a paper on the structure of the Chara, by Mr. Varley. 
 Mic. Trans. TRANS.] 
 
 f Meyen's Physiologic, vol. iii. p. 339, &c. 
 
SPECIAL MORPHOLOGY I CHARvE. ] 63 
 
 the more complicated Chara, as the object of his examination, the 
 former affording an example of one of the simplest cases of this kind of 
 germination. In some species we find, instead of branches inserted in 
 a circle, short thick cells, which, however, are also placed in a whorl, 
 and filled with large starch-granules, and from these new plants are 
 developed under favourable circumstances. We certainly cannot call 
 these buds ( 93.). As the plants grow entirely in water, every cell 
 having an independent vitality, as it were, the plant increases up- 
 wards as it is constantly decaying below, and hence there can be no 
 trace of any root -like development. In the axils of the branches, where 
 also a few spherical cells exist, repetitions of the whole plant (buds) are 
 formed from newly generated cells, and, on the plant dying off to one of 
 these spots, each new plant generated from one of the buds is indepen- 
 dently developed. As, in the stage of which we speak, there is, of course, 
 no difference to be perceived between stem and frond, the word " bud " 
 can only have a general signification, and not the more definite meaning 
 which it acquires in the Gymnosporce. Of the motion of sap in the cells 
 of the Chara we have already spoken ( 40.). 
 
 A treatise on- " the development of the Chara, by Karl Miiller," (Bo- 
 tanical Journal of von Mohl and Schlechtendal, 1845. p. 393.,) which 
 appears to be a most carefully written work, unfortunately did not come 
 into my hands soon enough for me to do more here than call attention 
 to it. 
 
 92. On the lateral branches, generally in the axil of the above- 
 mentioned pair of cells, five cells may be seen spirally wound round 
 a thick mass, and having their parallel extremities surrounded by a 
 kind of pentagonal crown. From this thick granular mass, a large 
 cell (spore) is formed, filled with large granules of starch, mucus 
 and oil globules, and with a substance that closely invests the 
 spore-cells, and, from being at first transparent, subsequently be- 
 comes green or red, and finally black. The five investing cells 
 then either become cartilaginous, and remain until the whole 
 decays after germination ; or they are converted into a gela- 
 tinous state, and then speedily dissolved after the sporocarp has 
 fallen. Close below this sporocarp there may generally be seen, 
 at the same time, seated upon a short cylindrical cell, another 
 cell, which is at first simple and spherical, but from which eight 
 
 Sqy. always eight?) cells are gradually developed, which become 
 attened, and enclose a cavity that appears from its origin to be 
 filled with a dense grumous mass. The eight cells expand into 
 closely compressed radii, arranged side by side, increasing the 
 circumference and depth of the whole body, whilst red granules 
 are gradually deposited upon their inner wall. The dark contents 
 are meanwhile developed into other cells, so that in the perfect organ 
 a conical cell projects, from the cell forming the pedicle, into the 
 cavity, and a cylindrical cell is formed from the middle of each of the 
 eight cells of the wall. These new cells, which likewise contain 
 pale-red granules, bear on their free extremity several spherical or 
 truncated cylindrical cells, from which project many long filaments 
 composed of minute cells. The spherical cells and the filaments 
 
 M 2 
 
164 
 
 MORPHOLOGY. 
 
 form a dense coil in the centre of the cavity. In each separate 
 cell of the filament we at first see a grumous mass, which, how- 
 ever, subsequently disappears, giving place to a spiral fibre coiled 
 up in two or three turns, and which manifests a peculiar motion on 
 escaping from its cell. These mysterious organs have, as yet, 
 without any reason, been termed anthers. 
 
 By way of illustration, I take the reproductive organs of Chara vulgaris 
 (fig. 128.). We are still, unfortunately, deficient in the perfect investiga- 
 tions necessary to elucidate the development of these spores ; consequently, 
 
 explanations are out of the question in the present case. We possess, 
 however, the valuable results obtained by Fritsche* from his admirable 
 researches into the nature of the so-called anthers (antheridid) ; although 
 there remains much to be done here in tracing the mode in which the 
 cells originate. Thuret f has written a treatise upon the spontaneously 
 moving spiral fibres (which there is a disposition amongst botanists, 
 although without the slightest foundation, to call spermatozoa), he dis- 
 covered two delicate moveable cilia attached to these formations, which 
 have also been since observed by Amici.J 
 
 SECTION II. 
 
 THE GYMNOSPOR^E. 
 
 93. The plants are developed from a cell generally invested 
 by a special membrane, except a few of the Liverworts, in such 
 
 * Fritsche on the Pollen, St. Petersburgh, 1 837, p. 9. 
 
 f Thuret, Ann. des Scienc. Nat., vol. xiv. August, 1840; Botanique, p. 65. 
 
 j Amici, Flora, Aug. 14. 1844, No. 30. p. 516. 
 
 18 A is a branch of Chara vulgaris, with sporocarps and anthers (antheridia) : two 
 of the small lateral branches have been cut off from the upper pair. , Early structure 
 of the sporocarp, composed of five parallel cells. C. Ripe sporocarp, cut longitudi- 
 nally ; the inner cell (spore) is filled with starch. D is a part of the contents of the 
 antheridia. E, Cellular filaments, with the moving spiral fibres. 
 
SPECIAL MORPHOLOGY: GYMNOSPOR^E. 165 
 
 a way that the cell, expanding into a longer or shorter tube, 
 protrudes one extremity at a definite place from the spore-mem- 
 brane ; from this extremity the new plant is gradually developed 
 by the formation of new cells, whilst the other end decays and 
 dies with the membrane of the spore. 
 
 On examining the conditions, unbiassed by any previously conceived 
 opinions, we shall perceive that there can be no more striking analogy 
 than the one presented between the germination of the spores of the 
 Cryptogamic stem-plants, and the behaviour of the pollen-granules of the 
 Phanerogamia upon the stigma, even as the history of the development of 
 the spores and the pollen -granules, no less than their structure, are almost 
 wholly identical. It seems to me, that nothing but a mere cleaving to 
 acquired prejudices, and not a simple observation of nature, could lead to 
 the discovery of an analogy between the sporocarp and the phanerogamic 
 fruit, or between spores and seeds. I can readily believe that it may be 
 difficult to people grown old in such opinions to renounce them, and 
 arrange all their preconceived knowledge in accordance with these newer 
 views, especially where they are not themselves the founders of the new 
 truth ; and I have not, therefore, flattered myself with the hope of meet- 
 ing with a speedy recognition of the truth of my theory of the propa- 
 gation of the Phanerogamia. These prejudices will, however, in part 
 vanish when the matter is exhibited in its entire connection ; for even if 
 my views were not based upon direct observation, but were a mere 
 hypothesis, it must be admitted that it was well devised, since it removes 
 the enigmatical separation between Cryptogamia and Phanerogamia, 
 and at a point where a higher unity is first to be expected, and ex- 
 plains the most widely differing facts from one natural law instead of 
 from two. This simplification of the grounds of explanation is, however, 
 one of the most important methodic claims of a sound natural philoso- 
 phy. It will be sufficient here cursorily to point out the general re- 
 sults; their special development must be deferred till we treat of the 
 individual groups. 
 
 94. The main morphological distinction of the Gymnospora 
 and the Angiospora is found in the formation of an axis (stem, 
 caulis Auct.), and leaves (folia), of which the latter, for the most 
 part, dying off and formed anew, contain the actual vital paren- 
 chyma, the former only an essential elongated cellular mass, con- 
 necting the leaves and contributing to their nutrition ; while (with 
 the exception of the still imperfectly investigated Mosses and 
 Liverworts) the leaves are exclusively the agents of the formation 
 of the propagating cells, the spores and the pollen-granules. 
 
 Although an examination of the difference between leaf and stem in 
 this group of plants will justify us in considering it as very marked when 
 compared with accidentally similar forms in the preceding orders, for 
 instance in Sargassum, it is still extremely difficult, if not impossible, 
 to base the distinction upon morphological grounds ; we must, therefore, 
 do the best we can, and not even disregard physiological indications, 
 such as will be adverted to in the course of the paragraphs. The cause 
 of this is evidently owing to our not possessing any morphological 
 history of development of i\\e Aganifr, and, consequently, no sound basis, 
 
 M 3 
 
166 MOKPHOLOGY. 
 
 as we have obtained in the case of the Phanerogamia.* We cannot, there- 
 fore, as yet express a common law for the peculiar relation existing between 
 leaves and propagating cells, owing to the difficulties which have hitherto 
 presented themselves in Mosses and Liverworts. For the rest, it appears 
 tolerably easy to bring this law into harmony with the nature of the/stem 
 and leaf. The latter alone contains, especially, the perfect living cells, in 
 them alone the nutriment that has been taken up is specially concentrated ; 
 consequently it is peculiarly here that a sufficient quantity of assimilated 
 matter can be formed to bring about an organic crystallisation, cellular 
 formation ; and it is only in these cells that, under the circumstances of 
 the quantitatively limited growth of the leaf, such an amount of assimi- 
 lated matter can be accumulated as to bring them into a position to begin 
 an independent process of vegetation. 
 
 Here, for the first time, we meet with a special formation of organs, 
 since a morphological distinction is produced in the process of develop- 
 ment, and we find, on the one side, a quantitatively unlimited stem or 
 axial part, and, on the other, a limited lateral part; that is to say, in the 
 former the axis or stem, in the latter the leaf. To this we may add 
 in the higher groups, another separation of the stem into stem in a more 
 limited sense of the word, and into root, depending upon the distinction 
 between the opposite directions of the unlimited and continuous de- 
 velopment of the stem part, or axis. 
 
 95. The GymnosporcR are essentially distinguished, in an 
 anatomical point of view, by the formation of vascular bundles 
 in the stem or in the leaves. The individual development of the 
 separate cells belongs also to a very far higher stage, since, with 
 the exception of the Mosses, we everywhere clearly distinguish 
 spiral thickening layers. Finally, there is no group in which we 
 do not meet, in the separate species or parts of the plants, with a 
 perfectly developed epidermis with stomates. 
 
 I have already remarked above ( 26.), that I see no reason why 
 we should not apply the term " vascular bundle " to the circle of elon- 
 gated cells in the stem of the Mosses and Liverworts, since it has a 
 similar position and exercises similar functions, if we compare it with 
 the vascular bundles of the Phanerogamia without the so-called spiral 
 vessels, as, for instance, in the Ceratophyllum, which has likewise a simi- 
 lar anatomical structure. The bundles of elongated cells establish a 
 striking anatomical distinction between Gymnosporce and Angiosporce, 
 nothing bearing any resemblance to them appearing in the latter. The 
 considerable development of the spiral thickening layers forms a no less 
 special difference between these two groups, and it is remarkable that 
 there is not a trace of this formation to be met with in Mosses. 
 
 A. ASEXUAL PLANTS (PL agama). 
 
 96. The Ayamce present three stages of development : 
 1. The Liverworts form the transition from the Angiosporce to the 
 
 * What requires to be essentially specified concerning stem and leaf must be deferred 
 till we treat of the Phanerogamia, and then our remarks on the subject will be perfectly 
 applicable to the Agamce, except in the cases where previous notices of the latter make 
 limitations necessary. 
 
SPECIAL MORPHOLOGY: AGAM^E. 167 
 
 Gymnosporce. The propagating cell is usually either wholly de- 
 veloped to a new plant, or it remains partially in the external mem- 
 brane and dies off. 2. In the remainder, the propagating cell is 
 developed into tubular utricle, one of whose extremities remains in 
 the outer membrane of the spore, and decays afterwards, whilst at 
 the other end cells are formed, which range themselves into a pecu- 
 liar formation (the germ, proembryo). At one part of the latter, a 
 stem-likes tructure is developed from a denser group of cellular 
 * tissue ; and from this a bud, if we may use the word, arises, from 
 whence the new plant is unfolded. Here, however, this essential 
 difference presents itself, either (a) that this axial structure is only 
 capable of development in an upward direction, as in the rootless 
 Agamcz (the Mosses and Liverworts), or (b) that it is developed both 
 upwards and downwards (Agamce with roots, the remainder, Lin- 
 naeus's Filices^ with the exception of the Rhizocarpece}. All agamic 
 plants present the remarkable peculiarity of having the sporangium 
 absorbed soon after the development of the spores, which always 
 occur in a quaternary combination *, so that the ripe spores remain 
 free in the sporocarps. They differ essentially from the Angiosporce, 
 their distinction from which is further grounded on the equally im- 
 portant resemblance presented between the sporocarps and the 
 anthers of the Phanerogamia. On this account the sporangia are 
 generally termed parent cells. 
 
 The Conferva-like proembryo in the rootless Agamce, and the Ulva-like 
 proembryo of the others, afford a characteristic by which the groups are 
 most intimately connected ; whilst the Liverworts approximate on the one 
 side to the Angiosporce by their germination, and on the other to the 
 Gymnosporce by the formation of their propagating cells. The sporocarps 
 of the Kicciece and Blasice might perhaps present some analogies with the 
 sporocarps of the nucleolar Lichens. At the same time, however, the 
 proembryo, by its different modes of development into a plant, furnishes 
 us with a ground of separation into two distinct groups. In the 
 schematic ambiguity of the word " root," which we find in the place of a 
 clear idea among most botanists, it has escaped them that Mosses and 
 Liverworts have no analogue of a root, and that the bud rising from the 
 Conferva-like tissue of the proembryo, only morphologically limited 
 in an upward direction, developes itself into definite forms, stems and 
 leaves (fronds), while below it is lost in the Conferva-like threads 
 of the proembryo, and is thence incapable of all further development 
 in this direction in a morphologically distinct manner. We might say, 
 with C. F. Wolff, that there is only one punctum vegetationis present 
 here, whilst in the remainder two, an upper and a lower punctum vegeta- 
 tionis, manifest themselves, being divided by the intervening primary cells, 
 which cause the course of development into two opposite directions, 
 upward to the stem and downward to the root. On this account almost 
 all perennial rootless Agamce decay away below in proportion as 
 they develope upwards, whilst the other kinds are developed in both 
 directions and are thus able to increase in mass. A physiological dif- 
 ference corresponds remarkably with the morphological one mentioned. 
 
 Compare H. Mohl, in the Flora of 1833, p. 33. 
 M 4 
 
168 MORPHOLOGY. 
 
 The rootless Agamce agree so far with the Gymnosporce, that they show- 
 no trace of a distribution of the fluid from a definite point through the 
 plant, or even appear to admit of the possibility of such a thing. Indeed 
 they do not need liquid water for the nutrition of all their separate parts, 
 yet they require an atmosphere saturated with vapour. A plant of 
 Polyfrichium, for instance, with its lower extremity in water, and its 
 surface protected from evaporation by oil, or exposed to a dry atmosphere 
 in a state of agitation, will fade as far down as it is out of the water, and 
 decay, but will vegetate vigorously again as soon as it is surrounded, by 
 means of a glass bell, with an atmosphere saturated with aqueous vapour. 
 
 a. Rootless Agam&. 
 IV. LIVERWORTS (Musci HEPATICI). 
 
 97. The developed plant, like the Mosses, has no proper root. 
 The stem manifests two main forms : first, the ordinary one, analo- 
 gous to the stem of the Mosses ; and secondly, another in which it 
 is expanded into flat and more riband-like form, instead of in a linear 
 direction. The former has always fronds (leaves), the latter, only the 
 rudiments of such, or none at all. The former is seldom upright, 
 but recumbent ; the latter (caulis frondosus) is either partially 
 developed in a filamentous form, and only flattened at the extre- 
 mity, or wholly and entirely flat ; in both cases it is differently 
 formed, but most frequently forked or digitate, and very rarely 
 pinnate. In a small number, for instance, Riccia fluitans, Antho- 
 ceros l&vis, &c., the whole plant consists only of tolerably uniform 
 flattened cells, ranged side by side, which can neither be considered 
 as stem or frond. Here the bifurcated division predominates very 
 considerably, and the manner in which the plants grow in all 
 directions from one point gives the Ricciecc in part a great resem- 
 blance to Lichens, Fronds (leaves) occur in all Liverworts, at 
 least as parts of the fructification, although in the case of the last- 
 mentioned this is somewhat doubtful. The forms of the leaves are 
 very various. With but few exceptions, the leaves are so directed 
 that they lie in one plane on either side of the stem ; on a flat stem 
 they are very stunted, and occur upon the lower surface only. The 
 leaves are occasionally cut into filiform segments, more rarely simple, 
 frequently multifariously lobed at the margin, either bifid or multi- 
 fid. In the bifid we often find a large and a smaller lobe (^auricula), 
 and the leaf folded together in the line of division between them. 
 The stem has frequently two kinds of leaves ; larger ones above, 
 which appear to be in two lines on a depressed surface, and smaller 
 ones varying in form, and which occur only upon the lower side of 
 the stem (amphigastria y stipules). In the axils of the leaves, buds are 
 developed, and from these ramifications which give not unfrequently 
 a pinnate appearance to the stem, owing to the leaves expanding 
 in one plane surface. Even in Liverworts, particular cells occa- 
 sionally emancipate themselves from the general combination of 
 individuality, and become developed into new plants; whilst in 
 
SPECIAL MORPHOLOGY: LIVERWORTS. 169 
 
 connection with the plant they are converted into small cellular 
 corpuscles, often surrounded by a peculiar crescentic cup-shaped or 
 flask-like elevation of the upper cellular layer (conceptaculum), as, 
 for instance, in the Marchantia. 
 
 Until a very recent period, Liverworts (with the exception of a few 
 individual and unimportant researches) were merely objects of petty 
 species-making, it is only in our own day that two men, Lindenberg * 
 and Gottsche f, have zealously directed their minds to the subject ; to the 
 latter we are especially indebted for the interesting facts he has con- 
 tributed concerning these beautiful plants. I cannot myself venture to 
 say much on the subject, as I have not as yet had any opportunity of in- 
 stituting very extended investigations into the nature of these plants. 
 
 More comprehensive investigations into the history of their develop- 
 ment were first afforded us by Gottsche (loc. cit.\ relative to Junger- 
 mannia bicrenata, Preissia commutata, Blasia pusilla, Pellia epiphylla, 
 to which we may also add the observations of Mirbel on the Marchantia 
 polymorpha. These acceptable contributions, however, still leave much 
 to be desired, particularly in reference to the origin of the cells and the 
 development of the leaves. From what has been published, we learn that 
 the development of the spores exhibits no such sharply defined type as in 
 the succeeding groups of the Agamce, at least not such as in the Mosses 
 and Ferns. 
 
 The forms unfolding themselves manifest as yet a very vague character. 
 In the lower, leaves are wholly wanting ; and here, consequently, the pre- 
 dominance of fancy over observation, which we so frequently meet with, 
 has caused much to be said of the notion of the fusion of the leaves in the 
 stem. As no leaves are present in the Jungermannia multifida, none are 
 to be found, but in this case they are just as little fused into the stem 
 as in Melocactus and Euphorbia meloformis. It does not at all follow 
 that a plant must have leaves' and a stem, but it is certainly purely 
 in accordance with our experience to assume that some plants exhibit 
 two essentially different processes of development, and that from these, 
 two essentially different forms, as leaf and stem, may appear: where 
 nature abides by only one of these processes of development, a stem 
 without leaves will alone occur ; and where the process is again different 
 from this, neither stem nor leaf will be found. If we do not seek for 
 definite conceptions of the history of the development of a plant by an 
 inductive course, we may give free scope to our fancy, but we shall never 
 learn to understand nature. 
 
 In the Angiosporce we could not distinguish individual growth and 
 individual repetition by gemmation, on account of the morphologically 
 undefined character. Similar examples occur in the Liverworts in the 
 ramification of the flat stem without any preceding formation of buds. 
 In the Mosses no case of the kind occurs, as far as I know. In the Ferns 
 and the Rhizocarpece a few instances present themselves ; but not after- 
 wards, unless we except the case of the Podostemece> with which we are 
 still very imperfectly acquainted. 
 
 The forms of leaves appear only gradually in this group. In the 
 
 * Lindenberg, Ueber die Riccieen, Nov. Act. L. C. xviii. 
 
 f Gottsche, Anatomisch-Physiologische Untersuchungen iiber Haplomitriwn Hookeri, 
 Act. A. C. L. C. N. C., vol. xx. pt. i p. 207. At the present moment, unfortunately, 
 another excellent set of observations by the same author are not yet in the hands of the 
 public. 
 
170 MOEPIIOLOGY. 
 
 lowest they are entirely wanting ; in the Marchantiacece they appear as 
 small membranous narrow strips upon the lower side of the flat stem. In 
 the Jungermannice the most frequent form is the bifid, folded together, 
 and often associated with stunted leaves at the lower side of the recum- 
 bent stem. We still require more comprehensive observations of the 
 history of the development of leaves than Gottsche (loc. cit.} has been as 
 yet able to afford us. In the bifid leaves we must mention the peculiarity 
 that in the smaller lobes, which are at first always flat, the cells some- 
 times increase only on the surface, and not at the margin, expanding in 
 such a manner that the surface is inflated like a bladder, until finally the 
 lobe of the leaf becomes hood-shaped. 
 
 I must refer to what is stated under the head of the Lichens and 
 Mosses for the import of the particular cells of the parenchyma of the 
 leaf and stem, which, regarded as peculiar organs (the so-called gemmce, 
 brutknospen), dev elope into independent plants. According to Bischoff 
 (Bot. Terrain.), both the cells of the stem (Jungermannia bidentata) and 
 those of the leaves (J. exsecta) separate themselves as propagative cells 
 (Brutzellen) from the plant, and isolated cells shoot out and develope 
 while still connected with the parent plant into small cellular bodies ( J. 
 violacea), which separate from the plant, and grow into new plants, as in 
 Mnium androgynum among the Mosses. The development of these 
 structures had been thoroughly worked out by Mirbel in the case of 
 Marchantia potymorpha. 
 
 98. The organs of reproduction in Liverworts do not differ 
 essentially from those of the Mosses ; but the envelopes appear 
 more clearly as special organs, or as more decidedly distinct from 
 the other foliar organs. 
 
 A. A definite number of leaves, differing more and more in form 
 from the others, as we examine them^from without inward (or upon 
 the stem from below upwards), partly unconnected and partly 
 growing together at their lower part, surround the organs serving for 
 the formation of the spores, and thus compose a blossom (Jlos). Here 
 we may frequently distinguish an inner circle of essentially dif- 
 ferent leaves generally grown together into a cup-like form, as 
 constituting the perianth (perianthium). Between these and the 
 origin of the fruit a peculiar cup-like organ (calyx, Gottsche) is 
 often found, which is sometimes developed downwards in a re- 
 markably unequal manner on the opposite sides, so that the pe- 
 duncle of the fruit arises from the base of a hanging sac. In most 
 Liverworts these blossoms are single ; in many they are, however, 
 grouped together in a definite manner upon a flat stem, and thus 
 form an inflorescence (i'nflorescentia). In this we may distinguish 
 the blossoms from the stalk supporting them, the peduncle (rhachis), 
 on which the blossom always forms a small head. The end of the 
 peduncle is sometimes simple, as in Lunularia ; sometimes expanded 
 in a knob-like form, Grimaldia ; and sometimes either shield- or disc- 
 shaped, when it is generally lobed, as in Marchantia. 
 
 We cannot speak specially of the formation of the blossom in the 
 Liverworts, and of the calyx in its two forms (if indeed the two structures 
 really have the same signification), until we have obtained those fuller 
 
SPECIAL MORPHOLOGY : LIVERWORTS. 
 
 171 
 
 reports now in preparation by Gottsclie on the history of their develop- 
 ment. Bischoff* has furnished us with beautiful analyses, enriched by 
 his admirable powers of delineation, but unaccompanied by any history 
 of development, and constantly interspersed with inapplicable compari- 
 sons. 
 
 B. The blossoms enclose the first germs of the fruit (germina), 
 intermixed with the so-called sap-filaments (Saftfaden, the para- 
 physes). They consist of an envelope (calyptra), and a nucleus ; 
 the upper end of the former is of variable length, directed upwards, 
 and often terminates in a funnel -like expansion. 
 
 By way of illustration I subjoin a diagram of the germs of the fruit of 
 Marchantia polymorpha (fig. 129.). Gottsche has made a step in ad- 
 
 129 
 
 vance of other observers in his investigations into the origin of the 
 structure : according to him it seems certain that the nucleus becomes 
 subsequently developed into the investment or case, but the "how" is 
 by no means perfectly clear in this process. At first it appears to be a 
 simple cell, which afterwards passes over into a small ovate body of cel- 
 lular tissue. 
 
 C. On its further development, the envelope is gradually torn 
 open, and the sporocarp, now becoming fully formed, emerges from 
 it. In Anthoceros alone it appears raised like a little cap, from 
 separating below the point. In the Ricciece it remains closed, as 
 the nucleus does not become at all elongated in its formation. In 
 the nucleus itself we can only distinguish two portions of cellular 
 
 * Bischoff, Bennerkungen uber die Lebermoose, &c , in N. A. L. C. vol. xvii. pt. ii. 
 p. 909. (1835). 
 
 129 Marchantia polymorpha. A, A part of the plant. a, Flat procumbent stem, 
 fc, Thinner erect part of the same, c, Lobed expansion of the stem, which bears upon 
 its lower surface the sporocarps (rf), surrounded by foliaceous organs. B, The lobed 
 expansion of the stem bearing the sporocarps, seen from above : the slit in the two 
 upper lobes corresponds to the attachment of the stem (&) of the former figure. C is 
 the germen, fully developed. At a we see the nucleus already appears as one single 
 large cell in the interior; at c is the so-called style; at b the so-called stigma. D : a, the 
 so-called elar, from the ripe sporocarp ; b, the spores. 
 
172 MORPHOLOGY. 
 
 tissue ; a lower one, which, excepting in RiccieG, is elongated into a 
 pedicle (seta) ; and an upper one, which becomes a spherical sporo- 
 carp (sporocarpium) in Jungermannia pusilla, and a filiform one in 
 Anthoceros. The cellular tissue of this upper part is, again, very 
 variously formed. The most external layers of cells become thick- 
 ened, and form the wall of the sporocarp, which is afterwards torn 
 up from above downward in various ways. In rare cases a portion 
 of the central tissue remains under the form of a central columella, 
 long in Anthoceros, or short as in Pellia epipliylla. Generally speak- 
 ing, it is wholly converted into two different forms of cells : parent 
 cells (in each of which four spores are formed and become clothed 
 by a special membrane), which subsequently become absorbed, and 
 elongated fusiform cells, containing from one to three spiral fibres, 
 and which sometimes appear loose amongst the spores (Fegatella 
 conica), sometimes adhering to the columella (Pellia epiphylla), some- 
 times on the margin (Jungermannia Mcuspidata), or on the point (7. 
 pinguis), or on the inner surface (./. trichophylla) of the valves ; or 
 in rare cases, as in the Ricciece, they are entirely absent. They are 
 termed elaters (elateres). 
 
 The development of the originally homogeneous cellular tissue into 
 such different kinds, that the homogeneous is torn away from the hetero- 
 geneous in consequence of their hygroscopic and elastic properties, occurs 
 here as in the Moss capsule ; and at any rate, during the present imperfect 
 state of our knowledge, we have as little to do in the one case as the 
 other with a separation into original separate parts merely grown together. 
 The manner in which the separation of the parts is effected is very various ; 
 sometimes there only appears a cleft (Monoclea), or the wall is split more 
 or less deeply into valves (valvulce) varying in number from two to eight 
 (Pellia epiphylla^ J. platyphylla, complanata), or into many teeth 
 (denies), more rarely into irregular shreds (Grimaldia hemisphcericd). 
 In more rare cases a separation takes place around the fruit, so that the 
 upper portion falls off as a cover, as in Fimbriaria; in the Ricciece it 
 remains closed until destroyed by external agencies ; in Riccia itself it 
 is absorbed, so that the spores lie free in the cavity of the calyptra. 
 More exact observations probably yet remain to be made concerning the 
 development of the spores. I noticed that there were in the earliest 
 stages always four spores free in the parent cell. I have not hitherto 
 discovered any trace of a division of parent cell by the growing in of a 
 partition wall, as Meyen describes*; but my observations are as yet 
 very incomplete. We have some excellent remarks by Hugo Mohlf on 
 the formation of the spores in Anthoceros Icevis, which appears to cor- 
 respond closely with the formation of the pollen. 
 
 D. The antheridia, whose forms and development entirely cor- 
 respond with those of Mosses, consist of a pedicle, which varies in 
 length, or is entirely wanting ; and of the upper part, which is 
 always spherical or ovate. The leaves rarely form special enve- 
 lopes for these structures, although several leaves are frequently 
 crowded more closely together at the end of the stem, concealing 
 
 * Meyen, Pflanzenphysiologie, iii. p. 391. 
 f Mohi| Linnea, vol. xiii. p. 273. 
 
SPECIAL MORPHOLOGY: LIVERWORTS. 
 
 173 
 
 130 
 
 antheridia in their axils, and are then combined together as a catkin 
 (amentum). In flat-stemmed Liverworts, the antheridia are always 
 imbedded in a cavity in the substance of the stem, opening out- 
 ward. In many we find them very much scattered upon the 
 surface (Pellia epiphylla)\ in others a definite part of the stem, 
 rising in a disc-like form, bears the antheridia (Fegatella conica) ; in 
 others, again, this disc rises shield-like upon a pedicle, and is then 
 frequently notched, lobed, &c., at the margin, as, for instance, in 
 Marchantia polymorpha. 
 
 As I purpose saying what is necessary of the signification of these 
 antheridia under the head of Mosses, I will here 
 pass the subject by, merely giving Fegatella co- 
 nica as an illustration (fig. 130.). I must, how- 
 ever, be permitted to remark that here, also, hasty 
 observations have led to remarkable misconceptions. 
 Almost all manuals speak of flask-shaped anthe- 
 ridia extending upwards into a long neck : none 
 such, however, are to be met with. In Marchantia 
 polymorpha and others, the cavity has a flask-like 
 form, enclosing the antheridia below, but open as 
 a narrow canal at the top, which sometimes rises 
 cup-shaped above the surface of the stem, as in 
 Anthoceros, as a papilla, in Pellia epiphylla, or as 
 a pedicle, in Riccia. Within, this cavity is in- 
 vested with a dense epidermis. On a superficial 
 examination the flask-like outline of this epider- 
 mis has been mistaken for the antheridium, which 
 is entirely separated from that membrane, lies 
 under the canal, and is always rounded off at 
 the end in an upward direction. In like manner 
 the so-called cuspides in Riccia do not belong to 
 the antheridia, but to the elevation of the paren- 
 chyma at the margin of the cavity enclosing these 
 antheridia. 
 
 99. The roundish stem of the Liverworts has a wholly si- 
 milar composition to that of Mosses. The leaves, on the other hand, 
 consist, without exception probably, of merely one simple cellular 
 layer. The flat stem presents many varieties, consisting frequently 
 of one simple layer of thin-walled cells, or it exhibits in its axis the 
 elements of the ordinary stem. The parenchyma around this is 
 formed of one or many cell-layers, often covered on the surface 
 with a perfect epidermis, containing stomata of a peculiar kind, 
 namely, wart-like, elevated cellular masses, perforated at the point 
 by an intercellular passage, which leads into a cavity invested with 
 lax and often flask-shaped cells. In Fegatella and Marchantia the 
 cells of the central mass of the stem have beautifully porous or 
 
 180 Fegatella conica. A, A portion of the little plant, with two disc-like elevations 
 of the stem (a, a), in which the antheridia are imbedded. B, A part of a section of 
 one of these elevations. The hollowing in is of a flask-like form, furnished with a 
 tough epidermis. The antheridium consists internally of a cellular sac, filled by 
 one large cell. 
 
1 74 MORPHOLOGY. 
 
 reticulated thickening layers. The pedicle of the sporocarp con- 
 sists always, up to the period of maturity, of a delicate cellular 
 tissue, which expands with wonderful rapidity, but at the same 
 time also decays very quickly. The wall of the capsule consists, 
 with few exceptions, of an epidermal layer (of flat and mostly 
 brown-coloured cells), and of an inner layer of spiral-fibrous cells. 
 
 Liverworts deserve, in an anatomical point of view, much more 
 thorough and comprehensive investigations than they have as yet met with. 
 We most certainly possess the complete monography of Mar chantia poly - 
 morpha furnished us by Mirbel, who has also given us plates which do 
 more to dazzle by the brilliancy of their colouring than to satisfy, on all 
 points, with respect to their fidelity to nature : but Mirbel leaves many ques- 
 tions unanswered, and his statements have already met with many correc- 
 tions. Here, as everywhere else, we look in vain for an exact and complete 
 history of the course of development. The formation of the spiral fila- 
 ments in the elaters and the walls of the fruit have been observed by 
 Meyen. According to his views, they arise from the perceptible con- 
 fluence of the globules of chlorophyll into a spiral band. Gottsche posi- 
 tively denies this to be the case, and, as far as I have been able to con- 
 vince myself in Pellia epiphylla, I think he is in the right. They differ 
 in their fully developed condition from all other spiral filaments by their 
 deep brownish yellow colour, which reminds us of the cells of the sheaths 
 of the vascular bundles in the Ferns. A few special peculiarities present 
 themselves in Liverworts ; thus in the Marchantice we find air-cavities, 
 in Pellia epiphylla a singular system of intercellular passages, which 
 convey, not air, but a yellowish and, in the case of Var. ceruginosa, a 
 reddish juice.* Still more remarkable is the system of tubes discovered 
 by Gottsche in Preissia commutata, running through the cells, and 
 apparently perforating their walls : the only analogy with this case pre- 
 sents itself in the tubular convolutions of the root-cells of Neottidium 
 nidus avis (vol. i. . 39). 
 
 V. MOSSES (Muscr FRONDOSI). 
 
 100. The spore-cell expands, emerges from its torn outer coat, 
 and, new cells being developed at the free end, forms for itself 
 a filamentous tissue, composed of linear cylindrical cells ranged 
 end to end (the proembryo). At one point, the filaments of this 
 tissue become contracted into a node composed of closely com- 
 pressed roundish cells ; this node, elongating itself upwards, becomes 
 the stem, on which leaves are simultaneously formed. More rarely 
 the plant remains simple (as in the annual Phascum, and in the 
 perennial Polytrichum), but there generally appear at the axils of 
 the leaves small buds, by which means the stem ramifies. The 
 form of the uniformly simple flattened leaves (which are never 
 lobed) varies between almost circular, linear-lanceolate, and linear; 
 they sometimes exhibit two streaks of denser, more compressed, 
 
 * Compare Wiegmann's Archiv, Jahrg, v. vol. i. p. 280. (1839). 
 
SPECIAL MORPHOLOGY : MOSSES. 175 
 
 and elongated cells (nerves) proceeding from the base, which some- 
 times stop at the middle of the leaf, and sometimes run along its 
 whole length ; in some, as in Mnium punctatum, we also find two 
 marginal nerves. The leaves are simple, dentated or ciliated, 
 generally scattered (spirally ?) round the stem, sometimes apparently 
 two-ranked, the stem with the leaves looking as if pressed flat (as 
 in Neckera crispa, Hypnum undulatum, &c.). In some few Mosses 
 the leaves actually do occur in two lines, and then differ very much 
 from each other in their structure, as in Fissidens. Here the face 
 of the leaf is folded together, and embraces the stem with the next 
 leaf; above, however, it is continued in a simple, laterally flattened, 
 uniform lamella (similar to the leaves of the Iris). In many 
 Mosses the curved leaves are all bent at the point towards one side 
 (folia secunda), as, for instance, in Hypnum cupressinum, lycopo- 
 dioides, scorpioides, &c. On the first appearance of the stem, it 
 exhibits, especially near the leaves, more or less numerous, longer 
 or shorter filaments of cylindrical cells (adhering fibres, rhizince), 
 which have been termed roots or root-fibres when they appear 
 below, and sap-filaments (parapliyses) when they occur above, espe- 
 cially between the organs of propagation. 
 
 Our knowledge of the course of the development of Mosses, and of the 
 morphological laws by which it is regulated, are still very defective ; for 
 instance, we are wholly unacquainted with the history of the develop- 
 ment of the leaf, and consequently of the importance of its relation to the 
 stem. We have as yet nothing more exact regarding the germination 
 than what the observations of Hedwig* have given us, although there has 
 been no lack of fantastic specious theories. When I find a description 
 of moss germination beginning thus " Soon after the escape of the seed 
 there unfold themselves, as it appears from the solution of several decaying 
 germ-granules," &c. I lose all further desire to continue the perusal. 
 Here we may see at once that the author cared less to give a certain and 
 clear exposition of a strictly scientific observation, than to expatiate in 
 an assumed ingenious manner upon incomplete and superficial views. A 
 fundamental repetition of these investigations is earnestly to be desired ; 
 and until this has been made, that is, until the morphological relation 
 existing between leaf and stem has been clearly ascertained from the 
 history of development, nothing definite can be said concerning the mor- 
 phology of Mosses. A short notice of the mere facts is given in the 
 paragraph. The proembryo has been already described as Conferva 
 castanea Dillw, and as Catoptridium smaragdinum, in Schistostcga 
 osmundacea. According to more recent views, the Moss has been 
 regarded as formed of Confervo3 grown together, under the impression 
 that such a confusion of ideas would make the matter more compre- 
 hensible. 
 
 Thus much is at any rate apparent from the history of germina- 
 tion, that we cannot speak here of a root as morphologically opposed 
 
 * Hedwig, Fundamenta Hist. Nat. Muse. Frond, Leipzig, 1782.; Theoria Genera- 
 tionis et Fructificationis Plant. Crypt., Leipzig, 1798. I have unfortunately not 
 become acquainted with the very recent work of Bruch and Schimper, and consequently 
 I do not know whether it contains anything more. 
 
176 
 
 MORPHOLOGY. 
 
 131 
 
 to the stem. On isolating a 
 young plant of Funaria hygrome 
 trica (fig. 131.), it will appear 
 to be merged below into the Con- 
 ferva-like cells of the proem- 
 bryo (b, b\ or rather grown into 
 it, and only separated with mor- 
 phological distinctness in an up- 
 ward direction (a). This justi- 
 fies the definition of frondose 
 Mosses as rootless Agamce. My 
 investigations into the develop- 
 ment of the leaf, which are un- 
 fortunately still very imperfect, 
 show with certainty, at least in 
 Sphagnum, that the leaf as in the 
 Phanerogamia is protruded from 
 the axis, and that, consequently, 
 the idea of a leaf and stem, as I 
 define them, may be fully applied 
 to Mosses. The stalks often 
 range themselves irregularly, especially in the upright stem (here they 
 are sometimes pyramidal), but likewise in the recumbent and floating 
 stem ; they are more rarely (apparently) pinnate (as, for instance, even in 
 Hypnum molluscum and Crista castrensis &c.) in most stems pressed to 
 the ground. The condition of the highly hygroscopic leaves, when per- 
 fectly dry, is also peculiar and important with respect to the determina- 
 tion of species, as they curl up in a very definite and diversified manner (as, 
 for instance, in Orthotrichum crispum). In Mosses growing in the water, 
 the central nerve remains frequently upon the stem, as a little point 
 (caulis spinulosus, in 
 Fontinalis) after the 
 destruction of the sub- 
 stance of the lamina. In 
 some Mosses small la- 
 mellae are found, placed 
 lengthwise, either upon 
 the central nerves (Ca- 
 tharinea) (fig. 132.), 
 ( Schistidium), or upon 
 the whole surface of 
 the leaf (Polytrichum). 
 We but rarely find 
 different leaves upon the same Moss, as in Sphagnum. Here the lateral 
 stalks are collected in little bundles, two generally hanging down, while the 
 others stand straight out : these latter have always differently formed, nar- 
 rower leaves than the former, and both generally deviate regularly in their 
 form from the stem leaves. Occasionally the leaves first originating in ger- 
 mination differ from those subsequently formed upon the full-grown plant 
 
 131 Funaria hygrometrica. The little plant (a) has arisen in such a manner from the 
 filaments of the proembryo (6 6), that no distinctly marked radical extremity is to be 
 defined below, the plant passing gradually into the filiform cells of the proembryo. 
 
 132 Section through middle of leaf of Catharinea undulata. Upon the central nerves 
 (c) are lamellae, placed lengthwise (a) ; at b, leaf-cells. The central nerve consists 
 of much thickened, liber-like cells, and other larger thinner- walled cells enclosed by it. 
 
 132 
 
SPECIAL MORPHOLOGY : MOSSES. 
 
 177 
 
 (into which their forms, however, gradually merge) (fig. 131.). The adher- 
 ing fibres are also at times developed from the leaf-cells, as, for instance, 
 in Calymperes, Syrrhopodon, &c., and are regarded here as parasitical 
 Conferva ; a view that is evidently devoid of reason, since the immediate 
 development of individual leaf-cells into filiform cells is generally the 
 first beginning of their formation. 
 
 There are many examples in this group of separate cells of the stem 
 (Mnium androgynum\ as well as of the leaves (Syrrhopodon prolifer\ 
 severing themselves from the connection of individuality of the whole 
 plant, and introducing an independent process of cell-formation, from 
 which a little cellular body proceeds, emancipates itself from the plant 
 and develops into a new cell. These have been named proliferous buds 
 (gemmae proliferce, bulbilli). They are neither buds nor bulbs, if we 
 connect definite conceptions with these words, and not something defined 
 in opposition to all laws of the formation of ideas, as " A bud is that body 
 from which a new plant may proceed, and which is neither a spore nor 
 seed." Investigations on the development of these cells are, however, 
 still incomplete ; we are indebted to Meyen* (Mnium androgynum) for the 
 best we possess, and from his statements it appears certain that a single 
 cell of the extremity of the stem becomes the base of the new 
 individual. 
 
 102. A. Sometimes terminal, sometimes lateral, closed buds, 
 composed of many, most frequently narrower and differently 
 formed leaves, and many somewhat irregular adhering fibres (sap- 
 filaments, paraphyses) which often occur in the interior of the bud, 
 may, as the special coverings of certain organs, destined to develop 
 themselves into the sporocarp, be comprised under the term of 
 blossoms (flores). 
 
 It appears to me, in a twofold point of view, to be purely sporting with 
 the subject to regard the blossoms of Mosses as essentially monosexual, and 
 naturally collected into an inflorescence, merely for the sake of dividing, 
 without any reason whatever (but purely in accord- 
 ance with wholly arbitrary and inapplicable analo- 
 gies with the higher plants), that which nature 
 exhibits to us as a wholly independent structure, in 
 order ingeniously to put it together again. In our 
 present knowledge of the blossoms of the Mosses, 
 there is at any rate no indication that any definite 
 parts within it are more closely combined by nature, 
 and, consequently, nothing that can give probability 
 to the view of the composition of the whole blossom 
 from separate florets. Here, as everywhere else, I 
 strictly abide by that which nature actually yields. 
 Secondly, the opinion that all the blossoms of 
 Mosses are essentially of one sex is untenable, be- 
 cause, at the present time at least, there can be 
 nothing said of sex with reference to Mosses ; not- 
 withstanding that the pistillidia and the antheridia 
 may be situated upon different plants, as, for in- 
 stance, in Funaria hygromctrica (fig. 133. ), it 
 
 * Meyen, Wiegmann's Archiv, Jahrg. iii. vol. i. p. 424. 1837. 
 
 133 Funaria hyqrometrica : two young plants, n, With the sporocarp (still enclosed 
 by the calyptra (c), and very young) in the act of development, and b bearing anthers. 
 
 N 
 
178 MORPHOLOGY. 
 
 being in the present day mere fiction to ascribe any sexual signifi- 
 cation to the latter. Besides this, the floral leaves are by no means 
 distinctly different from the true leaves, into which they generally pass 
 by imperceptible gradations, and there is no appearance of the formation 
 of a calyx, which would, indeed, constitute the most essential morpholo- 
 gical distinction between the Mosses and Liverworts. Even for this 
 reason, it is impracticable to distinguish the separate blossoms and the 
 inflorescence in the Mosses. 
 
 B. The primary form of the sporocarp, the archegonium (germen), 
 is that of a shorter or longer ellipsoidal, attenuated corpuscle, stalked 
 at the base. It consists merely of a simple layer of cells, the envelope 
 (calyptra), which extends upwards into a longer or shorter filament, 
 expanded somewhat funnel-like at the extremity, and enclosing a 
 nucleus free at all parts except the base. This conceals, under a 
 simple epithelium, a delicate walled, uniform, cellular tissue, ca- 
 pable of development. 
 
 The archegonium of Mosses is so strikingly similar to that of the Liver- 
 worts, that whatever may be said of the one, applies also to the other. 
 We stand, unfortunately, in the midst of such uncertainty here, that all 
 our attempts at a morphological explanation of what follows, even where 
 they may not be purely visionary, are still wholly unstable ; so it is cer- 
 tainly not worth while to attempt going beyond the point to which the bare 
 fact may lead us. How has the archegonium originated ? Is the separa- 
 tion into nucleus and calyptra original, or been produced subsequently 
 from continuous cellular tissue ? Has the nucleus or calyptra been first 
 formed ? In what relation do both parts stand to leaf and stem, &c. ? 
 These are questions which must be answered, by means of a previously 
 and carefully pursued history of development, before we can entertain a 
 remote hope of arriving at a scientific comprehension of the capsule of 
 Mosses. It will, of course, appear most evident, that designations such 
 as style and stigma for the filiform extremity of the calyptra must be alike 
 unmeaning and false, since they designate organs of the Plianerogamia 
 defined according to morphological and physiological characteristics. 
 The inner cellular tissue of the nucleus consists in the earliest condi- 
 tions that have, as yet, been observed, of but a few cells (often of no 
 more than some twenty in the cross-section). From this tissue are de- 
 veloped the operculum, the peristoma, the wall of the capsule, the colu- 
 mella and the speedily disappearing sporangia, and, finally, the spores; 
 from which we may satisfactorily see the falseness of the expression 
 massa sporigena, as applied to this cell-tissue.* Concerning the filiform 
 end of the calyptra, the inappropriately termed stylus, there is still 
 much doubt, whether it is a canal, or a solid mass ; and, if the former, 
 whether it is hollow from the beginning, or only developed by subsequent 
 expansion into a canal. All this can only be decided with certainty 
 by the history of development. It is certainly in favour of the opi- 
 nion of the original difference of the capsule and the nucleus, that a de- 
 cided integument is subsequently developed upon the sporocarp formed 
 from the nucleus, since, as yet, at any rate, we are unacquainted with 
 any instance of a cellular layer, originally connected with other cells, 
 
 * We might just as well term the yolk of the egg massa ptcryyogena, because birds, 
 amongst other things, have also feathers. 
 
SPECIAL MORPHOLOGY: MOSSES. 171) 
 
 being converted into an epidermal layer. When Bischoff* maintained 
 that the term epidermis, used by Mohl, is inapplicable here, owing to its 
 being at variance with the morphological signification, I know not what 
 he can mean, since, as we have just shown, we know nothing about the 
 morphological signification of a sporocarp. On the other hand, the sim- 
 ple cellular structure of the nucleus renders it in the highest degree pro- 
 bable that it is only a simple organ, and that all the various regions 
 that appear in the sporocarp originate by internal separation (which is 
 partially of a purely mechanical nature), and are all parts produced from 
 one and the same mass of tissue, and from one and the same organ ; at all 
 events the idea of the capsule being formed from the growing together 
 of as many leaves as the peristoma shows dentations, as maintained by 
 many (Bischoff f among others), is a most perverted one. For, as has 
 already been remarked, the whole section of the nucleus (which, besides 
 the dentations, must also form the columella and the spores) has in its 
 early condition fewer cells than there are subsequently teeth ; and, how- 
 ever moderate we may be in our claims, we must demand at least one 
 cell for each leaf in its first deposition, setting aside that, as far as the 
 structure of the inner peristoma is concerned, the whole thing is devoid 
 of sense, and that the assertion must fall to the ground, being a mere 
 fiction. J 
 
 C. In the development of the archegonium, the calyptra is torn 
 off at the base, and remains, for a longer or shorter period, thus 
 hanging to the sporocarp, by the expansion of which it is some- 
 times also laterally split. A small piece of the calyptra always 
 remains at the base, and this, in connection with the somewhat de- 
 veloped point of the stem, forms a small sheath (vaginula) around 
 the base of the sporocarp. In the nucleus we may distinguish, (a) 
 an upper, (5) a middlle, and (<?) a lower mass of cellular tissue, 
 which are variously developed at a to the seta, at b to the theca, 
 and at c to the operculum and peristoma. 
 
 * Bischoff, Handbuch der Terminologie, p. 687, Bemerk. 33. 
 
 t Bischoff, Handbuch der Botanik, vol. i. p. 430. 
 
 \ That even such sensible men and excellent observers as Bischoff should give them- 
 selves up to this childish sporting with comparisons, must be wholly inconceivable to 
 those who have not studied the history of modern philosophy since Kant, and become 
 acquainted with the injurious influence exercised upon the development of our scientific 
 progress by the apparently intellectual sense, but actually mere shallow twaddle, which 
 Schelling gave forth as natural philosophy. (See the work of Fries, entitled 
 Ileinhold, Fichte, and Schelling, Leipzig, 1803.) A few hollow set phrases, endowed 
 with such an unmeaning power of generalisation that they were alike applicable to all 
 subjects, and garnished with the trivial comparisons of superficial wit, which is far more 
 common than scientific acuteness, sufficed to lull the great mass of those who would 
 willingly know, without having the trouble of learning, into the pleasant delusion that 
 they had actually seized science by the forelock. Even in science, unfortunately, num- 
 bers give strength ; and he who understands how to throw dust in people's eyes, will, at 
 least for a time, be regarded with consideration ; and he who may be hindered, by devo- 
 tion to one special branch of science, from working out the philosophical groundwork 
 for himself, will find it difficult, if not impossible, to remove himself from the general 
 intoxication of a philosophical mania of the day. Thus, uncommon minds have been 
 estranged from an earnest and strictly scientific research of nature, and, Buffering their 
 activity to be fettered by prevalent prejudices, have been lost to what is purely philo- 
 sophical and scientific, and wasted their best energies in the visionary dreams of an 
 unbridled fancy. 
 
 N 2 
 
180 MORPHOLOGY. 
 
 a. The lower cellular tissue is very much elongated, and thus 
 forms a filiform support for the rest; sometimes it becomes 
 blended with the middle one by a gradual swelling, forming the neck 
 or collum, or it forms a more sharply defined thickening of a differ- 
 ent form, the apophysis, especially marked in Splachnum. 
 
 b. The middle portion forms an urn-shaped, almost cylindrical, 
 seldom obtusely angular, or plano-convex organ, and becomes de- 
 veloped into different layers: (1.) to a central, either cylindrical or 
 more spherical, cellular mass, the columella ; (2.) to the coating of the 
 theea ; and (3.) to a delicate cellular tissue lying between the other 
 two, the cells of which, developing as sporangia into four (?) spores, 
 become dissolved and absorbed, so that the spores are left free. Each 
 spore-cell secretes within the sporangium a peculiar membrane, 
 which is either smooth, or covered with larger or smaller warts and 
 areolas. The wall of the theca itself consists, externally, of an inte- 
 gument in which several layers of a thin-walled, close cellular 
 tissue are formed the outer membrane (membrana. external), inter- 
 nally of several layers of close cellular tissue the inner membrane 
 (membrana inferno), surrounding the spores. Between these two 
 lies a layer of extremely porous, often almost filamentous, loose 
 cellular tissue, which is sometimes absorbed by the time the sporo- 
 carp is ripe. 
 
 c. The upper portion of the cellular tissue of the nucleus is de- 
 veloped into such heterogeneous cellular structures, that it sepa- 
 rates, in drying, into many parts, by the unequal contraction, and 
 the rending of homogeneous from heterogeneous rows of cells, partly 
 from within outward, and partly in a lateral direction. A layer 
 of more solid cellular tissue, in the form of a cover (operculum), 
 either flattish, convex, pointed or peaked, separates on the exte- 
 rior from the upper portion of the nucleus, and, at the same time, 
 from the theca. In most Mosses an annular layer of three or four 
 rows of cells (annulus) occurs, obliquely interposed from below 
 and from without, upwards and inwards, between the theca and 
 the operculum. In the interior, the columella is naturally conti- 
 nued from the theca into the point of the operculum. Its ex- 
 tremity appears sometimes on the falling off of the operculum, as a 
 disc or membrane, closing the whole aperture of the theca (stoma). 
 The remaining cellular tissue, between the end of the columella and 
 the operculum, is developed into a highly hygroscopic tissue, which 
 separates in various ways, either only laterally, into from four to 
 sixty-four acutely pointed lobes, teeth (denies) ; or, at the same 
 time, from within outward, so that two rows of such lobules ap- 
 pear, the innermost of which, where broader and alternating with the 
 teeth, are called processes, and the narrower ones occurring be- 
 tween these processes, the cilia. The inner layer occasionally appears 
 to cohere, entirely or partially, into a membrane ; but the external 
 one more rarely. The cells of the external lobules, almost all 
 manifest the peculiarity that their lower and upper walls become so 
 
SPECIAL MORPHOLOGY: MOSSES. 
 
 181 
 
 disproportionally thickened, that the horizontal partitions formed, 
 by the drying of the cells, project laterally, as well as towards the 
 interior and exterior, and are then designated trabecula. The inner 
 lobules, when they are connected together as a membrane, are 
 always merely the remains of torn cells. 
 
 I have here given the history of the development of the archegonium 
 from confessedly proportionably circumscribed and incomplete observa- 
 tions of my own. By way of illustrating the terms applied to the indi- 
 vidual parts of the ripe capsule, I here give the analysis of the sporocarp 
 of Hypnum abietinum (fig. 134.) My investigations, combined with what 
 
 l.H 
 
 has here and there been contributed by others *, may perhaps suffice to 
 confirm the representation given. It is very evident that there are still 
 great deficiences to be lamented, and that innumerable questions present 
 themselves, especially as to the manner in which separate cells and 
 masses of tissues have originated. What appears from the facts with 
 which we are already acquainted is, that so far as the history of the 
 formation is known to us, a rending of a continuous mass of cellular 
 tissue, but nowhere a blending together of divided parts, is apparent, and 
 consequently that it is as yet, scientifically speaking, incorrect to regard 
 the Moss capsule as grown together from different pieces. The very 
 simple structure of the archegonium makes it certainly in the highest de- 
 gree improbable that it will ever be found to be grown together out of 
 different parts. The second point to be observed here is,that the arche- 
 gonium consists of continuous cellular tissue from within outward, and 
 consequently that the development into layers of different cells need not 
 
 * Especially H. Mohl, on the Spores of the Cryptogamia, Flora, 1838, vol. i. p. 33. ; 
 History of Development of the Capsule and Spore of (Edipodium Griffithianum, &c., 
 by W. Valentine, Ann. of Nat. Hist., Aug. 1839, p. 456, &c. 
 
 134 Hypnum abietinum. A, The upper part of the seta (a), with the theca (6), the peri- 
 stoma (c), and the operculum (d). B is a part of the inner peristoma, with pro- 
 cesses (), and cilia (ft). 
 
 N 3 
 
182 
 
 MORPHOLOGY. 
 
 135 
 
 necessarily extend throughout the whole 
 length. It is mere prejudice to regard 
 the external peristoma as appertaining to 
 the external, and the inner peristoma as 
 appertaining to the inner, membrane. 
 The anatomy of most Moss capsules near 
 a state of maturity* shows evidently that 
 the peristoma and walls of the theca do 
 not stand in any nearer relation to each 
 other than as cells to the parts of a plant 
 generally. This may be plainly seen, for 
 instance, in the section, cut lengthwise, 
 of an unripe capsule of Grimmia apo- 
 carpa (fig. 135.). Starting from a one- 
 sided and false view of the ripe fruit, 
 botanists have accustomed themselves to 
 regard all these anatomical individualities 
 as especial organs, and then to seek for 
 methodical arrangement for them; whilst 
 the true mode of observation shows us that 
 we have to do here with merely tolerably 
 regular remnants of a torn organ. If, in- 
 stead of inventing supposititious theories, 
 pains had been taken to carry out inves- 
 tigations with somewhat more exactitude, it would soon have been dis- 
 covered, at least in the inner peristoma, that there was no room here for 
 many of the very ludicrous hypotheses broached regarding the subject. In 
 the peristoma we must distinguish whether the third upper portion of the 
 archegonium occupies a considerable part of the whole length, so that the 
 peristomse may be developed into vertical rows of cells, as in most cases, or 
 whether, as in the Polytriclioidece, &c., it is merely the flat upper portion 
 of the theca, and is therefore rather a development in horizontal layers. 
 Here, then, the inner peristoma or the membranous expansion of the 
 columella are the same thing, and formed from one layer of cellular 
 tissue. In others, on the contrary, a simple (?) layer is developed into the 
 inner peristoma, directed inward from the wall of the operculum ; on 
 this first layer another follows, directed inward, the cells of which on a 
 section all, or the alternate ones, resemble acute equilateral triangles, the 
 bases of which are directed alternately outward or inward. In these 
 cells the horizontal and the lateral vertical partitions become especially 
 thickened, while the external and internal walls, on the contrary, become 
 blended with the superjacent cells, and then separate subsequently from 
 the other walls : thus the plaited membrane in Buxbaumia, Diphyscium, 
 &c. is formed with some degree of regularity. If, on the other hand, 
 cells that on a section appear uniform alternate with others (Hypnum 
 abietinum, figs. 134. 136.), the persistent lateral partitions of the former 
 
 * Compare the remarkably beautiful delineations of H. Mohl, loc. cit. 
 
 183 Grimmia apocarpa. Section, lengthwise, through an unripe sporocarp. The cells 
 are only marked upon the right side, a, The operculum ; b, the teeth of the simple 
 peristoma ; c, the epidermis ; d, the external, e, the middle layer of the wall of the 
 theca, the former consisting of elongated, and the latter of very loose, cells; /, the 
 innermost layer of the wall of the theca, bounding the space (g) in which lie the 
 spores; h, external layer of the columella, likewise bounding the spore cavity ; f, the 
 cellular tissue of the columella, tolernbly loose. 
 
SPECIAL MORPHOLOGY : MOSSES. 183 
 
 136 
 
 constitute the processes, and those of the latter the cilia, as, for instance, 
 in Hypnum, and Bryum. A perfect, closed cell never, however, concurs in 
 forming the folded membrane, nor the processes and cilia (so far as they 
 are free from the interior outward). A wider field for more compre- 
 hensive and exact observations is opened here than I have hitherto been 
 enabled to pursue. 
 
 I must not omit to mention a view which was first proposed by the 
 acute Robert Brown *, namely, that in most peristomoses* the regular 
 number of the teeth was 32, and that when fewer were present it must 
 be considered owing to a growing together of several into one. At first 
 sight this view presents much in its favour. But the circumstance that 
 this law is not applicable to Mosses, the peristomium of which exhibits 
 a greater number of teeth, is at once suspicious ; besides, the history of 
 development of the capsule of the Moss shows, as far as our knowledge 
 of the subject extends, that we cannot speak of growing together in 
 this case, but merely of more or less regular splitting down. Finally, 
 regularity of number in teeth is by no means so firmly established as 
 many might assume, for we not unfrequently find peristomse in which 
 there is one tooth too little, especially in the Mosses where the number 
 of the dentations exceeds 32. The almost regular divisibility of the 
 number of teeth by four must, however, always strike us as remarkable. 
 The reason of this appears to be based upon the nature of the vegetable 
 cell, and is thus determined with reference to teeth from their first forma- 
 tion. A comparison of the multiplication of cells in some of the Algce, 
 as, for instance, in Meyen's Tetraspora, with the almost constant forma- 
 tion of four spores and pollen-granules in one parent cell, together with 
 
 * Robert Brown's Miscellaneous Writings. (Germ. Trans. II. 734.) 
 
 186 Hypnum alrietinum. Cross-section of the still green sporocarp, in the region where 
 the cilia and processes are connected at the base. , A deposit of thickened cells form- 
 ing the operculum ; b, separate cells, forming the dentation of the exterior peristomia ; 
 c, thickened walls, formed by a row of cells constituting the cilia and processes ; the 
 latter consist of parts which project externally, in the form of a Gothic arch. 
 
 N 4 
 
184 MORPHOLOGY. 
 
 a few other facts, appears to offer an indication of a parent cell always 
 giving origin to two or four new cells, and that consequently in a limited 
 but uninterrupted formation, the cells formed and the equally definite 
 groups of cells must be almost regularly divisible by two or four. There 
 is certainly nothing beyond an indication to be looked for here, and it 
 would be mere empty play to attempt erecting an influential law upon 
 so frail a foundation. There are, besides, many deviations to be met 
 with in the development of the sporocarp. In the Sphagnum the pro- 
 truding archegonium breaks through the calyptra in an upward direction 
 instead of tearing it away from the base, but it does not form any long 
 seta. In the so-called Astomi the upper and middle part of the archego- 
 nium becomes developed into a simple, entirely closed capsule, only subse- 
 quently irregularly torn open, as, for instance, in Phascum. The amount 
 of cellular tissue that remains as a columella is also very variable, so that 
 sometimes there is scarcely a trace of it to be found in the ripe sporocarp. 
 In Andrecea a simple capsule is formed, which is rent lengthwise into 
 four lobes, which remain united at the apex and base. Finally, in a great 
 number of the Mosses the upper third portion of the archegonium forms 
 merely the operculum, without being further heterogeneously developed 
 inward : all these, consequently, are devoid of a peristoma. Meyen pre- 
 tends to have seen spores formed in Sphagnum at the end of a cellular 
 filament by the spontaneous separation of a parent spore, as in Liver- 
 worts. I have never been able to find these filaments, but I have easily 
 succeeded in pressing out four perfectly free spores in a young condition 
 from the parent cell (sporangium) in which they were enclosed. Finally, 
 we meet with a deviation in some Polytrichoidece, where four plates of 
 dense cellular tissue remain between the inner membrane of the theca 
 and the columella, dividing, until the sporocarp is nearly mature, the 
 space destined for the spores into four parts. Many other interesting 
 particulars may be found on this subject in Robert Brown's works * ; 
 we have also recently obtained very excellent contributions on the de- 
 velopment of the spores by Lantzius-Beninga. j The most important re- 
 sult of the latter work is the fact that the layer of the archegonium, from 
 which the spores are subsequently developed, consists originally only of 
 a single layer of cells, which are parent cells. Meyen says (in his 
 Physiologic, vol. iii. p. 387.), " Robert Brown appears to have been of 
 the opinion that the spores of Mosses are formed in the cells of the colu- 
 mella." Palisot de Beauvois had asserted that the true spores were 
 formed in the columella, and that the loose granules deposited around it 
 were the pollen. Robert Brown's assertions are directed against this false 
 view, which he fully sets aside in his usual sure and profound manner. 
 
 D. Little buds similar to those mentioned at A, or disc-shaped 
 as in Potytrichum, Splachnum, contain another peculiar organ (an- 
 theridium), which, as in the above mentioned, also occurs with 
 archegonia even in the same blossom. The earliest condition in 
 which it has as yet been observed exhibits a small ellipsoidal, 
 longer or shorter pedicled, cellular corpuscle, having a dark opaque 
 spot in the interior. Somewhat later, we may definitely distinguish 
 a simple layer of cells, enclosing a large central cell, filled with 
 turbid formative matter. Here we subsequently find cytoblasts, 
 
 * See R. Brown's Miscellaneous Works (loc. cit. II. 682 744-). 
 
 f De Evolutione Sporidiorum in Capsulis Muscorum. Gottingen, 1844. 
 
SPECIAL MORPHOLOGY : MOSSES. 
 
 185 
 
 and the whole central cell is finally filled with a close and very 
 thin-walled cellular tissue. In each cell a spiral fibre of two or 
 three coils is then developed. On their complete development the 
 spiral fibres lie free in their cell, and manifest under water a rapid 
 motion round their axes, which the free spiral fibres retain for a 
 time after the destruction of the cell, and thus move onward in the 
 water. In plants of the previous year we still find this organ, dried 
 and shrivelled together, and, as it appears, deprived of its contents 
 by an orifice in its upper part. 
 
 By way of illustration I give here the antheridia of Funaria hygro- 
 metrica (fig. 137 6, and 138.). With the exception of a few unim- 
 
 137 
 
 138 
 
 portant particulars, what is now given is all that we know of this organ, 
 from which has originated so much confusion of ideas in science. Thus 
 much appears fully certain, that neither in the history of their develop- 
 ment, nor in their structure, nor in their physiological relation, do they 
 show the most remote analogy with the anthers* of the Phanerogamia, 
 and, consequently , & ,that the application of this designation, together with 
 all the visionary matter (the pretended theories) based upon it, are al- 
 together devoid of all foundation, and therefore do not belong to science. 
 So far as I know, no observer has as yet spoken of the central cell, which 
 
 * Although it is in the highest degree erroneous to name these and similar structures 
 in the Liverworts anthers, yet, as they merit some peculiar designation, I retain this 
 expression, however inappropriate it may be, which has already been so generally used, 
 in order not to add to the confused nonsense that already characterises our terminology. 
 I would expressly remark here, as I have done elsewhere, that the etymology has no 
 influence whatever upon the determination of an idea, this being solely effected, in 
 regard to a technical expression, by a scientific definition. A technical term is merely 
 a sign easily conveyed by speech and in writing, which would have no sense were it not 
 interpreted according to the definition applied to it in this one particular science. The 
 best terms are always those whose etymological signification stands in no relation to the 
 
 187 Funaria hygrometrica : two young plants. a, With the sporocarp unfolding 
 (still enclosed by the calyptra (c), and very young (6) ), bearing antheridia. 
 
 188 A long section through a so-called male plant of Funaria hygrometrica (b of the 
 fig. 137.). A, On the apex of the stem are the antheridia (C), surrounded by para- 
 physes (It). 
 
186 MORPHOLOGY. 
 
 is so essential to the signification of the whole, and is so easily recognised, 
 as in the case of Sphagnum, where it may with the greatest ease be 
 isolated long before the origin of the cellular tissue. In like manner, 
 the delicate cellular tissue which necessarily precedes the formation of 
 the spiral fibres, and, according to my views, is far more essential than 
 the latter, has been treated as a secondary matter by most observers, 
 owing to the prejudice they had once adopted of considering the whole 
 organ as a pollen-vesicle, and the contents as the matter of fructification 
 (fovilla) ; entangling themselves in confusion in spite of their own senses. 
 The spiral fibres have elicited the most observation, owing to the mo- 
 tion they manifest ; and they have thus been elevated to the rank of 
 spermatic animalcules. In the course of my own careful examinations of 
 Polytrichum, I have never been able to discover this motion when no 
 water was applied upon the object-stage. When water was present, the 
 fibres exhibited a rapid motion about the axis of the spiral, on which 
 the fibre freed from the cell naturally assumed a progressive motion, in 
 accordance with the law of the archimedean screw ; I have never, like 
 other observers, succeeded in detecting another motion, as, for instance, a 
 change of the convolutions. As far as the form is concerned, I found 
 fibres which had a spherical head at one extremity, or an elongated swell- 
 ing gradually merging in the fibre, or a spherical protruberance below 
 the other extremity of the fibre, or finally a spherical head with, some 
 distance from it, an elongated swelling and, further below again, another 
 spherical swelling. I hold all these forms, of which the last-named were of 
 the least frequent occurrence, as mere unimportant irregularities occasioned 
 by the adhesion of mucus, and not to be the heads of supposed spermatic 
 animalculae. I have also observed, where a simple head was present, that 
 there was as often a progressive motion with the pointed end forward 
 as the reverse. (See Plate II. figs. 9. and 10., with the explanation). 
 The circumstantial description of the views of those who suppose that 
 they have here found spermatic animalcule may be met with in Meyen *, 
 where the discrepancies occurring in the observations of others are re- 
 marked upon. 
 
 I will venture upon a supposition regarding the morphological signifi- 
 cation of these parts when I speak of the ovule of Phanerogamia ; of 
 their physiological importance we know as yet nothing. 
 
 103. The structure of Mosses also is still very simple. The 
 stem exhibits in most cases a closed circle of elongated cells, some 
 narrower and very thick-walled, others wider and thin-walled 
 (circle of vascular bundles), separating the enclosed parenchyma- 
 tous mass (medulla) from the outer portion (cortex). The leaves 
 mostly consist of a simple layer of tabular parenchymatous cells, 
 which have the lateral walls frequently porous, as Dicranum. The 
 upper and lower walls not unfrequently exhibit a papillose pro- 
 jecting thickening, as in Ortliotrichum crispum. The nerve con- 
 sists either only of a few layers of somewhat more elongated cells, 
 or of two bundles of elongated thick-walled cells, which arrange 
 
 subject, and which in the present, advancing state of science, may thus place us beyond 
 the reach of all the philological dilettante, with their ostensibly scientific remodelling 
 of technical terms, and necessarily resulting increased uncertainty and diffuseness of 
 terminology. 
 
 * Meyen, Physiologic, vol. iii. p. 208. 
 
SPECIAL MORPHOLOGY: MOSSES. 
 
 187 
 
 themselves above and below on the leaf-cells ; or, finally, it is com- 
 posed of an actual vascular bundle, that is, a large bundle of the 
 above-described (liber?) cells, enclosing elongated wide thin-walled 
 cells (vessels), which are either interposed between the two halves 
 of the leaf, consisting of a single layer, as in Catharinea, or received 
 between the two layers forming the leaf as in Potytrichum. The 
 seta consists of similar elements to the stem, only that here the 
 cells are generally thinner and longer. The cortical cells of the 
 seta, the epidermal cells of the theca and of the operculum, the 
 cells of the peristoma, as well as frequently the cells of the ad- 
 hering fibres, have the cell-walls varying in colour from a light to 
 a dark brownish yellow. The cells of the peristoma generally ex- 
 hibit irregular wart-like thickenings upon their walls, which often 
 appear so prominent, that in the case of Bryum ccespititium, for 
 instance, the points of the dentations seem to be narrowly and 
 deeply notched at the sides. 
 
 It is further remarkable, that the epidermis appears most per- 
 fectly developed on the collum and the apophysis, exhibiting 
 stomates here. There is generally also a small quantity of loose 
 spongy cellular tissue beneath it. 
 
 Simple as the structure of Mosses is, we are very deficient in exact 
 observations regarding many particulars. * Thus the little stem of Bux~ 
 baumia aphylla exhibits much that is interesting, as, for instance, the in- 
 dication of a reticular thickening of the cell-wall in the medulla. The 
 leaves of Mosses and their nerves, also merit more thorough investigation 
 than they have hitherto received. In Catharinea undulata (fig. 139.) 
 the leaf, as in most other Mosses, with the exception of the species of 
 Polytrichum, consists only of one layer of cells (b). The central nerve 
 (c), however, which supports the affixed lamellae (#), consists of an upper 
 and lower epidermis, between which a true vascular bundle is interposed. 
 This (see fig. 140.) consists of liber-cells (b d), enclosing between them 
 
 HO 
 
 * Structure of the Seta in Funaria hygrometrica, by E. Lankestcr, in Ann. of Nat. 
 Hist., by Jardine, Hooker, and Taylor, Feb. 1840, p 361. 
 
 139 Section through the central part of a leaf of Catharinea undulata. a, On the rnid- 
 nerve (c) are erect longitudinal lamellae; b, leaf-cells. The mid-nerve consists of very 
 much thickened liber-like cells, and thin-walled wider ones enclosed by it. 
 
 140 Catharinea unduJata. Section, lengthwise, through the mid-nerve of the leaf. 
 
188 
 
 MORPHOLOGY. 
 
 TTT 
 
 long, very much expanded, cylindrical cells (c) (vessels in the simplest 
 form). Robert Brown made the correct observation that in Catharinea the 
 lamellae are only inserted upon the mid-nerve, while in Polytrichum they 
 are found upon the whole surface of the leaf. (See his Miscellaneous 
 Writings.) It does not seem to me that Treviranus (in Linnasa, vol. xv. 
 p. 3. plate 3. fig. 6.) refutes this view, or establishes his own that the 
 whole is to be regarded as a nerve in Polytrichum. The lamellas placed 
 upon the surface of the leaf in Polytrichum exhibit the peculiarity that 
 the lower cells are always thin-walled, while the upper and lateral es- 
 pecially are very much thickened. In P. yucccefolium these upper walls 
 are bent in, so that each lamella shows a furrow upon its free edge. 
 
 Many have contested the view of 
 there being marginal nerves in the 
 leaves of Mosses, but without having 
 examined the subject. In Mnium 
 punctatum, for instance, they are 
 strikingly evident, and formed from 
 thickened cells ranged in layers 
 (fig. 141. A b). The cells of the la- 
 mina of the leaf (a) in this plant like- 
 wise exhibit interesting peculiarities 
 from the manner in which they are 
 ranged together, as may be seen from 
 fig. 141. B, C). In a group* of 
 Mosses consisting of Sphagnum, Oc- 
 toblepharum, Leucobryum, Dicranum 
 glaucum, and Weissia verticillata ? 
 the leaf is essentially composed of 
 two different kinds of cells ; namely, 
 some that are closed, narrow, containing chlorophyll, and others broader. 
 These latter distinctly exhibit thickening layers, either merely as large 
 pores, which subsequently become actual apertures, or, as in Sphagnum, 
 also spiral fibres ; they lie either in the same plane with the green cells 
 {Sphagnum), or they cover the reticular layer of green cells on both 
 surfaces, in layers varying from one to five. Much contention has been 
 kept up, by Meyen especially, concerning the structure of the Sphagnum 
 leaf; but this must be considered to be wholly set at rest by Mohl.f 
 
 The stomata on the capsule of Mosses, however simple the subject 
 may be (there being really not the slightest difference between these and 
 the openings found in the Phanerogamia), have likewise given rise to 
 wonderful discussions ; and botanical mystifiers, instead of treating nature 
 simply, as sound sense dictates, have been pleased to express themselves 
 as follows : "The pores, as peripheric members allied to the spiral ves- 
 sels, although in their structure they cannot be compared in any respect 
 to the true pores of the epidermis (the reason wherefore neither is nor 
 
 * LeucophanecE, according to Hampe. 
 
 f Anatom. Untersuchungen iiber die porosen Zellen von Sphagnum. Tubingen, 1837. 
 
 a, Epidermis of the lower surface ; b and d, liber-like cells ; c, vasculose expanded 
 cells. 
 
 141 Mnium punctatum. A, A section through the margin of the leaf: a, leaf-cells; 
 
 b, marginal nerve. J9, Partition between the leaf-cells in their upper part, very much 
 enlarged. C, A few leaf-cells seen from the surface ; the fine lines separating the 
 cavity of one cell from the other can easily be explained by a comparison with B. 
 
SPECIAL MOHPHOLOGY: CLUB-MOSSES. 189 
 
 can be explained), yet manifest a tendency towards this form." Sad in- 
 deed, that men of intellect should seek science amid such a confusion of 
 words ! By others, Robert Brown among the rest, stomates have been 
 considered as channels for the evacuation of the spores ; this, however, 
 they cannot be, since they never open a communication between the 
 spore-cavity itself and the exterior. The spongy cellular tissue below 
 them always passes gradually into a close cellular tissue, the internal 
 membrane, as it approaches towards the spore- cavity. They do not deviate 
 in the most trifling degree in Polytrichum alpinum from the ordinary 
 structure of the stomata, although such would appear to be the case from 
 the. incorrect delineation of Treviranus (see as above, fig. 18.). I have 
 myself been unable to examine the pores of the capsule of Lyellia ; but 
 if the delineation of Treviranus (fig. 17.) be correct, they have nothing 
 to do with the stomata, and are organs of an entirely special kind. I 
 would remark, that, although I am not confident of the fact, I believe I 
 have seen spiral fibres in the cells of the peristome ; for instance, in 
 Hypnum triquetrum. 
 
 b. Agamic Plants having Roots. 
 VI. CLUB-MOSSES (LYCOPODIACEJS). 
 
 104. A perfect history of the development of the Lycopodiacece 
 remains still a desideratum. Only so much is certain, that in the 
 germination of the larger spores, which will be mentioned, a true 
 root appears. In the perfect plant, the stem, which is almost always 
 recumbent, develops roots on the lower side, along its whole length, 
 and dies off from below upward. The leaves always follow one 
 another closely around the stem, and are sometimes twisted in such 
 a manner as to appear as if they were ranged in one plane on op- 
 posite sides of the stem. The branches which are developed from 
 the axillary buds often stand similarly, in such a manner that the 
 ramification is pinnatifid, or the bifurcating branches are erect and 
 arranged in pyramidal forms ; in rare cases the stem is flat, and the 
 leaves far asunder, as in Bernhardia complanata. The leaves are 
 almost always narrow, lanceolate, similar to the leaves of Mosses, 
 but bearing more resemblance on the recumbent stems (where they 
 evidently stand in two rows) to the leaves of the Liverworts, and 
 are likewise smaller and of different form on the under side of the 
 stem. All are provided with a simple mid-nerve. The greatest 
 deviation is in the stem of the Isoetes, which is shortened into a 
 thick disc, and has long, narrow, grass-like leaves, that enclose 
 one another below in a sheath-like manner. In a few of the Ly- 
 copodia, the axillary buds are developed into a somewhat more 
 fleshy condition in all their parts, and spontaneously (?) separate from 
 the stem to constitute bulbels (bulbilli). 
 
1 90 MORPHOLOGY. 
 
 It appears to me, that the Lycopodia are most nearly allied to Mosses 
 and Liverworts, from the little we as yet actually know of the history of 
 their entire morphological development.* Isoetes may constitute a sepa- 
 rate family allied to these, or, still better perhaps, be reckoned as 
 belonging to them ; at any rate, a moderately exact comparison will 
 suffice to show that this plant does not belong to the Rhizocarpece, and 
 that it cannot either constitute a transition stage from any immediately 
 approximate family to the Rhizocarpece. The only resemblance that 
 has led to their being placed together was the circumstance that, in 
 both, the reproductive organs were situated below. (With equal justice 
 Raja Pastinaca and the Scorpion might be brought into the same family, 
 since both have a sting in the tail.) But, as the statement was once 
 printed, it availed little that more exact observations showed Isoetes to 
 be devoid of any analogous characteristics, or even the most remote re- 
 semblance to the Rhizocarpece; DeCandolle alone appears to have had 
 more correct views on the subject. Linkf, a few years ago, again coupled 
 the two together, invita natura* 
 
 105. A. At the base of the leaves (which are sometimes com- 
 pressed into a kind of club at the extremity of an extended leafy 
 stem, and assume somewhat different forms), or more rarely in an 
 indentation of the leaves (for instance, Tmesipteris\ there arises a 
 cellular knob, whose external layers of cells become the wall of the 
 sporocarp, and whose inner cells, as parent cells (sporangia), 
 generate four spores each, invested with a peculiar membrane, 
 which seldom exhibits warts or points, after which the sporangia 
 become absorbed. In the Bernhardice the sporocarps are placed 
 upon the points of the shoots, two or three grown together. The 
 ripe sporocarp is round, kidney or crescent shaped, and tears with 
 a vertical cleft (as in Lycopodium annotinum), or a horizontal one 
 (L. inundatum), the margins of which are often lobed, (as in L. cana- 
 liculatum). In Isoetes the sporocarps are somewhat immersed in 
 the base of the leaf, and covered by a heart-shaped scale. They 
 contain, among obliquely directed cellular filaments, small cellular 
 sacs, with many small spores exhibiting the ordinary formation, 
 and other sacs which enclose four larger spores, consisting of cells 
 provided with the ordinary integument, and having a thick crust 
 of carbonate of lime (?). 
 
 Mohlf has proved, as incontrovertibly as it was possible without 
 
 * The interesting experiments on the germination of the larger spores were 
 pursued by Bischoff, and first made known by him ; notwithstanding which, he says 
 (Die kryptogamischen Gewiichse, p. 97.)> " We find no distinctly separated main 
 roots in the Lycopodia," because he had only the old developed plant in view. This is 
 certainly a remarkable illustration of the extent to which this routine-like method in 
 science may blind the eyes of people even against their own discoveries. 
 
 See Filicum Species in Horto Ilegio Botanico Berol., Berlin, 1841 ; a work which 
 is twenty years behind the discoveries made in all things relating to general science. 
 
 ( Mohl, Ueber die morphologische Bedeutung der Sporangien der mit Gefiissen 
 versehenen Kryptogamen, Tubingen, 1837, p. 28. 
 
SPECIAL MORPHOLOGY : LYCOPODIACE^. 
 
 191 
 
 knowing the history of their development, 
 that the sporocarps are definite modifications 
 of the parenchyma of the leaf. An acquaint- 
 ance with the mode of their development 
 leads, however, to the same results. In Iso- 
 etes we are still deficient in more exact inves- 
 tigations. It seems to me, however, that, con- 
 sidering the exactly similar structure of the 
 large and small spores, the difference of size, 
 and the investment of (probably) carbonate 
 of lime, together with the somewhat greater 
 complexity of the fruit owing to the persist- 
 ence of the cellular tissue, are matters of 
 very subordinate importance. Here, too, we 
 must seek for elucidation solely from the his- 
 tory of development. 
 
 B. In some of the Lycopodia we meet with another form of the 
 fruit, which is rounded, tetraedric, opens by a longitudinal cleft 
 into two trilobed valves, and encloses four large spores, which 
 consist of one spore-cell and a very tough investment covered with 
 warts or reticulate stria3. The contents, according to Bischoff*, 
 are a delicate cellular tissue. 
 
 The large spores are certainly identical with the large spores in 
 Isoetes; and if even their contents be cellular, this must be merely owing 
 to a further stage of development, f 
 
 106. The stem of the Lycopodiacece consists of a mass of rather 
 loose parenchyma, intersected by a central simultaneous ( 26.) 
 vascular bundle. This vascular bundle generally has the vessels 
 scattered through it in irregular lines and bands, and mostly sur- 
 rounded by a deposit of brownish thick-walled parenchyma. The 
 vascular bundles, passing into the leaves and lateral stalks, often 
 run in an oblique direction through the parenchyma, separating 
 from the principal bundle a long way below where they pass off 
 into the leaf. The leaves consist of several layers of roundish 
 parenchyma, intersected by a vascular bundle, and invested by an 
 epidermis exhibiting stomata on both surfaces. The wall of the 
 sporocarp has mostly two layers, the external one displaying flat 
 cells with tough curving lateral walls, and the inner thin-walled 
 
 * BischofF, Die kryptogamischen Gewachse, p. 110. 
 
 f The Lycopodiacece were the only cryptogamic plants against which the anther-mania 
 had not heen directed; when (Jan. 18. 1842) Link, not content with his discovery of 
 anthcridia in Lichens, likewise provided the Lycopodiacea: with antheridia, which he 
 maintained were the larger spores. (Froriep's Notices, vol. xvi. p. 74.) Men are 
 always nearest to a new stage of advancement when they have carried out a definite 
 folly in all its systematic completeness. Now, therefore, when there remain no further 
 antheridia to be discovered, it is to be hoped that this worn-out plaything will be cast 
 aside. 
 
 '* Lycopodium annotinum. A, The spore -leaf, with the capsule; B, the same in a 
 longitudinal section ; C, spores (semen Lycopodii). 
 
192 MORPHOLOGY. 
 
 cells. In Lycopodium inundatum the inner cells exhibit thick annular 
 fibres, similar to what we find in the fruit of the Liverworts. 
 
 The epidermis of the upper and lower surface of the leaves in L. 
 stoloniferum differs very much. The cells of the upper one are thicker 
 walled, and have lying upon them, here and there, long cells, which are 
 beset on the outer side with from two to three rows of warts. The cells 
 of the under surface are thinner walled, and contain chlorophyll ; while 
 between the two a somewhat spongy cellular tissue is interposed. The 
 stomata are only found upon, and close to, the leaf-rib of the Lycopodia. 
 The annular fibres in the capsule-wall of L. inundatum were first 
 observed by Bischoff *, who, however, gives an incorrect and very far- 
 fetched explanation of them,, that might be at once refuted by a consider- 
 ation of their early condition. 
 
 VII. FERNS (FILICES). 
 
 107. In the germination of the Ferns the spore-cell breaks 
 through the external membrane and expands, in some even at an 
 absolutely definite, previously indicated point, into a longer or 
 shorter tube, whose extremity forms new cells, which gradually 
 arrange themselves into a flat, generally bilobed, proembryo ; a few 
 of these cells expand downward into adhering fibres. At a definite 
 part of this proembryo there is formed a group composed of thicker 
 cellular tissue, and, by degrees, a small ovate corpuscle, one ex- 
 tremity of which is prolonged into a root, and the other into a bud, 
 forming the stem and leaf. 
 
 The stem then assumes two essentially different modifications, in 
 one of which it does not expand, and in the other of which it docs 
 so to a great length between every two succeeding leaves (which are 
 always closer together at their first origin than they appear subse- 
 quently). In the first case the stem mostly creeps subterraneously, 
 so that the leaves alone appear above the ground, as in Pteris 
 aquilina, or it creeps upon the ground or up trees and rocks (as in 
 Lomaria scandens) ; in the second modification it again exhibits two 
 further differences, according as the root, and subsequently the 
 stem, constantly does or does not die off from below. In the former 
 case it rises but inconsiderably above the earth, occasionally lying 
 obliquely in it (as in Aspidium Filix mas) ; in the latter case it grows 
 (but only under the tropics) into a considerable sized trunk, some 
 twenty or thirty feet in height (tree-fern, as, for instance, Cyathea, 
 Dicksonia, Alsophila., &c.). Almost all stems exhibit adventitious 
 roots (radix adventitia\ arising in a peculiar mariner from the stem, 
 and occasionally investing the trunk with a thick network (as 
 Cyathea Schansin). 
 
 The leaves of Ferns are mostly stalked, seldom sessile, generally 
 divided into lobes at the margin (occasionally in the most various 
 
 * Die kryptogamischen Gewiichse, p. 109. 
 
SPECIAL MORPHOLOGY: FERNS. 193 
 
 and beautiful manner), seldom simply undivided, always flat, and 
 having vascular bundles (nerves, nervi), the ramifications of which 
 are varied and elegant. The leaf is generally connected by a con- 
 tinuous cellular tissue with the stem, on which account the older 
 leaves only wither, to the lower hard part of the leaf-stalk, without 
 falling off. Occasionally, but rarely, a layer of early- withering 
 cellular tissue forms a true articulation (articulatid), so that the 
 leaves become detached from a defined surface (as in Cyathea 
 arbor -ea). Such an articulation (?) never occurs in the continuity of 
 the same leaf, and on this account there are no true folia composita 
 in Ferns. 
 
 Buds are, on the whole, but seldom found in the leaf-axils ; yet 
 they do occur, as, for instance, in the case ofAspidium Filix mas. On 
 this account the stem of Ferns is mostly simple, and always so in 
 the tree kinds. Here, too, a furcate division of the stem at it apex 
 appears to take place without any axillary buds, as in Polypodium 
 ramosum. In the axillary buds, as well as in the terminal bud of 
 the stem, the leaves are rolled together in a spiral manner (circinate 
 aestivation, (Bstivatio circinata).' 
 
 In a few tropical Ferns small hollows occur in the axils of the 
 leaves, at first covered by the epidermis, and filled with a peculiar 
 spongy cellular tissue. Hairs and glands are more rarely met with 
 in Ferns, while, on the contrary, all are more or less covered with 
 small, quickly-withering scales (palece). 
 
 The other extremity of the young plant developes itself down- 
 wards into the earth as a multifariously ramified root, which, as 
 already remarked, soon dies off again in many of the Ferns. 
 
 It frequently happens that individual cells, or groups of cells of 
 a leaf, separate from the individuality of the whole plant, form 
 tubers, and subsequently grow independently into a new plant. 
 These young plants are formed from the leaf-surface, and especially 
 in the angles of the division of the leaf. 
 
 We have some beautiful investigations, as, for instance, those by 
 Kaulfuss*, on the first development of the plant from the spore (fig. 143.) ; 
 
 143 
 
 * Das Wesen der Farnkriiuter, &c., Leipzig, 1827. 
 
 143 Pteris speciosa. a, Germinating spore ; b, early condition of the proembryo 
 c, antheridia. 
 
194 
 
 MORPHOLOGY. 
 
 144 
 
 but even these are very far from being complete : there is no reference 
 whatever made here to the first origin of the new cells. There is, how- 
 ever, some importance to be attached to the observation, that there 
 appears in the proembryo an ovate corpuscle free at both ends, which 
 naturally, therefore, remain capable of propagation in opposite directions, 
 
 by which the morphological distinc- 
 tion of stem and root (fig. 144.) first 
 appears in the series of vegetable 
 forms. Our knowledge regarding 
 the extensive history of develop- 
 ment is, however, very deficient, 
 and we need far more exact and 
 fundamental investigations on the 
 relation of stem and leaf, as well as 
 on the formation of the furcated 
 divisions of the stem and the germi- 
 mation, since without such observa- 
 tions little that is of importance can 
 be said upon the subject. 
 
 The morphology of leaf and stem, 
 as far as it is applicable to Ferns, 
 must be derived from the Phanero- 
 gamia ; the term frond (frondes), as 
 applied to the leaves, is here quite 
 superfluous. 
 
 We know, as yet, nothing of the signification of the accumulation of 
 pulverulent cells * in the axilla of tropical Ferns, which Von Martius once 
 asserted, without any reason, to be antheridia ; they may perhaps be 
 wholly analogous to the lenticels of Phanerogamia (see below). 
 
 108. A. In all cases spores are formed in the tissue of a true 
 leaf, which either appears wholly unchanged or is attenuated by the 
 non-development of all or of the most superfluous part of the 
 parenchyma around the principal nerves : I call it the spore-leaf 
 (sporophyilum). Where it differs but little, or not at all, from the 
 ordinary leaves, it shows upon the back, or on the margin, differently 
 formed, scattered accumulations (sori) of sporocarps, which are 
 generally entirely or partially covered by a definitely formed fold of 
 the epidermis (the indusiuni). The several sporocarps are commonly 
 fastened to a somewhat elevated mass of cellular tissue, which 
 appears as a short pedicle or as a seam, more seldom as an elongated 
 pedicle (as, for instance, in Hymenophyllum), and they are formed 
 in the following manner : From the parenchyma of the leaf (that 
 is, from those pedicles) there rises a cell, which soon separates into 
 two, one cylindrical and one spherical. In both, new cells are 
 formed ; in one they form the pedicle of the sporocarps, the others 
 fill the spherical terminal cell (capsula) ; the most external consti- 
 
 * Compare H. Mohl, De Structura Filicum Arborearum, Monach. 1833, p. 7. 12. 
 
 144 Pteris spec. B, Germinating plant : a a, the two lobes of the proembryo ; b, the 
 first leaf of the young plant ; c, the root. A, A longitudinal section of a somewhat 
 earlier germinating plant : , lobes of the embryo ; 6, first leaf of the plant ; c, root ; 
 d, terminal bud. 
 
SPECIAL MORPHOLOGY: FERNS. 
 
 195 
 
 tute a cellular wall, and the internal ones parent cells (sporangia) for 
 the spores, being absorbed soon after the latter are perfectly de- 
 veloped and have been invested with a special membrane covered 
 with warts or folds. From the parietal cells a series of cells is 
 formed, running either vertically or obliquely from the pedicle 
 almost entirely round the capsule, or forming a horizontal zone at a 
 greater or lesser distance from the top of the capsule, and in such a 
 manner that its inner, and upper and lower contiguous walls become 
 very much thickened, while the other walls remain thin. These 
 cells constitute what is termed the ring (annulus) ; by its unequal 
 contraction in drying, the capsule is opened for the escape of the 
 spores. In other Ferns the small quantity of parenchyma developed 
 around the nerves forms in its interior groups of parent cells and 
 spores, so that the lobules of the leaf swell spherically into capsules, 
 and, occasionally bursting open by means of an imperfectly com- 
 pleted ring, shake out the spores (as, for instance, in Ophioglossea, 
 Osmundacecs). 
 
 B. It is only in the proembryo of Ferns that we find organs simi- 
 lar to the antheridia of Mosses and Liverworts ; here they occur 
 either upon the margin or upon its upper surface, and are most 
 spherical and unpedicled. 
 
 By way of illustration of the above, I will give circumstantially the 
 delineation of a part of the spore-leaf of Pteris chinensis (fig. 145. A, B), 
 
 145 
 
 and of Adiantum pubescens (fig. 145. (7), as well as an analysis of the cap- 
 sule of Scolopendrium qfficinarum (fig. 146.). 
 
 145 Pteris chinensis. A, Part of the spore-leaf: a, b designates the direction of the 
 section. B .- a, b is the leaf; c c its thickened margins ; d d, folds of the margins (m- 
 dusia) ; e e, capsules. C, Part of the spore-leaf of Adiantum r ,<bescens, with some 
 sori, or heaps of sporocarps, covered with reniform indusia. 
 
 o 2 
 
196 
 
 MORPHOLOGY. 
 
 146 
 
 The easily- traced history of de- 
 velopment of the capsule (as I have 
 given it according to my observations 
 on Blechnum gracile) relieves me 
 from the necessity of wasting one word 
 in refuting the imaginary origin of 
 the capsule from a leaf rolled inward, 
 and which, of course, has been duly 
 derived from a fantastic imagination. 
 
 Mohl* has refuted this and the other 
 view, that the sporophyll is formed 
 by the blending of a leaf and a twig ; 
 entering into the subject with more 
 profoundness of argument than such 
 unscientific sports of fancy, in my opi- 
 nion, merit, and, with his ever-manifest 
 acuteness of comprehension, has ap- 
 plied the results of his own excellent 
 investigations to develop the simplest 
 and most natural, and consequently 
 
 also the only true, view of Fern fruits. The formal mania for discovering 
 antheridia in the Cryptogamia for a long time failed to find support in the 
 class of the Ferns ; for stomates and the groups of spiral cells in which the 
 spiral vessels of the leaf-nerves terminate, the indusium, and other parts, 
 although termed anthers, could not for any length of time be main- 
 tained to be such. Fortunately for those who delight in sporting with 
 words without affixing any definite ideas to them, a few glandular hairs 
 (cells, of which the last, which was spherical or ovate, contained some 
 gum and mucus) were found near the capsules in some specimens of 
 Ferns; they were pronounced to be anthers, and the discoverers rejoiced in 
 the self-satisfaction of having followed the course of science. Habeant 
 sibi ! I can corroborate the fact of there being glandular hairs in many 
 Ferns, and, indeed, on the very peduncle of the sporocarps, but they are 
 decidedly wanting in the case of a great many others. For my part, I am 
 surprised that no one has as yet insisted upon the presence of the organs 
 of sense, as eyes and ears, in plants, since they are possessed by animals ; 
 such an assumption would not be a bit more absurd than the mania of 
 insisting upon having anthers in the Cryptogamia, simply because they 
 are found in the Phanerogamia. 
 
 We are indebted to Nagelif for the discovery of the antheridia. It 
 is very easy to confirm his assertion by direct observation (fig. 143.). 
 They do not differ essentially from those of Mosses and Liverworts. 
 
 109. The stem of Ferns consists of a mass of parenchyma, tra- 
 versed by simultaneous vascular bundles (26.), and may, when 
 
 * Mohl, Morphologische Betrachtungen iiber das Sporangium der mit Gefassen 
 versehenen Kryptogamen, Tubingen, 1837, p. 11. 
 
 f See Zeitschrift fur wiss. Bot. von Schleiden und Nageli, vol. i. part i. p. 168. 
 (1844). 
 
 146 Scolopendrium officinarum. A, The ripe capsule : a, the pedicle ; b, d, c, the ring ; 
 c, the place where the capsule is torn open. B, Part of the ring of a capsule that is 
 burst open : a, the side turned from the capsule. C : a, the spore ; 6, the same (after 
 the removal of the external membrane) with a cytoblast. 
 
SPECIAL MORPHOLOGY : PERNS. 197 
 
 the latter are in a more or less closed circle, be distinguished into 
 medulla in the interior and cortex in the exterior. The vascular 
 bundles lie in their vertical course alternately side by side, so as 
 to form a net, the meshes of which furnish, at their upper part, 
 branches of the bundles to the leaves and branches, where the latter 
 are present ; we find a few isolated vascular bundles in the medulla 
 of the arborescent Ferns, which pass out through those meshes 
 into the leaves. The vascular bundles have often a band-like, or 
 channel-shaped form, compressed from within outwards; and are 
 generally surrounded by a sheath of thick-walled elongated cells 
 coloured brown (by tannin and humic acid ?) ; and bundles of such 
 cells alone also traverse the stem. The parenchymatous cellular 
 walls, on dying, speedily acquire a more or less dark brown colour. 
 It is well known that many Ferns contain a large quantity of tannin. 
 The parenchyma, especially the base of the leaf-stalk, often con- 
 tains much starch (as, for instance, in the Marattia cicutafolia), 
 which serves in some of the South Sea Islands as an article of 
 food. The vascular bundles are composed of porous vessels, having 
 the pores small, or most frequently with slits ; sometimes, however, 
 as in the leaf-stalks, we find spiral vessels which admit of being 
 unrolled. The leaves but rarely consist of one single cellular 
 layer (such being only the case in the HymenophyllecB), but generally 
 of several, forming two laminae : an upper one, composed of short 
 cylindrical cells, vertical to the surface of the leaf, and an under 
 one, formed of loose spherical, or sponge-like, parenchyma. More- 
 over, the two sides are invested with a true epidermis, which always 
 exhibits perfect stomata on its lower surface. The upper epider- 
 mis not unfrequently consists of several layers of cells. Isolated 
 bundles of liber cells are often met with above and below the 
 vascular bundles of the leaves. The leaves contain a large quantity 
 of potash salts. 
 
 The attempt to represent the stem of the Fern as merely composed of 
 leaf-stalks grown together is so entirely at variance with the law 
 of its development, and, consequently, so totally devoid of foundation, that 
 we do not deem it worth while to contest the point. Germination shows 
 that there is a rudiment of the stem prior to the formation of the leaves 
 and leaf-stalks. We may refer for the anatomy of the stem to Mold's 
 work, which we have already mentioned, and which certainly still leaves 
 much to be done, although he can scarcely be blamed for the deficiency. 
 We now feel the want of the history of the living development, and a 
 much greater service would be rendered to science if one of the many 
 travellers in Brazil would furnish us with the result of an accurate inves- 
 tigation of this development in the stem of an arborescent Fern, instead of 
 adding a couple of thousand dried new species to the 80,000 which we 
 already possess, and which are scarcely worthy of notice while we continue, 
 as at present, hardly to have a certain knowledge of any one single speci- 
 men. The annulus of the sporocarp exhibits a structure similar to the 
 teeth of the fruit of the Mosses. I think I have, detected very delicate 
 spiral fibres in the cells of the walls of the fruit in Ophioylossunt 
 and Osmunda. 
 
 o 3 
 
198 MORPHOLOGY. 
 
 VIII. THE HORSETAILS (EQUISETACE.E). 
 
 1 10. The spore-cell of the Equisetacea expands into an utricle, at 
 one extremity of which new cells are formed, that gradually acquire 
 the form of a many-lobed flat expansion, a simple cellular layer, 
 several cells of which become elongated into filiform adhering fibres 
 (the proeinbryo). At one point of this proembryo there appears 
 a cellular node, which develops itself upwards into the bud, stem, 
 and leaf, and downward to a root. The main stem appears, how- 
 ever, to die off very speedily in the case of most, while in its place 
 are developed from the axillary buds of the first leaves lateral 
 branches, which run horizontally below the surface, never assume 
 a green colour, and whose lateral branches partly rise in a vertical 
 direction, and appear above the ground. All the stems of the 
 EquisetacecR are round, mostly furrowed and regularly elongated 
 between the successively ranged leaves (internodium, internode). 
 At the roots of the leaves the stems are somewhat contracted, and 
 easily break off (nodi, nodes). The leaves are small, scaly, ranged 
 in a whorl, and grown together by the lower part of their margin 
 into a sheath closely surrounding the stem. The axillary buds of 
 the stem above ground burst in a remarkable manner through the 
 base of the leaves, and form whorls ; these have also, less frequently, 
 lateral branches. The individual lateral branches are not invariably 
 elongated, but enlarge spherically between every two circles of 
 leaves, become fleshy, and then readily separate from the stem into 
 their individual joints. 
 
 I have not myself enjoyed any opportunity of observing the germina- 
 tion of the EquisetacecE ; and the description given is taken from 
 Vaucher* and Bischoff.f But both leave very much to be desired. It 
 is inconceivable to me how any one can say " new cells appear, new 
 cells seem to occur between," without even touching upon the obvious 
 inquiry " whence come these cells ? " It is an evidence of the difficulty 
 that there is in giving a correct account of what we have observed ; and 
 assertions of this nature are all but untrue, since it merely amounts to 
 this, that in one case he saw a few, and in others many cells, the position 
 and interposition of the cells originating in fancy and not from observa- 
 tion. We must remark, that in the primary stem the first leaf-circles 
 are scarcely removed from each other, and that the expansion of the 
 internodes of the stem begins higher up. 
 
 111. At the points of the stems above ground, or of their 
 branches (often in peculiar branchless stems), several closely con- 
 tiguous leaf-whorls become developed into an ovate fructification. 
 The individual leaves (sporopliylld] change in a peculiar manner, 
 assuming the form of a hexagonal disc, attached by a pedicle at its 
 
 * Mem. de Mus. d'Hist. Nat. vol. x. p 429. 
 f Die kryptogamischen Gewachse, p. 40, et seq. 
 
SPECIAL MORPHOLOGY : THE HORSETAILS. 
 
 199 
 
 centre. From five to seven hemispherical sporocarps are developed 
 from and upon the lower and inner surface of the disc. Two 
 layers of the cellular tissue of these form the wall of the fruit. 
 The inner cells become parent cells (sporangia), and from each of 
 these one spore is produced from a distinct cytoblast. Two spiral 
 fibres are simultaneously formed in the parent cell, which at first 
 completely cover the inner wall, are rounded off at both extremities, 
 and somewhat flattened out, and are firmly closed together. The 
 spiral coils are subsequently somewhat separated by the expansion 
 of the parent cell. When the spores are quite mature, the hvgro- 
 scopical spiral bands tear the delicate wall of the parent cell, and 
 wholly separate from each other, although they remain adhering by 
 the centre to the spore. The sporocarps then split longitudinally, 
 and emit the spores. 
 
 The whole fructification of the Equisetacece (fig. 147. A, B) is not to 
 be distinguished setting aside the actual development of the parent 
 cells of spores (fig. 148. A D) from the antheriferous inflorescence of 
 
 14' 
 
 148 
 
 Tax-us* by any morphological or anatomical characteristic, on which 
 even a merely specific distinction can be established. This peculiarity 
 was, however, for a long time put under contribution by the fancy of 
 botanists, and, as may naturally be supposed, the antheridia mania did 
 not suffer the Equisetacece to escape. As nothing else appeared, the 
 unfortunate spiral fibres were chosen, as occasionally a few mucus 
 granules might be seen adhering to them. As early as 1833f Mohl gave 
 a correct explanation of these, and I myself had often followed the history 
 of their development, which it is extremely easy to do, always arriving 
 
 * Compare also Mohl's Sporang der Kryptog. p. 7. 
 
 f Mohl, Flora of 1 833, on the Spores of Cryptogamic Plants, p. 1 5. ; and the work 
 before quoted. 
 
 147 Equisetum limosum. A, Fruit-bearing extremity of the stem, 
 leaf, seen from the side ; magnified strongly. 
 118 Equisetum arvense. 
 
 B, Separate spore- 
 
 A, Young mother-cell, with a spiral layer of thickening : the 
 
 dotted lines show the spore shining through, with its large cytoblast. B, The same 
 mother-cell, seen from above. C, The spore from it. D, Completely developed 
 mother-cell, with the spore in it ; a, interval between the turns of the spiral fibres. 
 
 o 4 
 
200 MORPHOLOGY. 
 
 at the same results, although at the time I was unacquainted with Mohl's 
 observations. That Link*, in the year 1841, should speak of antheridia 
 in a work where one might expect to find not only a complete use made 
 of the materials at the author's command, but likewise a thorough inves- 
 tigation of the subject treated of, makes one almost envy the man who 
 knows how to make work a matter of so little moment. Meyen says 
 nothing of this subject, the Lycopodiacece and Equisetacece not being 
 treated of in his system of Physiology. 
 
 112. The stem of the Equiseta consists of a somewhat lax par- 
 enchyma, separated by a circle of from six to ten successive closed (?) 
 vascular bundles ( 26.) into medulla and cortex. In the under- 
 ground stem the external cortical cells become by degrees more 
 tough in the walls, and porous. Air-cavities occur alternately with 
 every two vascular bundles, formed in the cortex by tbe laceration 
 and resorption of the cellular tissue. A similar opening occurs in 
 the axis of the medulla. The vascular bundles are developed from 
 within outward, contain, most internally annular vessels, then spiral 
 vessels, and finally porous vessels. The first portion formed soon 
 dies off, the cells tear, and thus an air-hole is formed in the vascular 
 bundle itself; and we often find the annular or spiral vessels pro- 
 jecting into this aperture, or their remains fallen into it. In the 
 furrowed stems there lie upon the projecting ridges bundles of thick- 
 walled, elongated (liber) cells ; such a layer often appearing under the 
 whole epidermis of the stem, as, for instance, in Equisetum fluviatile. 
 The vascular bundles at the nodes range themselves closely into 
 a circle, and give off from here twigs, which pass into the leaves 
 and lateral branches. The parenchyma at the nodes has also 
 smaller and closer cells. The leaves have one vascular bundle, 
 and on their outer surface one bundle of liber ; and between the 
 two w T e find an air-passage. Their free unjoined extremities 
 are mostly, with the exception of the middle part, composed 
 of two thin cellular layers, dry and membranous. They are 
 furnished in the middle, like the stem itself, with an exceedingly 
 firm epidermis, which distinctly exhibits stomata, arranged mostly 
 in rows, and whose cells are for the most part thickened towards 
 the exterior in a wart -like manner. In the cellular walls, especially 
 in these wart-like projections, we find deposited a large quantity 
 of silica, in the form of small lamellae, which may be isolated by 
 means of concentrated sulphuric acid, which only destroys the vege- 
 table substance ; they unite, however, on being heated from the 
 action of the potash salts present, and then retain in the ashes the 
 perfect forms of the living plants.f The inner layer of the wall 
 of the sporocarp is formed of the most beautiful spiral fibrous cells. 
 The spherically enlarged stems below the surface contain, in a close 
 cellular tissue, starch (?) and oil, and have only very small, imper- 
 fectly developed vascular bundles. 
 
 * Link, Filicuni Species, &c., p. 9. 
 
 f Struve, De Silicia in Plantis nonnulla. Berlin, 1835. 
 
SPECIAL MORPHOLOGY: SEXUAL PLANTS. 201 
 
 One peculiarity I often met with in the subterraneous stems. The 
 somewhat elongated cells which bound the air-passages, at a late stage 
 begin to develop cells in their interior. These penetrate particular 
 places in the wall of the mother cell, and project as utricles into the air- 
 cavities, then expand into a perfectly globular form, become cut off by 
 constriction, and thus fill the air-space up a second time with lax globular 
 cellular tissue. I cannot yet decide whether this is a diseased or a 
 regular structure. 
 
 B. SEXUAL PLANTS (PL gamica). 
 
 113. The sexual plants are at once characterised, as a large 
 and connected division of the vegetable kingdom, by the peculiar 
 manner in which a new individual is formed, and by the double 
 and essentially distinct organs which are required for this purpose. 
 Firstly, they develope four cells, clothed by a peculiar membrane, 
 within a mother-cell (sporangium of the Agamce), which becomes 
 absorbed subsequently, so that the former, when perfectly mature, 
 lie free in a little sac composed of cells (sporocarp of the Agamce). 
 This sac is called the anther (anther a\ the spores are called pollen 
 or pollen-granules (granula pollinis), and the special membrane by 
 which they are clothed is the external pollen-membrane. Secondly, 
 they produce a cellular body free in any case at the apex, of oval 
 or elongated form, in which one cell becomes so much enlarged 
 that it causes the absorption of a part of the surrounding sub- 
 stance, and thus a considerable cavity is produced in the body. 
 This body is called the seed-bud (or ovule) (gemmula) ; the great 
 cell is the embryo-sac (sacculus embryoniferus}. The sac contains 
 cytoblasterna, from which (excepting in the Rhizocarpeci) new cells 
 are formed, gradually filling the embryo-sac, until, as sometimes 
 happens, the growing embryo again displaces them. The develop- 
 ment of the new plant proceeds by the expansion of the cells of 
 the pollen-granules into a tube, which under favourable circum- 
 stances penetrates to the embryo-sac. The other end of the pollen- 
 tube dies away while the extremity in the sac developes new cells, 
 which become arranged into the form of the rudimentary plant, 
 the embryo. 
 
 I have here only drawn attention to those points admitted with re- 
 spect to the Phanerogamic plants by all the best observers of recent 
 times. (With regard to the Rhizocarpece, see the special explanations.) 
 I have here displayed the essential facts, namely, the analogy of the 
 course of formation and the nature of the pollen with those of the 
 spores of the Agamce, and the wholly*sinrilar conversion of the pollen 
 into a tube, of which one end (though it must be freely admitted that 
 we do not know precisely how) forms new cells, which gradually arrange 
 themselves and form the new plant, while the other end dies away ; com- 
 paring this with the germination of Mosses, Ferns, &c. : and, while I 
 have distinctly marked this comparison, it will at once have become evi- 
 dent what new phenomenon is met with in the sexual plants, namely, 
 
202 MORPHOLOGY. 
 
 the appearance of the seed-bud (ovule), within which alone the deve- 
 lopment of the appointed end of the pollen-tube into a new plant can 
 take place. Directing our attention to the universally occurring, and 
 consequently essential, characteristics presented by the seed-bud, namely, 
 the disproportionately great developement of one single cell (the em- 
 bryo-sac) within a cellular body free at one end and containing cyto- 
 blastema, out of which, at least in all the Phanerogamia, cellular tissue 
 is formed, there is clearly displayed an analogy, which can scarcely be 
 mistaken, with the antheridia of the Mosses and Liverworts ; and we 
 have in this structure an interesting example in the vegetable world, of 
 a fact often presenting itself in the animal kingdom, namely, a deter- 
 minate product of the formative force (a morphological organ) present 
 in one group, without possessing the same physiological importance which 
 it has in another group, and without the morphological organ becoming 
 a physiological organ. On the other hand, when we have conceived the 
 comparison in these two large groups, we may make the reasoning, evi- 
 dently deducible from the resemblance, of service as a safe point of de- 
 parture from which to arrive at further analogical conclusions. If we 
 have identified the pollen-grain and the spore, and if we have found 
 their development into new plants to be similar in the main points, we 
 may venture to expect similarity in the less important particulars. It is 
 now certain that in the Agamce one end of the tube of the spore (as in 
 the Ferns and Equisetacece) can, without the aid of any other organ, 
 develope new cells as the foundation of a new plant. Hence, I seek in 
 the Phanerogamia also the essential cause of the formation of new cells, 
 and consequently of an embryo, in the power of development of one end 
 of the pollen-tube, which is perhaps called forth and modified by the 
 action of the embryo-sac, but which appertains simply and exclusively 
 neither to this nor its contents. We do not by this means acquire 
 any results as to the nature of the sexual plants, yet we do gain a valu- 
 able leading principle to guide us in further researches, and in the 
 critical examination of the results obtained. Thus, the opinion which 
 I delivered on the formation of the embryo of the Phanerogamia 
 would have been justified, even if decided observation did not support 
 me, and if Meyen * had been right in asserting that the new cells 
 are formed externally on the apex of the pollen-tube (and not in the 
 inside of it, as I have seen). This mode of formation might occur in the 
 Agamce, as, for instance, Mirbel actually asserted in his work, already 
 referred to, on Marchantia, which researches I indeed must consider 
 very imperfect. On the other hand, the opinion that the first cells of the 
 embryo are not formed inside the embryo-sac, while the pollen-tube re- 
 mains outside it, is supported by the analogies to be drawn from the inves- 
 tigation of the Rhizocarpea, where the embryo is undoubtedly formed by 
 the end of the pollen-tube, outside and scarcely in immediate contact 
 with the embryo-sac ; leaving out of consideration the improbability 
 that, in this process, three forms so essentially different should be exhi- 
 bited, without even being respectively confined to definite groups, as 
 Meyen j" must allow from his own researches. 
 
 114. All sexual plants possess stem and leaves, the latter at 
 
 * Physiologic, vol. iii. p. 307, et seq. 
 
 f Physiologie, vol. iii. p.. 307, 308., compared with 310, 311., and, still more de- 
 cidedly, 313. 
 
SPECIAL MORPHOLOGY : RHIZOCARPE^. 203 
 
 all events, in the parts of the flower. In the Phanerogamia the 
 anther is unquestionably only a modified leaf, the seed-bud (ovule) 
 probably only the modified extremity of a stem ; in the Rhizo- 
 carpece no explanation of the kind can be given, from the imperfect 
 knowledge of the course of development. 
 
 a. Plantce athalamicce. 
 
 115. The character of this group, and the distinction from 
 the Phanerogamia^ is the fact that the seed-bud (ovule) and pollen 
 separate as independent bodies from the plant, and the tubular ex- 
 pansion of the pollen-cell penetrates the seed-bud subsequently, 
 and then becomes developed into a perfect plant in one act of 
 vegetation. 
 
 IX. RHIZOCARPE^E. 
 
 116. In the Rltizocarpea two very distinct parts become 
 detached from the old, in order to the production of a new 
 individual, namely, pollen-grains and seed-buds (ovules). The 
 former have the usual structure, consisting of a single cell (pollen- 
 cell), with an external pollen-membrane. The others present the 
 following structure : a very large cell, with firm walls, containing 
 large grains of starch, mucilage, and oil (the embryo-sac], is sur- 
 rounded by a white, coriaceous membrane, which is formed of very 
 minute, scarcely distinguishable cells ; this membrane forms, at one 
 extremity, a papilla (nucleus), which is covered sometimes by three 
 lobes of the same membrane (in Salvinia), or by these three united 
 into an envelope open at the point (in Marsilea), which is called 
 the simple coat of the bud (integumentum simplex). The whole is 
 enclosed in a cellular sac, the sac of the seed (sacculus) (as in 
 Salvinia), or in a layer of cells so gelatinous as to be almost con- 
 fluent (as in Pilularia and Marsilea). The cell of the pollen- 
 granule extends itself into a tube of variable length (long in 
 Salvinia, shorter in Pilularia.). During the same time the cells of 
 the nucleus are developed near the apex of the embryo-sac, 
 become clearly distinguishable and laxer, filled with chlorophyll, 
 and at length break through the nucleus, so that they project free, 
 forming the nuclear papilla (mammilla nuclei). If a pollen-tube 
 now comes in contact with these cells, it penetrates deeply 
 between them until it reaches a layer of small green cells which 
 covers the embryo sac (Pilularia and Salvinia), and then it ex- 
 pands in a vesicular form, displacing the surrounding cellular 
 tissue, which, however, continues to be developed, and projects 
 from the seed-bud as a green body of variable size. In Salvinia it 
 forms two depending lateral processes, while in Pilularia a portion 
 of the superficial cells become elongated into capillary filaments. 
 In the vesicular extremity of the pollen-tube cellular ti^ue is 
 
204 MORPHOLOGY. 
 
 developed, which, taking the form of the embryo, one end finally 
 breaks through nuclear papilla of the seed-bud, which up to 
 that time appeared as a thin-walled sac, and now assumes the form 
 of a round sheath (Pilularia), or a flattened, bilabiate body (Sal- 
 vinia). In Salvinia the embryo, when it emerges, produces a 
 pedicle which expands above into a flat discoid body, swimming on 
 the water (first leaf, cotyledon), from the point of attachment of 
 which, below a vertical slit in the same, a bud previously existing 
 in a rudimentary condition develops into a little stem clothed with 
 leaves on both sides, and sending out adventitious roots below. 
 In Pilularia the projecting end of the embryo develops into an 
 upright filament of a green colour (first leaf, cotyledon), at the base 
 of which a pre-existing bud develops into a stem with long fila- 
 mentous leaves. The part of the embryo opposite to the protrud- 
 ing end becomes the root, and breaks through, at a later period, 
 the green papilla of the seed-bud, which also then appears like 
 a sheath. Full-grown plants of Pilularia and Marsilea grow 
 in boggy ground. Their slender stem runs horizontally forward 
 with elongated internodes, producing at the side, and always some- 
 what to the under side of the clavate expanded apex, leaves which 
 in Pilularia are filiform, in Marsilea consist of a long stalk (petiolus) 
 and a four-lobed blade (lamina) ; on the under side the stem con- 
 stantly shoots forth adventitious roots, branches by the develop- 
 ment of axillary buds, and apparently also by a bifurcating division 
 of the apex of the stem. Salvinia, on the other hand, floats freely 
 on the surface of the water; its equally slender stem, with short 
 internodes, bears on both sides shortly-stalked, flat, ovate leaves, 
 sends down adventitious roots in the water from the fruit-stalks, 
 and ramifies little by development of axillary buds. Azolla, a 
 tropical genus, resembles a delicate floating Liverwort. Its course 
 of development is as yet wholly unknown. 
 
 When in the year 1837*, in my survey of the history of development, 
 I observed that I believed that, with respect to the Rhizocarpece in par- 
 ticular, much yet remained to be investigated, I had three points in view ; 
 first, the peculiar formation of the reproductive organs, described indeed 
 by many, but by no one properly understood ; secondly, the inconceivable 
 imperfection of all preceding accounts of germination ; and, thirdly, an 
 isolated observation on Salvinia. In reference to the first point, the 
 essential resemblance of the so-called large spore to the seed-bud, and of 
 the smaller to the pollen-grain of the Phanerogamia, appeared especially 
 remarkable. Touching the second point, it struck me that the germi- 
 nation indicated either the simple development of a plant already per- 
 fectly organised in a rudimentary condition (in the Phanerogamia), or 
 the development of a single cell into a new plant (in the Cryptogamid) ; 
 but that in the treatises upon the germination of the Rkizocarpece there 
 had been no idea either of demonstrating the existence of an embryo 
 capable of development, or of tracing a single spore-like cell in its 
 
 * Wiegmann's Archiv, Jahrg. 1837, vol. i. p. 316. Schleiden's Botanischcn Beitrag. 
 vol. i. 
 
SPECIAL MORPHOLOGY : RHIZOCARPE^E. 
 
 205 
 
 gradual evolution into a plant. Finally, in the third place, I had seen, 
 in a transverse section of a seed-bud of Salvinia, which had lain some 
 time to germinate in water, a filiform cell which ran obliquely through 
 the green cellular tissue from a somewhat lateral point of the embryo-sac, 
 and hung out considerably beyond the seed-bud, but appeared to be torn 
 away here. As soon as I had an opportunity, I made a minute investi- 
 gation, and soon had the satisfaction of discovering the whole process of 
 germination, such as I have described it in the paragraph, first in Sal- 
 vinia, and afterwards, with less trouble, of confirming it, in Pilularia. 
 In Salvmia, with the exertion of all my patience, I have only succeeded 
 three times in making the section so fortunately as to lay open the entire 
 course of the pollen -tube. Since it runs obliquely, and the minute seed- 
 buds present externally no points by which they can be held, the section 
 becomes naturally a matter of chance. In the somewhat later stage of 
 development of the seed-bud the form of the nuclear papilla becomes a 
 sufficient guide for an accurate section. In Pilularia (fig. 149.), on the 
 
 149 
 
 contrary, I have often succeeded in extracting, in a free condition, the 
 pollen -grains (fig. 149. B} with the vesicular expanded extremity of their 
 tube (E) in the seed-bud (C) perfect and uninjured. Here it is not 
 very difficult to trace the whole course of development. Three or four 
 pollen-tubes usually penetrate into one seed-bud here, but only one 
 passes deeply down and becomes the embryo (fig. 149. B, b, C, d, E) : 
 
 149 Pilularia globuUfera. A, Transverse section through a seed-bud at the commence- 
 ment of development : a, gelatinous coat ; b, coriaceous coat ; c, embryo-sac, filled 
 with starch and oil-globules ; d, nuclear papilla. B, Pollen grains : cr, fresh from the 
 pollen-sac ; b, swollen in water, and beginning to produce tubes. C, Upper part of the 
 seed-bud, after the penetration of the pollen-tube (d) : a, coriaceous coat ; b, embryo- 
 sac ; c, nucleus and nuclear papilla ; k, layer of cells which separates the pollen-tube 
 from the embryo-sac. E, Pollen-tube prepared free, from C : at the upper part it 
 exhibits the now uncovered portion which was enclosed in the outer pollen-membrane ; 
 in the middle, the slender, proper tube ; and below, the broadly expanded portion, now 
 filled with cellular tissue, which developes into the embryo. D, Upper end of the 
 seed-bud, in a still more advanced condition : a, coriaceous coat ; b, embryo -sac ; c, nu- 
 cleus and nuclear papilla expanded into a sac, through the development of the embryo ; 
 rf, stem-end of the embryo (e) ; g, first leaf (cotyledon) ; h, pollen-tube ; /, first axil- 
 lary bud ; filiform elongated external cell of the nucleus ; k, layer of cells, which 
 separates the embryo from the embryo-sac. 
 
206 
 
 MORPHOLOGY. 
 
 150 
 
 from the shortness of the pollen-tube the granules themselves are situ- 
 ated quite near, upon the seed-bud ; by degrees they lose their external 
 membrane, and then appear, like three or four pyrifbrm utricles, issuing 
 from the seed-bud (tig. 149. D, h), which Mtiller* actually imagined 
 them to be. The course of development of Marsilea I have not yet had 
 the opportunity of making out; what Esprit Fabref has published on 
 the subject I unfortunately only know from Meyen's Year Report J, 
 where the account, whether from the fault of the author or the reporter 
 I know not, is very superficial and imperfect. The great agreement of 
 the structure with Pilularia leads to the expectation that no essential 
 deviation will be found to exist. There are two more points connected 
 with the course of development to which I must call attention. The 
 pollen-tube, as has been stated, does not come 
 into immediate contact with the embryo-sac, since 
 the apex of the latter is closely invested by a 
 simple layer of green cells (fig. 149, C, k, D,k). 
 Before the nuclear papilla is fully formed, the 
 membrane of the embryo-sac is very tough, 
 and almost coriaceous ; subsequently it expands, 
 so far as it is covered by that cellular layer 
 of the nuclear papilla, hemispherically (in Sal- 
 vinia\ or even into a long cylinder rounded off 
 above (in Pilularia), and thus exhibits at this 
 region an extremely delicate membrane, which is 
 continuous below with the unaltered tough one 
 (fig. 149. Z>, b). The pollen-tube, which pene- 
 trated and has become vesicularly expanded, 
 forms a very delicate investment over the deve- 
 loping embryo for a long time after (fig. 149. e\ 
 which even remains attached up to a very late 
 period on the point where the pollen-tube entered, 
 which can always be recognised by the three to 
 five contiguous cells appearing brownish as if 
 dead. Two extremities may be distinguished in 
 the part of the pollen-tube which has entered : the 
 upper closed end, which went first in the act of pe- 
 netration (fig. 150. //); and the other, which loses 
 itself externally in the pollen-granule (fig. 150. x). 
 The former is firmly applied upon the layer of 
 cells investing the embryo-sac ; it may be called 
 the stem end, and the other the root end. In the rest of its periphery 
 the pollen-tube, and therefore the embryo, remains quite free. Close 
 beside the stem end, immediately at the point where its connection with 
 the cellular layer of the nuclear papilla ceases, is now developed the bud 
 (figs. 149. A /, 150. &), which may here be regarded as a first lateral 
 bud, an axillary bud 9f the first leaf (figs. 149. D, g, 150. rf), or coty- 
 
 * On the Germination of Pilularia globulifera, in the Flora, 1 840, No. xxxv. p. 545. 
 (Otherwise an excellent treatise, with many very accurate observations.) 
 t Ann. des Sc. Nat. 1837, April, p. 221. 
 j: Wicgmann's Archiv, 1838, vol. ii. p. 82. 
 
 150 Pilularia globulifera. A considerably advanced stage of development, a, Seed- 
 bud ; 6, axillary bud of the embryo ; c, the nucleus, expanded into a sheath for the 
 embryo; d, first leaf; e, first root; .r, pollen-tube; y, collar-like thickening of the 
 coriaceous coat. 
 
SPECIAL MORPHOLOGY: RHIZOCARPE^E. 207 
 
 ledon, since the proper terminal bud does not become developed on 
 account of its intimate connection with that cellular layer investing the 
 embryo-sac, already alluded to. The difficulty of drawing this parallel 
 in the discoid cotyledon of Salvinia is only apparent, if we take the 
 cotyledon of Lemna, for instance, as the basis of the comparison. The 
 first lateral bud growing forth then forms a horizontally advancing stem, 
 a rhizome (rhizoma), wholly agreeing with so many Phanerogamia, as, 
 for example, Asparagus. In Salvinia no further development of the 
 radical extremity occurs, but in Pilularia a root (fig. 150. e), which is 
 to be regarded as an adventitious root, is always produced on the side of 
 the stem, exactly opposite the bud, immediately beside the firmly at- 
 tached radical point. 
 
 117. On the full-grown plant are formed, from the lower part 
 of the leaf-stalk (in Marsilea quadrifolia), or at its base (Marsilea 
 pubescens, Pilularia), little nodules, which subsequently grow out 
 into a fruit, borne upon a stalk, which is sometimes long, some- 
 times short, or (as in Salvinia) a little branch springs from the 
 base of the leaf-stalk, hangs down in the water, and produces a 
 number of little fruits arranged upon it in the form of a spike. 
 
 The fruit of Marsilea is nearly ovate, compressed on two sides. 
 A tough, coriaceous coat, subsequently opening in two valves, 
 surrounds a cavity which is divided into two chambers by a lon- 
 gitudinal septum, imperfect at the upper part, and each of these 
 compartments is again divided by transverse septa into from five 
 to twelve chambers. From the region of the point of attachment 
 of the fruit, on the upper side, where the longitudinal septum is 
 wanting, runs a cord of gelatinous cellular tissue, wholly free 
 except at that point of attachment, which bears on each side from 
 five to twelve little sacs, also composed of gelatinous cellular 
 tissue, and hanging down in these lateral chambers. Through 
 these sacs, almost entirely on the outer side, runs a cord of dense, 
 but also gelatinous, cellular tissue ; and the two kinds of repro- 
 ductive organs are attached to this in such a manner that the seed- 
 sacs, fewer in number, only occupy the more central portion, that 
 next the longitudinal septum. The stalked seed-sacs so enclose 
 the already described seed-buds that the nucleus is turned toward 
 the stalk ; they subsequently dehisce. The anthers are irregular, 
 pyriform sacs, containing a great number of pollen-granules, which 
 are composed of a pollen -cell, external pollen-membrane, and in 
 addition to these a special gelatinous coat. 
 
 The fruit of Pilularia is globular. The equally tough, coria- 
 ceous coat, subsequently dehiscing in four valves, surrounds a 
 cavity which is divided into four chambers by vertical septa. In 
 the middle of the outer wall of each chamber runs a cord of gela- 
 tinous cellular tissue, which bears the anthers and seed-sacs on its 
 inner side. The latter are distinguished from those of Marsilea by 
 the nucleus lying on the side opposite to the stalk. Here, also, the 
 seed sac dehisces, and allows the seed-bud to escape. The anthers 
 are like those of Marsilea, but the pollen-grains want the gela- 
 
208 
 
 MORPHOLOGY. 
 
 tinous envelope, while their external pollen-membrane is tough 
 and studded with papillae. 
 
 In Salvinia the seed-buds and anthers are in distinct fruits. On 
 each spike is to be found an upper fruit, somewhat removed from 
 the rest which are crowded together, and this alone contains seed- 
 buds. The fruits are vertically furrowed, like a melon, and in 
 each projecting ridge runs an air-passage, again divided by a hori- 
 zontal septum ; otherwise, the cellular tissue surrounding the cavity 
 has delicate walls, and becomes gradually dissolved without any 
 regular dehiscence of the fruit. Into the cavity of the fruit pro- 
 jects, from the base to about half-way up, a central columella, 
 spherically expanded above, which bears upon its globular end in 
 one kind of fruit the seed-sacs, in the other the anthers. The 
 peduncle of the ovate seed-sacs is composed of several collateral 
 rows of cells. The sac (a single layer of cells) encloses the seed- 
 bud (the nucleus of which lies as in Pilularia), and separates with 
 the seed-bud from the peduncle. The peduncle of the globular 
 anthers consists of a single row of cells. The external pollen- 
 membrane is very thin and smooth. 
 
 Azolla is not, I believe, nearly sufficiently investigated ; what 
 has hitherto been found allows of no reference to the analogous 
 organs in the Rhizocarpece above mentioned. I myself have not 
 been able to examine any yet, and I refer to Robert Brown* and 
 Meyenf for more special details. 
 
 For the illustration I give the analysis of the reproductive organs of 
 Salvinia natans (figs. 151, 152.). The course of development of the 
 
 151 
 
 152 
 
 I) 
 
 * Verm. Schrift. vol. iii. p. 22., and vol. i. p. 162. ; and the Atlas of Flinders's Voy- 
 age, which contain Ferd. Bauer's beautiful illustrations. 
 
 f Acta Ac. C. L. N. C. vol. xviii. part i. p. 508. 
 
 131 Salvinia natans. Portion of a flowering plant, with two leaves, a branch dipping 
 down iti the water, from which a tuft of rootlets springs, and which bears at the lower 
 part capsules with pollen-sacs (anthers), and above, somewhat removed from the rest, a 
 solitary capsule (ff), which bears seed-sacs. 
 
 133 Salvinia natans. A, Pollen-sac. B t Poll en -granules ; two compressed, with their 
 
SPECIAL MORPHOLOGY : RIIIZOCARPE^E. 209 
 
 fruit, which promises results in the highest degree interesting, is up to 
 this time a pium desiderium. The Rhizocarpecp have found no place 
 in Meyen's System (!). From what is known, and what I have myself 
 seen, this much follows, that there is no room at present for fictions of 
 blending together of organs and the like. On the other hand, from the 
 situation of most of these fruits (comparing them with the Lycopodiacece), 
 it is exceedingly probable that we have to do merely with a small 
 portion of a leaf, developed in such varied ways in its interior. But 
 this does not at all give a different import to the anthers and seed-buds 
 from that universally admitted for sexual plants ; and the fact that in the 
 Phanerogamia the anther only is formed from a leaf, the seed-bud pro- 
 bably only from a stem, is thus peculiar to this group, but by no means 
 an essential part of the conception of anther and seed-bud. To attach 
 in this way to every word an absolute definition, and not to use it to 
 express misty schemata of the imagination, is the only way to bring 
 security and progress into science, and to free it from the nauseous and 
 not merely fruitless, but terribly destructive, indiscriminate use of words 
 by which no two persons understand the same thing. The process of 
 development appears to be especially peculiar in the seed-buds of Pilu- 
 laria. In some earlier conditions of these I found the seed-sacs filled 
 partly with delicate transparent globular cells, and partly with groups of 
 four tetraedrally-united cells; one of the latter gradually underwent 
 considerable expansion, but especially in one group which occupied 
 exactly the centre of the seed-sac, so that this soon filled the greater part 
 of the space, and could no longer be mistaken for anything else than the 
 future embryo-sac. All the rest of the cellular tissue appeared to be 
 subsequently converted into the coriaceous coat of the ernbryo-sac, and 
 the gelatinous one of the seed-bud ; but my observations on this point 
 are imperfect. 
 
 I have thus largely treated of the Rhizocarpece, only because in no 
 previous publications have the so desirable completeness and accuracy 
 been attained, and in the belief that I was able to furnish some not un- 
 important contributions ; besides, also, that their position, as a decided 
 intermediate link between the Phanerogamia and Cryptogamia, makes 
 an accurate knowledge of them in the highest degree important and 
 fruitful. 
 
 118. The structure of the Rhizocarpea is, on the whole, very 
 simple. The stem consists of a central vascular bundle, with some 
 spiral vessels, and a bark in which run a circle of large air-canals, 
 covered on the outer side by a simple layer of cells (in Salvinia), 
 or by several layers (in Pilularia and Marsilea). The septa of the 
 air-passages of the last consist of elegant stellate cells ; in both 
 Pilularia and Marsilea the vascular bundle is enclosed by a simple 
 layer of elongated parenchymatous cells with brownish walls. The 
 leaf of Pilularia, and the petiole of Marsilea, are formed exactly in 
 the same way as the stem of Salvinia, only they are, in addition, 
 covered by an epidermis with stomates. The blade of the leaf of 
 
 contents. C, Seed-sac. D, The same in longitudinal section : a, seed-sac ; ft, cori- 
 aceous coat of the seed -bud ; c, three-lobed coat of the seed-bud surrounding the 
 nucleus ; d, embryo-sac ; e, the place where the pedicle of the seed-sac was attached, 
 E, Apex of the seed-bud, seen from above. 
 
210 MORPHOLOGY. 
 
 Salvinia consists of an upper, under, and central layer of cells, 
 which are somewhat removed from each other, the space between 
 them being divided into large air-cavities by vertical septa, the cells 
 of which exhibit undulating walls. The upper layer consists of 
 polygonal cells, which have intercellular passages (stomates) between 
 them, opening into the air-cavities beneath. The upper surface is 
 also studded with tufts of hairs, composed of cells in a moniliform 
 arrangement ; the lower surface of the leaves, the stem and the 
 radical fibres, are covered with hairs of a somewhat different kind, 
 composed of cylindrical cells arranged into filaments, the last cell 
 of which is apiculate, and contains some dark- coloured substance. 
 The blade of the leaf of Marsilea consists (according to Bischoff) of 
 parenchyma, traversed by forked, branching vascular bundles, and 
 covered by an epidermis furnished with stomates on both (?) sur- 
 faces, and having the lateral walls of its cells serpentine. The 
 coriaceous coat of the fruit in Marsilea and Pilularia is composed 
 of from three to five layers of cells, elongated vertically to the sur- 
 face, of various colours, unequal in width, but all with thick walls ; 
 in Pilularia this is immediately invested on the inner side by 
 a brownish parenchyma, composed of small cells, and forming air- 
 cavities in the places between the fruit and the septum ; next to 
 this (and exclusively in Marsilea) by a layer of gelatinous cells, 
 which in Marsilea exclusively form the transverse septa, while in 
 Pilularia a double layer of thick, brown, minute-celled parenchyma 
 also traverses these. The longitudinal septum, also, in Marsilea 
 consists of gelatinous parenchyma. At its upper free border, from 
 the base of the fruit outward, runs a vascular bundle, which sends 
 off as many main branches as there are transverse septa, and these 
 main branches, divided by bifurcation about the middle and then at 
 the very bottom, form a complicated anastomosis. Of the outermost 
 of the very minute cells of the coriaceous coat of the seed-bud in 
 Pilularia) those situated in the half lying next the nucleus are 
 somewhat more elongated, so that they form a collar round the 
 seed-bud. In Marsilea, the exterior cells are elongated perpendi- 
 cularly to the surface, yellow, and pass immediately into the cellular 
 integument. 
 
 The history of development of the various masses of gelatinous cellular 
 tissue, which appear so peculiar in many respects, still remains an espe^ 
 cial desideratum. The cellular cord, bearing little sacs, which in Mar- 
 silea lies in the fruit, not more than two or three lines long, expands after 
 the dehiscence of the fruit, through absorption of moisture, to the enor- 
 mous size of a round filament from one to two lines thick, and four to five 
 inches long, the volume exceeding twenty or thirty times that of the 
 whole fruit. The layer of gelatinous cells, which enclose the seed-buds 
 in Marsilea and Pilularia, is also peculiar, and undergoes continual 
 change during the development, from the action of the water absorbed. 
 Many other specialities are to be found in Bischoff. * 
 
 * Kryptogamische Gewaehse, p. 72, et seq. 
 
SPECIAL MORPHOLOGY: PHANEROGAMIA. 211 
 
 b. Plantce thalamiccs. 
 
 1 1 9. Three especial points separate the Phanerogamia from the 
 Rhizocarpece, which approximate so closely to them in the most essen- 
 tial conditions. First, the course of development of the young plant ; 
 since the seed-bud (ovule) is penetrated by the pollen-tube while 
 still organically connected with the parent plant, and this end of the 
 pollen- tube, endowed with a capability of development, takes the 
 form of a rudimentary plant ; the embryo, which, suddenly arrested 
 in its growth, separates with the seed-bud (now called the seed) 
 from the parent, and then, after some time, throws off' its envelopes 
 and unfolds itself (germinates) into a perfect plant. Secondly, the 
 fact that the physiological difference of the two organs, seed-bud 
 and anther, is here also connected with the morphological opposition 
 of stem and leaf. Thirdly, the organs of reproduction are here 
 again enclosed (as in the Mosses and Liverworts, only under more 
 definite conditions) by a number of peculiarly modified leaves 
 forming the flower (flos). 
 
 Reviewing, under the guidance of what has been stated in the fore- 
 going pages, the whole series of stages by which Nature works her way 
 up to the Phanerogamia, if we banish all baseless dreams and nights of 
 fancy, as unscientific, and hold simply to the product of unprejudiced ob- 
 servation, the following conclusions become evident : 
 
 1. The cell is the simple element ; it is the whole plant, without organs, 
 and uniting in itself all physiological forces, a. Gradually, in portions 
 of it, or in the next stage where several cells are combined, though as 
 yet in exceedingly indeterminate forms, in entire individual cells, we note 
 the appearance of organs (sporangia) which are especially devoted to the 
 formation of reproductive cells, the spores, b. The form of the cells 
 combining to constitute a plant remains still undefined, but several of 
 these sporangia combine in a definite form as a sporocarp ; and, lastly, 
 c, in the Lichens the spore becomes perfected as an independant organ, by 
 the addition of a special coat. (The Chares remain still inexplicable). 
 
 2. Nature advances, causing the cells to combine into determinate, 
 fixed, elementary forms, in fact, into stem and leaf, at the same time re- 
 taining the sporocarp, which developes in its highest complexity, and 
 essaying the formation of a new organ essentially consisting of a large cell 
 enclosed in an ovate, cellular body, to which at this stage no definite 
 function is delegated. Neither this nor the sporocarp stands in definite 
 relation to stem and leaf (but there are still important deficiencies in our 
 observations). Lastly, the sporocarp and that other organ become sur- 
 rounded by leaves, which are modified in definite gradations, forming a 
 flower (Mosses and Liverworts). 
 
 3. Through the Lycopodiacece, Ferns, and Equisetacece, the sporocarp 
 becomes continually more definitely connected with the leaf, and the de- 
 velopment of the sporophyll (spore-leaf) into a peculiar modification (the 
 anther of the Phanerogamia) progressively more clearly marked. In its 
 highest condition in the KquisetacecE, the physiological oouosition of leaf 
 
 p 2 
 
212 MORPHOLOGY. 
 
 and stem, which had been completely unfolded in the Lycopodiacece and 
 Ferns, appears to retreat again. In Equisctacece and Lycopodiacece. , 
 nature apparently drops for a time that second organ mentioned in the 
 Mosses ; here, however, there is again great want of observed facts. 
 
 4. This is again taken up in the Rhizocarpece, and a definite physio- 
 logical function attached to it ; it becomes the seed-bud (ovule), and the 
 sporocarp the anther ; leaf and stem remain as morphologically and phy- 
 siologically distinct organs, without, however, the reproductive organs 
 being determinately divided between them (but here, again, there is great 
 want of investigation). 
 
 5. Lastly, in the Phanerogamia nature again takes up all the separate, 
 successively evolved and gradually completed elements, and combines 
 them into a perfect plant. Leaf and stem, morphologically and, in gene- 
 ral, physiologically separated, form the entire plant. The stem is de- 
 veloped at certain points into perfect seed-buds with definite function ; 
 the leaf, in like manner, into perfect anthers ; and both become enclosed 
 in definitely modified leaves, and constitute perfect flowers. Now, how- 
 ever, but with a constant retention of the essential, a wide field is opened 
 for the development of the separate parts into varied forms, under which 
 circumstances even particular earlier stages of individual organs reappear; 
 for instance, the leafless stem, flat in Lemna, solid in Melocactus ; the 
 sporophyll of the Ferns in the Cycadacece, perhaps even the develop- 
 ment of the anther out of a stem-organ (?) in Caulinia fragilis, the stem 
 of an Equisetum with the function of a leaf in Casuarina, Ephedra, 
 Cactecs, &c. * 
 
 I have here only insisted on the main points, in order that the survey 
 might be more easy, but there are many others which might be traced out 
 in the same manner. In the Mosses, for example, the stem originates as 
 an organ morphologically bounded at one extremity ; in the Ferns, &c., 
 morphologically limited in two directions, as stem (sensu stricto) and root ; 
 but in neither exists any relation with the two ends of the spore-tube. 
 This relation first appears in the Rhizocarpece, and in the Phanerogamia 
 it becomes so perfected that the stem, without exception, originates from 
 the penetrating, closed end of the pollen-tube, and the root from the op- 
 posite extremity. 
 
 For the rest, I leave the special establishment of what has been stated 
 in the paragraphs to the succeeding pages, only remarking, once more, 
 that all that is said about stem and leaf, so far as it agrees with what 
 has been previously mentioned, holds good also of the rest of the 
 Gymnosporce. 
 
 * I here expressly beg that no one will impute to me the folly of imagining that, in 
 what I have just said, I have cast a peculiarly profound glance into the mysterious 
 workshop of Nature, that I might, as indeed often happens in our days, by such an 
 assumption of wisdom establish a vain system which investigation would, perhaps, 
 to-morrow cast aside as rubbish. I have only adopted the means which, with our 
 human finite minds, we so often have recourse to in endeavouring to facilitate the 
 survey of the whole series of forms by a figurative representation. I am defended 
 against the danger of regarding it as anything more, by the healthy plainness which I 
 owe to my teacher Fries, from whose logic I have learned as much Botany as from all 
 botanical treatises put together. 
 
SPECIAL MORPHOLOGY: PHANEROGAMIA. 213 
 
 X. XL MONOCOTYLEDONS AND DICOTYLEDONS. 
 
 120. In the development of the pollen-tube into the embryo, 
 an essential distinction arises, according as there is formed one first 
 leaf (cotyledon) growing up from the whole circumference of the 
 rudimentary stem, or two or more first leaves, which collectively 
 embrace the stem, all on the same level. On this depends the dis- 
 tinction of Monocotyledons and Di- or Polycotyledons, with which 
 is connected many other essential peculiarities ; for instance, that of 
 the closed vascular bundles which are peculiar to the former, and 
 the unlimited bundles of the latter. Since, however, the dis- 
 tinction of the two groups can only be established in so few parts at 
 this stage of our inquiries, it is better, to avoid repetition, to treat 
 both together as Phanerogamic in the order of their individual 
 organs. 
 
 With all its correctness, I hold the division of the Phanerogamia into 
 Monocotyledons and Dicotyledons to be but provisional. A perfect 
 morphological system will certainly first necessitate the distinction of 
 Gymnosperms and Angiosperms. The former without germens (and 
 mostly with homogeneous wood), comprehending the Conifer^ Cycadacece, 
 Loranthacece, and Gnetacece(?) ; the latter with the young fruit in the 
 form of a germen (and mostly heterogenous wood), separating into 
 Monocotyledons and Dicotyledons. At present, however, our knowledge, 
 so generally imperfect in reference to the majority of points connected 
 with the course of development, does not allow of this division being es- 
 tablished and carried out with any completeness. 
 
 121. It will be universally admitted, that in its formation, every 
 Phanerogamous embryo attains to a stage in which it appears 
 within the cavity of the seed-bud as a little round or ovate body, 
 homogeneously composed of cells, and in which distinctions neither 
 of organ nor structure are to be discriminated. To start from this 
 condition, as a perfectly certain element, is sufficient, but it is 
 necessary to go back quite to this point to acquire a comprehension 
 of the fully formed embryo and the entire plant. This little body 
 forms all the cells, through which it grows and developes, inside 
 its own proper boundaries ; no organic parts are added from with- 
 out ; it is, therefore, the entire plant in its simplest rudiment. 
 The central portion first ceases to produce new cells; below (where 
 the pollen-tube penetrated the seed bud) and above (the point op- 
 posite the former) the formation of cells, and with it the deve- 
 lopment, proceeds, but in various ways and naturally opposite 
 directions. Below (the radical extremity) the embryo elongates 
 into a more or less conical point, the radicle (radicula). Above 
 (the cauline extremity) we find the following : the apex elongates 
 in a direction opposed to the rootlet, by the formation of new cells, 
 in such a manner that part of the new cells are constantly applied 
 upon the old ones, while part recompose the extreme point as 
 formative cells. At a variable distance below the apex there is a 
 
 F 8 
 
214 MORPHOLOGY. 
 
 region where new cells are also formed, but so that the new ones 
 are partly pushed outwards and partly persist as formative cells in 
 the vicinity of the stem. In this way a mass of cellular tissue is ex- 
 panded out in the form of a lamina from this region of the stem, ap- 
 pearing either as an undivided organ continuous in its whole circuit 
 at the base, or, divided from the very bottom into two or more 
 portions, it presents itself under the form of two or more organs 
 all situated in the same plane. Through the accumulation of cells 
 upon the elongating apex, the lateral region just described is re- 
 moved continually further from the peculiar throng of active cell- 
 formation ; perhaps it is on this account that its formative power is 
 exhausted after a certain time. The further enlargement of its 
 organs depends then solely on the expansion of cells already formed, 
 but this also has its limits. Thus, we find here two essentially 
 different form-producing processes, and we call their products ele- 
 mentary organs of the plant : Stem (caulis, sensu stricto) the pro- 
 duct of the first, formative force originally acting continuously 
 and unlimitedly in one direction ; Leaf (folium) the product of 
 the second, dependent force, which defines its own boundaries in 
 the manner peculiar to it. The first leaf or first leaves are called 
 cotyledons. If we refer the term to a line * drawn from the root- 
 end through the middle of the embryo to the stem-end, which 
 then answers at once to the direction of development both of root- 
 let and stem, the stem is called an axial structure (axis), the 
 leaves lateral organs (paries laterales, appendiculares). In most 
 cases, some more succeeding leaves, besides the cotyledons, are 
 formed on the embryo ; these, with the rudimentary stem on which 
 they are borne, are called the plumule (plumula). Then ensues 
 a pause in the formative activity, the embryo is finished, the seed 
 (the seed-bud surrounding it) is ripe. 
 
 In all common plants the root, stem, and leaves are so conspicuous, 
 that their distinction in language is much older than any trace of a 
 scientific contemplation of plants. At the same time, nothing has so 
 entangled science, for a long time deprived it of all secure foundations, 
 as those very three organs ; and for this reason : that men were contented 
 to transfer these into science as they were intuitively understood in 
 common life, and neglected to transform the obscure notions of the 
 sensuous perception, which vary with the mode in which an impression 
 is received in every individual, and are, therefore, wholly incommuni- 
 cable, into a clear definite conception framed from their characteristics, 
 and therefore universally communicable. DeCandolle begins : " Les 
 feuilles sont, COMME CHACUN SAIT, les expansions ordinairement planes" 
 &c. What, then, is a science for, if it brings us nothing more than what 
 every one knows without it ? One cannot dispute at all with most bo- 
 tanists whether anything is a leaf or not, because they do not seek in 
 any way to explain in what its characteristics are to consist, as, for in- 
 stance, Agardh, DeCandolle, Link, and others. The greater portion 
 throw in some character or other, which the most superficial knowledge 
 
 * Which may also be a curved line, from the action of external influences. 
 
SPECIAL MORPHOLOGY: PHANEROGAMIA. 215 
 
 points out to be insufficient, and that is all very well ; for instance, the 
 flat expansion, the bud in the axil, the respiratory function, and so on. 
 With the statement of that which leaves " ordinairement " are, nothing 
 at all is done ; in science we have precisely to insist on what is necessary 
 and constant. For the stem, in opposition to leaf and root, again, most 
 authors have no definition whatever ; or it is so fragmentary, that a very 
 moderate acquaintance with plants causes it to be cast aside, for instance : 
 The stem is the portion striving upwards, the axis of the plant (Kunth). 
 What, then, is the horizontally advancing rhizome of Asparagus, what 
 the flowering stem of Arachis hypogcea, nay, what even the twig of the 
 Weeping Ash ? (It is similar with Lindley, Link, and others.) Agardh 
 defines : The stem is that part of a vegetable from which the leaves ap- 
 pear to issue, and which appears to grow upward. That no scientific 
 definition can be built on mere appearances, every one will understand 
 who has not renounced all sound logic ; but what is the stem of Melo- 
 cactus, from which leaves neither issue nor appear to do so. But enough 
 of these examples. This much is clear, that we require, in science, 
 more definite and unchangeable characters, to keep apart the conceptions 
 which we wish to separate as actually different ; and, on the other hand, 
 such general characters that no member which belongs to the sphere of 
 the conception shall be excluded from it. By accurate and compre- 
 hensive investigations of nature, we are led to those distinct oppositions 
 of radicle and axis, of axis and leaf. The latter contrast is actually 
 manifested in nature ; whether it is to the purpose to attach chosen words 
 to it, is another question. The former contrast, as primary and ori- 
 ginal in the development, preeminently deserves an especial name, and 
 in this way every one knows certainly what he has to deal with, when 
 leaf, axis, radicle, &c., are spoken of ; and it is precisely on this that all 
 possibility of scientific intercommunication and progress depends. The 
 history of the formation of the embryo given above, which it may be ob- 
 served was known in its principal points long ago, nay, which is to be 
 found truly even in Malpighi*, refutes sufficiently all empty fictions as to 
 the origin of the axis from combined 
 leaf-stalks. Nature first displays 153 
 
 a little undivided body (fig. 153. #), 
 which immediately elongating up- 
 wards becomes axis, and downwards 
 radicle. The forms which we have 
 named leaves (fig. 153. b, c) issue 
 out of this axis which pre-existed : 
 and that fiction is to the effect of 
 nothing less than to describe the 
 origin of an existing thing out of the 
 blending together of two things 
 which have no existence. Nay, to cut off all possibility of such flights 
 of fancy, Nature itself had formed the embryo of Cuscuta, in which, 
 although it attains a considerable length, no leaves whatever are usually 
 
 * Anatome Plant., de Seminum Generatione, pi. xl. fig. 242. in Pisorum semine. 
 
 153 HypocJuzris radicata. Development of the embryo, a, Youngest condition : the 
 embryo attached upon the suspensor, composed of three cells, is a little globule formed 
 of cells, b, Somewhat older germ : the dotted line indicates the original body, from 
 which the two first leaves (cotyledons) rise upward on each side of the apex (terminal 
 bud), which remains free, c, The same, but in a more advanced stage. 
 
 p 4 
 
216 MORPHOLOGY. 
 
 found in the embryonic life, and only little scale-like ones at a very late 
 period after germination. 
 
 The different modifications of the form of the embryo and its parts 
 will be treated of subsequently when speaking of the seed. Here it was 
 only dealt with in order to become acquainted with so much of the 
 course of development as appeared necessary to the comprehension and 
 the establishment of what follows. Indeed, it is always dangerous to 
 interfere in the current of organic development and to define the com- 
 mencement. Are we to begin with the egg because the hen originates 
 from it, or with the hen because she lays the egg ? Great circumspection 
 is necessary to arrive at the simplest point of departure, and repetitions 
 are unavoidable, since, in order to completeness, we must make the 
 circle of development return again into itself. 
 
 122. After a variable period of rest, the development of the em- 
 bryo into a plant (germination) commences, upon which it throws 
 off the coats of the seed enclosing it. The same process which ef- 
 fected the perfect formation of the embryo now recommences ; 
 the radicle elongates into the root and forms branches, and the axis 
 elongates in its appointed manner, and at the same time conti- 
 nuously pushes forth leaves. Thus originates the simple Phanero- 
 gamous plant. The axis and leaves, however, gradually assume, 
 through different forms and conditions of position, a different mor- 
 phological import, until their power of development is exhausted 
 by the formation of a new individual, and ceases. From the axis 
 are frequently developed, in a way very different from the forma- 
 tion of the radicle and its ramifications, organs which, on account 
 of their many essential agreements with true roots, we call adven- 
 titious roots (radices adventitice). But the plant seldom or never re- 
 mains simple ; in the angles which the leaves make with the upper 
 internodes, the axils of the leaves, fresh processes of cell-formation 
 originate which form rudimentary axes and leaves, repeating the 
 formation of the embryo, but without radical extremities, and these 
 are collectively called axillary buds. Under certain circumstances, 
 also, new individuals of this kind originate on the axis, scattered 
 buds ; finally every axis, whether it be that of a simple plant, or 
 one which has issued from a bud, naturally terminates in the rudi- 
 ment of an axis, and a number of more or less rudimentary leaves, 
 which are collectively named the terminal bud. Thus we obtain 
 the following survey of the portions of the plant, which must be 
 individually more closely examined : 
 
 A. Radical organs. 
 
 1. The radicle and its development. 2. The adventitious roots. 
 
 13. Axial organs. 
 
 1. The axis and its development. 2. The receptacle, the disc. 
 3. The placenta. 4. The seed bud. 5. The seed. 
 
 C. Foliar organs. 
 
 1. The leaf. 2. The floral envelopes. 3. The stamen. 4. The 
 carpel. 5. The fruit. 
 
PHANEROGAMIA : RADICAL ORGANS. 217 
 
 D. Gemmal organs. 
 
 1. The bud. 2. The horizontal axis. 3. The infloresence. 
 4. The fruit-stalk. 
 
 E. The new individual, the embryo. 
 
 In the following pages I shall alter the arrangement a little, for 
 the sake of convenience. It suffices to have here summarily noted 
 the systematic arrangement deduced from the nature of the plant. 
 
 I know well that it is more to the purpose, enables us to avoid repe- 
 tition, and renders the comprehension more easy, to treat of the plant, at 
 least the essential particulars, according to the established plan : root, 
 stem, leaf, flower, and fruit. But there is an important error in all our 
 manuals, in that the complicated organs like flower and fruit, the de- 
 rived organs like rhizome, inflorescence, &c., are either not at all traced 
 back to the elementary organs, or what their nature may be is mentioned 
 so briefly under each particular head, that any clear survey of the whole 
 plant becomes impossible to the learner. But a correct insight into the 
 nature of the Phanerogamous plant can only be gained by placing the 
 reduction of all the separate parts to the two only kinds of elementary 
 organs, the axis and the lateral bodies, at the commencement of the 
 whole inquiry, so that the reference to these may accompany us into the 
 investigation of each individual part. 
 
 For the rest, the parts distinguished are, perhaps, in some cases mis- 
 takenly separated ; in others, perhaps, the essential differences are not all 
 completely kept asunder, indications enough of which will occur in the 
 subsequent descriptions. I therefore neither consider myself authorised, 
 nor at present able, to carry out a consequent natural division, and to 
 propound the wholly new terminology which this would require ; nor do 
 I believe that, in the present condition of science, any essential improve- 
 ment would be effected by such a step, since so many and so important 
 matters still remain unsettled, and therefore, instead of a fundamental 
 re- formation, a mere piece of patchwork would be the result. Where 
 I think corrections necessary, I will note them under the particular 
 heads. 
 
 A. RADICAL ORGANS, 
 
 a. True Root (Radix). 
 
 123. In germination, the process of cell-formation mostly re- 
 commences in the radicle of the embryo, in such a manner that the 
 outermost layer of cells of the extreme point of the root remains 
 unaltered, while the process of development begins immediately 
 beneath this ; continuous portions of the newly produced cells, 
 subsequently forming no fresh cells, become deposited toward the 
 base of the root, and other portions continue the process of de- 
 velopment immediately under the apex of the radicle, so that the 
 base and the extreme point contain the oldest cells ; the apex be- 
 comes pushed forward, and the youngest, and therefore most 
 delicate, cells are always situated immediately beneath it : in this 
 way the radicle of the embryo is developed into the root of the 
 plant. 
 
218 MORPHOLOGY. 
 
 Epiblema and vascular bundles are formed in the root in the 
 manner already described; the latter are so placed that they pre- 
 sent a closed circle in the cross -section. In Monocotyledons they 
 are closed or definite bundles; in Dicotyledons indefinite. They 
 enclose a minute pith. Liber-bundles, milk-reservoirs, and milk- 
 vessels are sometimes formed in the bark. 
 
 The distinction between main root in the immediate elongation of the 
 radicle, and branches of the root which issue from that subsequently, is 
 the only one morphologically essential ; on the other hand, it is neces- 
 sary, in a physiological point of view, as will be discussed hereafter, to 
 distinguish the simple, newest, and still advancing end, from all other 
 parts of the radical system. 
 
 That every true root has a distinct, even though minute, pith, i. e. 
 a parenchyma enclosed by a circle of vascular bundles, is demonstrated 
 by every longitudinal and transverse section brought beneath the mi- 
 croscope. 
 
 b. Adventitious Root (Radix adventitia). 
 
 124. Adventitious roots are developed, in a peculiar manner, 
 from the axis, either under favouring external conditions (as, for 
 instance, a considerable degree of moisture, artificially as in cuttings, 
 naturally through the weak axis lying upon the ground as in the 
 so-called runners)', or with specific regularity, as in Grasses, 
 plants with aerial roots, &c., and from the true root, but here in 
 perfect regularity. In the bark, close upon the vascular bundles, 
 originates a little conical group of formative cells, which separates 
 quite down to the base of the cone from the surrounding cells, and, 
 taking on the process of growth peculiar to the root, breaks a way 
 for itself through the bark and becomes free. In this act it usually 
 compresses that portion of the cortical parenchyma lying in front 
 of it ; this dies, is torn away, and often remains adherent for a long 
 time upon the apex of the root as a little cap, as, for instance, in 
 Equisetum, Pandanus*, &c. This must not be confounded with 
 the calyptra of the root on the adventitious roots of plants rooting 
 in water, such as Lemna'f, Pistia, &c. 
 
 In most of the tropical Orchidece, in many species of Pothos, the 
 adventitious roots, which may be developed either in the air or in 
 the ground, have a peculiar investment over their true epidermis 
 ( 29.). These appear to deserve a special name, and I call them 
 coated roots (radices velatce). 
 
 When the adventitious roots are produced regularly upon those 
 internodes of a species of plant exposed to the air, they are named 
 (with a superfluous term) aerial roots (radices aerece). 
 
 * According to DeCandolle, Organographie Vegetale, vol. ii. pi. 10. I have never 
 seen it in our hothouses. 
 
 ( Here we have a striking example of how senseless the terminology sometimes is. 
 The roots, hanging perpendicularly down in the water, of the floating Lemna are named 
 radices natantes. One might just as well talk of a swimming anchor, which, with 
 thirty fathoms of cable, does not yet reach the hottom. Such things never happen to 
 plain every-day people, only to a scholar who has wholly destroyed his healthy powers 
 of perception by book-wisdom and an in-door life. 
 
MANEROGAMIA : RADICAL ORGANS. 
 
 219 
 
 All rooting of an axis of a bud, except that of the embryo, 
 occurs by adventitious roots. The region just below the base of a 
 leaf appears to be most inclined to the production of roots. 
 
 In the formation of an adventitious root, a vascular bundle is 
 developed in it, issuing from the vascular bundle of the stem. 
 
 Only in very few manuals do we find a merely indicated, in none 
 a strictly and consequently traced, distinction between roots and adven- 
 titious roots, which are so thoroughly different in their course of develop- 
 ment and morphological import. Theories of the function of the root, 
 Vegetable Systems founded on the structure of the root, endless contests 
 about nutrition, the distinction between Monocotyledons and Dicotyle- 
 dons, &c., in short, a whole literature owes its origin solely to the 
 neglect of this essential distinction. In the Monocotyledons it often 
 readily happens that the adventitious roots are exclusively observed, and 
 this led Richard to divide plants into Endorhizce (with roots which break 
 through from the interior, Monocotyledons), and Exorhizce (the roots of 
 which are formed by the mere elongation of the radicle, Dicotyledons). 
 Dutrochet, who observed the formation of adventitious roots on a Di- 
 cotyledonous rhizome (stem), opposed, at once, that all plants are en- 
 dorhizous. Both are wrong. DeCandolle discovered the cap upon the 
 adventitious roots of Pandanus, and we had directly a great theory 
 about the spongioles (spongiolce radicales\ bodies which have no exist- 
 ence ; and those caps, the cap of the root of aquatic plants and of com- 
 mon root- ends, were all thrown together under this head. Had half the 
 time which has been wasted in the spinning out of such untenable and 
 useless hypotheses been applied to fundamental investigations, in what 
 a different position would Science stand ! 
 
 In most plants of which the radicle does not become developed, for 
 instance, most Grasses, Lemna, &c., the course of formation of adven- 
 titious roots may be traced completely even in the embryo ; more will 
 be said on this point under the head of the seed. For the others, the 
 rhizome of Phragmites communis and Nymphcea alba are to be recom- 
 mended. A peculiar structure, the physiological import of which is 
 still very obscure, the cap of the root (pileorhiza), occurs in the Lem- 
 nacece (fig. 154 156.), Pistiacece, and some other water-plants, e. g. Hy- 
 
 154 
 
 155 
 
 1M Telmatophace gibba. Embryo : a, the seed ; b, the cotyledonary mass ; c, the 
 radical end, with its covercle (embryotega, Gaertner) ; d, the bud breaking forth from 
 the transverse slit of the cotyledon ; e, protuberance which precedes the issue of an 
 adventitious root. 
 
 i55 Longitudinal section of the preceding. In the seed (a) may be distinguished the 
 testa, a thin endosperm, and the cotyledon, in the middle of which runs a vascular 
 bundle, which gives off one twig to the bud (d), and another to the adventitious root 
 (e). In the latter, the cap may be distinguished from the root itself. 
 
 148 T. yibba. The adventitious root from fig. 155. in longitudinal section, strongly 
 
220 MORPHOLOGY. 
 
 drocharis Morsus ranee, according to Meyen. Simultaneously with the 
 origin of the root under the bark (fig. 155. e\ a cellular layer (fig. 156. 
 b\ completely enveloping the little cone constituting the root, quite 
 down to its base, separates wholly from the cortical parenchyma in these 
 plants, still, however, retaining its vitality, and in vital connection with 
 the extreme point of the root ; the cellular tissue of the apex of the root, 
 and that of the cap of the root, always passing into one another here. 
 Under natural conditions, this cap of the root is persistent during the 
 whole life of the root, but if torn off it is never reproduced, and the 
 root dies. 
 
 In some parasites, e. g , in Cuscuta, and also frequently in ffedera, 
 the bark swells out into a disc (sucker, haustoriuni) over the developing 
 adventitious root, and this, originally applied flat upon the foreign body, 
 subsequently becomes concave, from the especial extension of its bor- 
 der, and (exactly as in the sucking-disc of the leech, or the pro-legs of 
 caterpillars) attaches the parasite to the support by a vacuum. From 
 the bottom of this disc springs the adventitious root, which, if it pro- 
 ceeds forward, penetrates the supporting body. 
 
 Comprehensive comparative researches into the anatomical structure 
 of adventitious roots are still a desideratum. The only accurate ones we 
 at present possess are from Mohl * and Mirbel t on the Palms. 
 
 125. The varieties of form in true and adventitious roots are 
 not very manifold, and they depend on their direction, arrangement, 
 as well in regard to the stem as among themselves, preponderating 
 formation of parenchyma in particular places, and formation of 
 wood, through the indefinite vascular bundles of the Dicotyledons. 
 No root is capable of producing buds. In a large portion of the 
 Monocotyledons, especially in the Grasses, and all those in which 
 the seed is furnished with an operculum (see, hereafter, under the 
 head of the Seed), even in some Dicotyledons, for instance, Nelum- 
 bium, the radicle is not all developed in germination. Conse- 
 quently, these have no true root ; in place of this, adventitious roots 
 are immediately formed (see the preceding paragraph). 
 
 All botanists fully agree, that everything developed from the plumule 
 and buds, above the cotyledons (leaves, and the readily distinguishable 
 aerial roots, as they are called, exceptedj, is to be reckoned as part of 
 the ascending axis ; but at one time they counted among roots, the bulb, 
 tuber, rhizome, many- headed root, premorse root, &c., clearly parts which 
 are developed from buds above the cotyledons; or raised an endless con- 
 tention, on manifestly unsustainable ground, as to whether these parts 
 are roots or not : certainly a right substantial proof of what perversities 
 are induced by the neglect of correct method, and the one-sided con- 
 templation of a solitary stage of formation torn from its normal con- 
 nexions. Most of these forms are now correctly disposed of, but a few 
 botanists still hold to a part of the old beaten path. J 
 
 * De Structura Palmarum. Munich, 1831. 
 
 f Nouvelles Notes sur le Cambium, Paris, 1839. 
 
 j Link (Philos. JBotan. edit. 2. vol. i. p. 361.), for instance, still retains the radix 
 
 magnified, a, The root, in which may be distinguished a central vascular bundle, and 
 a thicker bark, b, Layer connected with the apex of the root by persistent cellular 
 tissue, free in the remaining portions. 
 
PHANEROGAMIA : AXIAL ORGANS. 221 
 
 The direction of the root varies very much, often with specific regu- 
 larity ; but most of what was formerly included here belongs to the 
 axis (in the strict sense). One peculiarity is interesting in its relation to 
 the axis. In the germinating embryo the basis of the root soon becomes 
 a fixed point in the soil, the elongatory root proceeding downward 
 from this, through the earth. In rare cases, in loose mud with a firm 
 substratum, on the other hand, the point of the root very soon becomes 
 the relatively fixed point, from which the elongating root gradually lifts 
 the whole plant upward. This may sometimes be observed in solitary 
 bog-plants. From the descriptions, this is probably the cause, depending 
 upon the locality, of the peculiarity of the so-called Mangrove woods on 
 the shores of the rivers of tropical Africa and America. The peculiar root- 
 ing of some Palms, e. g. Areca oleracea, in which a number of adventitious 
 roots, springing out almost on one level from the base of the stem, lift up 
 this base a certain height free from the ground and retain it there, de- 
 pends upon the same cause. The light sandy soil does not give the base 
 of the root hold enough to allow a rapid penetration of the apex into 
 the earth, thence at least part of the elongation only removes its base, and 
 with this also the base of the stem, from the apex, consequently lifts 
 it upward, perhaps till the weight of the stem itself affords a sufficient 
 resistance. One might call it an organic example of the relativeness of 
 all rectilinear motion. 
 
 The arrangement of the branches in relation to each other present 
 manifold variation, which, for the most part, depends on the varied 
 position of the branches upon the main root, and their different amount 
 of development. 
 
 The preponderating development of parenchyma in certain places 
 produces either mere inequalities of the surface, in the simplest cases 
 papillae, the so-called radical hairs (fibrils) in moist, loose soils, or con- 
 siderable expansions above, below, in the middle or throughout the whole 
 length. By the formation of wood, the root of the Dicotyledons comes 
 wholly to resemble the stem ; I will give the necessary explanations 
 thereupon under that head. This one may well enough name with the 
 otherwise wholly useless term caudex. 
 
 B. AXIAL ORGANS. 
 
 a. Of the main Axis (Axis primarius), or the Axis of the simple Plant 
 (of the second Order}. 
 
 126. The axis which is produced from the embryo is called the 
 main axis (axis of the simple plant) ; those produced from buds, 
 secondary axes. 
 
 At the very outset of the consideration of the formation of axes, 
 we must premise that all, according- to the specific peculiarity of the 
 plant, live either during one summer only (one period of vegetation, an 
 annual axis), or have a longer duration (perennial axes). The former 
 I especially distinguish by the term stem (caulis in the strict sense), 
 the latter I call trunk (truncus). The former, again, live only for the 
 
 multiceps and prccmorsa, both true stems, among roots. Trcviranus (Physiologic, vol i. 
 p. 367.) still treats of bulb and tuber among the roots. 
 
222 MORPHOLOGY. 
 
 commencement of the vegetative period ; or only for the end, e. g. 
 the flower-bearing stalk ; or for the whole period of vegetation. 
 
 From the embryonic condition forward, leaves are continuously 
 developed at the apex of the axis, and, with minute differences, 
 always closely succeeding one another, so that there is never more 
 than a very short portion of the axis (internode, internodium) 
 between any two contiguous leaves. But the cells composing 
 this internode frequently continue for a short time to produce new 
 cells, until enough are formed wholly to perfect the structure of 
 the internode by their mere expansion and further development. 
 By this more complete development, the internode then either 
 becomes elongated, and thus removes the adjoining leaves to a 
 greater distance apart, or this does not take place, and thus the 
 leaves remain stationed immediately above one another. On this 
 depends the most important of all morphological distinctions in the 
 axial organs that between axes with developed and undeveloped 
 internodes. Axes exclusively composed of developed internodes 
 occur, indeed, only among the Dicotyledons. In all axes with 
 undeveloped internodes alone, in all Monocotyledons, and many 
 Dicotyledons, matters are so constituted, that each succeeding inter- 
 node, instead of becoming elongated, expands in diameter like a 
 disc, and each always to a somewhat greater extent than the pre- 
 ceding, so that thus a sufficiently broad basis is gradually acquired, 
 upon which the axis subsequently rises upward in a cylindrical form 
 by developed or undeveloped internodes. Under these circumstances, 
 however, the base of the terminal bud also naturally grows, and 
 this becomes a cone, of varying length, and of a varying degree of 
 acuteness. In correspondence with this, the undeveloped inter- 
 nodes are usually hollow cones fitting one over another. But they 
 do occur also as true discs, nay, even as discs with a concavity 
 sufficient to render them cup-shaped. 
 
 These two forms of the axis, with developed and undeveloped 
 internodes, and both according to their different duration, may 
 alternate repeatedly in the length of the same axis (and still more 
 in the various axes of a plant become compound by development of 
 buds). This composition is completely defined and limited by the 
 habit (habitus) in every single species of plant. 
 
 At the place where the leaf joins the axis, the node (nodus), this 
 frequently exhibits a peculiar expansion or contraction, or both, 
 and these, sometimes below, sometimes above, the base of the leaf, 
 or at others in both situations. This is most frequently met with in 
 developed internodes, especially where the base of the leaf occupies 
 the whole circumference of the axis, or where several leaves share 
 this entirely among them. Various conditions of structure correspond 
 to these external appearances, and the nodes are therefore divided 
 into : perfect nodes, where the peculiarity just described occurs ; and 
 imperfect, where it does not exist. 
 
 In rare cases a so-called joint or articulation (articulatio) is 
 formed, through anatomical conditions, in the situation of the node, 
 
PHANEROGAMIA : AXIAL ORGANS. 223 
 
 in such a manner that the axis readily breaks off here with smooth 
 fractured surfaces, or separates spontaneously from the plant at a 
 certain epoch, as in many flower or fruit stalks. 
 
 Moreover, the observation ( 68.) formerly made is to be repeated 
 here, that every part of a plant is capable of development in one, 
 two, or three of the dimensions of space ; therefore, besides the long 
 and slender, and the short, thick, almost globular, axes, there may 
 be flattened, strap-shaped, or foliaceous stems. 
 
 Finally, it must also be remarked here, that there are but very 
 few plants in which the axis is homogeneous throughout, at once in 
 form (as to a certain extent in Lemna, which consists solely of one 
 undeveloped internode) and in duration (the few perfectly annual 
 plants excepted, which form neither transitory internodes in ger- 
 mination nor flower-stalks of brief duration at a later period). 
 Most plants have heterogeneous axes, especially of such kind that 
 internodes of different form succeed each other (as in almost every 
 plant), or that the internodes differ in duration (as in the many 
 plants in which the lower internodes form a trunk, while the upper 
 remain as stem). 
 
 If we would avoid bringing the greatest difficulty into the study of the 
 stem, we must, throughout, very carefully separate the morphology, 
 strictly so called, from the anatomy.* The mere accident, I might say, 
 that the first Palm-stems were at once studied internally as well as ex- 
 ternally, has had much influence in the science. Without any anatomy 
 at all, the trunk of Draccena is essentially distinct from that of Calamus^ 
 and the distinction is exactly of the same hind as that between the 
 trunks of Mammillaria and dEsculus. Whether and what anatomical dif- 
 ferences (besides the general distinction between Mono- and Dicotyledon, 
 which is always premised here) are connected with these essential forms, 
 are questions for subsequent inquiry. 
 
 From the division into annual and perennial, into developed and un- 
 developed, internodes, proceed four forms, of which it is easy to find ex- 
 amples in the vegetable kingdom ; e. g. clearly developed internodes, 
 annual Cannabis, perennial ^Esculus ; clearly undeveloped internodes, 
 annual Myosurus (with the exception of the flower-stalk), perennial 
 Melocactus. It would be equally easy to find examples of the combina- 
 tion of these forms in the same plant, nay, even of all possible combina- 
 tions, which arise if we divide the annual internodes again, as above, into 
 these sections, according to their different duration. The stem of Avena 
 sativa frequently commences with a developed, speedily decaying inter- 
 node ; next follow several undeveloped internodes, becoming successively 
 broader ; then come again developed internodes.f The two last kinds endure 
 
 * As a most striking example of a confusion of ideas, I may here mention that Meyen, 
 in the second division (vol. i. of his Physiology; the first treats of the elementary 
 organs), under the head of " General Comparative Exposition of the Types, according 
 to which the Elementary Organs are combined in the Structure of Plants," treats wholly 
 and solely of the stem ; while, from under such a head, one can only think of the 
 study of tissues, organography, natural system, &c. ; anything, in fact, but what he 
 gives. 
 
 f The same occurs in Hordeum vulgnre. Apparently it depends, in both, on the 
 position of the grain on the surface of the earth, whether the first internode becomes 
 elongated or not. 
 
224 MORPHOLOGY. 
 
 through the whole period of vegetation ; these are succeeded by the de- 
 veloped internodes of the infloresence, only enduring in the latter part of 
 the vegetative period. In Zea Mays, the stem begins with a developed 
 internode, which soon dies ; this is succeeded by undeveloped internodes, 
 then developed, both enduring the whole period of vegetation ; then fol- 
 low again the undeveloped ones of the female inflorescence, only existing in 
 the end of the vegetative period. Chamccdorea Schiedeana begins with 
 undeveloped internodes, then follow developed ; both perennial. Nuphar 
 luteum begins with a developed internode, which soon dies ; then follow 
 undeveloped perennial internodes ; then one developed, appearing as a 
 flower-stalk, merely towards the close of the vegetative period. Lilium 
 candidum begins with undeveloped internodes which are perennial ; 
 then follow annual, developed internodes, &c. These examples might be 
 easily multiplied and completed. Some forms are characteristic of certain 
 groups of plants ; for instance, trunks with developed internodes in the 
 Cupuliferce, trunks with developed internodes in the fistular Palms, with 
 undeveloped internodes in the remaining kinds, stem with developed in- 
 ternodes in most of the Grasses, &c. Certain combinations are also cha- 
 racteristic ; for instance, perennial undeveloped, with annual developed 
 internodes, in all (?) Liliacece. But definite forms and combinations are 
 much more frequently found peculiar to single genera or species. Hitherto, 
 far too little regard has been paid to this condition of special regular se- 
 ries of developed and undeveloped internodes in the same axis. The 
 remarkable peculiarity of many genera and species, which, in germi- 
 nation, first form a developed internode, soon decaying again, and suc- 
 ceeded by undeveloped ones, has, in particular, been wholly overlooked. 
 Very different plants furnish examples of this : Zea Mays, Briza max- 
 ima, Phormium tenax, Nymphcea, Nuphar, &c., and at least very fre- 
 quently Avena sativa, and Hordeum vulgare. In the axis with unde- 
 veloped internodes, frequently, and the oftener when it has commenced 
 by a developed internode, the death of the single joints progresses gra- 
 dually upward, so that the axis, even when perennial, never attains any 
 considerable length; e.g. in Iris, bulbous plants, and most subterraneous 
 axes (rhizomd) with undeveloped internodes. 
 
 Here, however, I must enter somewhat more minutely into the course 
 of development of these forms of the axis. It has already been men- 
 tioned ( 74.) how every form must be produced solely from the ar- 
 rangement of the newly developed cells and their subsequent expansion. 
 On this depends all structure of axes. In the embryo, the upper end, 
 from which the axis is developed (the terminal bud), more or less resem- 
 bles a hemisphere, or a blunt cone. In this part chiefly goes on the 
 formation of new structure, and it always retains its general form. In 
 the axes with undeveloped internodes only, if they expand very much in 
 breadth, does it naturally acquire a larger base, and then becomes, ac- 
 cording to its specific peculiarity, either shorter and more blunt (as in 
 most subterraneous axes), or longer and more acute. The process of 
 formation which here takes place has not, indeed, by any means been 
 so accurately investigated as is necessary ; but still much may be per- 
 ceived with tolerable clearness. An eye only moderately accustomed to 
 such matters readily discovers in a plant the situations where an active 
 process of cell-formation is going on, in the apparently structureless 
 condition of the yellowish, almost fluid masses (first stage) , the situa- 
 tions where the cell-formation has ceased, in the distinct, indeed, but 
 very delicate, cellular tissue (with more homogeneous contents), which 
 
PHANEROGAMIA : AXIAL ORGANS. 225 
 
 however are still wholly pervaded by sap (second stage) ; lastly, the 
 cellular tissue, which has already attained a greater age, in the black- 
 ish appearance which is produced by the intercellular passages being 
 freed from sap, and containing merely air (third stage). When these 
 points are discriminated, the origin of the forms may be traced pretty 
 easily in most axes. 
 
 I. The arrangement of the cellular tissue is effected exclusively in the 
 first stage, and, in all probability, is conditioned: 
 
 1 . By the arrangement of the secondary cells in the mother-cells. If 
 they mostly lie in a linear arrangement in the long axis of the stem, an 
 elongated internode originates ; if they lie mostly towards the angles of a 
 tetraedron, an undeveloped internode ; lastly, if they lie chiefly in one 
 plane, this plane may stand at right angles to the axis, and the inter- 
 nodes will be much developed in breadth, or, it may be parallel to the 
 axis, and thus form a stem flattened on two sides. 
 
 2. By the form of the process itself, since this ceases in some situa- 
 tions earlier than in others. 
 
 A. The first distinction to be seized here is that between Monocotyledons 
 and Dicotyledons in general, depending on the division into definite and in- 
 definite, or closed and unlimited, bundles. In the Dicotyledons the process of 
 cell-formation never ceases on the outside of the vascular bundle, whence 
 the individual internodes, so long as they live, continually increase in 
 thickness ; while in the Monocotyledons the process of cell-formation 1. 
 ceases regularly from below upward, in the individual vascular bundles, 
 and thus a thickening of the individual internode by their means becomes 
 impossible ; but the increase of thickness of the axis itself may be 
 attained by the increasing diameter of the successive internodes (as is 
 shown more fully under Z>), and thence, when it rises perpendicularly 
 in a cylindrical form (if it be such as is represented under JB, or under 
 D\ it receives no increase of thickness from that time: or 2. a layer 
 of cells beneath the periphery of the axis retains its capacity of develop- 
 ment, and these continually increase the thickness of the axis by their 
 uninterrupted production of new cells, since in the newly-formed tissue 
 vascular bundles are simultaneously continually developed. This pro- 
 cess occurs, however, only in the Monocotyledons with undeveloped 
 internodes of a branching type, in Draccena, some Palms (Cucifera 
 thebaica\ and Aloinete. This second process of formation bears some 
 resemblance to that of the Dicotyledons, in so far that in both a connected 
 layer of cells remains capable of development around the whole periphery. 
 In both, the newly originating cells assume two forms, one portion join- 
 ing the cellular tissue between the vascular bundles, while another 
 portion belongs to the vascular bundle structure. But the essential dis- 
 tinction remains in this, that this latter portion only increases the 
 existing vascular bundles on the .outside in the Dicotyledons, while in 
 the Monocotyledons, on the contrary, it becomes transformed into new 
 isolated bundles. 
 
 B. If the process of formation progresses regularly from below up- 
 wards, while a definite plane of the basis ceases to produce cells, a cy- 
 lindrical ascending axis is produced. In elongated internodes this is 
 always the case ; therefore every internode may be clearly separated 
 from the axis by two cuts. 
 
 C. If the process of cell-formation ceases somewhat earlier in par- 
 ticular situations in the circumference than in others, the result is 
 the formation of axes with projecting angles ; for instance, three-edged, 
 
 Q 
 
226 MORPHOLOGY. 
 
 quadrangular, &c., stems. This condition is most striking when the process 
 of formation ceases very soon on two sides, so that a two-edged stem 
 is thus formed, which very often represents quite a thin plate, and is 
 frequently taken for a leaf, on account of the mistaken notion of regarding 
 the conditions of dimension in space as among the characters of special 
 organs. The best examples are afforded by Ruscus and Phyllanthus. 
 
 D. If it endures longer at the circumference than in the middle, 
 the following results present themselves. In the usual conical form of 
 the terminal bud, the process of cell-formation does not in this case occur 
 throughout the whole cone, but only in its outer layers, so that the 
 whole free surface of the cone contains the youngest cells : the whole of 
 the core of the cone is made up of the older. Here the axis usually rises 
 upward in a cylindrical form, not, however, by means of discs equally 
 deposited upon one another (as in A\ but by hollow cones applied over 
 each other. Every new internode is itself a hollow cone of this kind, and 
 therefore cannot be detached from the axis by a vertical section ; it can 
 only be removed by a section following the course of a conical surface. If 
 the process of cell-formation persists somewhat longer in the succeeding 
 internode than in the preceding, a longer hollow cone is produced, which, 
 consequently, stretches out over the base of the former, which should 
 properly be free ; and thus the new internode becomes broader in pro- 
 portion to the former, so much so, that the free borders of the successive 
 internodes, instead of lying in a vertical cylindrical surface, form a hori- 
 zontal surface (e. g. very often to be observed in Melocactus\ or, in 
 smaller degrees of projection, lie in a hemispherical surface, having its 
 convexity directed downwards (as, for instance, is seen in most stems 
 which are tolerably thick and enduring, in the first or next succeeding 
 internodes, e. g. in Zea Mays, &c.). 
 
 E. Finally, the forms become most striking where the cell-formation 
 ceases at the border earlier than in the centre ; directly the opposite of 
 what occurs in D. This seldom happens in a single internode ; it is usually 
 found where several very short, undeveloped ones, united together, form 
 but a mere disc. When, for example, a disc or a bluntish cone has 
 originally been formed, and the extreme margin loses the power of de- 
 velopment, while the newly forming cells in the middle continue to ar- 
 range themselves into a flattened form, the border will at first be capable 
 of yielding to some extent by the expansion of its cells ; but this soon 
 ceases, and it must become elevated, while the centre gradually developes 
 itself, into a hollow form, in the same way as a plate of lead becomes* 
 hollow when it is beaten out in the middle, and not at the edges. Ac- 
 cording as the time the process of cell -formation lasts, proceeds quickly 
 or slowly, and according as the arrangement of the newly produced cells 
 is restricted a longer or shorter time to the same plane, does the exca- 
 vated form become very different. From the quite convex internodes 
 which bear the florets in Anthemis, through the flat disc of ffelianthus, 
 the concave disc ofDorstenia, to the longish cup-shaped disk, almost closed 
 above, of Ficus, we meet with almost every possible gradation ; in like 
 manner we see the same from the convex fruit-bearing internodes of Po- 
 tentilla, through the cup-form in Rosa, to those completely closed and 
 blended with the ovaries in Mains and Pyrus. So that it may be clearly 
 seen, and I here call particular attention to the fact, that, in all these 
 hollow forms, the deepest point in the interior of the cavity corresponds 
 to the terminal shoot ; consequently it lies indeed mathematically lower, 
 but organically higher, on the axis than the internal walls of the cavity 
 
PIIANEROGAMIA : AXIAL ORGANS. 227 
 
 and the margin ; thus the lowest flowers in the Fig are the youngest, 
 like the innermost in Helianthus, the uppermost in Anthemis : equally 
 are the lowest carpels in the fruit of the Rose the youngest foliar-organs ; 
 the petals and calyx standing on the margin, the oldest. In the same 
 way, lastly, the lowest carpels in the Pomegranate stand organically higher 
 on the axis than the upper and larger carpels. One must not let the 
 contradiction between the geometrical definitions of space and the organic 
 relations lead us into error ; but get a clear apprehension of this pecu- 
 liarity. Only too readily are many authors to be noticed to whom this 
 relation has never become clear ; and thus, much else in the inflores- 
 cence and structure of blossoms remains to them obscure, and as a strange 
 peculiarity, which a more correct apprehension renders very simple and 
 natural. I shall have to enter more specially into this hereafter, when 
 speaking of the blossom. This condition occurs, indeed, most strikingly 
 in the internodes in the vicinity of the floral organs, but by no means 
 exclusively, for it appears also earlier, as in Melocactus, JSchinocactus, 
 Mammillaria, &c., where the end of the axis exhibits an infundibuliform, 
 or a cup-like form, and the terminal bud stands at the bottom of it, much 
 lower than the ten or more preceding internodes. 
 
 II. In the second stage above distinguished, the equal expansion, in 
 all directions, of the cells formed in the preceding stage, can alone act, 
 since, still wholly imbued with moisture, the cells must be nourished 
 tolerably equally on all sides. In this period, therefore, the volume may 
 indeed alter, but not the form or relation. 
 
 III. In the third stage, lastly, the expansion of the existing cells is 
 exclusively for the purpose of giving form. For the most part, indeed, 
 expansion of the cells according to their kind is conditioned by the 
 first formation in the first stage ( 78.), since the cells become most 
 intimately united in the directions in which they were in contact in the 
 mother-cell ; therefore, in other directions they are more loosely connected 
 and afford less facility to the passage of sap, and consequently to nu- 
 trition. Certainly, so far as our yet imperfect observations reach, it is 
 especially only the elongation of cells in the direction of the axis which 
 essentially conditions and produces the form of the developed internodes ; 
 especially, therefore, do we find it connected with the conditions men- 
 tioned in A as existing in the first stage. If we measure the length of 
 the cells in an internode (e. g., in Arundo Donax) which has just en- 
 tered the third stage, and afterwards the length of the cells in a full- 
 grown internode, we find at once that the expansion of the cells is quite 
 sufficient to account for the elongation of the whole internode. Since, 
 however, the cells enlarge unequally, we must only measure those in the 
 middle ; the result would be two small in the upper cells, and two great 
 in the lower. The former expand less, and cease sooner ; the latter, on 
 the contrary, elongate more powerfully, and continue for a longer time to 
 enlarge in the direction of their length : hence the so unfounded notion 
 of many, that the internodes grow lor a longer time at the lower end 
 than at the upper. 
 
 All that is brought forward and enlarged upon in these paragraphs 
 relates, of course, principally to the formation of the axis of the simple 
 plants (of the second order), in which all the conditions described can 
 actually occur in nature ; it has also its application to those simple plants 
 which originate as buds upon another, whether these become detached 
 and continue to grow, or, remaining, form a compound plant with that on 
 which they have been produced. Here again it is seen, that, as in the 
 
 Q 2 
 
228 MORPHOLOGY. 
 
 simple plant, every single internode is capable of development indepen-. 
 dently into a special form ; still more, the axes of the simple plants, in 
 their combination into a compound plant, are independent of one another, 
 and may assume wholly distinct forms, the combinations of which again 
 are then specifically definite for plants and groups of plants. 
 
 In all this exposition, moreover, I would and could give nothing 
 further than a general indication as to the course which nature here ap- 
 pears to take. Manifold as the researches on this point I have made are, 
 and I believe they have been sufficient, provisionally, to justify what I 
 have here published, yet must far more comprehensive and fundamental 
 investigations be entered upon on this subject before the study of it can 
 be brought at all to a conclusion. At present I know not of a single at 
 all profound history of the course of development, even of any one stem ; 
 and hence it may readily be imagined how insufficient that must be which 
 I alone have been able to work out in reference to this point. I have, 
 however, indicated the necessary course of the investigation, and correctly 
 exposed the question ; the future alone can solve it, by the co-operation 
 of many skilful powers. 
 
 History and Criticism. As, in the foregoing, has been mentioned and 
 too often indicated, the whole study of the stem suffers from the same 
 errors as the other parts of Botany. The word stem has only an abstract 
 meaning to most botanists, and thus is altogether useless in a scientific 
 point of view. Here, as everywhere else, there is a want of accurate 
 definition of ideas, because guiding rules for, and scientific regulation of, 
 the process of definition are absent. Without a history of the course of 
 development, and a definition of the conceptions obtained from this, we 
 remain in this case, as in every other, without any fixed point, and can- 
 not get beyond empty talking. One of the old school, for instance, says 
 the stem (stirps) is divided into stock (caudex), trunk (trunctts), stalk 
 (caulis). Rush-halm (calamus\ culm or haulm (culmus), scape (scapus), 
 &c. When we divide in science, two things must be observed : first, 
 that we divide according to one principle ; secondly, that this principle 
 be selected with reference to a purpose. The latter is to be determined 
 inductively ; the former is a purely logical inquiry, and its neglect a 
 wholly inexcusable logical blunder. In this point, those common sub- 
 divisions are in the highest degree bad ; they have no regulating principle 
 whatever, and are quite as senseless and unscientific as the subdivision of 
 vegetables in general into grasses, trees, roses, yellow flowers, green 
 stalks, and plants. I should like to see, for instance, how the stalk (caulis) 
 is to be distinguished from the culm (culmus) of grasses without anatomy, 
 or, on the contrary, what anatomical characters one could find to distinguish 
 the scapus of Hemerocallis from the caulis of Lilium candidum. It is 
 quite a ridiculous misconception to treat of the scapus under the head of 
 steins, since the sole character we can find for it is that of bearing 
 flowers, consequently it is properly a flower-stalk or an inflorescence : 
 under these circumstances, then, it belongs to the inflorescence and not to 
 the stem ; spadix would be j ust as much a form of stem as scapus, 
 calathium, &c. 
 
 With regard to the second point, I have already expressed and brought 
 forward proofs of my views, that in Botany we must unreservedly main- 
 tain the morphological principle as the highest. Therefore, we must 
 derive the subdivision from this in the first place, and once more the 
 course of development may alone be our guide.* 
 
 * Thus do we properly obtain the summary : Phanerogamia. A, Monocotyledons. 
 
PHANEROGAMIA : AXIAL ORGANS. 229 
 
 The mode of speaking in question is altogether without scientific 
 ground in another aspect. Calamus, culmus, scapus, &c., are quite 
 isolated phenomena, occurring in certain plants, isolated groups, some- 
 times not in the whole of the group, and therefore they do not belong to 
 general Botany, but merely to quite special parts of it. The Grasses 
 have special forms of stem just like most other families, and it is merely 
 a proof of logical confusion when a part of these forms are treated as 
 something general in general Botany, which, if (as, however, has never 
 happened) they are not designated as Monocotyledonous stems, have no 
 marks of distinction from many other forms, nor even as Monocotyle- 
 donous, if, for instance, we place together the stem of Mays and Trades- 
 cantia. General Botany has nothing to do with all these peculiarities, 
 and to treat them here, instead of directing attention to the fundamental 
 laws of the development of form, is but a certain means of wholly con- 
 fusing the learner, and giving him a barren host of words under the 
 name of science. 
 
 Hence arise the many wholly fruitless contests, with which time and 
 paper are wasted, as to whether a thing is calamus, scapus, &c. I am 
 inclined to look upon those who would wish to distinguish them as if 
 they said : calamus is the scapus on the Cyperacece, &c. Every dis- 
 cussion, without strictly scientifically defined conceptions, remains ever a 
 useless bandying of words, necessarily devoid of results. Just one example 
 may be brought forward here. Link * says : " The main stock (caudex) 
 consists of parts growing upwards, which are called trunk and stem ; and 
 of parts growing downwards, the roots. The main trunk is that de- 
 veloping from the embryo ; those which are developed from the buds are 
 exactly like this, are called branches, and also grow upwards. Flowering 
 stalks are branches, f The trunk grows upwards after it has taken root, 
 since originally the germ grows downward J, sends out roots , then it 
 directs its other extremity upwards and grows in that direction, having 
 grown downward previously." || Next come definitions of the ramification 
 of the trunk. " The direction of the ascending trunk is at first vertical, 
 but it not unfrequently takes another direction afterwards." Different 
 directions of the trunk and branches : " The length of the true \. trunk is 
 
 Structure, closed (or definite) vascular bundles. Axes : a, with undeveloped internodes, 
 1, 2, and the rest of the varieties; 6, with developed internodes, 1, 2, &c. varieties. 
 H, Dicotyledons. Structure, unlimited vascular bundles. Axes: a, with undeveloped 
 internodes, 1, 2, &c. varieties; b, with developed internodes, 1, 2, &c. For the sake of 
 convenience, I have here united Monocotyledons and Dicotyledons in the consideration 
 of single organs ; and thus arises, but only apparently, the inconsequence that the 
 division of the axes, according to closed or unlimited vascular bundles, appears to be 
 more general and distinct than the morphological ; but, as I say, it is only apparent, 
 since the closed and unlimited vascular bundles give no principle of distinction at all 
 for axial structures, but a distinction in the structure of the entire groups of plants. I 
 mention this expressly here to avoid the accusation of inconsequence. 
 
 * Elem. Phil. Bot. ed. 2. vol. i. pp. 53. 221, et seq. 
 
 f What, then, is the branch of the Weeping Ash ? what the horizontal rhizoma ? what 
 are runners ? what the flowering stalks of Arachis hypogcea, &c. ? None of which grow 
 upward. 
 
 { Untrue : only the root, not the germ. 
 
 Untrue : most embryos have already a distinct root, which merely elongates. 
 
 || Untrue ; since what grew downward (the root) never grows upward, and what 
 grows upward has never grown downward. 
 
 4- Apparently only inserted to substantiate the meaningless statement which succeeds, 
 since there is nothing about a division into true and false fitems in the whole book, 
 lie-sides, it directly contradicts what goes In-fore; since the piimary trunk of the em- 
 
 ^ 3 
 
230 MORPHOLOGY. 
 
 at the same time its height, since the long prostrate trunk of Calamus 
 Rotang is a runner. * The tall Palms have a cauloma. f The stem of 
 the Grasses originates in a different manner from that of the other Mono- 
 cotyledons. The germ (keim, this is the name Link gives the cotyledon) 
 is wholly wanting, or a scutellum J appears in its place, which, without 
 bud (! !), passes directly into the stem, which sends out roots below and 
 grows upward above. I should wish to retain the name ' halm ' solely 
 in reference to the following. The thick stem of Mays is very peculiar, 
 proceeding, as out of a bud, from the apex of a stem exactly like the 
 former, between the leaves. I would wish to call the upper stem halm || , 
 did this not differ so much from the customary language, therefore I 
 rather give this name to the former. This stem has a two-fold analogy 
 with the stem and with the germ (cotyledon) of the other Monocotyle- 
 dons." J. Later on (page 301.) follow the so-called anamorphoses of the 
 trunk. ^[ " The cauloma (palm-stem) occurs only in the Monocotyledons, 
 and originates from leaves, which emerge one out of the other, and, in 
 fact, from their sheaths. ** Merely a slender (! !) filament of stem unites 
 these leaves ff. The number of leaves increases unceasingly, and thus the 
 cauloma !J;| acquires increased thickness. But then that slender stem 
 grows larger, since new parenchyma is formed, and in this new ligneous 
 bundles. Thus the cauloma does not become thickened upward j| ||, but 
 retains exactly the same diameter ; nay, the lower portion is not un- 
 frequently thinner than the upper, on account of the withering leaf- 
 sheathes. J4 The cauloma grows slowly, and plants which have it remain 
 
 bryo is certainly a true stem, and yet may be prostrate : in the twining stem the length 
 and height are different. 
 
 * Whence does Link know this? To me it is very probable that this is the primary 
 axis. 
 
 f Is not that a stem ? No one has taken it for anything else yet. 
 
 \ This scutellum is identical, in every respect, with the cotyledon in its development, 
 and is never wanting in the Grasses. 
 
 Has Link ever beheld one single embryo of a grass and its bud which is distinctly 
 separated from the scutellum ? 
 
 || Why, is not evident. 
 
 4 If the germination of the oat be compared with that of maize, no distinction at all 
 can be observed. The cotyledon (scutellum) does not become elongated : the large 
 bud comes forth, in both, from the slit in the cotyledon ; originally forms a developed 
 internode ; next some undeveloped, and then developed internodes ; in short, there does 
 not exist the slightest distinction when one examines accurately. If the germination of 
 AUium and Avena be compared, one cotyledon will be found in both, and in both this 
 encloses a formed bud, below a little slit. In AUium the cells of the cotyledon become 
 elongated, so that the root, stem, and bud are removed somewhat from the seed ; in 
 Avena not : this is the sole distinction. But people must look into things. 
 
 H" An expression equally superfluous and misapplied ; for conditions of structure and 
 differences of form are thrown together under it without distinction. 
 
 ** Either false, or meaning nothing. The leaves never come out of leaves, but out 
 of the stem. But in the Grasses, also, and in all plants with sheathing leaves, one leaf 
 surrounds another. 
 
 If Has Link ever seen a single Palm germinate, or examined a section through the 
 active terminal bud of a Yucca or a Palm ? 
 
 J j: The trunk of Palms and of Yucca never increase in thickness when once a sufficient 
 base has been formed, but ascend vertically upward : the leaves originate on the thick, 
 homogeneous, undivided mass of the rudimentary portion of stem in the terminal bud. 
 
 This is diametrically opposed to the truth. Neither parenchyma nor vascular 
 bundles ever grow, in unbranched Palm-stems, after they have passed out of the con- 
 dition of bud. 
 
 |||| A direct contradiction of the statement a few lines before. 
 
 J.J. This has no meaning whatever. If the cauloma, as such, is thicker above than 
 below, it must have increased in size upward ; if, hoAvever, it means that the cylin- 
 
PIIANEUOGAMTA : AXIAL ORGANS. 231 
 
 a long while devoid of stem ; sometimes they never acquire one.* The 
 Duckweeds have a very short cauloma, which grows out into a stem." f 
 Next comes a third anamorphosis, the corm ! The bulb is to be reckoned 
 with this. J Fourth anamorphosis, the rhizome. " From the base of the 
 trunk, under ground, stems often come out which grow downward from 
 the first" &c. 
 
 What are all these anamorphoses ? Are they stems, or not ? If they 
 originate from stems, what forms of stem precede them ? What is the 
 common character of the stem and its anamorphoses ? what is its universal 
 distinctive mark ? To all the questions which immediately crowd into 
 every even half-logical head, not one answer is to be found. But I think 
 I have given enough of this. Superficial treatment of imperfectly 
 observed facts characterises the whole of this exposition. Moreover, 
 there are very many botanical manuals in which all is still more illogical 
 and unscientific than here, and this may suffice for a general criticism of 
 the whole existing literature of the stem. 
 
 No one has hitherto sought to elucidate the structure of the axis from 
 its course of development ; but, instead of this, space has been given to 
 the strangest fancies, and it has even been asserted that the stem is 
 nothing but a number of petioles grown together. One may, indeed, 
 calmly declare that the people who assert such a thing do not understand 
 themselves ; since, otherwise, they would see that when they assert a 
 blending together, they must point out, that is, demonstrate, how two 
 separate parts become united by the process of growth, while they have 
 not yet made one single search for such, the only possible demonstration. 
 The investigation would clearly at once refute the affair. A portion of 
 these men might readily come to their senses if they were only to trace 
 one complete course of development. There is another portion, how- 
 ever, whom this will not render capable of clear vision. These are the 
 people who think that they are able to make the forms with their words, 
 instead of receiving them from nature. They do not suspect that 
 natural history definitions, as a rule, are not artificially pieced together, 
 but discovered inductively ; and they feel themselves very clever when 
 they can assert that the stem, which has always been an undivided 
 whole, can still be regarded as compounded of petioles, although such is 
 not the case. To this class Gaudichaud || appears to belong, whose so- 
 
 drical cauloma is thicker with the leaves on than without them, it is a superfluous 
 triviality. 
 
 * Above it is said, " The stem is never wanting." Here, however, is meant merely 
 that they never acquire a long stem, which is also the case in other plants without a 
 cauloma. 
 
 f I am unable even to form an idea of what similarity Link finds between a Palm- 
 stem and a Duckweed. The latter never has any stem formed. The whole plant con- 
 sists of one single internode, and there is no terminal bud to this. 
 
 \ If Link had only observed with some attention the development of the stem of 
 Allium angulosum or senescens from germination forward, he would have seen that there 
 is not the slightest difference between it and the so-called cauloma of Yucca, leaving 
 out of view variation of mass. In Palms and the species of Allium the lowest internodes 
 die gradually ; in the Palms only for a period ; in the bulbs uninterruptedly, otherwise 
 every bulb would become a Palm-stem. Link has recently, also, brought forward all 
 this again as original wisdom in an otherwise worthless essay, without recollecting his 
 former absurdities, and the correct views of others which already existed. 
 
 Above it is said all stems and all branches, at least at first, grow upward ; nay, 
 therein lay the solitary character of the stem. 
 
 || Gaudichaud, Recherches sur I'Organographie, la Physiologic, et 1'Organogenie 
 des Vegetaux. Paris, 1841. Beyond all description, superficial and frivolous. (See my 
 review in the new Jena Lit. Zeit. 1842.) 
 
 Q 4 
 
232 MORPHOLOGY. 
 
 called new theory amounts to the harmless joke, that in future we are 
 not to call the plant a plant, but a leaf; the leaf not leaf, but foliar-part 
 leaf; the stem not stem, but stem- part leaf ; and so on. I think we 
 ought not to interfere with anybody's pleasures ; but this is not science. 
 Finally, we have a third class of naturalists, with whom there is no 
 contending, who appear to have chosen their motto from St. Augustine : 
 " Credo quia absurdum est" These look down with a shrug upon the 
 poor empiric who sees no more in things than his senses, his logical 
 intellect, and his healthy reason show him. They argue thus : Just 
 because the impression shows us the stem first and the leaf afterwards, 
 it must be directly the opposite in the spiritual perception, which is 
 directly opposed to the dim-eyed and rude perception of sense. These are 
 the people who have bestowed upon us the nonsense of ideal abortions, 
 and ideal blendings of parts, &c. There is no contending with them, 
 because they recognise no conformity to law in our intellectual powers, 
 consequently no deciding rules and no forum, 
 
 b. Varieties of Direction. 
 
 127. In germination, every axis of the simple plant (of the 
 second order) developes straight upward from the ground on which 
 it grows, so that a line which connects the extremities at the ter- 
 minal bud and the radicle, describes a straight, or almost straight, 
 line perpendicular to the plane of the soil, consequently, in most 
 cases, to the surface of the horizon. The plants which germinate 
 floating in water only apparently deviate from this law, because 
 no fixed point is afforded them, in the fluid medium, on which they 
 can erect themselves; therefore they develope horizontally (float- 
 ing) even from the beginning. But this vertical direction only 
 remains law for the further development of the axis when the 
 latter has acquired, in proportion to its mass, a broad enough base, 
 depending upon the mode of development of the lowest internodes, 
 a secure attachment in the soil, depending on the requisite deve- 
 lopment of true or adventitious roots, and, lastly, a sufficient 
 rigidity depending on the conditions of structure. The extreme 
 and incessantly developing apex alone retains, throughout, the 
 tendency to grow upward. Here, also, the conditions often alter- 
 nate in the length of one and the same axis, according to specific 
 peculiarities. For instance, the straight commencement is fol- 
 lowed by some weaker internodes, then again by stronger which 
 rise upward (caulis adscendens), or several stiff internodes are suc- 
 ceeded at the end by some lax ones (caulis nutans). In rare cases 
 the originally vertical but weak internode is followed by firm 
 tough ones, which grow forth always flat upon the ground, as, 
 for instance, in Nymphcea, the axis of which never rises from the 
 soil. Moreover, the axis in the course of its formation either 
 grows out straight, or has a peculiar tendency to twine, whereby 
 it appears to be twisted round its own axis when it grows free ; or 
 if in contact with a slender firm object, it twines spirally round 
 this, and obeys specific laws as a left or right rolled spiral. Lastly 
 
PHANEROGAMIA : AXIAL ORGANS. 233 
 
 must be noticed that relation between two succeeding internodes 
 where they do not lie in a straight line, but form with one another 
 an angle which is often definite (caulis geniculatus}. Very often 
 the main axis, from being made up of undeveloped internodes 
 alone, which gradually die from below upward, remains always 
 under ground as an underground stem or trunk (caulis, truncus 
 hypog&us). 
 
 It is wholly false to ascribe universally to nascent plants, a direction 
 absolutely vertical to the earth. As the germination of Viscum on the 
 side or under surface of a branch proves, the direction of the plant in 
 general stands in no relation at all to the direction of gravity of the 
 earth. The axis of every plant originally grows in a straight line away 
 from the level of the soil in which it is fixed, and properly never alters 
 this direction ; but the internodes already formed often take another 
 position, from the causes mentioned in the paragraph above. More 
 remains to be said about this hereafter, under the head of Germination. 
 
 The causes of the spiral twisting of the axis round itself, or round a 
 foreign object, as well as of the knee-like bending of the nodes, are alto- 
 gether unknown. "We have from Mohl* an excellent treatise on the 
 point ; but he was not able to discover the cause. I will here very 
 briefly discuss the terms right and left wound stem, in regard to which 
 much confusion prevails. The natural conception is this : The plant is 
 developed from below upward, consequently it ascends ; if, now, we use 
 the expressions left and right concerning the plant, this can only have a 
 meaning when we place ourselves in its position ; but we turn to the 
 left in ascending if we have the axis of revolution to the left, to the 
 right if we have it to the right. If we refer it to the course of the sun, 
 we can evidently, in regard to our northern hemisphere, only bring the 
 southern half of each revolution turned toward the sun into relation 
 with its course, and then the right wound spiral would go with the sun, 
 the left wound against it. Linnaeus f strangely used these terms in the 
 opposite way, evidently starting from an obscure conception ; and many 
 others have followed him therein. Many have quite reversed the thing, 
 called left right, and right left, till the whole matter had become con- 
 fused. The reference to the course of the sun is moreover a very im- 
 perfect mark. It appears to me, however, that left and right wound 
 cannot well be understood in any other way than that which I have 
 given. 
 
 In conclusion I will add, that all the peculiarities here mentioned are 
 equally shared by the axes originating from buds. In reference to the 
 first point, it must be recollected that the bud is a plant, the base of 
 which is limited from the very origin ; that consequently the primary 
 and natural direction of its growth is in a line perpendicular to the plane 
 passing through its base. Sometimes, but not often, this direction be- 
 comes changed in the subsequent internodes into one parallel with the 
 main axis. 
 
 c. Of the secondary Axis. 
 
 128. Buds may originate in the axil of every leaf (axillary 
 buds), or, under favourable circumstances, at any point on a woody 
 
 * Von den Rzinken uncl <loin Winden der Sclilingpflanzcn. 
 f Philosopliia Botanica, ed. 2. Gluditsch, p. 39. 
 
234 MORPHOLOGY. 
 
 trunk (adventitious buds) ; from these, as from the embryo, pro- 
 ceed perfect plants with axis and leaves, but, by reason of their 
 origin, without radicle extremity ; therefore, if they become inde- 
 pendent, they become possessed exclusively of adventitious roots. 
 Connected with the main axis these are called secondary axes ; 
 when annual, twigs or shoots ; when perennial, branches ; and the 
 kind of combination in general, the ramification of the plant.* 
 There are very few perfectly simple plants (of the second order) ; 
 most are compound, at least in this way, that their buds produce 
 flowers ; but as every inflorescence arrests the further development 
 of the axis, we may call those plants simple the axillary buds of 
 which are exclusively flowers. The mode of ramification is the 
 chief characteristic of the peculiar physiognomy of the whole plant 
 (the habit, habitus). There is no regularity in the adventitious 
 buds ; but the position of the axillary buds is conditioned by the 
 position of the leaves, and follows at once from this when all the 
 buds are uniformly developed. But this does not often take place, 
 since regularly appointed buds either remain wholly undeveloped, 
 or form only transitory flowers, and thus are the same as unde- 
 veloped buds, at least to perennial plants. Thus in Lemna no 
 terminal bud is formed, but only two lateral buds ; these usually 
 soon divide from the parent plant, and become developed in the 
 same manner, and so on. Viscum album forms a flower- bud in 
 every terminal bud ; and as the leaves, and therefore the buds, 
 stand in pairs upon the axis, the stem appears to be repeatedly 
 bifurcated. In very many, especially of the perennial, Monoco- 
 tyledons, it is regular for no axillary buds, except those growing 
 into inflorescence, to come to perfection ; thus, in most Palm- 
 stems, and the so-called arborescent Liliacece, Yucca, Aletris, &c. 
 The same occurs in some Dicotyledons, e. g., Carica, Tkeophrasta. 
 Further, the varying rapidity and force of development determines 
 peculiar forms. If the main axis is developed little or not at all, 
 in proportion to the secondary axes, the so-called caulis deliquescens, 
 the vanishing stem, is formed (as in Prunus spinosa) ; if all the 
 secondary axes are developed with proportionately equal force with 
 the main axis, the plant exhibits commonly a very long, ovate 
 shape (axis ramosus), as in the Lombardy Poplar; if the lower 
 branches are developed more quickly than the upper, so that all 
 the points lie in one plane, the fastigiate plant (axis fastigiatus) 
 results, and so forth. But the especially important point, as cha- 
 racteristic of the landscape, is the death of all the lower branches 
 in perennial plants, whereby is effected the so characteristic sepa- 
 ration of the tree into trunk and crown, or simple and ramified 
 axis. 
 
 Finally, I have to mention here that the main axis very often 
 dies soon after it has become developed out of the embryonal con- 
 
 * Inflorescence and fructification are really quite the same, namely, ramifications ; 
 inasmuch as the terminal shoots or twigs bear flowers, &c. 
 
PIIANEROGAMIA : AXIAL ORGANS. 235 
 
 dition, while one or more of the lowest lateral buds grow on, and 
 horizontally beneath or above, the surface of the soil, without ever 
 erecting themselves, the axes proceeding from their lateral buds alone 
 rising up free into the air. These horizontal axes proceeding from 
 lateral buds, I name, exclusively, root-stocks or rhizomes (rhizoma). 
 Examples are found in Pteris aquilina, Equisetum arvense, Phr ay- 
 mites communis, Carex arenaria, Gratiola officinalis (?), Dentaria 
 lulbifera (?), &c. 
 
 The buds have to be treated at length hereafter ; here merely the for- 
 mation of axes was in question. On the relation of lateral parts (here 
 the secondary axes) to an axis (here the main axis), what is requisite 
 has already been stated and remarked in the General Morphology, as the 
 forms arising out of it denote nothing exclusively botanical. Here it was 
 merely necessary to mention what laws of development the varieties may 
 depend upon. Very important it was, accurately to define the concep- 
 tion of a true rhizome, since, heretofore, the word has been so played 
 with, that pretty nearly every possible part of a plant that ever is subter- 
 raneous has been understood by it, and at last no one knows what a rhi- 
 zome really is, although the word is in general use. I think it is conve- 
 nient to define and restrict the expression as in the paragraph. By this 
 we shall have a name for a definite peculiarity in the mode in which 
 many plants survive for a number of years, which certainly deserves a 
 special name. The development of the rhizome is easiest to trace in 
 germinating Asparagus. The systematists will object that they cannot 
 begin with such distinctions in their dried plants. I cannot help them. 
 The living plant is the object of our science, not the hay which we pre- 
 serve as a miserable make-shift in our blotting paper ; and a living, 
 scientific principle, like the history of the course of development, can 
 alone give Botany a value. Many, indeed, there may be to whom Botany 
 is nothing but the science of the Herbarium : with these I have no 
 concern. 
 
 d. Of the Structure of Axes. 
 
 129. Like all other parts of a plant, every axis, in its earliest 
 condition, is composed of cellular tissue ; in this are gradually 
 formed the vascular bundles, closed or unlimited (see 26.). This 
 is common to all Phanerogamia. I know of no Phanerogamous 
 plant (except Wolffia Hork.*) without vascular bundles (even if 
 without vessels. 26.). 
 
 Besides these, are formed, in different arrangements in different 
 plants ( 27.), liber-cells, sometimes as bundles, sometimes as a 
 closed ring, or scattered singly in the parenchyma, intermediate 
 forms between liber and parenchyma ( 27.), sometimes isolated, 
 sometimes in bundles ; milk-vessels ( 27.), and reservoirs for pe- 
 culiar secretions ( 24.), spiral-fibrous and porous cells ( 18.), in 
 groups or scattered; lastly, air canals and cavities ( 24.), the 
 former frequently regularly arranged, especially in aquatic and 
 bog plants, the latter mostly occupying the axis of the internodes, as 
 
 * JFolffiii Mlclich'i mihi = Lemna arrhiza Micheli. W. Deliki tnihi = Lennirt Jti/nJlna 
 Delile. 
 
236 MORPHOLOGY. 
 
 in the Grasses, UmbelUfercR, &c. Every axis is originally clothed 
 with epidermis or epiblema ( 29.), according to the medium in 
 which it vegetates. On this, therefore, are frequently formed all 
 the appendages of epidermoid tissue, especially glands, hairs, &c. 
 and corky matter ( 29.). The varieties resulting from these 
 are so manifold, that, at present, it is only with great difficulty, if 
 at all, that they can be treated generally ; the varieties which re- 
 sult from the different arrangement and nature of the vascular 
 bundles, are of more importance, and may be subjected to a more 
 general examination. All vascular bundles are usually separated 
 from their fellows by parenchyma ; more rarely they form a per- 
 fectly closed circle. The separate bundles are either placed in 
 a single circle (as in most Dicotyledons), or scattered in the paren- 
 chyma. The latter, again, collectively form a circle, which, like 
 the preceding, encloses a definite portion of cellular tissue (pith) 
 in the centre (e. g. in most Grasses, many UmbellifercB, Nyctaginece, 
 Chenopodiacece, Amarantacece), or such an arrangement does not ma- 
 nifest itself (in cane-like Palms, Grasses with solid stems). The 
 latter distinction seems to me very unimportant, since it varies in 
 closely related plants, in one and the same family, e. g. in Mays 
 (vascular bundles scattered throughout the parenchyma) and Pha- 
 laris (scattered vascular bundles enclosing a pith). In all cases 
 where the arrangement of vascular bundles indicates such a boun- 
 dary between included and excluded parenchyma, the inner is called 
 pith (niedulla), the outer bark (cortex). The portions of cellular 
 tissue between the vascular bundles, maintaining the connexion 
 between the pith and bark, are termed great medullary rays. In 
 the simplest plants merely a central vascular bundle occurs, or a 
 perfectly closed ring of elongated (vascular bundle) cells, like that 
 in the Mosses, which, however, again encloses parenchyma in the 
 centre (e. g. in Ceratophyllum). In flat stems, as in Spirodala, Ruscus, 
 they lie in one plane (in a line on the transverse section). Con- 
 sequently they both have merely bark and no pith. 
 
 The bark is composed, in addition to epidermis, of cellular tissue, 
 in which we can in general distinguish merely an uniform paren- 
 chyma, but sometimes, especially in perennial axes, two layers ; 
 
 1. the outer, which consists of elongated cells, with thick but 
 almost gelatinous and generally porous walls, the boundaries be- 
 tween which are often quite undistinguishable, and the intercellu- 
 lar spaces of which are filled with intercellular substance ; and 
 
 2. the inner layer, which is generally formed of roundish, thin- 
 walled, lax parenchyma. In the latter alone occur reservoirs for 
 secretions, milk-vessels, special forms of cells with special contents ; 
 in the former, scarcely anything but cells, containing homogeneous, 
 colourless or red juices, and sometimes crystals. The two layers 
 occur most distinctly defined in the trunks of which the cuticle 
 does not form cork until a late period (as in the Cactacece) ; in other 
 trunks and steins they very often pass gradually into each other. 
 In front of the vascular bundles, in the inner layer of the bark, fre- 
 
PHANEPvOGAMIA : AXIAL ORGANS. 237 
 
 quently lie either liber-bundles, or liber-bundles carrying milk-sap, 
 actual milk-vessels, or milk-sap passages. Since these often respect- 
 ively exclude each other, while often there is no trace of any of 
 them, the liber certainly cannot be called an essential constituent 
 of bark (as the innermost layer) ; still more inaccurate would it be 
 to term the cambium-layer, which much rather appertains to the 
 vascular bundles, the innermost layer of the bark. 
 
 In trunks (Stammen) the epidermis sooner or later forms corky 
 substance, which is either gradually cast off in layers, as at first in 
 the Birch, often merely becomes destroyed gradually by atmospheric 
 influences, and thus, in part, acquires considerable thickness, as in 
 the Oak, or, as often happens, the outer part of the inner layer of 
 the bark and the outermost liber layer are thrown off together, and 
 never reproduced. In the last case, new liber and internal cortical 
 layers are formed annually, but with a peculiar form of cells resem- 
 bling corky tissue ; and the outermost are in like manner annually 
 thrown off, as, for instance, in the Vine. 
 
 The pith, lastly, is composed of parenchyma alone, which, in its 
 older condition, becomes thick-walled and porous. It often con- 
 tains, also, solitary ramified liber-cells (Rhizophora Mangle), milk- 
 vessels, reservoirs for peculiar secretions, &c. 
 
 The vascular bundles originate after the cellular tissue, in the 
 same order as the latter ; or rather, as the cellular tissue is gradually 
 formed, a part of it passes gradually into vascular tissue. The 
 direction of the vascular bundles wholly depends, therefore, upon 
 the direction of the organising force. On account of this, also, the 
 distinction between developed and undeveloped internodes, ex- 
 plained in 126., forms the chief basis for the course of the vascular 
 bundles. In the former, when the process of formation proceeds 
 from below upward, in horizontal discs, the vascular bundles are 
 straight, tolerably parallel to the axis of the internode, e. g. in Tra- 
 descantia, Tropceolum ; where, on the contrary, one hollow cone is 
 set upon another, as it were, in the terminal bud, the vascular 
 bundles at their first development hold a course from the base to 
 the apex of the cone, therefore from the circumference of the in- 
 ternode to its centre, and afterwards, as new internodes are super- 
 posed, the vascular bundles of the first cone are developed forward 
 through the succeeding ones, to the circumference, where they enter 
 the leaves or buds They make, therefore, a curve convex toward 
 the interior, the length and convexity depending on the form of 
 the terminal bud. The curve is very convex in Yucca, Mammillaria, 
 &c. ; more elongated in the Palms, Drac&na, Iris, &c. Since all 
 new portions in the axis are formed outside the primary vascular 
 bundles, whether they be increase of thickness to the vascular 
 bundles, as in Dicotyledons, or the rudiments of new bundles, in 
 Monocotyledons, the older and deeper vascular bundles, running 
 towards the periphery to the leaves and buds, must necessarily cross 
 the more superficial, ascending bundles, or their developing masses, 
 which have originated outside them. This condition is naturally 
 
238 MORPHOLOGY. 
 
 most distinct when the vascular bundles are closed; but we see 
 plainly enough, in Mammillaria or Melocactus> the bundles going to 
 the basis of the lowest leaves, coming out from the most internal 
 parts of the wood, and running past in a curve across all the subse- 
 quently developed parts. 
 
 At the point where a leaf is given off, in the Dicotyledons always, 
 in Monocotyledons at most indistinctly, often not at all, several 
 neighbouring vascular bundles become applied together, to form a 
 loop (ansa\ from the circumference of which pass off the vascular 
 bundles of the leaf and the axillary buds. 
 
 Wood is formed from the unlimited vascular bundles of Dicoty- 
 ledons, by their longer duration. The new cells originating be- 
 tween them, which correspond to the medullary rays, become 
 again parenchymatous or medullary-ray cells, for these latter 
 becoming compressed at the sides, by the enlargement of the vas- 
 cular bundles, deviate somewhat in form from the common paren- 
 chymatous cells. 
 
 Frequently, however, one or more cells remain as parenchy- 
 matous cells, and so begin to form medullary rays in the midst of the 
 wood (called small medullary rays), which sometimes go on develop- 
 ing for a long time, and sometimes cease at an early period. The 
 wood does not generally grow uniformly continuously ; in those 
 parts, especially where, owing to climatal conditions, an alterna- 
 tion occurs every year between the active and dormant periods of 
 vegetation, more vessels are formed at the beginning of the period of 
 vegetation, and at its close wood-cells which are narrower and have 
 stronger and thicker walls. By this means a division of the wood 
 into more or less concentric hollow cylinders is occasioned, or 
 those circles on the transverse section which are commonly termed 
 annular rings. 
 
 In the Dicotyledons, where the vascular bundles are situated in 
 several circles, they gradually unite together as they are succes- 
 sively developed, and form a close mass of wood, in which run 
 then the separate vertical cords of the separate vascular bundles 
 belonging to the cambium, giving the wood a peculiar appearance, 
 which is beautifully exhibited in the species of the Pisonia. 
 
 There is but little that can be said generally of the composition of the 
 axis from the separate forms of the elementary parts and of the tissue ; 
 all forms occur in the stem, and it is only in the case of individual 
 groups of plants that we meet with certain forms or combinations 
 specially or exclusively. Thus the Labiate are distinguished by having 
 a square stem, the margins of which are formed by four strips of distinctly 
 characterised cortical substance. The majority of the Euphorbiacece 
 have milk-vessels, as the Asclepiadacece and Apocynacece are provided 
 with their peculiar intermediate form between milk-vessels and liber- 
 cells. Nepenthes is distinguished by having elongated spiral cells, which 
 occur scattered in large numbers over every part of the stem. The 
 distinction between pith and bark is not an universal essential charac- 
 teristic for plants, as may be seen by the innumerable transition stages 
 occurring between them. The two continually merge into one another. 
 
PHANEROGAMIA : AXIAL ORGANS. 239 
 
 That we only speak of medullary rays in the case of Dicotyledons arises 
 from mere want of exactness of language, since the cellular tissue between 
 the vascular bundles of the Monocotyledons is just as much a medullary 
 ray as between the vascular bundles of the Dicotyledons, and as little 
 changed in its cellular formation as in those Dicotyledons where the 
 vascular bundles are very far removed from one another. Moreover, the 
 cells in highly compressed vascular bundles, especially in the external 
 parts of the stem of the Monocotyledons having a cambium circle, assume 
 precisely the same form and arrangement as the medullary cells ranged 
 in radial horizontal rows in the Dicotyledons, as, for instance, in the stem 
 of Aletris fret grans. 
 
 We are able to assert very little generally concerning the structure of 
 the bark, since nothing is unconditionally true, with the exception of the 
 foundation being always composed of cellular tissue. No combination of 
 definite forms of the elementary organs is peculiar to all barks ; some 
 forms occur, however, so frequently, that it would appear desirable to 
 draw attention to them. Here I must, however, distinguish between 
 Monocotyledons and Dicotyledons. 
 
 A. Monocotyledons. I am unable, from deficiency of a sufficient 
 number of investigations, to say anything important of the structural 
 relations of this group. As far as I know, the bark constantly consists 
 exclusively of parenchyma, which is more elongated in the interior than 
 towards the exterior having more chlorophyll towards the exterior, 
 but gradually losing it towards the interior, so that the cortical paren- 
 chyma constantly merges into the pith, wherever there is no sharp line 
 drawn by the formation of a wholly closed circle of strongly thickened 
 parenchymatous cells, which connects a ring of vascular bundles, as, for 
 instance, in Pothos. According to Mohl*, most Palms have a peculiar 
 layer, varying in thickness at different times, composed of thick- walled 
 parenchymatous cells, placed immediately under the epidermis. In 
 Grasses and the Cyperacece we find immediately below the epidermis 
 separate bundles of liber- cells. The cells of the epidermis above these 
 generally continue to have thin walls ; whilst in those parts where 
 parenchyma lies below, their walls become extremely thick, as, for 
 instance, in Papyrus antiquorum. 
 
 B. Dicotyledons. 1. Annual Bark. In this we may, besides the 
 epidermis, distinguish three parts of the bark ; they do not, however, 
 constitute anything essentially characteristic of the bark, which fre- 
 quently only consists of a parenchyma, which at most merges gradually 
 into a tissue similar to the external cortical layer towards the exterior. 
 The three portions are the external and internal cortical layer, and the 
 liber-layer. 
 
 Of the latter there is frequently not the smallest trace present, as, for 
 instance, in Cheiranthus Ckeiri, in a few species of Solanum, and most 
 of the Ribes, in Iledcra (?), Viburnum Lantana, Mesembryanthemum, in 
 most of the Crassuhicece, Chenopodiacece, &c. Where this liber-layer is 
 present, it consists of isolated liber-cells (as, for instance, in Cornus alba), 
 or liber-bundles (as in most Dicotyledonous trees), both being distributed 
 in the cortical parenchyma, and generally in such a manner that their 
 course corresponds accurately to that of the vascular bundles, or else it is 
 composed of a more or less accurately closed circle of liber-cells (as, for 
 instance, in Syringa, Fraxinus). Together with the liber-cells we 
 
 * De Palmarum Structura, 12. 
 
240 MORPHOLOGY. 
 
 occasionally find milk vessels or passages, as. for instance, in Rhus. 
 More frequently, liber-cells containing milk (in Apocynacece}, or true milk 
 vessels (as in Ficus Carica), or milk passages (as in Mammillaria qua- 
 drispina), take the place of the simple liber-cells. 
 
 The middle cortical layer, which is properly only traversed by the 
 liber-cells and the parts by which they are represented, consists mostly 
 of roundish, very loose cellular tissue, generally containing much chloro- 
 phyll. Here and there we find it ranged in vertical rows. Individual 
 cells, or rows of cells, with crystalline accumulations, coloured juices, oils, 
 &c., or with disproportionately thickened walls, are frequently inter- 
 spersed : occasionally three or more cells, the uppermost and lowermost 
 of which, being acutely pointed, form peculiar fusiform groups, and then 
 usually contain peculiar substances (as, for instance, Pinus sylvestris). 
 
 The external cortical layer has hitherto, as far as I know, been entirely 
 overlooked* ; it appears, nevertheless, seldom to be wholly absent, and 
 in a large number of plants, and groups of plants, it is so distinctly 
 characterised, that it quite forces itself upon one's notice. It is only in 
 a few plants that it has met with any attention, and there it has been 
 described as a liber-bundle, although it really differs very materially 
 from liber. The following are the characteristic marks of this tissue, as 
 distinctive from cortical parenchyma. The cells of this layer are always 
 vertical, elongated, very thick walled, but soft, and so far similar to 
 liber-cells ; they are, however, always applied upon one another by hori- 
 zontal walls, seldom exceeding ^y^th of an inch in length. They almost 
 invariably exhibit more or less large pores, which frequently form dis- 
 tinct, beautifully ramified canals in the thick walls ; they contain little or 
 no chlorophyll, but merely homogeneous, colourless, or sometimes reddish 
 juices, and here and there crystals. The cells are always connected 
 together by intercellular substance, and their limits therefore frequently 
 obliterated, so as to make them appear like apertures in a soft pulpy 
 mass ; when the cells are separated from each other, the intercellular 
 substance shows itself with remarkable distinctness between them, as a 
 secretion from them ( 59.). This layer is found in many plants 
 most strikingly developed, and sharply defined from cortical paren- 
 chyma, although in various modes of distribution: 1. As a per- 
 perfectly closed layer (penetrated in some cases only by small canals 
 opening into stomata), as in most of the Cacttf, Melianthus major, 
 Euphorbia splendens, Syringa vulgaris, Begonia argyrostigma, Allan' 
 thus glandulosa, Rosa, Aristolochia Sipho, Piper rugosum, Cacalia 
 Jicoides, Cotyledon coccinea. 2. Divided into many bundles, so that the 
 green cortical parenchyma reaches the epidermis between them (in which 
 case we find stomata there), as in the Chenopodeaccs, Amaranthacece, Mal- 
 vacece, SoJanacece, Umbelliferce\, Justicia, Eranthemum, &c. 3. Where it 
 may be quite distinctly recognised as a special layer, but still passing 
 quite into parenchyma at the borders, as in Carya, Pyrus Mains, Pavia, 
 Iledera, Acer, Daphne, Ptelea, Rhus, Viburnum, Cornus, Ficus, Semper- 
 vivum globiferum et laxum, Sedum pallidum, Cotyledon arborescens. 
 4. More completely merging into cortical parenchyma, and therefore less 
 
 * Hartig maintains that he was the first to draw attention to this tissue ; as, how- 
 ever, the researches on which he grounds this claim are at present unknown to me, I 
 am unable to say with what justice. However, I attach less to being the first to observe 
 a thing, than to observing it correctly. 
 
 f See my papers on the Physiology and Anatomy of the Cacti. 
 
 j The so-called liber-bundles are beneath the epidermis in these five families. 
 
PHANEROGAMIA : AXIAL ORGANS. 241 
 
 distinct, as in Ribes, Alnus, Elceagnus, Juglans, Populus, Salix, Carpinus, 
 Castanea, Corylus, Quercus, Cytisus, Cornus mascula, Sambucus, Rham- 
 nus, Tilia. 5. Finally, I have found this layer either entirely absent, 
 or only to be recognised in the external cellular layer, as in Cheiranthus, 
 Hippophde, Mesembryanthemum, and the so-called tree-carnations. On the 
 whole, the external cortical layer seems to stand in a definite relation to 
 the formation of cork, and to be more sharply defined in proportion to the 
 tardiness with which the latter appears (as, for instance, in Cactacece, 
 Aristolochia Sipho, Cacalia ficoides) : the contrary, however, also occurs, 
 as, for instance, in Mesembryanthemum. 
 
 2. Perennial Bark. The development of the vascular bundles from 
 the cambium is always accompanied by a similar development of the 
 bark, since a part of the cells that have newly originated in the cambium 
 attach themselves, towards the interior, to the vascular bundle, a second 
 part continues to develop as cambium, and the remainder attaches itself 
 externally to the old bark. Thus we find that, similarly to the annual 
 rings of the wood, definite layers of bark are formed in every period of 
 vegetation, being composed, according to the peculiar character of the 
 primary bark, of mere parenchyma, liber and parenchyma, or of alternate 
 layers of parenchyma and liber, or of alternating layers of true paren- 
 chyma and such as is interrupted by liber-bundles. From this the layer 
 of liber frequently becomes broader towards its inner side, in proportion 
 as the wood thickens, so that the liber-bundles exhibit a beautiful wedge- 
 like appearance in a cross-section. This new formation of bark is, 
 however, marked by great specific differences : in some plants it is rapid 
 and decided, as, for instance, in the Lime-tree ; in others very slow and 
 partial, as in the Beech. The thickness of the bark depends partly 
 upon this, and partly upon the following causes : sometimes, even in the 
 first period of vegetation, and then generally uniformly, the epidermis 
 is developed into a cork-tissue (as in most trees) ; less frequently this 
 occurs later, in that case beginning at separate spots, and extending 
 itself by degrees, as, for instance, in the Cacti and leafless Euphorbiacece 
 ( 29.). The cork-tissue varies in hardness and durability. It 
 most frequently consists of tabular cells, already described in the 
 First Book, which are sometimes thickened in alternate layers, as, for 
 instance, in the Cacti ; and more rarely somewhat radially elongated, as 
 in the Cork Oak, or Cork Elm. In the last named, and in the Maple, it 
 acquires considerable thickness, but at the same time is easily destroyed 
 by atmospheric influences in the case of the Maple. In its usual form it 
 generally lasts longer, and becomes frequently very thick, constituting 
 the so-called bark of the tree, as, for instance, in Quercus Robur. 
 Occasionally the cork is found in the bark, in the condition of separate 
 layers of an easily destroyed tissue, in which case it falls off in horizontal 
 bands, or shreds, having a specifically definite form. 
 
 In some stems new layers of a parenchyma, very similar to cork-tissue, 
 are developed from the cambium ( ?) with cortical parenchyma (in Ribes\ 
 or alternately with cortical parenchyma and liber (as in the Vine) : this 
 parenchyma (termed periderma by H. Mohl) likewise contains easily 
 destroyed layers, so that the whole external bark drops off, and then, 
 as in the case of cork-formation, layers of periderma and liber are 
 successively shed. (This is strikingly exemplified in Pinus sylvestris.} 
 We are, however, very deficient in the necessary investigations. We 
 have to thank H. Mohl for the first exact work on this point.* I have 
 
 * On the Origin of Cork and Bark. Tubingen, 1835. 
 R 
 
242 MORPHOLOGY. 
 
 myself endeavoured to throw additional light upon the origin of the 
 cork-layer.* The first formation of the periderma is still, however, very 
 obscure. 
 
 The pith consists essentially, and very generally, of parenchyma, 
 without any manifestation of special layers in it. When old it becomes 
 either very thick-walled and porous, or it is destroyed, and then leaves 
 large air-cavities, as, for instance, in many Grasses, Umbelliferce, &c. 
 There frequently remain alternate, isolated, firmer layers of pith, and 
 thus form an air-cavity divided off into chambers placed horizontally one 
 upon the other, as, for instance, in Juglans regia. Interspersed in the 
 pith we find spiral cells, thick-walled porous cells, cells with peculiar 
 juices, milk-vessels, air-passages, and even, in the case of Rhizophora 
 Mangle, peculiarly-branched liber-cells, t In many of the woody Ro- 
 sacecB there are peculiar vertical and horizontal rows of very thick 
 porous cells, &c., in the pith. Innumerable plants yet remain to be in- 
 vestigated. Many more isolated phenomena might be noticed, but nothing 
 can be made of them at present. { Vascular bundles alone, with one 
 exception, are found in every axis, and, consequently, these are almost 
 the only parts of which the distribution and nature are susceptible of 
 general treatment. In the first place, we must mention one common dif- 
 ference affecting the nature of the vascular bundles, and their relative mass 
 compared with the cellular tissue of the axis. The vascular bundles either 
 preponderate in mass, and their elementary parts are generally very 
 much thickened, and the axis, having thus greater firmness, is termed a 
 woody stem or stalk ; or the vascular bundles are present only in a pro- 
 portionately small mass, separated from each other by larger quantities of 
 cellular tissue, and their component elementary parts, in a great degree, 
 or principally, have thinner walls, and then the whole mass of the axis is 
 softer, the thinner lax or still flexible, and the stem or stalk is termed 
 succulent : the last-mentioned is also, with superfluous diffuseness, called 
 herbaceous. In the succulent axes the course of the vascular bundles is 
 generally much more simple and regular, as may be seen in the different 
 internodes of the one and the same axis (which may be woody below and 
 succulent above). The distinction between a woody and a succulent axis 
 agrees still less with that of stem and stalk. We often find in the same 
 class some species having succulent, and others woody stalks ; and not un- 
 frequently a whole family have exclusively succulent stems. 
 
 The arrangement and course of the vascular bundles are, however, the 
 most important points to be considered. In the main paragraphs I have 
 given the general features, but I will here enter somewhat more specially 
 into the question, as, at the same time, I separate the individual groups. 
 I add the following particulars as the general result of my own researches 
 on this subject, without, however, maintaining that they are to be received 
 as the ultimate expressions of a natural law : 
 
 1. The origin of any vascular bundle, as well as the development of 
 one already extant, presupposes, without exception, the presence of a 
 cambium-layer, as every new formation of structure, in and upon the plant, 
 presupposes the existence of a process of cell-formation. By cambium, 
 cambium-layers, formative layers, we understand nothing more than 
 a cellular tissue, which has not yet ceased to develope new cells, in contra- 
 
 * On the Cacti, loc. cit. 
 
 f Wiegmann's Archiv. Jahrg. v. (1 839), part i. p. 232. 
 
 j As, for instance, the remarkable gelatinous (?) masses, beset with crystals, lying in 
 special cells, found in the epidermis of Justicia, and in the bark and pith in Eranthe- 
 
PHANEROGAMIA : AXIAL ORGANS. 243 
 
 distinction to those tissues in which there is no longer normally any 
 process of cell-formation going on. The latter consist in such cases 
 either of living parenchymatous cells, in which, under favourable in- 
 fluences, such a process of cell-formation may recur, as, for instance, in 
 the germination on Monocotyledonous leaves, &c., or of relatively dead, 
 very woody cells, in which such a process of development can never be 
 revived, as, for instance, in the older part of a vascular bundle, wood, &c. 
 
 2. In all cases we find that the new cells in the cambium-layer, and the 
 new vascular bundles, or the thickening mass of the older vascular bundles, 
 are developed from the base towards the apex of the axis, from the older 
 into the new internode, and from the main to the secondary axes, but 
 never the reverse. 
 
 3. Only in the Gymnospermce, Monocotyledons, and Dicotyledons does 
 a cambium- layer occur in the circumference of the axis ; and where this is 
 present it forms the limits between bark and pith or medullary cellular 
 tissue. In the Monocotyledons this cambium-layer only occurs as an 
 exception, and is, of course, independent of the separate, invariably 
 definite, vascular bundles ; in the Gymnospermce and Dicotyledons this 
 layer is never wanting, and is so constituted that the cambium of each 
 separate vascular bundle of the simple or outermost ring also belongs to 
 the general cambium-layer, and is connected by the cambium masses, in 
 front of the medullary rays, into one continuous layer. Moreover, every 
 individual, unconnected, isolated vascular bundle, has its own cambium. 
 
 4. The main difference must still be deduced from the nature of the 
 vascular bundle, which corresponds with the great natural divisions of 
 plants. Other distinctions that have been advanced are untenable, and 
 are based upon deficient observation of all existing conditions. 
 
 5. All asexual Gymnosporce can grow upward only, owing to the de- 
 ficiency of a cambium-layer. All Gymnospermce and Dicotyledons grow in 
 thickness as well as height. In the Monocotyledons we find both condi- 
 tions, sometimes manifested exclusively as terminal growth, and then, 
 again, the latter combined with continuous increase in thickness. From 
 this we cannot, however, deduce any classification of the Monocotyledons, 
 since both conditions are met with in the same family, as, for instance, in 
 the Liliacece and in branched Palms (?). 
 
 I. Asexual Gymnosporcp,. 
 
 These all agree in having simultaneous vascular bundles, and, as far as 
 I know, in that no cambium-layer occurs in any stem, by which the latter 
 might be further thickened when once formed. The structure is in general 
 very simple. Liverworts and Mosses have only a simple central vascular 
 bundle, without so-called vessels. The Lycopodiacea have only a central 
 vascular bundle, generally forming an irregularly-lobed figure in the 
 transverse section, this being occasioned by the arrangement of the vessels. 
 The vascular bundles, going into the leaves, run for a time upward in the 
 bark before they enter the leaf. The stem of Isoetes is formed in a very 
 different manner, and here we find a ring of vascular bundles, undeveloped 
 internodes, and a constant and successive dying off from below. Mohl has 
 made very exact observations on this subject. 
 
 Ferns have an extremely deficient stem-formation, exhibiting sometimes 
 developed, and sometimes undeveloped, internodes ; in all, however, there 
 is but a simple ring of vascular bundles. The vascular bundles rise 
 vertically in the developed internodes, and, at the starting point of the 
 
 R 2 
 
244 
 
 MORPHOLOGY. 
 
 vessels of the leaves, form loops by their mutual combination, from which 
 these are given off. In the undeveloped internodes they rise up in ser- 
 pentine lines, forming, by their alternate approach and retreat, longer or 
 shorter, narrower or broader, meshes, from the edges of which the vascular 
 bundles of the leaves branch off. These latter not unfrequently run for 
 a time upwards in the pith, before they pass through the meshes and enter 
 into the leaves. H. Mohl has given us minute anatomical observations on 
 the Fern-stems, but we are unfortunately still wholly deficient in a 
 history of their development. 
 
 The Equisetacece have all developed internodes and a simple ring of 
 vascular bundles. We are still without any very exact observations, or 
 special history, of their development. 
 
 157 
 
 II. Sexual Plants. 
 
 A. RHIZOCARPEJS. 
 
 These, again, have an extremely simple structure of stalk and stem, 
 together with a central vascular bundle, which contains only a few 
 weakly-developed vessels. 
 
 B. GYMNOSPERM^E. 
 
 The whole of this division is devoid of stalks, having only stems. The 
 Cycadacece have only undeveloped, and the Conifer ce and Loranthacece only 
 developed, internodes. All have a cambium-layer under the bark on the 
 outer side of the simple vascular bundle ring, and the stems are conse- 
 quently capable of being indefinitely thickened ; the vascular bundles are 
 indefinite. In the Coniferce we find a ring of vas- 
 cular bundles (the medullary sheath of older bota- 
 nists) surrounding a pith, which even in the first 
 year close into a woody cylinder (fig. 157. h, k). The 
 portions of wood corresponding to the vascular bun- 
 dles run quite perpendicularly, and only leave very 
 narrow crevices for the escape of the little bundles, 
 branching from the inner part of the vascular bun- 
 dles, which intersect the wood obliquely, and ascend 
 for a time into the bark before they pass into the 
 leaves (fig. 157. h, i). These points will be made more 
 plain by means of the accompanying diagram of a 
 section of a piece of the stem of the Fir. The 
 Loranthacece do not appear to differ in their ar- 
 rangement from the Conifers. 
 
 InCycas revolutawe find also a simple ring of vas- 
 cular bundles, from the innermost part of which the 
 vascular bundles for the lateral parts run through 
 long meshes (which are formed by the alternate 
 retreat and closing together of the vascular bundles, 
 
 d. a. <?. c 
 
 157 Abies excelsa. A longitudinal section of the apex of a tree, of two years' growth 
 in the lower part, and only one year's growth above the lateral branch. a, The wood 
 divided into two annual portions (annual rings). b, The medullary sheath ; that is to 
 say, the oldest portion of the first annual ring, or original vascular bundles. Between 
 a and b, the pith, shaded with cross lines, c, Cambium-layer, d, Bark. /, Lateral 
 branch, e, A leaf, from the axil of which the lateral branch has originated, g g, Re- 
 
PHANEROGAMIA : AXIAL ORGANS. 
 
 245 
 
 rising in undulating lines), into the bark, describing an arc somewhat 
 convex upward and towards the interior ; these vascular bundles do not, 
 however, pass directly into the leaves, or leaf-scales, but first compose, 
 parallel with the periphery, arcs of vascular bundles, running horizontally: 
 from these, distinct vascular bundles branch off for the leaves. The very 
 unimportant materials at my disposal did not allow of my extending 
 my observations further. 
 
 C. MONOCOTYLEDONS. 
 
 The most simple plants of this division have no vascular bundles, as, 
 for instance, IVolffia : those nearest allied amongst the Lemnacece first 
 exhibit definite indications of these ; in Spirodela we even find them 
 combined with spiral vessels, but distributed in a plain surface as the 
 necessary accompaniment of a flat stalk. Many of the Najadece, as, for 
 instance, JVajas, Zanichellia, Ruppia, have only a central vascular bundle. 
 In the remainder we meet with the following modifications : 
 
 1. Developed Internodes. 
 
 The stalks and stems have always several rings of vascular bundles 
 (fig. 158. d), which occasionally enclose a pith, where a circle of vascular 
 bundles are connected by a ring of thickened parenchyma. This is often 
 the most external (usually) (fig. 158. c\ often a more internal one, as in 
 Pothos. A portion of the vascular bundle passes through the nodes into 
 
 158 
 
 159 
 
 the leaf, whilst a part rises into the next internode (fig. 159. d). Small twigs 
 branch off from all the vascular bundles that pass through the nodes, 
 
 mains of the scales of the bud : the one to the right only for the terminal bud of the 
 preceding year ; to the left for this, and also for the axillary bud, from which the 
 branch has arisen, h, A leaf at the one year old portion of the stem, together with the 
 adhering vascular bundle, i, Base of the leaf on the second year's portion of the stem, 
 with the vascular bundle appertaining to it. k k, Wood of one year's growth. 
 
 158 Ruscus aculeatus. Transverse section of the stalk, a, The epidermis, b, The 
 bark, c, A ring of thickened cells, by which the external vascular bundles are connected 
 into a continuous zone, and thus separate the pith and bark, d, Vascular bundles scat- 
 tered through the pith. 
 
 159 Zea Mays, natural size. A section made lengthwise through a macerated portion 
 of the stalk, a, The leaf. 6, The axillary bud. c, Adventitious root, d, Vascular 
 bundles, in their course from below upward : they give one branch to the leaf, and 
 another, or several, to the nodal plexus (e), and to the bud (6). 
 
 R 3 
 
246 
 
 MORPHOLOGY. 
 
 forming a confused plexus in the node, which, for the most part, merges 
 into the axillary bud (fig. 159. e). The innermost vascular bundles in the 
 nodes supply the lowest leaves, the external bundles the upper ones, as in 
 Grasses, the cane-stemmed Palms, and the Commelinacece. There are 
 many groups that have not yet been examined. The whole of the vas- 
 cular bundles in the same internode are simultaneously formed and 
 developed, and the internode itself, when perennial, does not continue to 
 increase in thickness, whether the plant becomes branched or not. The 
 primary, like the secondary, axes only grow upwards ; in fact, they are 
 devoid of a cambium-layer. 
 
 2. Undeveloped Internodes. 
 
 The stalks (in Pistia obovata, for instance), and the stems of Palms, 
 herbaceous Liliacea, bulbs of Allium, Lilium, &c., have a conical terminal 
 bud, sometimes longer, and 
 sometimes shorter, in accord- 160 
 
 ance with which the vascular 
 bundles run from below and 
 the exterior, upward and 
 towards the interior, and then 
 from thence upwards and ex- 
 ternally, to pass into a leaf 
 (fig. 160. d and e). The arc, 
 which is convex towards the 
 interior, is longer or shorter 
 according to the length of the 
 terminal bud; and the vas- 
 cular bundle likewise passes 
 through a longer or shorter 
 portion of the whole axis, 
 according to the same con- 
 ditions. 
 
 In the full-grown stems of 
 the Palms, the vascular bun- 
 dles connected with the upper 
 leaves do not reach the base 
 of the stem, notwithstanding 
 the length of the arc. In 
 the simplest case the vascu- 
 lar bundles are wholly 
 isolated ; they are, however, 
 more frequently connected 
 by intermediate branches, 
 seldom from within exter- 
 nally, but often laterally with 
 
 180 Diagram of the course of the vascular bundles in the monocotolydenous stem, with 
 undeveloped internodes, and roundish, conical, terminal hud. a b, The lower, fully de- 
 veloped, part of the stem, c c, External firmer portion of the stem formed by the 
 closer course of the vascular bundle, d d d, Vascular bundles running as far as the 
 cicatrices of leaves that have died off. e e e e e, Leaves in the bud in the order in which 
 they are developed, with the vascular bundles belonging to them, f /, The latest- 
 formed leaves : all that is cut off by the line x y above the stem has originated at the 
 same time with the pair of leaves (,r x). 
 
PHANEROGAMIA : AXIAL ORGANS. 
 
 247 
 
 one another. From this cause, as well as from a more or less extended 
 vertical course of the vascular bundles before they form the arc, the ex- 
 ternal part of the stem is composed of a thicker cylinder of vascular 
 bundles (fig. 160. c c), whilst the inner portion, composed only of arcs, 
 becoming more and more isolated toward the centre, and cellular tissue 
 increasing in quantity in the inverse proportion, appears much looser. 
 However simple we may consider the course of the vascular bundles in 
 the Monocotyledons in judging of them according to H. Mohl's re- 
 searches *, it is, in fact, but seldom so ; nevertheless, H. Mohl's repre- 
 sentation affords the simplest and clearest delineation, 
 and gives the type from which all the analogous struc- 
 tures must be deduced. Occasionally, however, the 
 course actually appears as direct as that indicated by 
 the diagram, as, for instance, in the subterranean stem 
 , of Iris chinensis (fig. 161.). The separate vascular 
 bundles, especially so far as they form the arc, by no 
 means always run in one and the same vertical plane, 
 their emergence deviating frequently about 50 and 
 
 more, of the circumference of the stem, laterally, from 
 the vertical of their starting point, as may be easily ob- 
 served, for instance, in Yucca gloriosa. The Xantho- 
 rhcea australis (fig. 162.) appears to me to differ most 
 strikingly from the simple type of the stem. Here the 
 fascicles of the vascular bundles, emerging into the 
 leaves (e, e, e\ evidently have a threefold origin from 
 three different zones of the stem (aa, bb, cc). Quite 
 in the interior another plexus of vascular bundles 
 
 * De Palmarum structura. 
 
 161 Iris chinensis, natural size. Longitudinal section of the subterranean stem. 
 a a, Cortical layer, b U b", Three leaf cicatrices, b" b"" b v , Remains of three leaves 
 which have been cut off, with the vascular bundles running to all six leaves, c, Youngest 
 leaf, still in the bud stage: to the right may be seen the terminal bud as a scarcely 
 perceptible elevation, at the right side of which the next leaf will be formed. 
 
 16 ' Xanihorhoca australis, natural size. Longitudinal section through half the di- 
 ameter of a piece of stem (.r ). The arrow indicates the direction from within 
 outwards. The course of the separate vascular bundles has been carefully exposed by 
 artificial preparation, a, b, c, The three regions of tiie external part of the stem, which 
 give off vascular bundles for the cords (e e e) running into the leaves, rf, The inner 
 lax part of the stem, with very irregularly inclined vascular bundles, whose course 
 
 K 1 
 
248 MORPHOLOGY. 
 
 appears, the course of which, however, I could not make out, as the piece 
 in my possession was not sufficiently large for me to trace it. Still 
 it appeared to me that the vascular bundles, /, /*, had not yet quite reached 
 the middle of the stem. It will at least suffice to draw the attention of 
 more favoured observers to this striking structure, and will give a better 
 representation of it than the miserable trash of Gaudichaud (Plate X. 
 figs. 10. to 15.). Perhaps the history of the development of Aletris fragrans 
 will afford the first some conclusions on the point : An old stem of about 
 4*25 Paris inches in diameter consists of two parts : the primary stem, 
 about 7 lines in diameter, in which the vascular bundles exhibit the 
 usual arc-like course ; and an external, much more solid zone, gradually 
 formed by the cambium-layer. The vascular bundles passing from within 
 to the leaf-cicatrices permeate this external layer in a perfectly horizon- 
 tal direction. The external layer becomes divided, however, again into 
 four zones, which produce the appearance of annual rings when seen in 
 the transverse section. The three external ones are, when taken together, 
 of about the same thickness as the fourth internal one : they differ in this, 
 that in the external ones the fibres do not ascend vertically but obliquely, 
 consequently in a spiral round the axis, and wind towards the left ; in the 
 second in like manner, but winding towards the right ; in the third, 
 again, turned towards the left, and finally becoming gradually horizontal 
 in the fourth. I may remark here, that whilst the parenchyma is 
 arranged in vertical rows in the primary stem, it appears to be in hori- 
 zontal rows between the external vascular bundles, in the manner of the 
 medullary rays. 
 
 An essential difference presents itself here, according as the formative 
 layer is limited to the terminal bud (above the line x, y, in the woodcut fig. 
 160.), or whether there is a continuous layer in the whole circumference 
 of the stem below the rind, which is then bounded internally by it. The 
 latter occurs in the case of normally-branching stems, as, for instance, in 
 the Draccence,Aloinece,&n&Aroidece, the former in normally-simple stems, 
 as, for instance, in the Tulipacece, and Palms with undeveloped inter- 
 nodes. Beautiful investigations on this subject may be found, accompa- 
 nied by the carefully selected results of earlier observations, in Unger 
 (see his Bau und Wachsthum des Dikotyledonenstammes, Petersburg, 
 1840, page 34.). 
 
 I must finally make mention of the singular stem-formation in the 
 tropical Orchidacea. A large portion of these, such, for instance, as are 
 commonly described as having tubers, have not very thick stems (gene- 
 rally branched), with abbreviated internodes. Those branches, however, 
 which come to blossom, produce a peculiar form that has hitherto been 
 known as tuber (knolle). Either one of the more central internodes of 
 the blossom-bearing branch swells into a disproportionate mass of very 
 varying shape, or all the lower internodes of the branch form a longer or 
 shorter, more or less thick, fleshy mass. In both, as, for instance, in 
 Epidendrum cochleatam and Bletia Tankervillice, the regular course of 
 the vascular bundles may be distinctly observed, but in the case of the 
 last-named plant (I know not whether the same holds good for all simi- 
 larly formed) there is a peculiar vascular system intended for the new 
 lateral buds. Little branches pass from the external vascular bundles, 
 
 appears most enigmatical in the case of those which, like //, have not yet reached the 
 middle of the stem, when they cease, as in the drawing. 
 
PHANEROGAMIA : AXIAL ORGANS. 245 
 
 and run together in a horizontal direction below the rind, from both sides 
 up to the buds. On cutting vertically through one of these stems, we find 
 a transversely severed, strikingly large group of vascular bundles below 
 the rind, corresponding to each internode. It unfortunately happens with 
 the Orchidacece, as with the Cacti, that it is a matter of difficulty to obtain 
 a sufficient quantity of material to ascertain the anatomy or its history of 
 development. 
 
 D. DICOTYLEDONS. 
 I. Stalks. 
 
 The stalks frequently exhibit no essential differences from those apper- 
 taining to Monocotyledonous plants, since the distinction of the unlimited 
 or indefinite vascular bundles is often imperceptible in the growth of one 
 year. But the vascular bundles generally close in the first year into a 
 simple circle, and the external parts in several circles to form a ring, so 
 that the parenchymatous masses separating the individual bundles are 
 compressed together into medullary rays. In most cases thej vascular 
 bundles run from below upward in straight parallel lines. They form a 
 loop where the leaf begins, the edges of which furnish vascular bundles 
 for the leaf and the axillary bud, and the pith of the bud is thus brought 
 in connection with that of the stem by means of their opening, as in the case 
 of Tropceolum. THe vascular bundles supplying the leaves and buds gene- 
 rally separate from this loop exactly at the point where they enter the 
 leaf. Sometimes, however, they first pass through a longer portion of the 
 parenchyma of the pith or the bark (as in the Amaranthacece and Cheno- 
 podiacce).* In perfect nodes, loops of vascular bundles are seldom found 
 passing across the stem ; in general the parenchyma merely appears to be 
 tougher and closer at these points. We are here, on the whole, very 
 destitute of accurate investigations, more especially with regard to the 
 first year's stalk with undeveloped internodes. 
 
 II. Stems. 
 1. Developed Internodes. 
 
 A. With a simple Ring of vascular Bundles. 
 
 Here the vascular bundles very seldom run parallel, but generally in 
 serpentine lines, alternately approximating and retreating from each 
 other ; the meshes thus formed are filled by the medullary rays. Where 
 liber-bundles lie in front of the vascular bundles they follow the same 
 course. f Large and small medullary rays, and annual rings, are formed in 
 the manner indicated. Wherever there is a leaf, one large or several 
 
 * Very admirable observations on this last-named point may be found in Unger, 
 Bau, &c., des Dikotyledonenstammes, Petersburg, 1840. 
 
 f In this manner is formed that beautiful network which used formerly to serve the 
 West Indian beauties as a natural lace veil, and which was derived from Daphne Laaetta 
 (Palo di Laghetto, Lace bark tree, Bois de dentel/e). 
 
250 
 
 MORPHOLOGY. 
 
 smaller loops are formed (fig. 163. B), 
 from whose circumference the vascular 
 bundles are given off for the leaf and 
 axillary bud, while the openings furnish 
 parenchyma for the formation of the 
 bud. The vascular bundles of every 
 newly developed internode stand in 
 immediate connection with, and are im- 
 mediate prolongations of, that portion of 
 the vascular bundle of the preceding 
 internode still capable of development, 
 and thus the cambium of the vascular 
 bundles forms a continuous net through 
 the stem and branches of the whole plant. 
 During the developments of the vascular 
 bundles of the stem, and those con- 
 nected with them, and belonging to an 
 axillary bud that grows into a branch, 
 the base of this branch becomes more 
 and more covered with newly formed 
 wood. We thus see the same condition 
 established as in the Monocotyledons : 
 an under lateral branch crosses all the 
 layers of wood passing to the upper 
 parts. The difference is merely, that in 
 the Dicotyledons they are portions of 
 the continuous mass of the progressively 
 developing vascular bundles ; while in 
 the case of Monocotyledons they are 
 discrete parts, new vascular bundles. 
 The wood is very various in its composition ( 26.). 
 
 163 
 
 B. With several concentric Kings of vascular Bundles. 
 
 As far as I know, this condition is only met with in Piper (?) and 
 Pisonia ; and, perhaps, in a few of the Crassulacea, as in Crassula. 
 The separate vascular bundles continue to grow, and finally close into a 
 firm woody mass ; each, however, retains its own cambium, and likewise 
 a small portion of parenchyma, not perfectly dislodged : such, at any rate, 
 
 163 JEsculus Hippocastanum, natural size. A, A longitudinal section of the end of a 
 twig some time before the bursting of the bud : a, the pith ; b, the wood ; c, the bark ; 
 d d, cicatrices of the uppermost leaves of the former year ; e e, the vascular bundles of 
 these leaves; ff, the axillary buds of these leaves, with their scales, and the vascular 
 bundles belonging to them ; g, terminal bud of the twig, ending in a blossoming 
 panicle ; h h, cicatrices of the lowest scales of the bud which have fallen off, together 
 with the axillary buds already visible : somewhat above this, the still-closed scales, 
 together with their vascular bundles ; i, medullary mass, which enters into the axillary 
 bud. B, Deeper part of a twig in the region of a leaf cicatrix, and a (severed) 
 axillary bud, the bark removed from it on the side turned towards the spectator : 
 i, crevice between the portions of the wood for the passage of the medulla into the 
 bud. Below this crevice there are seven others, lying in a semicircle, for the escape 
 of the vascular bundles destined for the leaf. 
 
PHANEROGAMIA : AXIAL ORGANS. 
 
 251 
 
 is certainly the case in Pisonia. An old stem of Crassula (?) which I 
 once examined seemed to bear some resemblance to this. Here the 
 wood consisted entirely of wood-cells. Many separate vertical cords of 
 parenchyma were seen scattered through this mass, each having from 
 two to three spiral vessels. 
 
 All the conditions touched upon here still require a minute study of 
 the history of their development. 
 
 164 
 
 C. Stems of Climbing Plants. 
 
 The stems of many tropical climbers (Lianes, Llanos} exhibit a pecu- 
 liar structure, which has long been misunderstood. Even in our own 
 indigenous plants we meet with some indications of it. In the first year, 
 most of them exhibit nothing striking, if we do not regard the generally 
 square stalk as such ; and we find that they have a simple ring of vas- 
 cular bundles, which closes towards the end of the first period of vege- 
 tation into an ordinary wood cylinder. In the following years, however, 
 the peculiarities are more and more 
 strikingly manifested, consisting in the 
 wood not being uniformly developed to- 
 wards the exterior throughout its whole 
 circumference, but ceasing to grow at 
 definite parts, often regularly, and as 
 frequently in a fantastically irregular 
 manner, allowing the substance of the 
 bark to replace it. In this manner stems 
 are produced, which, in a transverse 
 section, exhibit the most varied distri- 
 bution of the wood. We meet with the 
 first indications of this peculiarity in 
 our indigenous species of Clematis 
 
 forming stems (fig. 164.), in the strikingly 
 broad and regularly arranged large me- 
 dullary rays (a) ; and in the six narrower portions of wood (&),. which 
 are not nearly so fully developed towards the exterior as the six broader 
 ones (d). To these we may add the Bigno- 
 niacece. After the wood has continued for 
 some time to be regularly developed, it ceases 
 growing in four different places (figs. 165 
 167. ), so that the bark is no longer pushed 
 outward ; and on the further development of 
 the wood in the remaining places, the bark 
 forms, in the transverse section, four septa 
 of variable thickness between the four portions 
 of wood. 
 
 In some species these cortical masses become 
 a definite degree broader in each succeeding 
 
 165 
 
 161 Clematis vitalba. Transverse section of the stem. , The pith, b, The smaller 
 wood-bundles, c, The large medullary rays, d, The larger wood-bundles, e, The 
 bark. 
 
 165, '66. :;. Transverse sections of stems of the family of the Biynoniacece, natural 
 size. At a we see the wedge-shaped cortical portions entering between the wood. 
 
 165 The four interposing portions (a, 6) may be plainly seen even by the naked eye. 
 
252 
 
 MORPHOLOGY. 
 
 167 
 
 annual ring, so that a sharply 
 marked step is formed on 
 each side (fig. 166.); in an- 
 other species all that is 
 formed are four very thin, flat 
 plates, wholly separated (in 
 consequence of drying) from 
 the wood (fig. 167.). Gau- 
 dichaud* collected this stem, 
 and has drawn it, like the 
 rest, very rudely. Linkf says, 
 " In order to form a branch, 
 a portion of the wood accompanying the pith turns to the side, and, by 
 its increase, forms the branch. Sometimes the young branch goes out 
 from a three or four year-old stem or branch, separates the layers, and 
 thus makes its appearance on the surface. It is then seen as a wedge in 
 the wood of the old branch, which is larger or smaller according to the 
 modification of the branches. If the nodes stand in a cross [how can 
 the nodes stand in a cross ?] four wedges are seen standing opposed to 
 each other. Very large wedges of this kind are found in the stems of 
 the BignoniacecB from Rio Janeiro, such as I now have before me." If 
 Link here means the portions of stem mentioned, coming from Gaudi- 
 chaud, this is but an evidence of sad superficiality. Still more striking 
 is the cross-section of many climbers of the family of Sapindacea. A 
 hasty glance would lead us to imagine that we had here a cylinder of 
 wood surrounded with bark in which other stems or branches with their 
 bark had become blended in their growth (figs. 168,, 169.). A minute 
 observation, however, refutes this view at once from the absence of pith 
 in the exterior woody masses. It is especially peculiar here, that, as 
 appears from Gaudichaud's 
 is not continued 
 
 TV \J \J\JL V JlltlOO\_-O J-U J.O ^OLJV^J.Cl>lAjr MV-'X-' dlACtJl A-lV^i V^j iii.tll/2 c*O 
 
 audichaud's showy pictures, this separation of the wood 
 uniformly throughout the whole length of the stem, but 
 
 * Loc. cit. tab. xviii. fig. 4. According to him, Bignonia capreolata would exhibit 
 the same phenomenon ; and this is to be found in some botanical gardens. A history 
 of the development of this peculiarity is very desirable. 
 
 f Element. Phil. Bot. ed. 2. vol. i. p. 273. 
 
 They consist of parenchyma, and concentrically arranged bundles of very much thickened 
 gold-coloured liber-cells : the wood exhibits no annual rings. The medullary rays are 
 present in the wood-wedges, which form, as it were, the continuation of the interposed 
 portions of the bark ; but they are far less conspicuous. The wood, besides the wood- 
 cells, contain also some parenchymatous cellular tissue. 
 
 166 The tissue of the wedges (a, a), passing in by step-like gradations from the bark, 
 is very remarkable. It exhibits distinct medullary rays, which are continued from it 
 to the pith, whilst they are very indistinct in the rest of the wood. Between the me- 
 dullary rays there are bundles of thick-walled and densely porous parenchymatous cells 
 (similar to many liber-cells ; as, for instance, in Cereus), and a great number of very 
 broad, thin- walled, scarcely perceptible, porous cells, whose steeply ascending transverse 
 septa exhibit strikingly evident reticulated fibres, the interstices of which are filled with 
 a membrane, closely beset with fine pores. 
 
 167 The narrow intervening pieces of bark (a a) consist here of but little cellular 
 tissue, and a greatly preponderating quantity of liber. Annual rings are not distinctly 
 traceable in the wood. The wood consists principally of parenchyma, having only thin 
 bundles of wood-cells. 
 
PHANEROGAMIA : AXIAL ORGANS. 
 
 163 169 
 
 253 
 
 170 
 
 in places (at the nodes ?) the woody masses merge partly into each other, 
 while the separation occurs again in a different mode of distribution. 
 Finally, the most astonishing phe- 
 nomena are seen in the families 
 of the AristolochiacecB (fig. 170.), 
 Asclepiadacece, Malpighiacece, and 
 the BauhinicB (fig. 171.), in 
 which, in the transverse section, 
 the woody mass appears divided 
 in the strangest ways by cortical 
 substance, separated into various 
 portions, and often elegantly 
 lobed. A great part of these 
 aberrant forms of stem were 
 brought home by Gaudichaud 
 from his voyages, and he has 
 represented most of them in a 
 very negligent manner in his 
 
 superficial book. A. de Jussieu has made better use of these mate- 
 rials, having inserted a most excellent investigation of the Lianes in 
 his monograph of the Malpighiacece, in which he has, by ingenious use 
 of the few materials for the history of development that were at his com- 
 mand, at least traced up these singularities to the general type of the 
 Dicotyledons. I pass by here a few other abnormal conditions, as, for 
 instance, the Phytocrene, described by Wallich (PI. Asiatics rariores), 
 
 168, 169. Transverse sections of stems from the family of Sapinrfacea>, natural size, 
 a, 6, Woody masses, wholly separated by bark from the main stem (c). In fig. 168. 
 these are homogeneous throughout ; but in fig. 160., on the contrary, arranged radially 
 around a cellular tissue occupying the middle, intermediate in character between pith 
 and medullary ray cells. 
 
 168 The annual rings are wanting in the central portion, as in the three peripherical 
 masses : the medullary rays are not very striking, and run in waving lines. The peri- 
 pherical portions have points (in one lying excentrically) from which medullary rays 
 pass out, but are without trace of pith. 
 
 169 Here, also, the crescentic marks in the five peripherical wood-masses are the 
 places whence medullary rays set out ; but these places are not composed of cellular 
 tissue : the linear arrangement of the wood-cells is continued through them, and even 
 porous tubes occur in the middle of them. The lines, however, in which the wood- 
 cells lie, make a slight curve at their entrance and exit from the crescentic mark ; and 
 thus this originates as a mere optical phenomenon. 
 
 170 Aristolochia biloba. Transverse section of the stem, a, Considerably developed, 
 deeply torn cork, magnified about four times. 
 
254 
 
 MORPHOLOGY. 
 171 
 
 because, from want of material, I could say nothing of importance about 
 them, and I look upon mere guessing as a most objectionable method in 
 Botany. 
 
 The great diameter of the porous tubes may, apparently, be regarded 
 as a general peculiarity in the ligneous structure of all climbing plants. 
 These have also strikingly large pores which (as I have never yet seen 
 in vessels) form even ramified canals, as is seen particularly well in 
 Bauhinia. 
 
 2. Undeveloped Internodes. 
 
 These have scarcely been investigated at all in the Dicotyledons. 
 Most of them remain very short, since they die below as they increase 
 upward. They belong principally to the subterraneous steins and 
 
 171 Bauhinia: spec. Cross-section of a stem one-third of the natural size, a, Wood- 
 masses, partly with strikingly large porous tubes, b, Cortical substance, c, Bun- 
 dles of true wood, arranged in a simple circle, very evident on account of their whitish 
 colour, with straight radial medullary rays. The principal masses form eight larger 
 portions of wood, the cross-section of which resembles more or less a Japanese fan, with 
 an almost always distinguishable pedicle of cortical parenchyma, and at the same time 
 traversed in the interior by anastomosing streaks of cortical substance. With the 
 exception of the circle of vascular bundles (c), the rest of the wood is chiefly composed 
 of parenchyma ; and the medullary rays run in curving lines. The cortical tissue con- 
 tains liber-cells and liber-bundles, even to the very interior of the stem. The wood- 
 bundles (c) do not run vertically, but obliquely laterally ; yet the section in my 
 possession is only about a line thick. 
 
PHANEROGAMIA : AXIAL ORGANS. 255 
 
 rhizomes. The leafless Euphorbiacece, Carica, Theophrasta, Nym- 
 phcea, and Nuphar, as well as many Cactacece, afford excellent material. 
 I at present know of no other researches in reference to this point, ex- 
 cept my own very imperfect ones into the stems of Cactacece, especially 
 Mammillaria, Echinocactus, and Melocactus. The vascular bundles at 
 first make an arc of considerable curvature ; by the gradual develop- 
 ment of the pith the curvature becomes almost effaced, and it only re- 
 mains in the upper part, where the vascular bundles pass off to the leaves. 
 The first succeeding layer developed in the vascular bundle is applied 
 over and ftp beyond this, dividing at the point where the primary vas- 
 cular bundle goes off to the base of the leaf, and uniting again above to 
 pass up to the base of a leaf situated higher up. The next layer of 
 structure forms in the same way, by splitting and reuniting, two meshes, 
 one for the primary vascular bundle, and one for the portion of the first 
 layer of increase running to the upper leaf, then above this it runs up 
 to the base of another leaf. This structure is continued up throughout 
 the whole stem, which thus possesses a form of wood exhibiting perfectly 
 regular meshes or areolae, which appear to be formed by an alternating 
 superposition of vascular bundles, and each give passage to a bundle 
 coming from the innermost part of the wood. Of course, there is here 
 a perfect crossing of the vascular bundles going to the lower leaves by 
 all the subsequently formed portions of vascular structure, and by a 
 little care we may make preparations not very unlike the structure of a 
 Monocotyledonous stem with undeveloped internodes. The whole struc- 
 ture bears great similarity to that of the arborescent Ferns, allowing 
 for the different nature of the vascular bundles and the difference of 
 dimension. 
 
 Many interesting varieties in the structure of the wood occur here 
 also ; and the wood of the Mammillarice and Melocacti, composed en- 
 tirely of peculiar spiral-fibrous cells, is particularly worthy of notice. 
 
 The stems of the Rhizanthece (Blume) appear to be altogether aber- 
 rant and irregular in their structure ; I cannot say anything about them, 
 since I have no material, and I refer to the researches of Unger and 
 Goppert presently to be named. 
 
 Even Moldenhauer * remarked, that one and the same vascular 
 bundle varied in its structure in different parts of its course. As a 
 general rule, we may say that in the Monocotyledons the vascular 
 bundles are simplest in their lower part, often, for instance, in the 
 Palms, composed at that part solely of elongated parenchyma (liber) ; 
 in the middle becoming more complicated from within outward, exhi- 
 biting almost all the forms corresponding to the varied expansion of the 
 cell ; above, they become simpler again, particularly where they pass off 
 into a leaf or branch, and consist frequently merely of such elements as 
 correspond to a considerable expansion in the longitudinal direction after 
 the appearance of layers of thickening. In the Dicotyledons the vas- 
 cular bundles appear to have a tolerably uniform structure below and in 
 the middle, but toward the upper end the onward developing portion of 
 each older bundle passes into the form of a primary bundle, or, in other 
 words, every primary vascular bundle of a new internode appears as the 
 immediate prolongation, not of the primary bundle of the preceding 
 internode (which rather runs to a leaf), but of the layer of increase of 
 
 * J. J. P. Moldenhauer, Beitrage, &c. 
 
256 MORPHOLOGY. 
 
 this, the elementary portions of which do not correspond to any expan- 
 sion in the longitudinal direction. 
 
 Literature, History, and Criticism. 
 
 We possess few or even no general fundamental researches into the 
 history of development of axial structure. Most authors present merely 
 anatomical investigation of dead specimens. I refer here to the following 
 as the only important essays that I know of : 
 
 J. J. P. Moldenhauer, Beitrage zur Anatomic der Pflanzen. Kiel, 1812. 
 An analysis of the stalk of Maize, masterly in every respect, considering 
 its time. 
 
 H. Mohl, DePalmarum Structura. Monachi, 183L 
 
 H. Mohl, Untersuchungen liber den Mittelstock von Tamus elephan- 
 tipes L. Tubingen, 1836. 
 
 Unger, Ueber den Bau und das Wachsthum des Dikotyledonen- 
 Stammes. St. Petersburg, 1840. 
 
 Unger, Beitrage zur Kentniss der parasitischen Pflanzen. Ann. des 
 Wiener Museum, vol. ii. 1841. 
 
 Goppert, Ueber den Bau der Balanophoren, &c. Act. Acad. L. C. N. C. 
 vol. xviii. Suppl. 1841. 
 
 Goppert, De Coniferarum Structura Anatomica. Breslau, 1841. (See 
 my review in the Neuen Jenaer Allg. Lit. Zeit. 1842, No. 15. 
 
 Schleiden, Beitrage zur Anatomic der Cacteen. From the Mem. de 
 1'Acad. Imp. des Sc. de St. Petersbourg p. div. Sav. vi. ser. t. iv. (Leip- 
 sic, Engelmann, 1842). 
 
 Miguel, Ueber den Bau der Melocacteen, Linnaea, Bd. 16. (1842), 
 p. 465. 
 
 Harting, Bydrage tot de Anatomic der Cacteen (Tydschrifft voor na- 
 turlyke Geschiedeniss an Physiologic door van Hoeven en de Vriese, 
 Bd.IX. 1842). 
 
 A. de Jussieu, Monographic des Malpighiacees. Paris, 1843. (Con- 
 tains excellent investigations on the structure of stems in climbing 
 plants.) 
 
 Naudin, On the Rhizome of Narcissus Pseudonarcissus in the Ann. 
 des Sc. Nat. 1844. Ser. iii. t. i. Botanique, p. 162 176. 
 
 V. Martins, Ueber den Structur des Palmenstammes, Miinchn. gel. 
 Anz. 1845. 
 
 Many isolated notices, not connected or compared according to any 
 leading principle, are to be found in Meyen (Physiologie), Bischoff 
 (Botanik) ; and in Treviranus (Physiologic), especial abundance of the 
 literature of the subject. 
 
 Almost all that has been said by isolated authors is wholly useless, 
 either because they have had no regard to the history of development, or, 
 if they have noticed this, have spoken so indiscriminately of growth, 
 increase and enlargement, without distinguishing whether new cells have 
 originated, cells already existing expanded, or merely become trans- 
 formed into different tissues by the alteration of the form and configura- 
 tion of their walls. 
 
 Two notions there are especially which have long sadly confused our 
 science, from which a correct method would have completely saved us, 
 since both were, at least at the time, and in the species on which they 
 were built up, wholly unfounded fables, having no connection with any 
 guiding principles, and consequently never should have assumed scientific 
 
PHANEROGAHIA I AXIAL ORGANS. 257 
 
 perspicuity, much less, as did happen, have served as a temporary basis 
 for theories pervading the whole science of Botany. 
 
 The first is the idea of Desfontaines of the distinction between Mono- 
 cotyledons and Dicotyledons, that the former develope new structure in 
 the centre of the axis, and grow in the inside (plantce endogence), while 
 the latter produce ligneous substance close under the bark, and deposit 
 it on the inner side, and thus grow on the outside (pi. exogence). All 
 this had no greater foundation than the fact that in the Mondcotyle- 
 donous axis the vascular bundles are farther apart in the centre ; conse- 
 quently, in the preponderance of parenchyma, the substance is more lax. 
 It was not ever attempted to make even a superficial observation of the 
 process of growth; if it had been merely observed that the vascular bundles 
 going to the lower leaves, consequently the older, crossed those going 
 to the upper leaves, which must be the younger, a child might have 
 been made to understand at once that a growth of new vascular bundles 
 in the interior was an absolute impossibility. Nevertheless, upon this 
 empty fancy, which a child might have refuted, De Candolle built a grand 
 system of vegetables, which it never did require the distinguished and 
 comprehensive researches of Mohl to overthrow. 
 
 The second notion is that of Du Petit Thouars, which was not less 
 ill-grounded, which, as expressed by him, would be upset by every, 
 even the most superficial observation, and even in its more refined subse- 
 quent statement is by no means established, but has important and ap- 
 parently irresistible objections against it. Du Petit Thouars thought 
 that all increase of thickness of the axis resulted from the descent of 
 roots from the buds. Such a crude notion scarcely required refutation. 
 On the other hand, it was afterwards stated that the formless but or- 
 ganisable substance (the cambium) was gradually organised from the 
 buds downwards. The only possible foundation for this view, namely, 
 evidence obtained by thorough investigation of the history of develop- 
 ment, is still due from all its assertors, the latest, Gaudichaud, &c., in- 
 cluded. Therefore it is already to be set aside as devoid of foundation. 
 But the contrary can be made good, that, in the first place, no cambium 
 ever exists as a formless fluid in the plant, unless we would so call the 
 cytoblastema enclosed in the cells ; secondly, that, so far as observation at 
 present reaches, cells are always formed in cells, that this cell-formation, 
 according to the observations I have made in the Cactacece, &c., pro- 
 gresses from below upward ; thirdly, that the axillary bud is already 
 formed in the terminal bud before the axis begins to increase in thickness, 
 and that certainly the cells of the bud are organised into vascular bundles 
 from the vascular bundles of the stem upward into the bud, and not in 
 the reverse direction. By these remarks the whole notion seems to me 
 to be for the present set aside, and it would require quite other support 
 than that which Gaudichaud's imperfect attempts in anatomy and phy- 
 siology could give it. 
 
 Lastly, I must notice the most recent views of Martius on the struc- 
 ture of the stems of Palms, &c. Martius asserts, that here the vascular 
 bundles, the primary structure of which is sketched out in the conical 
 terminal bud, on the whole, as I have already explained it (Wiegmarn's 
 Arcliiv, 1839, 219.*), do not merely grow upwards into the leaves, but 
 also downward, by their lower end, in the stem. These facts I must 
 
 * Beitraige zur Botanik, vol. i. p. 29. 
 3 
 
258 MORPHOLOGY. 
 
 entirely oppose from my own observations. Hitherto I have never had 
 an opportunity of investigating living Palms, or more than small frag- 
 ments of dead ones. But from what I saw I believe I may venture to 
 conclude that the stem of Palms does not essentially deviate in such a 
 way from those of other Monocotyledons, that one may not transfer to 
 the Palms, in the main points, the laws of structure found there. Now, 
 so far as I know, such a process of growth does not occur in any Mono- 
 cotyledonous plant. According to my observations the newly produced 
 vascular bundles merely grow continuously upward. In advancing the 
 distinction of limited and unlimited bundles Martius follows me, but. in 
 my opinion, he has not conceived nearly clearly enough the distinction 
 between developed and undeveloped internodes, and in particular he has 
 not formed a clear conception of the peculiarities of the stem with un- 
 developed internodes, and the conditions of structure resulting there- 
 from. Moreover, he has left the meaning of the term onward growth 
 (Fortwachsen) of a vascular bundle equivocal. If it means that the 
 already existing elongated cells become transformed into vascular bundles, 
 it describes no peculiar process of growth, the vascular bundles were 
 already to be distinguished in their elementary condition ; but if it means 
 that the cells themselves, of which the vascular bundles are composed, 
 are produced subsequently, originating above first and proceeding down- 
 ward, this is, I believe, erroneous. It is necessary to bear in mind the 
 essential distinction between Monocotyledonous axes with and without a 
 cambium circle, in order to understand these structures. Where no 
 cambium exists there are no other new cells formed besides those in the 
 point of the bud. But where there is cambium, all development, and so 
 also the development of new vascular bundles in the stem, proceeds up- 
 wards and outwards, never, so far a I have been able to observe, down- 
 wards or toward the interior. The lowest and innermost cells are always 
 the oldest, never the upper or outer (of course excluding the bark, to 
 which alone an endogenous growth can be ascribed). I must therefore 
 distinctly assert, that in the Palms, as in all Monocotyledons, the lower 
 end of an older vascular bundle never reaches down into an internode 
 lower than that in which the lower end of its first rudiment originated. 
 
 e. Review of Axial Structures and Terminology. 
 
 130. The following distinctions appear to me to be of impor- 
 tance from the points of view treated in the foregoing paragraphs. 
 
 1. Duration. 
 
 A. Annual. Stem (caulis). 
 Internodes (internodia). 
 
 a. Only existing in the beginning of the period of vegetation, 
 
 fugacious (internodia funacid). 
 
 b. Enduring the whole period (int. annua). 
 
 c. Only existing in the latter part of the period of vegetation 
 
 (int. serotina). 
 
 B. Perennial. Trunk (truncus). 
 
PHANEROGAMIA : AXIAL ORGANS. 259 
 
 2. Position on the Soil. 
 
 A. Above ground (epig&us). 
 
 B. Under ground (hypogceus). 
 
 3. Form. 
 
 A. Developed internodes (int. elongata). 
 
 B. Undeveloped internodes (int. abbreviate?). 
 
 C. Disciform expanded internodes (int. disciformia). 
 I). Concavely expanded internodes (int. concava). 
 
 N. B. Rigid, pointed, leafless, or defoliated internodes are 
 called spines (spince) ; soft, curling, and thus climbing round 
 foreign objects, tendrils (cirrhi, capreoli). 
 
 4. Various Internodes of the same Axis. 
 
 A. Bearing true leaves and branches (caulis and truncus). 
 
 N. B. Sometimes no leaves are developed (axis aphyllus), 
 or they fall off from the truncus, mostly at the end of the first 
 year (axis denudatus). The stem may grow out from the 
 terminal bud of an embryo, as in the simple stem, or out of 
 a trunk. A stem produced from a trunk might be called 
 scapus ; but this is a wholly superfluous term. 
 
 B . Bearing only bracts, bracteoles, or flowers, peduncle (pedunculi) ; 
 
 in a compound inflorescence the internode bearing a single 
 flower is called the pedicel (pedicellus). Receptaculum is a 
 superfluous expression in the Synantherece, pedunculus dis- 
 ciformis, conicus, &c., is simpler and more correct. Also in 
 Ficus, pedunculus coneavus. 
 
 C. Internodes between calyx and pistil, receptacle (torus), e. g., 
 
 in some Rosacece, torus disciformis (in Potentilla), torus con- 
 eavus (in Rosa). 
 
 a. Internodes between calyx and stamens (e. g., in Rubus), or 
 
 calyx and corolla (e. g., in Passiflora), the disc (discus), 
 e. g., planus (in Geum), d. tubulosus (in Cereus grandiflorus). 
 
 b. Internodes between corolla and stamens, androphore (an- 
 
 drophorum), e. g., a. elongatum (in Cleome). 
 
 c. Internodes between stamens and pistil, gynophore (gynG- 
 
 phorum\ e. g., g. conicum (in Rubus). 
 
 D. Internodes between calyx and seed-buds, as a hollow disc 
 
 enclosing the seed-buds, inferior germen (germen inferum), 
 e. g., in SynantherecB, Orchidacea. 
 
 E. Internodes between stamens and seed-buds, as a plate with the 
 
 borders curved inward together, in the cavity of which the 
 seed-buds occur, stalk-pistil (pistillum cauligenum). In 
 LiliacecK and Leguminosce (?). 
 
 F. End of the stalk in the germen, as support of the seeds, sper- 
 
 mophore (spermophorum), in seed-buds (gemmulce). (For the 
 parts of these see below, under the Seed-bud.) 
 
 5 2 
 
260 MORPHOLOGY. 
 
 5. As to the Nodes. 
 
 A. With imperfect nodes (caulis, truncus). 
 
 B. With perfect nodes. 
 
 a. Stalk (culmus). 
 
 b. Stem (calamus). 
 
 N. B. It is exceedingly useful to mark this distinction by 
 definite terms : but then we must name the stalk of the Caryo- 
 pliyllacece, most Umbelliferce and Labiates, culmus; the stem 
 of Bambusa, Calamus, Piper, Aristolochia, &c., calamus. In 
 other respects the expressions culmus and calamus have no 
 sense, since it could only be defined as a stalk, such as 
 occurs in the plants to which such a stalk is ascribed, 
 the former, namely, in some Grasses, the latter in some Cy- 
 peracece.* 
 
 6. Different Axes of Compound Plants. 
 
 A. Main axis produced from the terminal bud of the embryo 
 
 (caulis vel truncus primarius). 
 
 B. Secondary axis, produced from axillary or adventitious buds 
 
 (c. vel tr. secundarius). 
 
 N. B. Still connected with the main axis, called branch or 
 twig (ramus). 
 
 C. Ramification of the axis (ramificatio). Ramification of the 
 
 pedunculus (inflorescentia). 
 
 D. Secondary axis growing along underground, and its second- 
 
 ary axes alone rising above the soil, root- stock, rhizome 
 
 (rhizoma). 
 
 N. B. For secondary axes which lie upon the earth, because 
 they are too weak to stand erect, there are some special terms, 
 but these appear to me superfluous : jlagellum, stolo, sar- 
 mentum, runner, sucker, which are sometimes to be distinguished 
 by the foliation, sometimes by the rooting, now one way and 
 now another, and again may be different from the caulis 
 repens, humifusus, prostratus, procumbens, decumbens, sarmen- 
 taceus, and all the rest of this manufactory of words, and yet 
 cannot be separated by any characters. 
 
 E. It is useful to discriminate, according to the ramification and 
 
 duration, 
 
 a. The simple plant, the lateral buds of which are flowers (her- 
 
 bula), e. g., Cuscuta, Myosurus : 
 
 b. The branched stalk, herb (herba), e. g., Anagallis, Veronica 
 
 verna : 
 
 * How thoughtlessly a part of the terminology was made and applied cannot be seen 
 more strikingly than if we ascribe a calamus to most of the species of Scirpus, Carex, 
 &c., which, if scapus had any meaning, would fall altogether within its definition. 
 
PHANEROGAMIA : FOLIAE ORGANS. 261 
 
 c. With underground stems, stalks above ground, undershrub 
 
 (suffrutex\ e. g., Aconitum Napellus, P&onia officinalis : 
 
 d. Stem branched from below, without predominance of the main 
 
 stem, bush (frutex), e. g., Prunus spinosa, Juniperus Sabina : 
 
 e. Trunk, the lower branches of which soon die, and which only 
 
 bears a crown, tree (arbor), e. g., Pyrus torminalis, Fagus 
 
 sylvatica. 
 
 N. B. We also reckon among trees those stems also which 
 branch from below upward, but in which the main axis is 
 developed in far the greatest proportion, and may readily be 
 traced to the summit, e. g., Populus dilatata, Abies excelsa. 
 These might even be called ar bores fruticosce. 
 
 C. FOLIAR ORGANS. 
 a. Foliar Organs in general. 
 
 131. The leaves (JoKa) also may be divided into annual (folia 
 annua) and perennial (f. perennid) ; the former again into deci- 
 duous (f. decidua), which live only in the early part of the period 
 of vegetation ; yearling leaves (f. annua sensu stricto), which live 
 through the whole period ; and late leaves (/. serotina), which are 
 not perfected till toward the close of the period. With few ex- 
 ceptions every plant has temporary leaves, namely, the cotyledons 
 and frequently those next following them. The Orchidacece, some 
 species of Cuscuta *, and some Cactacece, are the only plants at pre- 
 sent known with certainty to be destitute of cotyledons. Others, 
 for instance the Rhizanthece, have not yet been sufficiently inves- 
 tigated. Many plants are wholly destitute of foliar organs between 
 the cotyledons and the peduncles of the flowers, as, for instance, all 
 the Cactacece, excepting Peireskia, and some species of Opuntia ; 
 in others these are annual, as in Alnus, or perennial, as in Pinus. 
 The floral parts, the leaves last perfected, exist in all Phanero- 
 gamous plants. 
 
 I. The general character of all foliar organs lies solely in the 
 history of development, as already has been shown ( 120.). It 
 follows from what was said there, that the leaf is, as it were, pushed 
 out from the axis; that the summit is its oldest, the base its 
 youngest part. It follows, moreover, that the power of develop- 
 ment in a leaf is limited, and never persists long when the terminal 
 shoot becomes removed from it by onward growth. Finally, 
 observation of the course of development also shows that the foliar 
 organ is altogether determined by the axis, as a definite product of 
 the fashioning organisation, that a protracted duration of the pro- 
 cess of development may indeed somewhat increase the volume 
 
 * In Cuscuta monogyna, for instance, the embryo has distinct foliar organs. 
 C. americana, arvensis, congesta, epilinum, epithymum, europcca, nitida, umbrosa, have no 
 trace of them. 
 
 s 3 
 
262 MORPHOLOGY. 
 
 and influence the internal structure, but never can change the 
 destined form. Thus, consequently, the leaf is the form, deter- 
 minate in its growth, and therefore morphologically, which proceeds 
 from the fundamental element of the plant, the axis, indeterminate 
 in its growth, and therefore morphologically indeterminate : this 
 definition includes all foliar organs, and excludes all axes. 
 
 I do not think that it will be possible, in the first place, to find a more 
 strict expression of the distinction between leaf and axis than is here 
 given, yet I feel deeply that it is very far from being the only correct 
 and sufficient one : but here again we require a much deeper penetration 
 into the history of development than up to this time has or could have 
 been attained (see Plate III., figs. 1 1 1 .). Progress will first become pos- 
 sible when we have resolved the whole process of formation in the leaf into 
 the history of the formation of its individual cells, which, as the most 
 difficult task in all Botany, will yet remain long unperformed. At the 
 same time it is not to be denied, that the distinction between leaf and 
 axis is the sole scientific basis for the whole morphology of the Phane- 
 rogamia. It has certainly been more easy to comprehend this since 
 Goethe's Metamorphosis of Plants has conjured up a presentiment of the 
 morphological unity of the law of formation, but little has yet been done 
 for the strict and scientific comprehension of the matter. As I have 
 already observed, the cause of this is the want of philosophical, especially 
 logical, exposition ; for it is not noticed that the obscure ideals of the 
 imagination must be elevated into conceptions capable of definition by 
 inductive method, to fit them for a properly scientific treatment. How 
 little our text-books fulfil this purpose has been already remarked. 
 Let us take another example : Link * says, " ' A leaf,' says Joachim 
 Junge, * is that which expands upward, or in length and breadth, from 
 the place at which it occurs, and the boundaries of the third di- 
 mension of which, that is. the inner and outer surface of the leaf, are 
 different from each other.' This definition excellently marks all foliar 
 parts." That this pretended excellent definition does not at all apply to 
 the parts of the flower (which certainly are foliar parts) is clear, but 
 it does not apply to any leaves of Pines, of Mesembryanihemum^ Sedttm, 
 Opuntia, nor to the scarious stipules of the Paronychiacece, &c. Link 
 says, further : " The main distinctive character of leaves is the position 
 beneath the buds. Every true branch originating from a bud," (yet 
 only from an axillary bud,) "is supported at its base by a leaf. . . but 
 all leaves do not support branches." How, then, does Link know that 
 these are leaves, when they are deprived of their principal distinctive 
 character? No science will be advanced in this way, but merely ground- 
 less chattering stereotyped. 
 
 II. When the leaf emerges from the axis it is a little conical 
 body, the base of which gradually comes to occupy the entire cir- 
 cumference of the axis, a stem-embracing or amplexicaul leaf (f. am- 
 plexicaule) ; or it shares the circumference of the axis with one or 
 more other leaves, which have originated with it on the axis in the 
 same plane, whorled leaves (f. verticlllata) ; or, lastly, it is confined 
 to a small portion of the circumference, without any other leaves 
 
 * Elem. Phil. Bot. ed. 2. vol. i. p. 410. 
 
PHANEROGAMIA : FOLIAR ORGANS. 263 
 
 arising from the axis in the same plane, scattered leaves (f. spar so). 
 These three positions of the leaves upon the axis are, most un- 
 doubtedly? the primary ones occurring in the plant. We find the 
 first in the cotyledon of the Monocotyledons ; the second in the 
 cotyledons of the Dicotyledons. But if we disregard, in the Mo- 
 nocotyledons, the character of embracing the stem, only looking to 
 the fact that one leaf alone is formed at one level on the stem 
 if we trace the further development of the leaves of Monocoty- 
 ledons, and of those of most Dicotyledons, since in the latter it is 
 only in a few groups that the later leaves are formed in whorls, 
 we find that the great majority of plants have scattered leaves. 
 If every vegetable axis be regarded as a cylinder, the bases of 
 the leaves must admit of being connected by a spiral line. More 
 minute investigation, then, shows that the distances of the bases of 
 the leaves on this spiral are not without law ; but a certain regu- 
 larity may be observed, and, in fact, the angle (angle of divergence) 
 made by two planes, passing through the middle of the axis and 
 the bases of two adjacent leaves, which angle therefore is the 
 measure of the distance of these leaves from each other, is on an 
 average 137 30' 28", consequently a number bearing no ratio to 
 the circumference of the stem (360) ; so that no two leaves ever 
 can be exactly in the same vertical line. In the course of the 
 entire axis the distances of the turns of the spiral alter, but always 
 regularly, sometimes even on account of accidental influences ; and 
 thus from the simplest fundamental condition proceeds an infinite 
 multiplicity of modes of manifestation, even when the various forms 
 of the axis do not interfere. Compare but the rosette of leaves of 
 Sempervivum tectorum, the stalk of Lilium Martagon, a shoot of 
 Populus dilatata, a cone of Abies excelsa, and the fruit peduncle 
 of Heliantlius annuus, which latter exhibits the regular position 
 of the leaves even through its fruit which originate from axillary 
 buds. 
 
 The study of the position of leaves has recently occupied so many 
 excellent labourers, that it indeed cannot be attributed to the want of 
 talent or applied industry if the results obtained are at present so little 
 satisfactory or certain. Rather have we to seek the cause in the inac- 
 curate methods, and, secondly, in our as yet so imperfect knowledge of 
 the nature of plants generally, especially of the laws of their morpho- 
 logical development. In reference to the first point, it must be remarked 
 that observation and research have been restricted wholly to isolated, 
 determinate conditions of the developed plant, when the abortion of 
 particular parts has so frequently already destroyed the regularity of the 
 rudiment, while at the same time the recognition of this fact has opened 
 the door to fancy, so that when the phenomena would not exactly suit 
 themselves to a preconceived hypothesis, this has been supported by a 
 supposed abortion of the parts. Two very opposite paths have been 
 struck out, one by the Germans, Schimper and Braun, the other by the 
 French, the brothers Bravais. Schimper arid Braun examined a count- 
 less multitude of cases, sought by the most accurate measurements 
 possible to obtain a series of results, which they used as a basis for an 
 
 s 4 
 
264 MORPHOLOGY. 
 
 induction, and believed that they thus discovered that, in an overwhelm- 
 ing majority of plants, spirals were the basis of the position of leaves, and 
 that the angles of divergence were rational parts of the circumference in 
 the series of fractions ^, ^, f , -f , T 5 F , ^ 8 T . . . , the law of which is at once 
 evident, since every succeeding member originates from the sum of the 
 numerator and denominator of the two preceding members. In all 
 these spirals it naturally holds, since the angle of divergence is a rational 
 fraction of the circumference, that, after a certain number of leaves, one 
 will again be exactly vertically over the first leaf. They found a 
 number of other laws for the sequence of the individual spirals of the 
 same axis, as well as on different axes of the compound plants ; at the 
 same time they observed other aberrant conditions, which were neglected, 
 partly as exceptions, partly as independent occurrences, in turn, of a 
 peculiar regularity. The brothers Bravais started from the consideration 
 of a mathematical spiral described about a cylinder, investigated the 
 laws of position of points marked upon this at equal distances, and of 
 deviations from them, when the distances of the turns of the spiral 
 decreased and increased, when the cylinder was supposed to be an acute 
 or obtuse cone, when a plane or concave surface. Then they sought to 
 apply the laws thus found to actual plants, in instituting a multitude of 
 very accurate and well-imagined measurements, defined the limits of 
 error in these measurements, and finally showed that there was nothing 
 to oppose their assumption of a single constant angle of divergence for 
 all spirals, since the deviations of Schimper and Braun's discoveries fell 
 within the limits of the possible error in the measurements. On account 
 of the irrationality of the angle of divergence to the circumference here, 
 no leaf ever stands exactly vertically over another throughout the whole 
 axis. The spiral is from its nature infinite, and only comes to a ter- 
 mination by cessation of growth of the axis. Under this law they 
 include all the cases of Schimper's series, above given, and many others 
 besides, which Schimper could only take cognizance of through the 
 assumption of a different kind of regularity. They call these leaves 
 curviserial (feuilles curviseriees). Beside these remains a series of 
 different cases, in which the leaf undoubtedly stands perpendicularly 
 over a preceding one ; these they call rectiserial (feuilles rectiseriees\ 
 of which they have not yet given their development of the laws : they 
 intimate, however, in their published views, that transitions from one 
 system to the other occur, from whence it may be concluded that perhaps 
 both may admit of deduction from one law. 
 
 Neither of the theories as yet possesses a safe foundation, since both 
 regard only the developed plant, instead of tracing the course of develop- 
 ment. The developed plant does not present itself as a mathematical 
 body, and none of its leaves exhibit a mathematically equal divergence ; 
 we cannot come to the point here without a certain amount of setting 
 right, and the admission of a pretty wide margin for errors of observa- 
 tion. The brothers Bravais say themselves, mathematical accuracy 
 is almost superfluous in such researches, which admit of it so little ; but 
 they are certainly too good mathematicians not to admit, that mathema- 
 tical laws which are not true to the hair's breadth are good for nothing. 
 On the other hand, the history of development would of course place in 
 our hands the power to find the mathematical laws confirmed with 
 perfect exactness by experience. It only needs to observe the leaf- and 
 flower-buds of Conifer^ Syn anther ece, &c. beneath the microscope, to be 
 astonished at the elegant and exact regularity which they here so strik- 
 
PHANEROGAMIA : FOLIAR ORGANS. 265 
 
 ingly exhibit in their rudimentary condition. Here careful preparation 
 and well-directed manipulation will safely admit of the measurements, 
 which must confirm the laws with complete exactness, or overturn them. 
 Moreover, the history of development alone can decide whether or not an 
 abortion has ever occurred, which expedient in particular the brothers 
 Bravais, like the whole French school since De Candolle, use rather 
 too liberally. Finally, the whole matter can only acquire especial 
 importance in botany, when we are in a condition to show, in the nature 
 of the plant, the cause why the leaves arrange themselves in a certain 
 spiral, why necessarily in this, and why they deviate therefrom under 
 certain conditions. Then will the matter first come forward as something 
 actually appertaining to the nature of the vegetable organism, since, for the 
 present, we really possess nothing but the examination of the nature 
 of the spirals in general, and the demonstration that, under certain pre- 
 suppositions, these laws found for spirals admit of confirmation in the 
 position of leaves. 
 
 Setting aside this want of more complete scientific establishment, 
 the theory of the brothers Bravais is undoubtedly far preferable. 
 Above all, the simplicity of the law is made good, and, according 
 to a sound method, that mode of explanation is always preferred, which, 
 under equal possibilities, traces back the greatest number of cases to 
 a single point of view. Under these circumstances, perhaps, Bravais' 
 theory may even indicate how, one time or other, the regularity of the posi- 
 tion of leaves may possibly be deduced. If we recollect the well-known 
 fact, that the usually greater development of root, on account of better soil 
 on one side of a tree, also corresponds to a stronger development of the 
 annual rings and branches on this side, if we bear in mind the so fre- 
 quently isolated course of vascular bundles, which, in that case, indicate 
 the path of the influx of sap from the root to the leaves, it seems to 
 follow from this, as from a regard to what has been stated generally 
 above in reference to the independence of the vitality of the cells, that also 
 the separate perpendicular portions of the axis, lying horizontally side by 
 side, have on the whole little influence upon each other, and are tolerably 
 independent in themselves. If, then, the greatest possible number of 
 leaves be placed upon the axis, and their most uniform possible distribu- 
 tion round the whole periphery, and thence the most uniform possible 
 nutrition be effected, two leaves, one following the other, must necessarily 
 have the greatest possible, and, in relation to the circumference, irrational 
 angle of divergence, which demand the angle found by the Bravais, 
 137 30' 28", completely answers. Of course this is at present but a 
 teleological ground of explanation, but such an one may serve until a 
 better, and the true one, be found, and it may even be the index pointing 
 where to seek the truth. 
 
 Since the buds become abortive much more readily than the leaves, and 
 often become quite displaced from their natural position by unequally rapid 
 maturation, the application which both the German and French savans 
 have made of their views to the inflorescence, seems to me to be so much 
 the less admissible, in the entire neglect of the history of development at 
 present, that it does not recommend itself by simplicity, but even deters 
 us by a rather complicated terminology. I will not by any means assert 
 that the authors have not succeeded in many instances in interpreting 
 nature correctly, but they have neglected the only possible and accurate 
 foundation the course of development ; and, therefore, there is too 
 great a danger, in accepting these doctrines, of introducing something 
 perhaps wholly false into science. 
 
266 MORPHOLOGY. 
 
 More details will be found in the following works : 
 
 Dr. Schimper, Description of Symphytum Zeyheri, &c., in Geiger's 
 Mag. fiir Pharmacie, B. XXIX. p. 1. et seq. 
 
 Dr. A. Braun, Comparative Researches into the Arrangement of the 
 Scales in the Fir Cones, &c. ( Veryl. Unters. ub. die Ordn. der Schup- 
 pen an den Tannenzapfen, fyc.) Nov. Act. Acad. C. L. N. C. T. xiv., 
 vol. i. pp. 195402. 
 
 Dr. Schimper, Essays on the Possibility of a Scientific Comprehension 
 of the Position of Leaves, &c. ( Vortrdge ub. die Moglichkeit eines 
 wissensch. Verstdndnisses der Blattstellung, fyc.) Published by Dr. A. 
 Braun, Flora Jahrg. xviii., No. 10, 11, 12 (1835). 
 
 L. and A. Bravais, Memoires sur la Disposition geometrique des 
 Feuilles et des Inflorescences, precedes d'un Resume des Travaux des 
 MM. Schimper et Braun sur le meme Sujet, par Ch. Martins et A. 
 Bravais. Paris, 1838. 
 
 III. The primary form in which the leaf makes its appearance 
 is, as I have above stated, always that of a little conical body which 
 is pushed out from the axis; its ulterior form depends entirely 
 upon the arrangement of the newly originating, and the expansion 
 of already existing cells, and the leaf is as little confined to a 
 definite circle of forms as any other of the organs, except the seed- 
 bud. It may be globular, ovate, elliptical, and prismatic, as well 
 as filiform, strap-like, and flattened in its expansion, and, by the 
 greater accumulation of the cells in the middle than on the 
 borders, or more flattened mode of expansion in the middle than 
 on the borders, the plane surface may also produce concave forms. 
 The most striking forms of this kind are called pouches (asci), as 
 in Sarracenia, Cephalotus, Utricularia. In all these forms occur the 
 modifications mentioned in the general morphology ; in the plane 
 leaves, especially the divisions and slight indentations of the border. 
 One of the most frequent forms, which is usually laid down as the 
 normal form, is this, the upper part is developed into a plane, the 
 blade of the leaf (lamina), the lower into a filiform part, the petiole 
 or leaf-stalk (petiolus), and in the latter may frequently be dis- 
 tinguished, still lower down, a somewhat thickened or expanded 
 portion, a sheathing portion (pars vaginalis), with which the leaf 
 partly or wholly embraces the axis. This latter portion is fre- 
 quently, especially in compound leaves, swollen into a greater 
 thickness (fleshy), and is then called the cushion (pulvinus) of the 
 leaf or petiole. As a general rule, the flat leaf is so developed that 
 its surfaces look more or less upward and downward, rarely so that 
 its borders have these directions, so that the axis lies in the plane 
 of the leaf, as, for instance, in many New Holland Myrtacece. It 
 is very different from this when a flat leaf of the usual development 
 makes a half turn on its base, so that its surfaces are thus also 
 placed vertically, as, for example, in Lactuca Scariola. One condi- 
 tion, which has already been mentioned when speaking of the axis, 
 occurs also in the leaf, and here becomes of much greater import- 
 ance. A joint (articulatio) is formed rarely (or never?) in the 
 Monocotyledons, frequently in the Dicotyledons, between the leaf 
 
PHANEROGAMIA I FOLIAR ORGANS. 267 
 
 and the axis, in consequence of which the leaf is, after a certain time, 
 thrown off from the axis, while in other cases it gradually dies and 
 decays on the axis itself. This true articulation is often repeated 
 in the continuity of one and the same leaf, either only so that a 
 joint is formed between the petiole and the lamina (e. g. in Citrus, 
 DioncBa), or in such a manner that in the flat sub-divided leaves 
 (e. g. f. pinnatisecta, palmatisecta, &c.), every lobe is connected to 
 the main body by a joint. These latter are called compound leaves 
 (y*. composita), and, according to the subdivision, digitate or 
 pinnate (f. digitata, pinnata, &c.). The separate parts are named 
 leaflets {foliola), and the part connecting all these is the common 
 petiole (petiolus communis). The leaflets can of course assume all 
 the forms of the leaf, in particular they may be again separated into 
 lamina, petiole, and pulvinus. In some New Holland Acacias 
 (e. g. Ac. heterophylla) the first leaves are compound ; they gradually 
 form fewer and fewer leaflets, till at last the part corresponding to 
 the common petiole alone remains, which then appears as a perpen- 
 dicular plate, and is called a pliyllodium, to distinguish it from the 
 other perfect leaves of the same plant. 
 
 Botanists who imagine that the object of Botany is merely the correct 
 definition of many species for their herbaria, will blame me for super- 
 ficiality and want of profundity, in that I have so briefly and roughly 
 treated the forms of leaves, which are the most essential grounds for the 
 definition of species. I cannot help this : I merely find in these, as it 
 ]imy happen, good and bad methods of nomenclature for various partly 
 or wholly divided surfaces or borders, for filiform or solid forms, nothing 
 at all botanical, much less, therefore, the properly scientific part of 
 botany. If a slender filiform leaf be called a petiole, I have no objec- 
 tion to it, if nothing else be called by this name but a stalk-like leaf; but 
 when it is superadded that the lamina is suppressed here, this is unscien- 
 tific and false : if a leaf merely developed into a plate be alone called 
 folium sessile, there is nothing to be said against the term ; but when, in 
 addition, it is said that the petiole is abortive here, this is again pure 
 imagination. Whence in all the world does it follow from the essence of 
 a plant that a leaf must regularly consist of lamina and petiole ? The 
 entire method in use up to this time, of describing the leaf according to 
 blade and stalk, and of reducing all other forms under this conception, 
 might so far have value, if we would, from the analogy of zoology, hold 
 by the most perfect form, in order to obtain a type, with which to connect 
 all others as deviations ; then, however, we must start from the com- 
 pound leaf, as evidently the most perfect. But it is as false to call all 
 deviations, abortions, and Nature's unsuccessful attempts at forma- 
 tion, as it would be ridiculous to say that in Monas lens the toes and 
 nails, the cartilage of the ear, &c. were abortive. Expressions such as 
 " Nature has here attempted, she has here deviated from her type," are 
 altogether unscientific, and no better than childish anthropopathy. In 
 Mesembryanthemum^ for instance, Nature has not deviated frotri the type 
 of leaf-formation, but her type is different here from what it is in other 
 plants ; each in its kind is perfect, attaining the grand purpose of all ve- 
 getable development, the development of the most manifold construction 
 of form from the very simplest elements. 
 
268 MORPHOLOGY. 
 
 I must here particularly remark, that there is no sense in explaining 
 the triangular leaves, e. g. in some species of Mesembryanthemum, as 
 leaves originally plane, which were then folded back and grew toge- 
 ther by the posterior surface, or in regarding the leaf of the Iris as one 
 folded together on the upper face, and with the sides grown together. 
 The only proof which could be given of this would be the history of de- 
 velopment, and this shows that such folds and growings together do not 
 occur, but that, formed originally like all other leaves, the latter leaf ex- 
 pands into a vertical plate, the former into a triangular one, and nothing 
 more. Through nothing else whatever can natural laws be established, 
 but we must trace back all forms to one, or rather deduce all from one. 
 That assertion would have a meaning only under the presupposition of 
 such a natural law. But the mere fiction of such a natural law may be 
 unconditionally repulsed. According to a fiction of Link's, in the same 
 way arbitrarily manufactured, the leaves of Abies excelsa, alba, &c. ori- 
 ginate from two with the upper faces grown together, which one sees 
 in the two mid-nerves projecting above and below. Truly Abies pecti- 
 nata and Pinus sylvestris have an indication of two free, parallel, vascular 
 bundles, but Abies excelsa, alba, &c. only of one, and in the latter the 
 upper and under halves are of a totally different structure ; finally, the 
 history of development shows decisively that only one leaf exists here, 
 and not two grown together. 
 
 I will add a few words respecting the pouches or pitchers which occur 
 in Nepenthes, Sarracenia, Cephalotus, Dischidia Rafflesiana and cla- 
 vata, Marcgravia, Norantea, Utricularia, &c. At present we have not 
 a complete history of development of a single species. The researches 
 which I made formerly into Utricularia unfortunately still remain very 
 imperfect. The pouches apparently present three different types : a. 
 In Sarracenia it is the lower part of the leaf which exhibits a form resem- 
 bling a cornucopia, while at the upper border runs out a flat expansion 
 (the lamina of the leaf) separated from the pouch by a deep incision on 
 each side. The lower half of the internal surface of the pouch is clothed 
 with hairs, directed downwards ; the upper part is smooth. In Nepen- 
 thes a pitcher-shaped structure is borne upon a long petiole, winged 
 below, then often tendril-like, and carries upon its upper border an 
 articulated (?) lamina, which originally closes the pitcher like a lid. The 
 inner surface is clothed in the lower part with little papillae of very de- 
 licate, succulent cellular tissue, while above the epidermis projects down 
 over these like the eaves of a house. In both, the cavity is formed from 
 the leaf in such a manner that the closed base of the pouch corresponds 
 to the base of the leaf (Sarracenia), or lies quite close to it (Nepenthes). 
 In Dischidia Rafflesiana and clavata, on the contrary, the opening of the 
 pouch is turned towards the base of the leaf; Cephalotus appears to 
 possess a structure similar to that of Sarracenia* In all the plants men- 
 tioned the pouch constitutes the main body of the leaf. (Some have 
 found pleasure in debating whether the lid in Sarracenia and Nepenthes 
 is the blade of the leaf or not, and how the individual parts are to be 
 traced back to the supposed normal leaf.) b. In Marcgravia and No- 
 rantea, on the other hand, according to Lindley, the pouches are formed 
 by the stipules, c. Lastly, in Utricularia, many separate little portions 
 of the greatly divided leaf unite to assume a very complicated form of 
 pouch. Originally these form a little, shortly-stalked, somewhat cornet- 
 
 * I only know Cephalotus and Dischidia from descriptions. 
 
PHANEROCAMIA : FOLIAR ORGANS. 269 
 
 shaped body, in the angles of the divisions of the leaves. In this little 
 body are especially developed the under side and the inner border of 
 the orifice (which does not increase much in size), so that the full- 
 grown pouch presents itself as a roundish and somewhat laterally 
 compressed body, which above is continuous by one angle with the stem, 
 while the other exhibits an orifice, which forms a little funnel projecting 
 inwards. The external orifice of this funnel is closed by a kind of 
 beard growing on the upper border ; the lower part of the internal sur- 
 face of the funnel is clothed with elegant hairs of various forms, but 
 very regularly arranged, while the internal surface of the pouch exhibits 
 peculiar hairs, consisting of two cells, each running out into a longer or 
 shorter arm. 
 
 In leaves, as in plants in general, all forms are possible, and almost 
 all actually existing, strict stereometric forms excepted. The termi- 
 nology depends either on comparison with mathematical figures, or with 
 objects presupposed to be familiar in common life. We have no sci- 
 entific rule for this, esthetic tact alone must be our guide. But within 
 the limits of certain vegetable groups, certain circles of forms do exclu- 
 sively occur ; and, under the guidance of accurate observation, we can 
 here establish more definite modes of nomenclature, which, however, are 
 only valid for these definite groups. But this belongs to special botany. 
 Lastly, it is wholly useless to teach the learner all the individual expres- 
 sions, since most of them, from the facts that they are merely figurative, 
 and that their correct application depends upon the degree of tact of the 
 individual, are differently explained and applied by almost every botan- 
 ist. I have adduced a stupid instance of this in the first part, and hun- 
 dreds of similar examples might be collected in reference to almost every 
 plant from the definitions of different botanists, and there is nothing 
 left for the student but, for every author that he wishes to use, to 
 begin the whole matter over again, and learn what is the exact sense in 
 which he uses the expressions.* 
 
 The most important point evidently would be the laying down of mor- 
 phological laws for the development of the forms of the leaf on one and 
 the same axis of one and the same plant, genus, family, &c. ; but nothing 
 has yet been done towards this. The following alone can be expressed 
 in very general terms : 1. The forms of the leaf low down on the pri- 
 mary axis are the simplest ; they exhibit gradually upward greater and 
 more manifold combinations, and return finally at the extremity to 
 greater simplicity. The secondary (lateral) axes usually begin in the 
 same way with imperfectly developed leaves (scales of buds), the forms 
 then becoming more complicated, and finally simpler again. The end of 
 the axis is here always known by the inflorescence. Both in the primary 
 and the secondary axes, the transition from the simpler earlier forms (the 
 cotyledons and bud-scales) into the variously developed leaves, is some- 
 times sudden, and sometimes very gradual through a number of interme- 
 diate forms. 
 
 2. Leaves which are formed under ground are always more simple 
 
 * If we went through the works of our most important systematists, we should, per- 
 haps, not find one single definition in which two different so-called technical terms are 
 not applied to the same fact ; and I believe that I am right in saying that all these 
 Latin and corresponding German descriptive terms mark no clear, and, in particular, 
 no botanical, definitions, but serve for description of his impressions, according to 
 the choice and skill of each individual, as well as any others which he might select ; 
 and to fill books or lectures with German translations of these Latin terms is a most 
 unconscionable waste of time. 
 
270 MORPHOLOGY. 
 
 than those produced upon the axis above the surface. The former have 
 usually the form of scales or spines. 
 
 3. Leaves which bear leaf-buds in their axils are generally more varied 
 in form than such (bracts) as bear flower-buds in their axils. 
 
 4. The forms of leaves on one and the same axis are commonly of 
 similar kind, or pass continuously into each other, within the limits of 
 one definite series. Yet there are some remarkable exceptions to this, as 
 in some Aracece, and especially in the Cycadacece. In these plants two 
 forms of leaf occur regularly upon the same axis : in the Aracece very 
 short membranous sheaths alternate quite regularly with leaves having 
 sheath, petiole, and lamina ; in Cycadacece most of the leaves are mere 
 broad fleshy scales, which are placed spirally round the thick undeveloped 
 stem, but among these occur, at first isolated, in well-grown stems more 
 frequently, the great, handsomely pinnate or variously divided leaves, 
 which regularly continue the spiral, taking the place of those scales : the 
 sheathing portion of these leaves corresponds exactly to one of the 
 scales ; instead of a developed petiole and lamina, the scale bears only a 
 little slender process. Only through most superficial observation could 
 Link have asserted that the leaves spring from the axil of a scale.* 
 
 IV. If we examine the cotyledon of most Monocotyledons we 
 find that, in its gradual development, it completely encloses the 
 terminal bud (plumula) ; indeed that the exceedingly delicate, soft 
 cells of the two borders of it become in part so firmly united, that 
 they may be regarded as grown together, only a little fissure, which 
 exists in all Monocotyledons, remaining. In germination the de- 
 veloping bud has not room to protrude through the little fissure, 
 so that it pushes the borders of it more or less forward, and then 
 these appear as a peculiar appendage on the middle of the coty- 
 ledon, as a membranous expansion of the border of the lower part 
 of the leaf, or as lobes on its base. Similar conditions also occur 
 frequently in the later leaves. In the Dicotyledons, a like con- 
 dition presents itself not unfrequently ; either the borders become 
 expanded like a membrane on the base of a petiole or stalk-like 
 leaf, or the emerging bud lifts up a longer or shorter membranous 
 sheath, or peculiar lobules are formed on the base of the petiole, 
 sometimes assuming the form of leaflets, and even connected with 
 the petiole by an articulation. In all cases, without exception, 
 they are, from the course of the development, parts of a leaf de- 
 veloped principally at its base, and in their essential nature, wholly 
 identical structures throughout all the Phanerogamia, though they 
 may vary most abundantly in their appearance. They have ac- 
 quired very different names, which have been created, partly merely 
 for particular families, partly solely for particular foliar organs. In 
 the Grasses these parts are called the ligule (ligula) : in other Mo- 
 nocotyledons, sometimes vagina stipularis, if large and rising free 
 from the lowest part of the leaf; vagina petiolaris, if small and 
 showing itself first higher up the leaf : in the Dicotyledons petiolus 
 alatus, stipules adnatce, if on the margins of the leaf-stalk ; ochrea, 
 
 * Wiegmann's Archiv, 184J, vol. ii. p. 372. 
 
I'HANEROGAMIA : FOLIAR ORGANS. 271 
 
 if sheathing, as in the Polygonacece ; or stipules (stipules), if appear- 
 ing like special leaflets stationed beside the base of the petiole ; 
 lastly, in the floral leaves, fornix, corona, nectarium, c., as in 
 Lychnis, Boraginacece, Narcissus, &c. They occur as stipules, es- 
 pecially in compound leaves, where, sometimes, they alone are 
 developed into a flat surface, while the leaf itself merely forms a 
 filiform process, e. g. in Lathyrus Aphaca. At the base of the 
 leaflets of compound leaves also little lobes sometimes occur, 
 which, perhaps originating in the same manner, are called stipelles 
 (stipellce). 
 
 The organs just mentioned are developed last of all the parts of the 
 leaf, as follows from the regular development of the leaf, from the sum- 
 mit to the base, but which may easily be demonstrated by observation of 
 any bud of a plant which has but any stipules sufficiently perfect to faci- 
 litate the investigation, as in Rosacece, e. g. Sorbus aucuparia, in Legu- 
 minosce, Ervum nigricans, Orobvs albus, Lathyrus sphcericus, Pisum 
 sativum (plate 77. fig. 1. et seq.), Robinia Pseudacacia, Psoralea affinis 
 and fruticosa, &c. Link* asserts the contrary, evidently because he has 
 never minutely examined the development of a bud, otherwise such an 
 assertion would be impossible. Subsequently, their development of 
 course goes forward more rapidly than that of the other parts, and they 
 not unfrequently envelope the leaf to which they belong, in the bud, 
 this acquiring its relatively large size at a later period by the expansion 
 of its cells. The terminology of the parts is quite endless, for every single 
 variation in the perfect plant is marked with a new name, without re- 
 gard to the nature and origin of the organ ; nay, a different origin is 
 sometimes designedly indicated by the name, where the most superficial 
 investigation would have shown that only one and the same part was in 
 question, e. g. vagina stipularis and petiolaris.\ Fancy has also been 
 busy here in filling up the vacuities, which no one had an inclination to 
 explain by fundamental investigation Growing together of the stipules 
 with the petiole, &c., are quite current expressions, but without the least 
 meaning ; there is no growing together in the matter : petiolus alatus 
 and stipulce adnatce do not differ the least in the world from each other, 
 beyond the so-called wings running out into a little point above, in the 
 latter. Arbitrary playing with words without any scientific foundation, 
 has here, as almost everywhere, made mere patch-work of the termi- 
 nology. 
 
 If we trace the development of these parts in the most different 
 families of Monocotyledons and Dicotyledons, we readily become con- 
 vinced that all are really one and the same part, a greater development 
 of the lower portion of the leaf or leaf-stalk ; and, indeed, in most cases, 
 particularly distinctly in the Monocotyledons, on account of the position 
 of the foliar organs in the developing bud, and the pressure thus exercised 
 
 * Elem. Phil. Bot. ed. 2. t. i. p. 465. 
 
 f Meanwhile, it is to be observed, that in some Monocotyledonous families two very 
 different things are included under one name, as in the Aracete. Here, e. g. in Pothos, 
 it not unfrequently occurs that the leaves are developed quite differently, alternating 
 regularly; one consisting of lamina, petiole, vaginal portion and stipular sheath ; the 
 succeeding one appearing as a mere thin membranous sheath, which is neither a stipular 
 sheath nor a vaginal portion, but an exceedingly aberrant form of the whole leaf. The 
 description of such a plant must therefore necessarily be folia dimorpha, foliit ince.qnali- 
 bus, cJtcniantibns, &c. 
 
272 
 
 MORPHOLOGY. 
 
 172 
 
 upon the lower portions, in the Monocotyledons especially, on the vaginal 
 portion of the leaf. A plant of the Oat may be examined just after 
 germination. Here there is a lanceolate, some- 
 what fleshy leaf (scutellum, Auct.) (fig. 172. c.), a 
 vaginal portion (a to ), which includes about a 
 quarter of the whole length of the leaf, and the 
 free border of this vaginal portion which is 
 pushed forward (ligula, b) by the protrusion of 
 the bud. With no imaginable pains can one 
 discover a cause which shall exclude this entire 
 organ from the definition of a leaf, or even make 
 its foliar nature doubtful ; and, disregarding ab- 
 solute size, colour, and fleshy consistence, which 
 vary so abundantly in all foliar organs, there is 
 not the slightest distinction to be found between 
 the cotyledon and the succeeding leaves of the Oat, 
 in the form and arrangement of the parts. If the 
 vaginal portion is shorter, the protruded border 
 somewhat larger, the thing has quite a different 
 name (vagina petiolaris\ and yet is altogether 
 the same : finally, if the vaginal portion is very 
 short, and the protruded border very long, it 
 must be called vagina stipularis, without anything different from the'fore- 
 going being signified. The last two parts are best found, in every 
 possible state of transition, and with them the petiolus alatus, which is 
 also just the same, in the families of the Hydrocharacece, Aracece, Sci- 
 taminecB, &c., in which I have analysed a sufficient number of sources of 
 development. In the bud, where the leaf is only a line, and the vaginal 
 portion half a line long, there can be no doubt about the nature of the 
 so-called vagina stipularis; but when the leaf with the petiole has 
 become two feet long, the vagina stipularis is several inches long, and 
 the vaginal portion, which unites the two, which has remained at only 
 half a line long, gets wholly overlooked in the usual way of examin- 
 ing these things, and the petiole and vagina are taken for two wholly 
 distinct organs. What I have observed in the above-named Leguminosce, 
 in Rosacece, Polygonacece, and some other families, leads immediately to 
 the conclusion that the organs called the sheath of the petiole, winged 
 petiole, ochrea, adherent and free stipules, in the Dicotyledons, are all 
 various forms of one and the same part of the lowest portion of the 
 border of the petiole or leaf, and again are wholly identical in nature and 
 development with the parts named in the Monocotyledons. The so- 
 called free separate stipules have no existence at all ; and, just as in the 
 vagina stipularis, their connection with the petiole is overlooked, 
 because the little piece by which they are connected is so small in propor- 
 tion to the whole leaf, and even to the stipule, that it falls quite into the 
 background. But when the leaf is examined before its cells expand, in 
 the bud, the point of union of the leaf and stipules forms so considerable 
 a portion of the whole length of the leaf, that there can be no more 
 doubt on the subject, that the stipule is a mere appendage of the border 
 
 172 Acena sativa. Germ plant, freed from the albumen, &c. ; viewed in front (left 
 fig.) and at the side in longitudinal section (right fig.), a, Body of the plant (stalk). 
 6, c, Cotyledon. Between a and b, vaginal portion of the cotyledonary leaf; above 
 this the ligule. c, Blade of the cotyledon, d, Outermost leaf of the bud, or plumula. 
 e, Adventitious root, which breaks through the very slightly elongated radicle. 
 
PIIANEIIOGAMIA : FOLIAR ORGANS. 27o 
 
 of the base of the leaf. The careful observation of the germination of a 
 leguminous plant with greatly developed stipules would suffice to esta- 
 blish this opinion without any application of more fundamental re- 
 searches into the course of development. For example, in Orobus aibus, 
 Lathyrus sphcericus, the first leaf after the cotyledon is a simply lanceolate 
 leaf passing immediately into a broadly winged petiole. The second leaf 
 is somewhat longer, yet still simple, and the two appendages adhering to 
 the sides of the petiole must be called stipules ; the third leaf is tripartite 
 (f. trifidum\ with stipules, the connection of which with the petiole still 
 appears very considerable ; lastly, the fourth leaf is a compound leaf 
 with two leaflets, a terminal point and stipules, the connection of which 
 with the long petiole is in proportions almost too slight to be noticed. 
 The condition is similar in Pisum sativum (Plate III. fig. 1.), and every- 
 where ; and from this alone it may be seen that petiolus alatus, stipules 
 adnatce, and stipulce liberce are one and the same part in different 
 degrees of development. The same gradual development occurs in most 
 buds ; and, for instance, in Prunus Padus the leaves of the bud run 
 through exactly the same series of forms from below upward as the 
 germinating Leguminosce. If this had been looked into, more than half 
 of that terminology would have been wholly superfluous, even for De- 
 scriptive Botany, if, as a general rule, all those processes which go off, 
 not merely from the borders, but at the same time from the surface, of 
 the leaf, were called ligula ; all distinct appendages of the border, petiolus 
 alatus (e. g. stipulce adnatce, lanceolat(e= petiolus alatus, alls lanceolatis)-, 
 finally, all parts which appear to be entirely free, stipulce (e. g. ochrea= 
 stipula vaginans), &c. In all these there are many further investi- 
 gations still to be made, since, when I can even say that I have minutely 
 traced the development in some fifty plants, this is far too few to carry 
 back the so various phenomena, with complete certainty, to their funda- 
 mental structure ; and there are still many families remaining in which 
 I have not hitherto had opportunity to examine any plant. A large 
 field for inquiry is especially left in the related parts of the floral leaves. 
 In Lychnis the course of development, in Narcissus both this and mon- 
 strosities (e.g. the double N. poeticus),show that this part exists as ligula; 
 wholly similar results may certainly be expected for the fornix of the 
 Boraginece, and other similar phenomena. Lastly, the nature of stipellce 
 has yet to be cleared up by the history of their course of development. 
 
 V. Every leaf, as already observed, originates as a little conical 
 papilla at a definite point on the circumference of the axis. Even 
 the sheathing leaves are produced in this manner, and at the point 
 which corresponds to the middle line (the mid-nerve) of the future 
 leaf by degrees, and as it is pushed up further from the axis, the 
 parts of its circumference take part more and more in the develop- 
 ment, and thus the base of the leaf gradually becomes broader, until 
 it completely surrounds the axis. If the development of cells, or 
 the expansion of existing ones, continues on the borders of the base 
 of the leaf, beyond the degree required to surround the axis, the 
 newly-formed, still soft and almost gelatinous cells of the two 
 borders of the base of the leaf become applied upon one another, 
 and become united as firmly as the cells of a continuous tissue ; in 
 this way the lower part of a leaf then becomes a closed, undivided 
 
 T 
 
274 MORPHOLOGY. 
 
 whole, surrounding the axis. If the lateral production of cells 
 is small, and the union takes place relatively early, this closed por- 
 tion forms a longer or shorter sheath, closely embracing the axis 
 (vagina clausa), as in many Grasses. If, on the contrary, the lateral 
 cell-production or expansion is considerable, and occurs relatively 
 late, so that merely the base of the leaf forms a flat projecting 
 border round the axis, the leaf is said to have the stem growing 
 through it (folium perfoliatum), e. g. Bupleurum perfoliatum. 
 When the axis is angular, and produces thin, more or less projecting 
 plates upon these angles (the so-called winged axis, axis alatus), a 
 similar process may enter into the bud in such a way that a flat leaf 
 is connected at its base with the simultaneously-developed wing or 
 angle of the axis, so that the full-grown leaf appears to be directly 
 continuous with this. Such a leaf is said to run down the axis 
 (folium decurrens), e. g. in Carduus, or, by a wholly unfounded 
 fiction, a leaf blended by growth with the axis (axis folio adnatus). 
 Where several leaves arise simultaneously, or almost simultaneously, 
 at about the same height upon the axis, the bases of the leaves be- 
 come gradually approximated during development ; and here it may 
 readily happen that they approach so close that the same process 
 occurs between the bases of two different leaves, as has been 
 already described in the two borders of one and the same leaf. 
 Thus it happens, then, that leaves, which in their origin and at their 
 summits are free and isolated, in their ulterior development and at 
 their bases form an undivided whole (leaves grown together, folia 
 connata). The leaves of Lonicera Caprifolium afford one of the 
 examples simplest and easiest to trace. Two foliaceous organs 
 which originate one above the other on the same axis (e. g. petal 
 and stamen), or a leaf and the bud developed in its axil (e.g. the 
 bract with the flower- stalk in the Lime), may grow together one 
 above the other, in the same way. 
 
 Lastly, a process almost diametrically opposite to this may occur, 
 where, namely, a leaf is developed, but becomes suddenly arrested 
 in its development in a way yet unknown, whether through mere 
 mechanical pressure or some other cause, by the more rapid and 
 powerful development of the contiguous leaves ; so that either the 
 little original papilla escapes notice, on account of its relatively 
 minute size in the full-grown part, or the little prominence actually 
 becomes effaced by the subsequent development of the part, or, 
 finally, the little rudiment of a leaf dies and gradually decays. In 
 this case the leaf is said to be abortive : an instance easily traced is 
 afforded by the third perigonial leaf of Carex, which aborts in this 
 way, while the two others form the so-called utriculus. And not only 
 may whole leaves become abortive in this way, but even individual 
 portions of a leaf of which the rudiments already exist : thus it is 
 not at all rare for the so-called stipules to become disproportionately 
 developed in the rudimentary leaf, while the proper lea restrained 
 in its growth, gradually disappears from sight. The bud-scales 
 (r amenta} on the perennial buds of Corylus avellana may serve as 
 
PHAN 7 EROGAMIA : FOLIAR ORGANS. 275 
 
 examples, being in fact nothing else than the stipules of an abortive 
 principal leaf. 
 
 Finally, the same influence to which the parts closely crowded 
 in the bud are subject, may merely cause the un symmetrical deve- 
 lopment of the two halves a particular foliar organ, so that one 
 side, or that part of the leaf lying on one side of the mid-nerve, 
 assumes a form different from that of the other half, of which the 
 species of Begonia afford a striking example. 
 
 The processes of development sketched here are the only ones in the life 
 of the plant to which the words "growing together" or "abortion" can be 
 applied, if we would confine ourselves within the boundaries of a circum- 
 spect, scientific activity. " Growing together " only has a meaning when 
 I apply it to the union of two originally actually distinct parts, in con- 
 sequence of a process of growth ; "abortion" only when I understand by 
 it the arrested development and destruction of a part already actually 
 existing in a rudimentary condition. Nothing, certainly, has confused 
 or led botanists more from their point than the misuse of these two 
 words. That many take it to be much easier to build fancies about a 
 phenomenon according to an arbitrarily chosen type, and to settle the 
 question by a word thus tin-own in. than to be compelled to see, after 
 weeks and months of painful investigation, that their so beautifully 
 imagined type is nothing, I readily believe ; but must nevertheless assert 
 that in the latter alone lies genuine scientific activity, while the former 
 are toys of such who neither do nor wish to understand that the aim of 
 our endeavours in Natural Science, is a theory of the actual and not of 
 our imaginations. The misuse also depends altogether upon an empi- 
 rical and methodical faultiness, upon an empirical, in so far that we are 
 yet wholly without the facts on which to establish scientifically a law of 
 the position of leaves for Phanerogamic plants in general, as for the 
 individual groups, while abortion and growing together can, in any case, 
 only be used for the explanation of exceptions to a well-grounded law ; 
 upon a methodical, since an observed regularity may indeed serve in 
 many cases to make us remark upon the possibility of a natural law 
 lying at the bottom of it, but still is not the law itself, the actual exist- 
 ence, much more the decision, of which is then first to be sought for and 
 established.* Here we have the misuse of the comparative method, 
 on which I have before animadverted. If we find five leaves in a definite 
 position in definite order in a series of plants, and in another plant, allied in 
 many respects to the former, only four, comparison will of course lead 
 us to guess that one leaf is abortive here, and call upon us to investigate; but 
 it is this very investigation alone which can decide as to actual abortion. 
 Any other mode of inquiry is as impossible as it would be unscientific. The 
 individual case would have to be excluded if, in mathematical development 
 from constituent metaphysical principles, we could deduce a law accord- 
 ing to which exactly five leaves must stand in this position, where then 
 the necessity conditioned by an exceptionless mathematically definite 
 law would suffice to establish the decision ; " for this appearance a leaf 
 must have been obliterated here." We have no such laws at all in our 
 
 * See, on this head, the excellent elucidations of Fries, Versuch einer Kritik der 
 Principien der \Vahrscheinlichkeitsrechnung, Brunswick, 1842. 
 
 T 2 
 
276 MORPHOLOGY. 
 
 natural science, except in the pure study of motion, least of all in the 
 barren, empirical beginnings of our Botanical efforts. 
 
 b. Structural Condition of the Foliar Organs. 
 
 132. 1. The nascent leaf consists, like all nascent parts of 
 vegetables, of cellular tissue ; determinate cords of cellular tissue 
 are first gradually organised into vascular bundles, and in fact this 
 process proceeds from the vascular bundles of the axis, and advances 
 gradually into the leaf. In many foliar organs, especially the 
 parts of the flower, no vascular bundles are ever formed. The 
 vascular bundles of the leaves are distinguished by the most incon- 
 veniently chosen expressions, nerves or veins (nervi, vena}. In 
 Monocotyledons with undeveloped internodes, the whole of the 
 vascular bundles together (?) of the internode bounded above by 
 the leaf, pass into the leaf. In all other plants, many at least 
 of the vascular bundles entering the leaf are minor twigs of the 
 vascular bundles of the axis ; in the Dicotyledons proceeding exclu- 
 sively, in great part, from the borders of the loop of the vascular 
 bundles of the axis. The course of the vascular bundles in the 
 leaf depends essentially on the form of the latter. In flat leaves, 
 petioles, or vaginal portions, the vascular bundles lie in one plane ; in 
 relatively thick leaves, &c., they lie scattered (Palms) or in a circle 
 (species of^4loe, Mesembryanthemuni). The vascular bundles rarely 
 run separately through the whole leaf (as in the last named) : they 
 mostly anastomose in various ways with each other by lateral 
 branches ; frequently in the petiole, in such a manner that all the 
 vascular bundles entering it unite into a single one, and then 
 separate again in the blade of the leaf. The form of the combina- 
 tions is very varied : in many Monocotyledons the branches are 
 short, going off at right angles ; in others, and in most Dicotyledons, 
 more varied, so that a net with polygonal meshes is formed. 
 
 De Candolle*, in particular, has devoted great pains to tracing up the 
 distribution of vascular bundles in the leaf to certain types, and to the 
 application of these to the division of plants into definite groups. I can- 
 not perceive any regularity in it. The mode of distribution is as manifold 
 as the form itself of the leaf upon which it is dependent, although De 
 Candolle strangely takes the matter in the opposite way. The nearest 
 allied plants often exhibit a different form of leaf, as also wholly different 
 modes of distribution of the vascular bundles, e. g. Alisma natans and 
 Plantago, Funkia and Hemerocattis, Hydrocharis and Vallisneria, Taxus 
 and Salisburia, Dortmanna and Isotoma, Sedum and Bryophyllum, 
 Peireskia and Opuntia, Salicornia and Beta, Dianthus and Lychnis, 
 &c. No general laws, therefore, can be deduced from these facts, 
 although it is right and useful most minutely to investigate and charac- 
 terise the individual groups, families, genera, and species, in this respect 
 as in all others. In many flat leaves we may distinguish one principal 
 
 * Organographie vegetale, vol. i. p. 289, et seq. 
 
PHANEROCAMIA : FOLIAR ORGANS. 277 
 
 nerve traversing the middle line of the leaf, and principal lateral nerves 
 passing off from this. According as the latter make an acute angle, or 
 are convex, toward the central nerve in their departure from it, De 
 Candolle* distinguished folia angulinervia and curvinervia ; the latter 
 he claimed for the Monocotyledons, but they also occur frequently enough 
 in Dicotyledons. When, on the other hand, the leaf is traversed by 
 several equally strong nerves starting from its base, De Candolle called 
 it folium rectinervium. These principal divisions were then further 
 subdivided. Others, for instance Link and Lindley, have other divisions, 
 because they make the principal distinctions depend on other forms. 
 These various, equally valid, opinions, show that there can be no law 
 here. These conditions are also quite inapplicable to the characterisa- 
 tion of plants and vegetable groups, excepting in isolated cases, where 
 certain conditions are constant within the limits of certain groups, e. g. 
 in Melastomacece, Scitaminece, &c., which, on the whole, are very rare. 
 
 2. The vascular bundles of the leaves are progressive bundles, 
 and they are so formed that (regarding the leaf as passing off hori- 
 zontally from the axis) the oldest parts lie above, the youngest 
 below. In the lower part also a cambium layer exists in the 
 Dicotyledons ; in the lower part liber-bundles accompany the vas- 
 cular bundles, and in the under part the vascular bundles, in rela- 
 tively thin and flat leaves, project above the surface (probably in 
 consequence of gradual development), while the upper part of the 
 leaf appears level. 
 
 "We are at present wholly destitute of investigations into the develop- 
 ment of the vascular bundles in the leaf, and need more minute obser- 
 vation of the condition of the unlimited bundles of Dicotyledons, and 
 their condition in lengthened duration of the leaf. In Pinus and Abies 
 I believe that I have been able to distinguish, in leaves two years old, 
 two layers of the vascular bundle (similar to the annual rings). 
 
 3. The parenchyma of the leaf is developed in the most varied 
 manner ; in general, in thick, solid leaves, it is composed externally 
 of small crowded cells containing more chlorophyll, internally, of 
 larger and looser cells filled with aqueous juices. Very often the 
 outer layer passes into a tissue, the cells of which are elongated in 
 a direction vertical to the surface of the leaf, are applied closely, 
 almost without trace of intercellular passages, and thus are pretty 
 sharply distinguished from the rest of the parenchyma, and occur 
 in the whole of the periphery of the leaf, not only in round and 
 triangular leaves, but also in flat ones, as in many New Holland 
 Myrtacea. In flat leaves, especially of Dicotyledons, there is very 
 often a separation into two layers, the upper of which has the cells 
 elongated perpendicularly to the surface, as just mentioned, filled with 
 much chlorophyll, while the lower is composed of looser, globular, or, 
 still more frequently, spongiform parenchyma containing little chlo- 
 rophyll. In thick coriaceous or fleshy leaves, for instance, in species 
 of Ficus and Peperomia, one or more layers of cells containing little 
 
 * Loc. cit. 
 T 3 
 
278 MORPHOLOGY. 
 
 but watery juices, often lie between the upper layer and the epi- 
 dermis : more rarely, in like manner, at the under surface of the leaf. 
 Besides these, there appear at given places, or dispersed in the 
 parenchyma, according to special peculiarities of the plant, spiral 
 fibrous cells, very thick, and closely porous cells, and cells contain- 
 ing peculiar juices and crystals. We find also milk-vessels and 
 passages, receptacles for gum, oil, and resin, also isolated liber- 
 bundles, the last especially in the thin elongated leaves of Mono- 
 cotyledons. Air-canals and air cavities are also found in the 
 leaves ; the last very regularly and beautifully arranged. 
 
 Here it is almost as difficult as in the axis, to make any general state- 
 ments. Almost all combinations of forms of the elementary organs, and 
 of the several tissues, are presented in the leaves ; and much confusion 
 has arisen from the attempts which have been made to seize arbitrarily 
 upon some conditions, which, though frequently exhibited, are not in- 
 variable, and to assume these as the type from which till deviations are 
 to be regarded as exceptions. 
 
 Let but the leaves of the Orchidacea be subjected to a complete and 
 close investigation, and such a multiplicity of combinations will be dis- 
 covered, that the attempt to account for them all by laws will be quickly 
 laid aside. The Aloinece, Crassulacece, Ficoidece, Piperacece, Proteacecc, 
 and others, afford similar examples. In many plants we certainly find 
 that division into a parenchyma more elongated, dense and green ; and 
 one expanded in all directions, looser and paler, strongly marked ; but 
 there are innumerable plants in which this is not the case in the 
 Dicotyledons, but particularly in the Monocotyledons : hence it is al- 
 together wrong to assume it to be the regular structure of the leaf. This 
 too could only be done by assuming, in an equally arbitrary manner, that 
 the flat leaf is the regular form. Amongst specialities, which cannot be 
 brought under the general laws, may be enumerated the following : the 
 frequent occurrence of spiral fibrous cells in the leaves of the Orchidacecc 
 of the tropics, and in Gesnera latifolia ;* the same in the stipules of 
 the Paronychiacece ; the peculiar stellate hairs which are projected into the 
 air canals of Nymphcea, Nuphar, Euryale, &c.|, the similar very sin- 
 gular layer of clavate, sometimes ramified, and greatly thickened cells, 
 traversing the layer of elongated parenchyma in the species of Nymphcea, 
 Nuphar, and Hakea ; the thicker or thinner layer of almost colourless 
 cellular tissue, which covers the layer of elongated cellular tissue in 
 many species of Peperomia^ and some of Ficus, whilst plants nearly re- 
 lated to them present nothing of the kind ; the monstrous crystals often 
 extending almost through the entire thickness of the leaf in the Agaves 
 and in Pontederia crassipes ; the cells often projecting into the air-canals 
 on both sides of the septa containing bundles of crystals (Turpin's bifo- 
 rines) in Aroidece., single large crystals in Pontederacea, or groups of crys- 
 tals in Myriophyllum and Proserpinaca ; the air-canals often arranged 
 with such elegant regularity in water and bog plants ; and the air cavities 
 in the leaves of the Grasses J, &c. 
 
 * But in none of its allies which I have been able to investigate. Here \ve may 
 most easily trace the gradual conversion of true spirals into porous structures Avith slit- 
 like pores. 
 
 f In a similar strange manner, also, in a rhizome of Rumex crispus (?). 
 
 \ Even in the very young leaves of the group we find very delicate transparent 
 
PHANEROGAMIA : FOLIAR ORGANS. 279 
 
 When milk- vessels are present, they for the most part follow the vas- 
 cular bundles, lying on their under side ; yet isolated milk-vessels are to 
 be found dispersed through the parenchyma. If we compare the de- 
 velopment of the vascular bundles of the leaves with those of the axis, 
 we shall find, as the natural connection of the leaf and axis indicates, that 
 the under surface of the leaf corresponds to the bark ; and, agreeably 
 with this, we find at times the external layer of bark extending out for 
 some distance into the leaf. 
 
 We have little to say respecting the structure of the pouch, for inves- 
 tigation is yet wanting to us here. In Nepenthes, as in many other 
 plants, the walls of the pitcher contain a large number of fine spiral 
 fibrous cells. In Utricularia, the intercellular spaces in the walls of 
 the pouch are strikingly large, and would be open, both internally and 
 externally, were they not always closed by one or two cells, like a stopper, 
 which bear upon their inner side peculiar four-armed hairs, and upon 
 their outer one or two plano-convex cells. 
 
 4. All foliar organs, soon after their origin, exhibit a delicate 
 epithelium, which, in plants vegetating under the earth or under 
 water, is converted in time into epiblema, and in those vegetating 
 above the surface is converted into epidermis. Some parts of 
 flowers are clothed with a peculiar sort of covering, holding an in- 
 termediate station between epithelium and epidermis. We shall 
 have subsequently to speak of this. To the epiblema stomata are 
 wanting. The epidermis is commonly provided with them. In flat 
 horizontal leaves they are very frequently wanting on the epider- 
 mis of the upper side, and they are usually only found where a thin 
 or spongiform cellular tissue is present beneath the epidermis ; in 
 floating leaves, on the contrary, the upper epidermis only has stomata, 
 and through the upper layer of condensed elongated parenchyma, 
 air-canals pass into the under and thinner layer of parenchyma; as 
 occurs also in leaves that are surrounded with dense, elongated cel- 
 lular tissue. All parts usually known as appendages to the epi- 
 dermis are also found occasionally on the leaves: even the cork 
 structure is sometimes found on the petioles of long-enduring 
 leaves, as, for example, in some species of Potkos and Ficus, as 
 well as on the leaves of Crassula, Bryophyllum, &c. 
 
 The cells of the epidermis are usually filled with a clear watery 
 fluid, which on the under surface of the leaf is sometimes colored 
 (red). They more rarely present crystals, and yet more seldom 
 offer any peculiar matter, as resin, or the like. The form of the 
 epidermis-cells is determined by the form of the leaf; long, slender 
 leaves usually present their epidermis cells elongated in the same 
 direction. The lateral walls of the epidermis-cells are often curved 
 in the form of waves, but this peculiarity has been too little in- 
 vestigated to be explained at present. 
 
 On the structure of the epidermis and stomata, enough has been said in 
 the first part. Respecting the occurrence of the particular appendages of 
 
 parenchyma, formed of large cells ; and this is destined by its laceration to form the 
 air-canals, e. g. Aiundo Donax. 
 
 T 4 
 
280 MORPHOLOGY. 
 
 the epidermis, nothing is to be said in general terms, but that hairs are 
 infrequent on the surfaces of leaves in Monocotyledons. It is, however, 
 to be remarked, that the leaves in the bud are sometimes furnished with 
 hairs, which on further development of the organ fall away, and leave 
 scars which are sometimes mistaken for original peculiarities. Nuphar 
 luteum * offers an example of this. Hairs consisting of a cylindrical cell, 
 bearing a spherical cell above, and attached upon little indentations in 
 the epidermis which they almost cover, are still more frequent : these 
 also are frequently destroyed, and leave deceptive scars behind. The 
 epidermis in their vicinity always presents some peculiarities. Of this 
 the generality of tropical Orchidacece (Pleurothallis ruscifolia), and many 
 of the Piperacece (Piper obtusifolium\ are instances. As has been men- 
 tioned under the subject of the epidermis, some leaves present peculiarities 
 in the stomata. In Nerium, Banksia, and Dryandra, small pits clothed 
 with epidermis, beset at the edges with hairs, are found upon the leaf, 
 and it is only at the bottom of these pits that the stomata occur. In 
 Saxifraga sarmentosa and cuscutcpformis, the stomata are ranged in 
 groups, and they are set closely together. The longer diameter of the 
 stomata is sometimes turned in one way, sometimes in another. In leaves 
 proportionally very long, it is parallel to the longer diameter of the leaf, 
 as in Grasses (Liliacece, Coniferce). In some leaves, and especially in 
 fleshy ones with leathery integument, the peculiar layer of secretion as- 
 sumes a very considerable thickness, and even causes the leathery con- 
 sistence of the integument. This secreted substance is in rare cases of a 
 very soft gelatinous nature, as in Hydropeltis. Some leaves, as, for in- 
 stance, many of the species of Saxifraga, have at their edges small groups 
 of very delicate walled cells, filled with opaque contents, over which the 
 epidermis is never perfected, but persists in the original condition of epi- 
 thelium. In these groups is secreted the great abundance of carbonate 
 of lime which occurs in these plants. 
 
 I shall speak of the development of individual cells or groups of cells 
 of the leaves into new plants further on, in connection with propagation. 
 
 c. Complete Review of the Foliar Organs. 
 
 133. The floral parts of a plant are here advantageously dis- 
 tinguished from all other foliar organs, and are termed flower- 
 leaves (phylla), whilst other leaves are termed true-leaves (folia 
 sensu stricto). 
 
 1. True Leaves (Folia). 
 
 A. Seed-leaves (cotyledons), generally round or flat, fleshy, 
 little divided, and never compound. (See under Embryo.) 
 
 B. Stalk or stem-leaves (folia caulina f). Their forms are 
 very various, as has been shown in the foregoing paragraphs. 
 Those immediately following the cotyledons are usually simple ; the 
 
 * Wiegmann's Archiv, Jahrg. iv. (1838), vol. L p. 51. 
 
 f The term is allowable here. As opposed to f. radicalia it has no meaning, since 
 the root never produces leaves. 
 
PHANEROGAMIA : BUD OKGANS. 28 1 
 
 next more perfect ; and again, as they rise into the vicinity of the 
 blossoms, they become again more simple. Filiform leaves, or 
 parts of leaves, when they twine around foreign objects, are termed 
 tendrils (cirrhi), as in Pisum, Clematis, &c. ; those which are stiff' 
 and pointed are termed spines (spinci) ; very concave leaves that 
 exhibit the form of a cup or pitcher are termed pouches (asci), as in 
 Nepenthes, Sarracenia, Utricularia, &c. According to their various 
 positions are again distinguished from the true leaves generally : 
 
 a. Leaves of the inflorescence ( folia flor 'alia). Indistinguishable 
 from the stem-leaves, but bearing in their axils a blossom or a 
 simple inflorescence. 
 
 b. Bracts (bracteci). Leaves different from the stem-leaves, and 
 bearing in their axils a blossom or a simple inflorescence ; for in- 
 stance, the scarlet-red leaves of the Salvia Horminum. To these 
 belong the glumes, of Grasses, which are simply two bracts (which 
 have commonly no blossoms in their axils), and the leaves which 
 surround the capitula of the Composite. A number of bracts, in- 
 closing an inflorescence, are also termed an involucre (involucrum). 
 The quickly-drying bracteaB of the Composites are termed scales, 
 or chaff (pale<z\ a word altogether superfluous. 
 
 c. Bracteoles (bracteolce), distinct from the stem-leaves, and 
 standing beneath the blossom, but upon its axis ; for example, the 
 two leaves under the blossom of the Aconitum, &c. 
 
 C. Bud-scales (tegmenta^. The very simple, mostly membra- 
 nous, and quickly-falling outer leaves of a bud which remains for 
 a length of time unexpanded. (See hereafter, under the Bud.) 
 
 2. Flower-Leaves (Phylla). See the Blossom. 
 
 A. Perigonial leaves (phylla perigonii). 
 
 B. Sepals of the epi-calyx (phylla epicatycis). 
 
 C. Sepals (sepald). 
 I). Petals (petala). 
 
 E. Pseudo-petals (parapetala). 
 
 F. Stamens (stamina). 
 
 G. Pseudo-stamens (jparastemones). 
 II. Carpels (carpella). 
 
 D. OF THE BUD ORGANS (Gemma). 
 
 a. Of Buds in general. 
 
 134. 1. The bud is the end of a main or secondary axis, as yet 
 undeveloped, but capable of development. We may distinguish : 
 1. The terminal bud (gemma terminates), the end of a developed 
 axis, itself capable of development. 2. The axillary bud (gemma 
 ) the end, capable of development, of a secondary axis newly 
 
282 MORPHOLOGY. 
 
 arising, according to law, in the axil of a leaf; since several buds 
 may arise, without irregularity, in one axil, that which developes 
 most vigorously is termed the main bud, the others accessory buds 
 (gemma aocillaris primaria and accessoria). 3. Lastly, the ad- 
 ventitious buds (g. adventitice), formed at the end of any (secondary) 
 axis capable of development, arising irregularly on the plant. In 
 all these we distinguish buds continually progressing in develop- 
 ment (g. vegetatione continua) ; from buds whose vegetating activity 
 rests for a time after their development into a bud (g. vegetatione 
 interrupta).* Again, buds are distinguished into those which, in 
 the natural course of vegetation, separate themselves from the 
 parent plant and become independent plants (g. plantiparce), and 
 those which always remain in connection with the parent plant 
 (g. ramiparci). Finally, buds are distinguished according to their 
 contents : there are the flower-buds (g. jftoriparce, alabastrus) ; the 
 leaf-buds (g. foliiparce) ; and mixed-buds (g. mixta). 
 
 The bud is the yet undeveloped rudiment of the elongation of an axis 
 already present, or for the formation of a new axis upon one already 
 existing. Since it is not necessarily in the nature of Phanerogamic 
 plants to bear true leaves, so it is not necessarily in the idea of a bud 
 that it should contain the rudiments of leaves, much less that the rudi- 
 ment of a leaf precedes that of an axial organ ; therefore the youngest 
 condition of a bud is merely one in which no rudiments of leaves exist. 
 I have styled the axillary and adventitious buds ends of an axis capable 
 of development, instead of describing thgm as the axis itself in unde- 
 veloped circumstances, for this seems to me a simpler and more universal 
 definition ; and the first origin of such bud appears to me to take place 
 within the parenchyma, so that that which projects as the visible bud 
 might, with equal right, be considered as the end of a particular mass of 
 cellular tissue. I shall speak of the origin of the axillary and adven- 
 titious buds when I come to the subject of propagation. One peculiarity 
 I must not omit here to mention, namely, the total absence of terminal 
 buds, capable of development, in certain plants. This occurs without 
 exception in the Lemnacece, whose flat stem never forms more than two 
 axillary buds, and has no terminal bud. The same remarkable circum- 
 stance is observable of the stems of Ruscus, developed above ground, 
 where every branch spreads out into a flat leaflike expansion, and 
 terminates in a spine instead of a terminal bud. This holds for the 
 short flower-bearing side branches, as well as for the thin, long, main 
 branches, out of angles of the leaves of which those flower-bearing branches 
 spring. Tiiis must not be confounded with those cases wherein a ter- 
 minal bud is indeed originally presented, but is very frequently abortive, 
 as in Syringa vulgaris ; nor with those where it is always developed as 
 a flower-bud, as in Viscum album. The accessory buds so frequently 
 occurring in the axils of leaves (see Keeper in the Linnsea, vol. i. p. 461.), 
 for instance, in Aristolochia Sipho, Gymnocladus canadensis, &c., cer- 
 tainly merit a more minute investigation of their development ; they 
 may of course often merely represent collectively the secondary axillary 
 and terminal buds of a solitary, the proper primary axillary bud, for 
 instance, certainly in Cornus mascula, Ptelea trifoliata, Salix caprcea, 
 
 * Which Linna?us called hybcrnacvla. 
 
PHANEROGAM1A : BUD ORGANS. 283 
 
 and the Malvacece ; in other cases it is at least probable, as in Aristolo- 
 chia Sipho, though in others, at least in the perfect condition, highly 
 improbable, as in Gymnocladus. Every terminal bud is but the progres- 
 sively developing end of a simple axis, and may have unlimited growth ; 
 the only limits are found in the completion of the last foliaceous and axial 
 organ into normal flowering parts, and apparently in the impossibility of 
 further endosmosis and of further nourishment, when the terminal bud 
 has become removed very far from its source of nourishment (the earth). 
 That the first determination does not necessarily ensue at a definite 
 epoch, on account of morphological laws of the elementary organs, is 
 shown by continuance of growth through flowers ; that the secomi limi- 
 tation of the longitudinal growth is an external one, is demonstrated by 
 the possibility of producing longitudinal growth in the utmost extremities 
 of an old stem by making slips of them. Links's distinction between 
 closed and open buds is quite useless ; all buds are originally closed ; 
 all buds are open during development. The only cases in which such 
 distinctions can apply, are when they develope immediately, and when 
 they remain closed for some time. 
 
 2. With the exception of the true tuber in Solarium and He- 
 lianthus (?), and of the tuber buds (tubercula), all buds have a de- 
 terminate number of rudimentary foliar organs. These foliar 
 organs are folded in specific ways (vernatio), and have a definite 
 position in relation to each other.* From the origin of the foliar 
 organs, it follows that when several arise at the same height, they 
 will always be at some time in such a position that their edges 
 will be in contact (vernatio simplex, foliatio valvata}.\ This posi- 
 tion often persists during the whole period of the bud remaining 
 as such ; it is, however, changed by various circumstances, not yet 
 clearly understood, but which appear to be caused by the indi- 
 vidual development of the separate leaves. In the vernatio the 
 following main forms maybe distinguished : the foliar organs are 
 either curled up in the direction of their length or their breadth, or 
 they are compressed together in irregular folds (vern. corrugativa). 
 In those leaves that are curled up lengthways, we distinguish sharp 
 folds from those which make rounder curves. 
 
 * Linnams used the expression foliatio in the way I do. Subsequently, and unneces- 
 sarily, the words pr&foliatio in the leaf-buds prcefioratio in the flower-buds, were substi- 
 tuted for vernatio and astivatio. I here restrict vernatio in the manner stated. The 
 matter required a name, and that word already exists. But, at the same time, we have 
 here an example of the completely unscientific character of terminology. The four last 
 terms are altogether superfluous, since in this condition it is all one whether the foli- 
 aceous organ be modified or not. On the other hand, the folding of a single leaf by 
 itself, and its position in relation to others, which are clearly two very distinct things, 
 are called by the same name. 
 
 f When there are only two leaves, a superfluous term, foliuiio application, is 
 applied. 
 
284 MORPHOLOGY. 
 
 A. Sharp folds. 
 
 a. Vernatio duplicativa. Simply folded together (forwards) upon 
 
 the upper surface of the leaf, as in Quercus, Tilia, and the 
 lamina of Liriodendron. 
 
 b. Vern. replicativa. Folded in the same way backward upon 
 
 the under surface of the leaf. 
 
 c. Vern. implicativa. The two borders folded in sharply for- 
 
 wards, as in the perigone of Clematis. 
 
 d. Vern. plicativa. Many longitudinal folds, as is seen, though 
 
 not quite perfectly, in Fagus and Carpinus, but better in 
 Alchemilla, and best of all in Panicum plicatum. 
 
 B. Rounded folds. 
 
 a. Vern. convoluiiva. Simply rolled up, as in Calla and Prunus. 
 
 b. Vern. involutiva. With both edges equally rolled up for- 
 
 wards, as in Alisma and Populus. 
 
 c. Vern. revolutiva. Rolled backwards in a similar manner, as 
 
 seen in Salix and Nerium. 
 
 In leaves curled and folded together the cross way, the most 
 important distinctions occur. 
 
 a. Vern. inclinativa. Incurved forwards, as in the petiole of 
 
 Liriodendron and Hepatica. 
 
 b. Vern. reclinativa. Recurved backwards, as in Aconitum. 
 
 c. Vern. circinata. Rolled up forwards from the point to the 
 
 base, as in Cycas. 
 
 In thefoliatio we distinguish the position of the foliar organs in 
 relation to one another, in general, from the position of individual 
 circles of foliar organs with respect to each other. With regard 
 to the first of these, the conditions have been pointed out. 
 
 A. Foliatio valvata. When the leaves only touch without cover- 
 
 ing each other with their borders. 
 
 a. Fol. valvata sensu stricto, in vernatio simplex. Flower in 
 
 Stapelia. 
 
 b. Fol. induplicativa (?), in vern. duplicativa. 
 
 c. Fol. implicativa^ in vern. implicativa^ as in the perigone of 
 
 Clematis. 
 
 B. Foliatio amplexa. When each leaf embraces all those within it. 
 
 a. FoL convolutiva, in vernatio convolutiva, as in Prunus ar- 
 
 meniaca. 
 
 b. FoL equitans, in vernatio duplicativa^ as in Iris. 
 
 C. Foliatio semiamplexa. When each leaf embraces with one 
 
 edge, and is embraced on the other. 
 
PHANEROGAMIA : BUD ORGANS. 285 
 
 a. Pol. contorta, in vernatio simplex (more than three leaves), 
 
 as in the flower of Dianthus and Linum. 
 
 b. Fol. obvolutiva. In vernatio duplicativa, as in Lychnis. 
 
 D. Foliatio quincundalis. When five leaves so lie that between 
 
 two external, quite uncovered ones, and two inner, quite 
 covered ones, the fifth is so interposed as to cover one of 
 the inner leaves with one edge, and to be covered at its 
 other edge by one of the external leaves, as in the flower 
 of Rosa. 
 
 E. Foliatio connata. When the leaves of a circle are so per- 
 
 fectly and intimately grown together that on the full de- 
 velopment they become ruptured from their common basis, 
 and fall away like a cap, as in some calices, for instance, 
 Eucalyptus, Eschscholzia ; and bracts, as in Aponogeton 
 distachyon, &c. 
 
 Finally. In respect to the position of individual circles of foliar 
 organs with respect to one another, the following have been distin- 
 guished : 
 
 A. Foliatio alternativa. When the members of the one circle 
 
 stand before the interspaces occurring between the members 
 of another circle, as in the calyx, corolla, and stamina of 
 Lysimachia. 
 
 B. Foliatio oppositiva. When the members of one circle stand 
 
 before the members of another circle.* 
 
 From this review, arranged as logically as possible, it is evident at the 
 first glance, that here, as almost everywhere, in the position of the 
 foliar organs in the bud, the terminology has been patched together 
 without the least reviewal and arrangement of the possible conditions, 
 without complete investigation of the actual, and therefore altogether 
 without any principles ; just as one or other inquirer lighted upon this 
 or that form, and gave it a new technical name, without reference to 
 those already existing, and without any scientific relations. We are 
 destitute, therefore, of certainly established technical names for some of 
 the most important distinctions, and in other cases have a number of 
 different words to express the same fact : such I have omitted, as alto- 
 gether superfluous. 
 
 Some other words which are chosen to designate peculiar forms in 
 certain plants of particular families are of no general value, and belong 
 evidently to special descriptions of particular groups : such are foliatio 
 cochlearis, in the flowers of Aconitum and Laminm, and foliatio vexil- 
 laris, in the flowers of the Papilionacece. I have retained Linnaeus' 
 term foliatio, by which to designate the position of the leaves in relation 
 to each other in the bud, as being the oldest and best; and for the 
 position of the individual leaves I have used the term vernatio, which 
 was before superfluous, as a distinction between the two conditions is 
 indispensable. 
 
 * Perhaps not actually existent in nature. Most of the instances which are usually 
 brought forward, e. g. the parts of the flower of Btrbernceir, Thyinchicete, &c., have only 
 been included here, through superficial observation : in the former there are alternat- 
 ing fJ-partite, not opposite 6-partite circles; in the latter, in like manner, 'J-partite, not 
 4- partite circles. 
 
286 MORPHOLOGY. 
 
 3. Since in the uninterrupted development of buds they become 
 axes and leaves, there is nothing general to be said further on the 
 subject which has not been mentioned already under those par- 
 ticular organs. We must not, however, pass over buds with un- 
 interrupted vegetation, since they appear to hold a place as a 
 peculiar organ of the plant. In these we find that the external 
 (undermost) leaves are modified in peculiar ways, their forms ap- 
 pearing simpler than those later developed (higher up) from the 
 same bud. They may be termed in general bud-scales* (tegmen ta), 
 and, according to their various origins, tegmenta foliacea, as in 
 Fagus and JEsculus ; t. stipulacea, as in Carpinus, Corylus, and 
 Betula ; and, lastly, t. vaginalia, as in the bulbs of Allium, Lilium, 
 &c. Again, there is an essential distinction between the pro- 
 pagative and branch buds : the first are developed in a very solid 
 and fleshy manner, either in all their parts, as in the generality of 
 bulbs and bulblets, e. g. in Lilium candidum ; or in their axial 
 organs, as in the true tubers, e. g. in Solanum tubcrosum ; or 
 in the foliar organs, as in the so-called solid bulb of Allium 
 ursinum ; or, lastly, in certain determined parts of the axis, as in 
 the European Orchidece, and the Dahlias ; but in the branch 
 buds this fleshy development does not occur. On the other hand, 
 in the development of the latter buds to branches their bud- 
 scales fall away ; but in the propagative bud they gradually die 
 away from without inwards, and envelope the bud with a thinner 
 or thicker layer of dry membranes. 
 
 Since it is most evident that bulbs are not roots, as many treat them, 
 but buds, there is no reason why the term tegmenta should not be applied 
 to those parts which, inasmuch as they are modified leaves, or parts of 
 leaves, and have essentially the function of shielding and covering that 
 part of the bud really capable of development, during the time of its rest 
 from vegetation, are clearly morphologically and physiologically the 
 same organs as the bud-scales. By applying the term tegmenta to these 
 also, we divest ourselves of one useless expression in terminology, which 
 is certainly again, ferula is a term wholly without etymological sense ; 
 and it is quite superfluous to discriminate between tegmenta and ramenta, 
 since both are parts of a leaf, or, more correctly, imperfectly, formed 
 leaves. 
 
 b. Structure of the Bud. 
 
 135. The structure of the bud has in part been sufficiently 
 discussed in the examination of the axis and leaf, but the several 
 peculiar kinds of bud require special treatment. We may, how- 
 ever, first make the general remark, that all buds consist originally 
 
 * Link's (Elera. Phil. Bot. ed. 2. vol. i. p. 467.) comparison of the bud-scales with 
 the cotyledons is either very idle, if it means merely that both are foliar organs, like 
 other leaves, or distinctly wrong, since the cotyledons have the function solely of nou- 
 rishing the embryo, and the coats of the seed effect the protection during the rest 
 from vegetation, while the tegmenta have only the function of protection. The nutrition 
 is carried on by the axis on which the bud is situated. 
 
PHANEROGAMIA : BUD ORGANS. 287 
 
 of parenchyma with very delicate walls, and that the vascular 
 bundles are subsequently prolonged in this : the thickening of the 
 cell- walls begins in those cells lying adjacent to the vascular 
 bundles of those parts on which the bud arises, and gradually pro- 
 ceeds into the bud. 
 
 So far as my observations extend, though they are, I must confess, 
 insufficient, the conversion of the cells of the buds into vascular cells 
 proceeds in all cases from the vascular bundles of the part on which the 
 bud arises. But it is easy to be deceived here, since the parenchyma of 
 the pith of the bud always is in continuity with the parenchyma of the 
 part on which the bud arises, and since the vascular bundles going to 
 the bud more frequently unite with the vascular bundles of the part 
 forming the bud, at the sides than in the upper and under part (where, 
 at least in axillary buds, the lower vascular bundles of the axis are 
 received by the leaf), and therefore it is difficult to perceive the whole 
 of the relations correctly in one section, particularly as it is necessary to 
 go back to the very earliest condition. It is self-evident that the 
 vascular bundles of the terminal bud are but a continuation of the 
 vascular bundles of the axis. On account of the difficulty of this investiga- 
 tion, I by no means set up my observations as affording conclusive argu- 
 ments against views opposed to them. I shall return again to this point 
 when I speak of propagation. 
 
 c. Of the particular Forms of Buds. 
 
 136. A. Buds developing in uninterrupted vegetation. These 
 may also be termed open buds, because they seldom or never exhibit 
 a closed form, since in these the leaves are gradually developed to 
 the perfect form and size, from the perfect rudiments contained in 
 the bud. Yet in these buds the foliatio is always such, that the 
 youngest and tenderest parts are defended from the influence of the 
 atmosphere, and almost wholly enclosed, 
 
 In tropical Monocotyledons, such buds are presented, with few excep- 
 tions, only as terminal buds ; in all other stems they are both terminal 
 and axillary : in this case they approach most nearly to the closed buds 
 of the following divisions. They occur also, though seldom, as adventi- 
 tious buds on the stalks and on the stems of Monocotyledons and Dicoty- 
 ledons, perhaps only in consequence of artificial means used thereto, by 
 cutting or wounding the barks : as an example of this, I may name here 
 the wounded stems of the species of Draccena and Cactus, with neither 
 of which, however, I had opportunity to convince myself fully, whether 
 the developing buds were truly adventitious buds, or rather axillary buds 
 corning into development, which, in Monocotyledons generally, especially 
 on main stems, but also in most Cactece, persist for a very long time in 
 the rudimentary condition. 
 
 B. Buds with vegetation dormant for a certain time. 
 
 1. Buds of Shoots. 
 
 a. Terminal and axillary buds of perennial plants, with periodi- 
 cally dormant vegetation. Of these we are only intimately 
 
288 MORPHOLOGY. 
 
 acquainted with the native trees of our woods and forests. It ia 
 characteristic of these, that the young leaves, which subsequently 
 come to perfection in the more developed axis, are enveloped whilst 
 in the bud by stipules, which, soon after the development of their 
 leaf, fall away (stipulce deciduce), as in Liriodendron, or in leaves 
 or stipules of simple structure, of which the laminar portion is 
 abortive (tegmenta) : and there are varieties amongst these, so far 
 that either only the external or inferior leaves, or stipules, appear 
 as coverings of the buds, as in Fagus ; or the coverings of the bud 
 seem to be continued into the interior of the bud, but alternate 
 with leaves capable of perfect development, which lie between and 
 are covered by them, as in Acer. The coverings of the bud are 
 for the most part tough, and almost leathery; they are often filled 
 and coated over with resinous juices, and then mostly fall off in the 
 development of the bud, but they also occur thin and herbaceous 
 in texture, and even change quickly into dry thin membranes, which 
 mostly remain upon the plant : these last are seen in Pinus. 
 
 The study of the bud is yet far from being complete : it requires much 
 comprehensive investigation. The best works which we possess upon 
 the subject are two essays of A. Henry.* But we want here the full 
 history of the development, without which nothing important can be 
 accomplished. The coverings of the bud are the undermost or inferior 
 leaves of the bud which is developing to an axis ; they are sometimes 
 many, sometimes few. Sometimes the internodes between the decidu- 
 ous (Fagus sylvatica) or persistent (Abies excclsa) bud-scales remain 
 undeveloped. All (?) plants here referred to develope yearly only one 
 simple bud, which was formed in the preceding year. A few plants 
 deviate from this rule in a manner which, after Linnaeus, may very 
 properly be called prolepsis. This occurs in some degree in AInus, in 
 which the under-leaves of the axillary buds are developed in the same 
 year that they are formed : hence the buds coming to development in the 
 spring are properly only terminal buds. Pinus deviates from the rule in the 
 most remarkable manner, in which all the leaves of the axillary and terminal 
 buds, gemma primaria, appear as bud-scales (tegmenta primaria\ and in 
 the next year, on the development of the bud, they fall away, all except 
 one little scalef, whilst the already formed rudimentary axillary buds, 
 (gemmce secundarice), which should only reach development in the third 
 year, are now developed ; on these secondary buds also the inferior 
 leaves are membranous bud-scales (tegmenta secundaria) ; and only the 
 two to seven of the upper leaves directly beneath the secondary terminal 
 bud, which almost always remain in a most rudimentary condition, 
 become developed into perfect leaves, and thus these, as the internodes 
 of the secondary bud do not develope, appear to arise, from two to seven 
 
 * Nova Acta A. L. C. N. C. t. xviii. p. 1. and v. xix. p. 1 
 
 f This is then of rather tough texture, and is merely the lower (in the bud con- 
 dition green) portion of the otherwise dry and membranous bud-scale. This is 
 remarkable for an interesting structure. The cells are all elongated, and in the middle 
 thickened by indistinctly porous deposits, almost to the filling up of the cavities. The 
 cells of the margins, on the contrary, where the bud-scale appears lacerated, exhibit a 
 very thin membrane, with a spiral striatiou of the utmost delicacy ; and the cells, which 
 appear on the border in the form of single hairs, tear, when pulled out, into a spiral 
 band, just like the hairs of the Mamittarier and Melocacti. 
 
PHANEROGAMIA : BUD ORGANS. 289 
 
 in number, and surrounded at the base by a membranous sheath, imme- 
 diately from the branch on which the primary bud was developed. Pinus 
 and Abies exhibit the further peculiarity that they develope two, three, 
 or more primary axillary buds to true branch buds only at lengthened 
 intervals ; otherwise, in Abies, the axillary buds only exist potentially. 
 In Pinus, as has been remarked, the leaves never form the end imme- 
 diately continuing the axis, but between them is always found a very 
 small rudimentary terminal bud, which is often merely indicated by a 
 little flattened papilla composed of a few cells. Some botanists, and that 
 even recently, have esteemed these leaves as a part of the divided axis ; 
 a view which does not involve an impossibility, since in the Rhizo- 
 carpece a ramification of the axis occurs without antecedent formation of 
 buds, but which, in the way it was put forward, was a mere fancy, in 
 which the question was not once examined by a thorough investigation 
 of the fully developed parts, much less by a study of the course of 
 development. 
 
 b. Adventitious buds of perennial plants, with vegetation periodi- 
 cally dormant. They are only distinguished from the foregoing 
 by the mode of development. Each stem, whether a common one 
 or a root stem, can develop a bud. These buds are caused, not 
 only by accidental and intentional wounding of the stem, but 
 also by the inclination of plants to develop buds at certain places. 
 Many plants exhibit upon their bark peculiar little groups of 
 lax, roundish cells, which originally lie under the epidermis, 
 which, however, is soon destroyed above them, leaving them bare 
 (lenticellce). The result of this exposure is, that at these places 
 the bark is rent by the distension of the bough or stem ; hence the 
 newly vegetating part of the bark comes in contact with the air. 
 It is principally at the edges of the rent bark that the adventitious 
 buds are found. 
 
 Link says (1. c. 337.), the adventitious buds are distinguished from the 
 axillary buds by their structure; in the latter the greater part of the pith 
 goes with the wood into the supporting leaf, and in the former the entire 
 amount of pith passes into the bud. Accurate observation shows that 
 the supporting leaf stands in no connection with the pith, and that from 
 the wood into these only small vascular bundles enter ; whilst, on the 
 contrary, a thick cylinder of pith, and at a later period, a complete 
 circle of vascular bundles, subsequently forming wood, enter into the 
 axillary buds ; and that further, the adventitious buds stand in no 
 immediate connection with the pith, but only with the medullary rays ; 
 of this every twig of the Lime will afford an example. 
 
 Respecting the import of the adventitious buds, I shall have to speak 
 again more fully when I come to the subject of reproduction. Here we 
 have merely to state in general terms the cause of their origination. It 
 is well known that injuries, such as the breaking or cutting off of a 
 branch, usually call forth a number of adventitious buds. Very little, 
 indeed, is yet known of the import of the lenticels in relation to this 
 point. That these are not, as De Candolle* supposed, root-buds, Du 
 Petit Thouars and H. Mohl (Flora, 1832, No. 5.) have proved beyond 
 all question, and as every attentive observer is aware. I believe that I 
 have obtained a pretty sure conclusion as to the import of these (perhaps a 
 
 * Organographie, v. i. p. 95. 
 U 
 
290 MORPHOLOGY. 
 
 very insignificant and accidental one), as above given, by close compari- 
 son of the shoots and stems of the Italian Poplar and the black Poplar 
 through all their steps. My knowledge goes no further, and there is 
 here again a hiatus, which certainly would have been partly filled up 
 already, had the time spent in useless ratiocination and writing about 
 these objects been rather applied to true investigation of nature. 
 
 2. Propagative Buds. 
 
 a. Bulbs (bulbi) are Monocotyledonous stems, with undeveloped 
 internodes, which gradually die away from below upwards, and 
 therefore remain always very short, with perennial leaves, whose 
 vaginal parts die away and enclose as thin membranes, the sheaths 
 of the inner leaves still living, and always fleshy and thick (bulb 
 scales), or more rarely die away speedily and leave bare the latter, 
 as in Lilium. They are formed either immediately from the em- 
 bryo, and then the sheathing part of the cotyledonary leaf becomes 
 the first bulb scale ; or they are formed from the axillary buds of 
 the bulb, or from the axillary buds of the stems which have sprung 
 from the bulbs, as in Lilium bulbiferum : less frequently they are 
 from adventitious buds on leaves or other parts. We distinguish : 
 
 A. The leafy bulb (bulbus foliosus). 
 
 1. The tunicated bulb (b. tunicatus), where many sheathing parts 
 are closed round, or embrace the axis pretty broadly, as in 
 Hyacinthus orientalis. 
 
 2. The scaly bulb (b. squamosus), where many sheathing parts, 
 relatively slender and short, are seated on the axis, as in Lilium 
 candidum. 
 
 B. The solid bulb (b. solidus), when the bulb is formed of one 
 single living sheathing part. 
 
 So far as my knowledge extends, no Dicotyledonous plant presents a 
 true bulb, although there is nothing impossible nor improbable in such 
 a thing ; since if we disregard the character of the undeveloped inter- 
 nodes, and thus make the definition more general, the subterranean stems 
 of Lathrcea squamaria, Dentaria bulbifera, etc. are bulbi squamosi. I 
 would, however, the less recommend such an innovation, since the dis- 
 covery of a true Dicotyledonous bulb would make the definition pro- 
 posed appear more to the purpose. Another question is, whether we 
 shall reckon the bulbels of some of the species of Oxalis here. I have 
 not myself found opportunity sufficiently to examine them, and therefore 
 leave them for the present among Dicotyledonous bulbels, since I make 
 the persistence of the bulb, as such, a character of its definition. On the 
 other hand, it is quite incorrect to separate the axillary bulb of Lilium 
 bulbiferum from bulbs : since it is a bulb in its structure, it always re- 
 mains a bulb, and it is formed in the axil of a leaf of a bulbous plant, 
 whether on the stem or the stalk, appears to be quite unimportant. 
 
 The three divisions of bulbs which we have given are practical sub- 
 divisions of bulbs, as such, according to their composition out of the 
 parts necessarily present to make them fall within the definitions. 
 
 It is inconceivable to me how the reticular bulb can be arranged as 
 A 3., simply because in some tunicated bulbs the external decaying coats 
 become at last fibrous. If this mode of classification were correct, we 
 
PHANEROGAMIA I BUD ORGANS, 
 
 291 
 
 must, on the same principle, have class 4 brown, 5 yellow, 6 red bulbs, 
 &c. ; we must class others, as containing starch, or gum, because their 
 inner scales sometimes contain starch and sometimes gum. In the 
 solid bulbs we have also heard of blending of the coats of the bulb ; a 
 sufficient proof that no one had taken the trouble to analyse the well 
 known examples of bulbus solidus, and to compare them together, much 
 less thoroughly studied the history of development. Each germi- 
 nating bulbous plant has, during the first year, a bulbus solidus (fig. 
 175.) on an infantine scale, because then only the thickened sheathing 
 part of the cotyledonary leaf is present (fig. 175. c). 
 
 175 
 
 176 
 
 Whether a bulb shall later be known as bulbus solidus or bulbus 
 foliosus depends upon the time required before the external sheathing 
 parts begin to die away, and upon the greater or less mass to which the 
 sheathing part enlarges. The distinction is not of vast importance, since 
 in the same genus are found the leafy bulb (Allium Cepa) and the solid 
 bulb (Allium ursinum) (fig. 176.). In families there is little or no con- 
 stancy of this character. I have traced the history of the development of 
 Allium Moli/, acutangulum, ursinum (fig. 176.); Gagea lutea, arvensis ; 
 Hyacinthus orientalis, Lilium pumilum (fig. 175.) ; and Tulipa sylvestris. 
 There is yet another point, which makes the precise definition of a bulb 
 very difficult. If we compare the series of gradations of the bulb from 
 Allium Cepa to Allium Porrum, and from this, through Allium sativum, 
 to the common Monocotyledon bud, especially to that with uninterrupted 
 vegetation, for instance, in Phormium tenax, it will be very difficult 
 to draw a line of distinction, which indeed scarcely seems to exist in 
 nature. 
 
 In treating upon axes and leaves, the most important matters con- 
 
 75 Lilium pumilum. Germination. A, Natural size : a, seed ; b, sheathing part of 
 the cotyledonary leaf; c, the sheathing part exhibiting a small solid bulb ; d, the radi- 
 cle. B, A longitudinal section through the under part of the cotyledon, somewhat 
 enlarged : b, c, d, as in A ; e, the body of the plant (stalk), and foundation of the bud. 
 C, A cross-section through the midst of B : c c, as before ; e, the largest (external) leaf 
 of the bud. 
 
 176 Allium ursinum, natural size. A longitudinal section through the solid bulb, 
 a a, Withered leaf, clothing the bulb as a membrane; b, flower-stalk; c, fresh leaf, 
 whose sheathing part encloses the next year's bud (d), which is the terminal bud of the 
 stem (e), which is continually dying away beneath. 
 
 u 2 
 
292 MORPHOLOGY. 
 
 nected with the structure of buds were discussed. There is little peculiar 
 to the bulb. The epidermis of the bulb-scales in Allium Moly covers a 
 cellular layer, flat cells of which exhibit the strangest and most irregular 
 forms, and seem to be interspersed between each other, somewhat in the 
 same way as the parts of the well-known child's toy, where a picture is 
 glued upon thin board and sawn up into irregular, variously-shaped 
 pieces, which fit into each other. These cells are thick-walled, and very 
 porous. In Gagea lutea and arvensis a layer of spiral fibrous cells is 
 found in the same part. In Allium ursinum and Colchicum autumnale 
 I do not recollect to have observed this ; nor have I seen it in any bulbs 
 with many leaves. 
 
 b. Bulbels (bulbilli). To plants not perennial by means of a bulb 
 (only Dicotyledonous?), the axillary buds are sometimes developed 
 into bulb-like forms, in which the leaves are only developed as 
 thickened, sheathing parts, and the buds separate from the parent 
 plant by the dying away of the supporting stem or stalk, and become 
 independent plants, as with Dentaria bulbifera. 
 
 From the want of personal investigation, and accurate ones from other 
 quarters, I am unable to say much upon these structures. I cannot 
 decide whether the bulbels of some species of Oxalis belong here. Bul- 
 billi ought to be definitely distinguished from true bulbs, in the manner 
 above stated. 
 
 c. Tubers (tubera). On underground stems the axillary buds 
 (of attenuated scaly leaves) are sometimes developed in such 
 fashion that the entire axis of the bud becomes thickened, fleshy, 
 and of a knobby form ; the leaves are quite in rudimentary con- 
 dition, or scarcely to be recognised, whilst the axillary and 
 terminal buds remain capable of development, and after the dying 
 away of the stems of the parent plant form new stems, as in 
 Solanum tuberosum. 
 
 The growth of the potato from an axillary 
 bud of an underground stem is easy to trace 
 (fig. 177.) ; and if we grow the potato in such 
 a manner that a part of the bottom of the stem 
 must remain above the surface of the earth (a 
 circumstance which occurs continually with po- 
 tatoes badly earthed up), we shall see all the 
 stages and degrees which exist between a per- 
 fectly normal axillary bud and a normal potato. 
 From want of the entire history of the develop- 
 ment, I cannot here decide whether the tubers 
 of the Helianthus tuberosus should be reckoned \ I) |I\I\T 
 
 here or not. Tubers of Cyclamen and others W|| *b> 
 
 certainly do not belong to this class : they are 
 stems. 
 
 d. Tuber buds, tubercles (tubercula). Many plants form small 
 tubers above the earth ; seldom (if ever ?), indeed, as axillary buds, 
 but frequently as adventitious buds, and especially on foliaceous 
 
 177 Solanum tuberosum. Bark of a filiform subterranean stem (a), cut into at b down 
 to the bottom of the axillary bud. c, The young potato ; d, scale-like leaf, which 
 bears the potato as an axillary bud ; x, outline, of the natural size. 
 
PHANEROGAMIA : BUD ORGANS. 
 
 293 
 
 organs, from which new independent plants develope so soon as they 
 are separated from the parent plants : sometimes this is a specific 
 peculiarity ; as, for instance, the tubers of the species of Amorpho- 
 phallus and other Aracece : sometimes they arise in certain plants 
 particularly readily in consequence of injuries ; as, for instance, in 
 the Gesneriacece on the broken surface, after cutting a leaf nerve 
 at the edge or the point of the leaf. 
 
 These tubercles hold the same relation to the tubers that the bulbels 
 do to bulbs, at least so it appears from what has been already made 
 known upon the subject ; for again, all of the plants belonging here 
 are far too insufficiently known in their development to admit of 
 our defining the relations of the tubercles to the occasionally equally 
 tuberculated stem. 
 
 e. Pseudo-tubers (tuberidia). In some plants a single, frequently 
 an axillary, bud is transformed in a peculiar manner. The paren- 
 chyma of the axis of the bud, which is situated over the vascular 
 surface, suddenly becomes exceedingly expanded in a solid and 
 tuberculated form, by means of the sudden commencement of new 
 formation of cells in isolated groups of cells ; in the axillary bud 
 this only occurs on one side (as in our native Orchidece), since, on 
 the other side, the pressure of the stem prevents such distension. 
 In Aponogeton distachyon, the -thick fleshy cotyledon with the end 
 of the root proves a corresponding obstruction ; hence here, also, 
 the development of the pseudo-tuber is only one-sided. In the 
 Dahlias, on the contrary, the tubercular development is equal on 
 both sides. The mass of cells enters between the base of the 
 cotyledon and the new adven- 
 titious roots, arising, at a very 
 early period, almost imme- 
 diately under the cotyledon, 
 and which, through the form- 
 ation of the pseudo-tubers, be- 
 come gradually removed far 
 away from the cotyledon. 
 
 The process of formation of 
 the pseudo-tubers in the indige- 
 nous Orchidacece, especially Or- 
 chis, Anacamptis, Gymnadenia, 
 Platanthera, and Ophrys, which 
 I have investigated in regard to 
 this point, so far as the species 
 were at my command, is in the 
 highest degree interesting ; I 
 sketch it here, after examples 
 easily to be verified in Orchis 
 Morio (fig. 178.) and latifolia. 
 In the axils of the lower 
 leaves (A, d,) occur axillary 
 
 I7B Orchis Morio. A, Natural size, young plant: a, tuber of the current year; b, scar 
 of that of the former year, cut away ; c, papilla which indicates the formation of the 
 
 u 3 
 
 178 
 
294 MORPHOLOGY. 
 
 buds (A, c, b). Soon after vegetation has commenced in spring the bud 
 of the second leaf begins to develop, the portion immediately above its 
 point of attachment first expanding and pushing its way downward (fig. 
 1 78. B) ; in Morio in a roundish, in latifolia in a very early recognisable, 
 two-lobed form. This expansion soon breaks its way through the base of 
 the leaf, in the axil of which the bud occurs, as well as through the va- 
 ginal border of the lowest leaf, and thus it becomes visible externally. 
 The part by which the bud is connected with the stalk does not increase 
 in thickness, but merely elongates, whereby the pseudo-tuber, bearing the 
 bud above upon its summit, becomes continually removed further from 
 the parent plant. Toward the close of summer, the pseudo-tuber which 
 has vegetated in the preceding year has become wholly destroyed ; that 
 of the current year adheres to the side of the one newly produced, and 
 still bears the remains of its stalk and leaves : the new pseudo-tuber is 
 at least so far perfected that in the following year it is capable of forming 
 roots for the nutrition of the plant. In consequence of this kind of de- 
 velopment of buds, every Orchis plant alters its place annually ; and, since 
 the lower leaves have an angle of divergence of about 129, this occurs 
 in such a way, that in the fourth year it returns pretty nearly to its 
 original situation. These pseudo-tubers are decidedly not roots in a 
 morphological sense, in all probability not in a physiological ; but at present 
 we have no facts on which to found a decision on this question. On the 
 other hand, in the beginning of spring, many adventitious roots, which 
 subsequently take upon themselves the nutrition of the plant, are always 
 formed from the stem above the pseudo-tuber, and below the first leaf. I 
 have no accurate researches yet on the mode of cell-formation in all this 
 process. The pseudo-tubers are traversed by vascular bundles, which run 
 in great numbers, mostly in arcs, from the apex to the base, and are sur- 
 rounded by lax, large meshed, cellular tissue, which in an early condition ex- 
 hibits upon its walls reticular currents of sap proceeding from a cytoblast ; 
 cells from six to eight times larger lie embedded in the above, forming 
 circles round the vascular bundles. In very young pseudo-tubers the 
 homogeneous, colourless, and gelatinous contents of these larger cells is 
 tinged of a violet blue by iodine ; as the pseudo-bulb grows older, this 
 colour passes through the colour of red wine to yellow, and at last the 
 gelatinous matter exhibits no reaction to iodine. But during the vege- 
 tation of the same in the following year, the gelatinous matter changes 
 again in the reverse way, till at last, in the decaying pseudo-tuber, a con- 
 dition once more appears when the gelatinous substance is not coloured 
 by iodine. The surface of the gelatinous mass manifests in its perfect 
 stage of development markings of minute retriculations, almost granular, 
 somewhat like the starch in the cells of a boiled potato. In the remainder 
 of the cells a very finely grained starch is gradually formed, which dis- 
 appears almost totally during the vegetation of the pseudo-tuber, so that 
 at last only isolated granules remain in each cell, adhering to the persistent 
 cytoblast. This peculiar structure in our Orchidacece is to be paralleled 
 with some tubers in the tropical kinds, in which, in like manner, the form- 
 ation of a tuber only changes one single internode; for instance, Bolbophyl- 
 lum (fig. 179. A), Gongora, Rodriguezia, Epidendrum (fig. 179. B). 
 But in the tropical Orchidacece this structure passes through forms such 
 
 next year's tuber ; d, lowest leaf of the plant ; e, second leaf, in the axil of which the 
 plant and tuber of the next year are formed ; f, adventitious roots cut off. B, Longi- 
 tudinal section through c of the preceding figure : , lower part of the leaf; b, rudi- 
 ment of the tuber which is formed out of the base of the axillary bud ; c, axillary bud, 
 the rudiment of the next year's plant. 
 
PHANEROGAMIA : BUD ORGANS. 
 
 295 
 
 as occur in Bletia into the true tuber, through Monachanihus, Catasetum, 
 Dendrobium, &c., into the usual structure of stems. In an exactly similar 
 manner to that in Orchis is formed the pseudo-tuber of Aponogeton 
 distachyon. The embryonary bud is attached laterally and free upon the 
 thick, fleshy cotyledon ; the radicula is developed quite regularly at first, 
 in germination ; but the portion of the embryonary bud between the 
 cotyledonary leaf and the following soon swells up into a fleshy body on 
 the free side, and then the full-grown, round pseudo-tuber becomes sepa- 
 rated from the cotyledon, while adventitious roots have been gradually 
 developed between the pseudo-tuber and the lowest leaf of the young 
 plant.* I do not know whether new pseudo-tubers can develope in 
 Aponogeton as axillary buds of the plant. 
 
 Lastly, in reference to the Dahlias, my investigations are still very 
 imperfect. The matter appears to me to stand thus : Two adventitious 
 roots are formed on the base of the cotyledon soon after germination. In 
 later conditions I found the young pseudo-tuber (no trace of adventitious 
 roots) under the cotyledon, but two of them pretty low down upon the 
 pseudo-tuber : I think these must have been developed between the 
 former adventitious roots and the cotyledon. I have given at length, in 
 my already often -quoted treatise on the Cactece, an account of the pro- 
 cess of multiplication of cells in the young tubers, contemporaneously with 
 the origination of oil passages. It consists in constant formation of cells 
 
 * What Flanchon (Ann. des Sc. Nat. 1844, Botanique, p. 107, et seq. ) has published 
 on this is altogether incorrect, and, like a good deal else in the same essay, a result of 
 very superficial observation. 
 
 179 A, Bollophyllum bulbiferum, natural size : a a, tubercular internode, the terminal 
 bud of which becomes the inflorescence; 6, leaf; c, dry, old sheathing leaves; an 
 adventitious root is breaking forth through the lowest ; </, older and non-tubercular in- 
 ternode. B, Epidendrum coc/tleatum, two- thirds of the natural size : a, b, <?, d, as before ; 
 c, the flower-stalk, cut off. 
 
 v 4 
 
296 MORPHOLOGY. 
 
 within cells and absorption of the parent-cells. In very young tubers this 
 process of development goes on in a zone outside the vascular bundles ; 
 at a later period it enters into many situations throughout the whole 
 tuber in vertical rays in the pith, in horizontal ones in the rind. In all 
 the young pseudo-tubers all the cells exhibit most beautifully a circu- 
 lation branching out in reticulated currents from the cytoblasts, and 
 running with the greatest rapidity. 
 
 All these forms here sketched have this in common, that they are 
 tubercular thickenings of a portion of an internode, at most of a whole 
 one (in the Dahlia), this alteration not contemporaneously affecting 
 the foliaceous organs or buds ; by this they all fall within a common 
 definition, and are at the same time clearly distinguished from the true 
 tubers, which always comprehend an entire axillary bud, i. e., all the in- 
 ternodes of an entire axis with its foliaceous organs and buds. The 
 so-called bulbs of Crocus belong here : they are nothing but the fleshily- 
 thickened bases of the axis of the bud. 
 
 In the great abundance of so-called tubercular plants, it is very possible 
 that other and quite different forms of peculiar modifications of buds 
 occur ; on account of the great dearth of our knowledge of their develop- 
 ment nothing more can be said about them nay, the examples of the 
 forms noticed cannot be increased. A time must first come when the now 
 usually so dry and spiritless systematic works will give something more 
 than Planta tuberibus perennans or Radix tuberosa, &c. Such inves- 
 tigations are in the power of every one who has a tolerably good simple 
 microscope, which may be bought for a very little money ; and they 
 would further science more than the description of one hundred new 
 species in the superficial way just adverted to, from which one in fact 
 learns nothing more than that they exist upon the earth. 
 
 Seed-buds (ovules, gemmuld). The last terminal and axillary buds 
 in the interior of the blossom assume a wholly peculiar form, of 
 which, however, I cannot speak until I come to the examination 
 of the apparatus for propagation. 
 
 E. THE FLOWERS. 
 
 137. We include both: a, every single organ of propagation by 
 itself, wherever unconnected with others on the same axis, through 
 a circle (or compressed spiral) of modified foliar organs (floral 
 envelopes), and b, every combination of several organs of propaga- 
 tion, collected within one floral envelope, and separated by this 
 from others, under the name of flower (flos) ; on the other hand 
 every collection of single flowers is an inflorescence (inflorescentia). 
 
 If we review the whole kingdom of Phanerogamous plants, and seek in 
 the multiplicity of forms for a guiding clue, our impressions will lead us 
 to something like the following ideas : 
 
 Two morphologically fundamental organs, axis and leaf, modified 
 toward this object in the preceding groups of plants; and two physiolo- 
 gically determinate organs, serving for reproduction, propagative cell, and 
 seed-bud (ovule), gradually developed ; the formative force of nature now 
 connects the propagative cell (pollen) with the leaf (anther), and the 
 seed-bud with the axis. We thus obtain two organs of reproduction at 
 
PHANEROGAMIA : FLOWERS. 297 
 
 once morphologically and physiologically determinate, two sexes (sexus). 
 But these have no definite relation to each other in space; this or that 
 leaf may be transformed into a stamen, this or that axis into a seed-bud, 
 on any individual plant. It is not inconceivable that we may yet dis- 
 cover a plant in which, without any apparent arrangement, here some- 
 times only a stamen, there sometimes only a common terminal bud, is de- 
 veloped into a seed-bud. But Nature seeks gradually to unite the two 
 parts continually closer, and thus we obtain, on a general survey, the 
 following stages of development in the Phanerogamia. 
 
 1. Isolated stamens and seed-buds, at first in different individuals, 
 then united in one individual, constituting in their forms the gradual 
 transition from the Cryptogamia to the Phanerogamia, become finally 
 united in great numbers upon one axis. With exception of the very 
 simplest, yet to be discovered case, we have this in the Cycadacece, Coni- 
 
 ferce, and Loranthacece. < 
 
 2. Inflorescences of this kind, in the simplest form, become sur- 
 rounded by a foliar organ of a peculiar form (spathe), and at the same 
 time the seed-buds become enclosed in a peculiar case (the germen in 
 Lemnacece). Gradually, at first through the position, then through the 
 addition of bracts (?) groups of stamens become collected around the 
 germen (Aracece, Naiadacce, Qrontiacece). 
 
 3. A circle of definitely modified foliar organs, encloses as floral 
 envelopes, the stamens or germens into monosexual flowers (Hydrocha- 
 ridece], or finally both into hermaphrodite flowers (Liliacece). 
 
 4. Now succeeds the development of the complete flower into the 
 greatest multiplicity of combinations of the different parts and their 
 forms, in a great number of Mono- and Di- cotyledonous families. 
 
 5. The single flowers approach closer together in the manifold forms 
 of the infloresence, in many other families. 
 
 6. Finally, the entire inflorescences contract so closely, and into such a 
 limited form, that they again appear like one simple whole ; the so-called 
 compound flowers, the highest stage of development of Phanerogamic 
 structure, on one side rising according to the Monocotyledonous type 
 through the Palms ^to the Grasses, on the other, according to the Di- 
 cotyledonous type, preceded by the inflorescence partly of the Umbel- 
 liferce, partly of the Leguminosce, to the Composites. 
 
 Thus we receive the impression of an incessant gathering of a greater 
 number of individual parts, under continually closer morphological con- 
 nection, into a unity, and of an unbroken series of gradually increasing 
 complications of fundamental organs, which are naturally divided ac- 
 cording to their principal stages, into imperfect flower, flower, inflores- 
 cence, and compound flower. But this is merely the aesthetic conception 
 which gives us the idea of Nature working like a human being, according 
 to a certain plan, and continually concentrating this. In the scientific 
 treatment of the matter we require very different and more accurate limit- 
 ations, of the definitions, in which no transitions, confusing the distinc- 
 tions, are possible. 
 
 It does not seem to me that hitherto much pains have been taken about 
 the accurate perception of the definition of a flower, or that we have 
 been very fortunate in the discovery of the correct expression. Ac- 
 cording to most definitions yet given, it would be rather difficult to 
 distinguish between flower and inflorescence. Kunth, in his Botany, 
 speaks of the flower, without anywhere saying what this may be, 
 wherein its essential characters consist, and what are the limits of 
 the definition of it. Bischoflf does the same, in his Botany. 
 
298 MORPHOLOGY. 
 
 Link says : " Flower is a bud altered through metamorphosis : it be- 
 longs to the terminal parts, and is known by the stamens and pistils." 
 How Link will by this means distinguish the inflorescence of the Aracece, 
 of the Composite, &c. from a flower, I do not see ; both are metamor- 
 phosed terminal buds, with stamens and pistils ; no investigation can 
 establish that the bud is a compound one in the former, which, indeed, 
 is not set up by Link ; for every leaf-bud, for instance, in the Lime, 
 has lateral buds ; and the greater or smaller development of lateral buds 
 cannot at all come into consideration in a metamorphosed bud. 
 
 Lindley calls the flower a terminal bud which encloses the propaga- 
 ting organs, and the foregoing objection is so much the more applicable 
 to his definition. 
 
 A. Richard says, " The flower is essentially constituted by the pre- 
 sence of one of the sexual organs, or of both sexual organs united on a 
 common organic receptacle ; they may, or may not, be furnished with a 
 definite envelope to protect them." This suits so excellently the cones of 
 the Coniferce and the spadix of true Aroidece, that Richard cannot truly 
 deduce from his definition of the flower why, by his rule, those are 
 inflorescences and these flowers. 
 
 These examples are sufficient to make good the reproof, that hitherto 
 Botany has never raised the question how the flower is distinguished 
 from the inflorescence, and yet the answer to this question is indis- 
 pensable. 
 
 The language of common life, starting from the unprejudiced impres- 
 sion, calls the spadix, with its spathe, the flower of the Aracece : it speaks 
 of the flower of the Clover, and means the entire head ; it says the Corn- 
 flower, and applies this name to the whole capitulum of Centauria. The 
 simple impression is at first always right ; and if science, in opposition to 
 it, calls those flowers not flowers but inflorescences, it must prove this 
 against the simple impression. This may, of course, be done satisfacto- 
 rily, but has hitherto been altogether neglected. Link* even sought to 
 defend the popular term in the Composites, against Cassini ; when he says, 
 however, that the people appear to have had a better knowledge of the 
 essential of the inflorescence of the Composites than Cassini, it is indeed 
 merely a jest. The people call the thing a flower for the very reason 
 that they have no knowledge at all of what is essential in the matter, 
 but refer merely to the impression of first sight. An obscure presenti- 
 ment of something true does, indeed, lie in this unprejudiced percep- 
 tion, as in the natural piety of the clown is indicated, even though in 
 obscure features, the Divine faith resting deep in the human spirit ; but 
 he who would endeavour to develope a philosophy of religion with the 
 limited insight and confused conceptions of a clown, would arrive merely 
 at confined and obscure mysticism. Science, in order to gain a distinct 
 consciousness of that which lies dark and hidden in impression and feel- 
 ing, requires scientific instruments, accurate abstractions, definite con- 
 ceptions, &c. Undoubtedly there lies in that complication of single 
 flowers into that which gives us the impression of a whole, with definite 
 limitation in the Composite, &c, something which marks it as a higher 
 morphological stage of development of Phanerogamic plants; and it is 
 just this new combination of isolated parts into a collective form of a 
 higher order which the unprejudiced popular sense at once compre- 
 hends. But these forms do not thereby stand nearer to the solitary 
 flower than to the inflorescence, as Link supposesf, but are, on the con- 
 
 * Elem. Phil. Bot. ed. 2. vol. ii. p. 78. 
 
 f This would be the same as saying 10OO stands nearer to 1 than to 999. 
 
PHANEROGAMIA : FLOWERS. 299 
 
 trary, separated from that by the entire series of different inflorescences, 
 and are gradually prefigured through these until they form, themselves, 
 a thoroughly new and more elevated unity. Of this unity of an entire 
 inflorescence we not only have, as yet, no scientific characterisation, but it 
 is even impossible at present, because we do not know sufficient of the 
 morphological laws of the plant in general, on which that unity also de- 
 pends. One thing, however, I am firmly convinced of ; namely, that we 
 have, as De Candolle has already half done, to regard the Composites as 
 the completion of the morphological development of the Dicotyledonous 
 plant, and the Grasses, which Link very sensibly places by the side 
 of these, as the highest stage of the Monocotyledons. In this view, also, 
 have I described the higher gradations of the Phanerogamia as continua- 
 tions, as it were, of those previously given. 
 
 But this way of looking at the matter, as I have already said, has, at 
 present, merely an aesthetic value, and such mingling of aesthetics with 
 science inevitably turns the latter from its purpose, and paralyses its 
 progress ; therefore I must oppose to this survey the rigid scientific 
 definition of the paragraph. We cannot enter at all upon that mode of 
 development, because its stages are not distinct divisions ; they rather rise 
 gradually from one to another, and thus cannot be kept apart with strict 
 scientific accuracy. In the examination of the heads of the Umbelliferce, 
 the Leguminosce, &c., especially, the distinction between inflorescence 
 and compound flower so completely confuses us, that it appears totally 
 impossible to obtain a definition which will strictly distinguish them. On 
 the other hand, the explanation of flower and inflorescence, above given, 
 furnishes us with quite strict distinctions, by means of which we may 
 readily comprehend each other in all scientific doings ; but this compre- 
 hension is useful solely in scientific terminology. If now, after this dis- 
 cussion, we consider some of the doubtful phenomena, we very readily 
 come to a decision whether we shall call any thing a flower or an inflo- 
 rescence. In the first place, I will present the case of the male flowers 
 of the ConifercB. In Abies we find a bud, of which the lower leaves are 
 developed, as in every leaf-bud, while the upper are converted at once 
 into stamens*; here we have the simplest flowers connected with the sim- 
 plest inflorescence, not, however, forming altogether a solitary flower : 
 the only analogue is the inflorescence of the female flower, t Here is a 
 bud the leaves of which cannot bear seed-buds, from the very fact 
 that they are leaves ; but in every axil of such a leaf (bract) an axis J 
 arises, and produces two seed-buds. In all the Cupressinece the forma- 
 tion of the male inflorescence is the same ; in the female the seed-buds 
 appear to be axillary buds (with adventitious buds) of the bracts. 
 
 According to the definitions given the proof is further afforded at 
 once, that the spadix of the Aracece is to be explained as an inflores- 
 cence, because it has no bract (and even in the simplest case, where only 
 one germen, with one stamen, on a spadix developed merely as a little node, 
 are enclosed in a scarcely visible membranous spathe, as in Wolffia). 
 
 * That the anther is here adherent to the hack of a bract is another of the purely 
 ideal fictions ; as if there were not hundreds of antherce extrvrsce, or of antheras cris- 
 tatce 
 
 f In Abies alba it not unfrequently happens that a portion of the lower leaves of the 
 female inflorescence become converted directly into stamens ; but then no axillary buds 
 are developed. 
 
 \ In Juniperus I guess, from yet imperfect researches, that the conditions are wholly 
 identical, and only vary by the seed-bud standing upright, instead of being suspended, 
 as in Abies. 
 
300 MORPHOLOGY. 
 
 Lastly, I will j ust offer a few remarks on the enigmatical family of Po- 
 dostemacece, in which we cannot yet well decide whether the complication 
 of germens and stamens together is to be accounted a flower or an inflo- 
 rescence. The history of development is altogether unknown ; young 
 buds of Podostemon ceratophyllum, preserved in spirits exhibited to 
 me the two stamens so closely approximated to the germen on the 
 scarcely perceptible stem, that the bract (?) standing on its base almost 
 formed a regular ternary circle with the two situated on the germen ; 
 it may be that the parts of a solitary flower are here thus separated by 
 eccentric development, since, in some others, e. g. Tristicha Thou. (Du- 
 fourea Willd.), a regular ternary floral envelope encloses a germen and a 
 stamen, and the flower appears tolerably regular in almost all the remain- 
 ing genera. 
 
 138. The following points must be taken into account in the 
 flower, deserving a more minute discussion, and they will, there- 
 fore, constitute the next sections : 1. The arrangement of the 
 flowers upon the plant, inflorescence, and the foliar organs 
 standing in relation thereto, the bracts and bracteoles ; 2. The 
 parts of the flower at the epoch of blooming ; 3. The transform- 
 ation and development of the parts of the flower into fruit; 
 4. The parts of the flower at the time when the seed is ripe. 
 
 Many matters I shall relate briefly, because they have been treated 
 previously in the proper places, and may conveniently be left out here. 
 I had rather, however, be useful in indicating a necessary reform of 
 science, than bring confusion and injury upon it by an ill-timed radical 
 revolution. 
 
 I. The Inflorescence. 
 
 139. It has already been stated that the inflorescence is 
 nothing else than the axis and its ramification where all the buds 
 are flower-buds. We here distinguish the solitary flower, either as 
 a terminal flower (flos terminalis), or as an axillary or lateral flower 
 (flos axillaris). The latter is sometimes naked (nudus), on account 
 of the suppression of the folia jloralia, or bractece. If the lateral 
 branch bears only one flower and bracteoles besides, it is called a pe- 
 dicel (pedicellus) below the flower, and the axis, to which the pedicel 
 is an axillary shoot, is called the peduncle (pedunculus). The as- 
 sumption of a pedicel to the terminal flower is purely arbitrary, 
 and at most to be maintained only by the presence of bracteoles, 
 and an articulation of the axis. The accumulated flowers always 
 stand, in a rudimentary condition, in a capitulum. From this, by 
 extension of the flower-stalk (pedunculus, here called rachis), comes 
 a spike (spica), by development of the pedicels an umbel (umbella); 
 by development of both, a raceme (racemus) : these are called the 
 simple forms of inflorescence, and in reality there are, and can be, 
 no others. If an inflorescence be enclosed in a single large bract, 
 this is called a spathe (spatha) ; if, on the contrary, it be enclosed 
 in a circle or contracted spiral of bracts, the envelope formed by this 
 circle of bracts is called the involucre (involucrum). The simple 
 inflorescences may become combined in manifold ways, on which a 
 number of useless terms have been founded, with reference to the 
 
PHANEROGAMIA : FLOWERS. 301 
 
 course of development, and composition, mostly merely naming the 
 peculiar mode of appearance in particular families ; e. g. anthela of 
 the Juncacece, glomerulus of the Cyperacea ; according to others, also, 
 of the Amarantacece and Chenopodiacea, moreover panicula, fasci- 
 culus, thyrsus, cyma, &c. with altogether indeterminate definitions. 
 
 If the manufacture of words, without principles of definition, without 
 thorough investigation of particulars, has prevailed anywhere, it has in 
 the study of the inflorescence. The study of the fruit perhaps excepted, 
 there is no part of Botany in which prevail such confusion, such a wild 
 waste of synonymes, and yet such imperfection and incompleteness of 
 the whole subject, as here. Perhaps Linnaeus even shares the blame here ; 
 for certainly no part was so superficially treated by him as the inflores- 
 cence which he named, without starting, as elsewhere, from accurate de- 
 finitions, merely according the superficial impression of some few condi- 
 tions with some words not even defined, but explained by examples. In 
 this path others followed, and only Roper, opening a new way, furthered 
 the study in many respects, yet without finding or ensuring accurate 
 results. As yet we have not the history of development of one single 
 inflorescence, though many fancies indeed, as they have originated one 
 out of another. Since no principles can be laid down for such play of 
 imagination, every one has his own, and every one takes the matter in a 
 different way, not merely in the more complicated, but, in some measure, 
 in the simpler forms of inflorescence. What a quantity of paper has been 
 written over during the last fifty years, on the import of the extra- 
 axillary inflorescence of the species of Solatium, on the spirally coiled 
 inflorescence of the Boraginacece ! but has one single botanist made an 
 attempt to look how they are formed, in order thus to explain their 
 nature ? And, disregarding this, what illogical confusion is ex- 
 hibited in the common classification of inflorescences by almost all 
 authors ! The inflorescence, say most, is the x arrangement of the 
 flowers upon the stalk. The division, therefore, can only be founded 
 on the difference of arrangement. But very few inflorescences are de- 
 fined according to this ; the spadix is distinguished by the substantiality 
 of the rachis ; the catkin, by the articulation with the plant, or with 
 Bischoff by the nature of the flowers ; the corymbus and fasciculus, 
 panicula and cymus, according to Lindley, by the order of blossoming. 
 Link, on account of the imaginary want of bracts in the Ficus, makes a 
 new word, in opposition to the calathium of Composite ; but he calls 
 the bractless raceme of the Cruciferce a raceme. Forms of inflorescence 
 are distinguished by the order of opening of the flowers ; but the inflo- 
 rescence of Dipsacus, which opens its flower from the noddle upward and 
 downward, is a capitulum, like those which open the flowers from below 
 upward. Here it is absolutely impossible for one individual to devise 
 means; only the earnest co-operation of many, especially of those who 
 have authority in science, will be sufficient to introduce gradually a 
 better and simpler, consequently an easier, treatment of the subject. 
 But when will the time come wherein the majority of botanists will, 
 not seemingly, but according to the spirit and the truth, keep science 
 steadily in view, instead of themselves and the gratification of their 
 own vanity ? 
 
 Starting from the simplest case, we gain the following mode of view- 
 ing the subject. Flowers originate from buds, and these originate, 
 except the terminal bud, normally only from the axils of leaves. The 
 first and simplest inflorescence is, consequently, the solitary flower at the 
 
302 MORPHOLOGY. 
 
 end of the axis, or in the axils of its leaves. In the terminal flower the 
 axes of the flower and of the stem are identical ; therefore a pedicel is 
 only to be distinguished when true articulation warrants a division of the 
 axis, or the true leaves suddenly pass into bracteoles. In a gradual 
 transition no distinction is possible. The leaf, where the axillary bud 
 becomes a flower, is called a floral leaf ; if it deviates importantly in 
 form and substance from the common leaves of its plant, it is called 
 a bract. But this transition from floral leaf into bract is not sudden, 
 as both, in a rudimentary condition, are exactly similar foliar organs, 
 so we often find on one and the same stalk all intermediate forms 
 between them ; and, for instance, in Veronica fruticulosa. Delphinium 
 Ajacis, Epilobium angustifolium, Verbascum thapsus, &c., no one can 
 declare where the floral leaves cease and the bracts commence : thus the 
 distinction between many solitary axillary flowers and a spike or raceme 
 becomes already a very uncertain one, which in the perfect plant cannot, 
 indeed, be strictly sustained in the examples referred to. But the devia- 
 tion from the common leaf often goes still further : the leaflets (bracts), 
 distinct and green in a rudimentary condition, e. g. in the Dahlias, 
 become little dry shreds of membrane in their perfect development, 
 and are called palece*; or they are altogether stunted, so that no trace of 
 them can be perceived in the perfect inflorescence (as in the Composites 
 to which is ascribed a receptaculum nudum). In like manner we find 
 a stunting and final disappearance of the bracts in the UmbellifercB and 
 Boraginacece. Among the former, in which the entire complication of 
 bracts in the simple umbel is usually called an involucel*, in the com- 
 pound one involucre^ Scandix Pecten, Astrantia caucasica, Bupleu- 
 rum, and Eryngium have true floral leaves, which pass gradually into 
 bracts, such as alone exist in Daucus hispidus and Hasselquistia cordata, 
 Oreomyrrhis eriopoda. In Petroselinum sativum and Heracleum spe- 
 ciosum the bracts of the compound umbel are already stunted ; in Caucalis 
 pulcherrima, wholly gone : in Chcerophyllum aromaticum, also, the bracts 
 of the simple umbel are small ; in Anthriscus, quite stunted internally : 
 finally, in Pastinaca, Anethum, and Pimpinella, almost all have dis- 
 appeared. In the Boraginacece the floral leaves pass gradually into 
 bracts in Cerinthe, mLycopsis the bracts are arrested in development up- 
 wards, finally, absent in Symphytum. 
 
 The Cupuliferce exhibit another peculiarity : one or more circles of 
 bracts (e. g. in Fagus\ or bracteoles (e. g. in Quercus), become blended 
 with each other, and continue to grow with the ripening fruit. This has 
 been called a cupula.\ Something similar occurs in the bracts ofJEuphor- 
 biacece, where ten bracts are usually blended together, the free apices of 
 the five inner being usually different and bent inwards, while in the 
 outer the perfectly free apices, or the bases of them, become developed in 
 a fleshy (glandular) manner. Both phenomena fall completely within 
 the definition of the spathe. In the Cruciferce there appear to be scarcely 
 any exceptions to the rule that no bracts exist ; and yet I believe I may 
 
 * Altogether superfluous terms. 
 
 f Better partial and general involucre. 
 
 \ Link (Elem. Phil. Bot. ed. 2. vol. ii. p. 109.) says the cupula does not yet exist 
 in the flower. He has apparently never looked into a flowering Cupuliferous plant. 
 Moreover, there is not here any peculiar part with leaves grown to it, as he says, but 
 the cupula originates solely from blended leaves. The cupula has no similarity to the 
 succulent coat of the seed of Taxus, and is not, as Link says, proper to the AmentacecE, 
 since, in the true AmentacecE, it does not occur at all ; only in the Cupuliferce, which 
 hence derive their name. 
 
PHANEROGAMIA : FLOWERS. 303 
 
 venture to assume, from some investigations (but few, I own), that they 
 do exist everywhere in rudiment, as, for instance, in Iberis. 
 
 As, on the one hand, very crowded inflorescences become stunted, 
 especially in the internal part, so in the excessive development of bracts, 
 the flowers in their axils are frequently abortive, chiefly in the outer 
 parts of a very crowded inflorescence (sterile bract, bractea sterilis). 
 To this are referable the common calyx (calyx communis, anthodium, &c.) 
 of the Composite, the similar circle of leaves which close the mouth of 
 the Fig, the outer scales of the Grasses (gluma Juss., calyx Linn., lepi- 
 cena Rich., teg men Palisot, glumce valvce Link), which either both or 
 one, sometimes the upper sometimes the lower have no flower in the 
 axil. Link acutely remarks on this point, that the Grasses have a 
 compound flower in respect of this, or more correctly an inflorescence, 
 similar to that of the Composites. We may apply to all these combina- 
 tions of bracts the general term blossom-envelope (Bluthenhiille), which 
 will then comprehend the involucrum of the Umbelliferce, the calyx 
 communis of the Composite, the cupula of the Cupuliferce, the invo- 
 lucrum of the Euphorbiacece, the gluma of the Grasses, &c. ; and, by 
 joining a clearer and more accurate distinctive name to the definition, at 
 once free us from a vast waste of terminology. 
 
 From these considerations the general law may be expressed, that, 
 excepting as a terminal flower, the solitary flower always, and only, 
 appears ^in the axil of a leaf, or in the place corresponding to that axil. 
 
 As in the branch-buds the distinction was required between principal 
 and secondary bud, so also here ; of which condition I believe no one has 
 hitherto thought : yet such secondary buds distinctly exist, for instance, 
 in the inflorescence of Apocynum androscsmifolium, hypericifolium, &c. 
 It is very difficult to say whether the peculiar condition of the in- 
 florescence, e. g. in Penstemon, belongs here, where, instead of one 
 (terminal) flower in the bifurcating division of the peduncle, there are 
 two, of which one with a longer pedicel projects beyond the other. 
 In like manner, the position of the flower of Helianthemum variabile 
 seems to me to be diverted toward one side of the pedicel, because it 
 originates from a secondary bud, while the terminal bud does not become 
 developed. 
 
 Another peculiar condition exists in the bract of the Limes. The 
 axillary bud, formed every year to persist through the winter, has two 
 opposite lateral bud-scales quite to the outer side, one of which remains 
 in this condition. But a bud is formed in the axil of the other, develop- 
 ing the same year, and becoming blended with the bud-scale, which 
 grows up with it, forms the peduncle, and thus exhibits a very decided 
 example of prolepsis, which outstrips the homologous organic parts of 
 the plant at least by three years. An actual blending of the pedicel 
 with the bracts, like this, occurs also in the male flowers of many Cu- 
 puliferce, e. g. in Corylus, and in the flowers of Saururus. 
 
 Finally, it must be noticed, that it very often happens, especially in 
 the peduncle, that the substance expands to a greater extent in the points 
 which are not the bases of the parts seated on it, and swells up around 
 those bases. Thus the parts attached upon it appear to have their base 
 sunk in little pits (e. g. in the receptaculum foveolatum of the Composite), 
 or completely imbedded in little cavities in the uniform mass, as in the 
 female flowers of Dorstenia. This condition occurs naturally most 
 frequently on very thick peduncles, developed into a woody or fleshy 
 substance. 
 
304 MORPHOLOGY. 
 
 A number of flowers, again, may be so collected together that they 
 appear more closely grouped, and assume a collective form. We must 
 first look at the simplest case as the basis, and this is afforded by the 
 progressive development. In a bud are formed internodes, which are 
 parts of one axis (here called rachis, or better peduncle, whereby one 
 useless word will be got rid of ), together with the leaves belonging to 
 them, and in the axil of every leaf a bud which develops into a 
 simple flower. In the rudimentary condition the internodes are unde- 
 veloped, but this development is something coming into action at a sub- 
 sequent period ; consequently, the inflorescence which is simplest and 
 nearest to the solitary flower, is the capitulum, an axis composed of 
 undeveloped internodes, with an axillary (flower) bud, the first internode 
 of which is not elongated. From this basis are developed all other 
 simple forms of inflorescence. The slightest possible alteration is the 
 development of the internodes of the peduncle. If this happen in the 
 longitudinal direction, the inflorescence is a spike (fares in pedunculo 
 elongato) ; if horizontally, a calathium (flores in pedunculo disciformi] ; 
 if the expansion take the form of a cup, it is a Fig (/lores in pedunculo 
 concavo)* ; lastly, if the peduncle elongate and become at the same time 
 very fleshy, it is a club, spadix (Jlores in pedunculo elongato carnoso). 
 But these forms do not constitute distinct members of a series : they pass 
 almost insensibly one into the other ; even the distinction between capi- 
 tulum and calathium is not capable of being maintained, and those 
 between spike, spadix, and capitulum (e. g. the capitulum elongatum) 
 are just as uncertain. 
 
 The second are the internodes of each single flower, which may be 
 developed in the same way ; attention has hitherto been paid only to the 
 one condition of development in lengthf, in the first internode between the 
 axis and floral parts (the pedicel J). By this a capitulum becomes an 
 umbel ; a spike, a raceme. The raceme and spike may then be again more 
 closely defined, according as the flowers stand spirally (e. g. spica spiralis 
 in Gymnadenia odoratissima) ; in whorls (e. g. spica verticillata, in 
 Myriophyllum verticillatum) ; pinnate or two-ranked (?); one-ranked 
 (e. g. racemus monostichus in Myosotis palustris^) ; or lastly, all turned 
 in one direction (e. g. racemus secundus in Digitalis purpurea), &c. 
 
 The pedicel is an internode of the floral axis, and in fact the one or 
 more occurring between the axil of the leaf of the axis, on which the 
 flower is situated, and the first foliar organs of the flower, or the last 
 internode between the last leaf or bracteole and the terminal flower-bud. 
 This internode may remain undeveloped just like a branch-bud (flos 
 sessilis), or become more or less elongated, or even acquire a fleshy con- 
 
 * This only differs in a relative manner from the calathium. Link (El. Ph. Bot. ed. 2. 
 vol. ii. p. 75.) gives as the distinction, that in the Fig the calyx communis is wanting, 
 whence it would appear that he has never examined one ; and when he says that it 
 originates from blended inferior calyces (that is, inferior ovaries), the words have no 
 sense ; since Ficus, like all its allies, has perfectly superior ovaries, and the flower is 
 even stalked inside the Fig. Nothing whatever is blended here. The cup-shaped 
 peduncle in the Fig is simple from its origin, and is so for a long time before any trace 
 of a flower can be seen. When the flowers are in the condition of buds, it is still 
 smooth, and only closely covered by the involucrum, as in the Composite. 
 
 f Whether any other occurs at the time of flowering I do not know. 
 
 \ Another proof of the want of logical acuteness which one meets with in all 
 manuals. It is the gravest error in scientific terminology to have two words for one 
 thing (pedunculus and pedicettus for the internode beneath a flower), and then to apply 
 one of these words to a widely different object (pedunculus to the axis on which flowers 
 are situated). 
 
THANEROOAMIA : FLOWERS. 305 
 
 sistence at a later period, e. g. Anacardium, &c. It differs still less from 
 the lowest internode of an axillary twig * than the flower-bud does from 
 the leaf-bud. Both are developed sometimes before the unfolding of the 
 bud (e. g. in the so-called gemmce stipitatce in Liriodendron, and the 
 flower-buds in Asclepias), sometimes during its unfolding (e. g. leaf-buds 
 in Tilia), sometimes not at all (e. g. lateral branch of Ligustrum vulgar e 
 and every flos sessilis). 
 
 The simple forms of inflorescence just mentioned, may combine 
 again in manifold ways into compound inflorescences. We have 
 here to distinguish the homomorphous (pure) from the heteromor- 
 phous (mixed), e. g. the so-called spica of the Grasses is a spica 
 composita; the umbella of the Umbelliferce an umbella composita = 
 pure inflorescences. But here we must necessarily distinguish between 
 a capitulum and an umbel, originating from the combination of several, 
 and yet similar to a simple inflorescence, both from the actually simple 
 and the properly compound (capitulis capitatis, umbellis umbellalis). I 
 would propose for this the name polycentric, since in capitula and umbels 
 the undeveloped axis represents, as it were, a centre from which the 
 flowers go out. Such polycentric capitula and umbels occur in most 
 Labiatce, e. g. in Marrubium infloresc., capitula polycentrica spicata. 
 The panicles of most of the species of Bromus and Festuca are spicce 
 umbellatce umbellis spicatis, or spicce racemosas racemis umbellatis, 
 umbellis spicatis. The anthuri of Rumex are (polycentric?) umbella 
 (capitula} spicatce spicis racemosis ; the inflorescence of many Labiate, 
 umbettcB (or capitula) spicatce = heteromorphous inflorescences, &c. 
 But here the mistake of the present mode of treating the inflorescence 
 comes in, that definite forms of inflorescence are predicated fully of 
 particular families, and thus combinations of the most varied nature 
 included under one name. Under panicle are comprehended the most 
 heterogeneous inflorescences possible, and the definition can only be such 
 as " All inflorescences of the Grasses which are not spica composita 
 (spica)" therefore a definition logically incorrect. So in many systematic 
 works every inflorescence among the Juncece is called an anthela ; but 
 how is it possible to distinguish this multiplicity of inflorescences by one 
 name, if we hold views at all sound of scientific terminology ? Is it not 
 the most frivolous trifling with words to name umbels, capitula, spikes, 
 racemes, and all their combinations, anthela, and yet to distinguish 
 anthela, capituliformis, spicceformis, &c., when anthela cannot here mean 
 anything but inflorescentia Juncearum ? It is inconceivable that a man 
 scientifically educated (not merely taught) can seek and find science in 
 such ringing changes on words. And this not all : the term anthela, 
 although it has no meaning, must also be applied to the inflorescence of 
 the Cyperacece, which, with its stunted flowers combined into a spike, 
 is entirely different in its essential nature. The cause, indeed, lies in 
 this : It is found too troublesome, in the cases of very complicated 
 
 * Link says it grows forth after and beneath the flower, and is thus distinguished 
 from the twigs. If he had actually traced the development of a few flower-buds, he 
 would know that there is nothing in this. Every branch-bud is formed, like the 
 flower-bud, as a gemma sessilis ; whether it developes single internodes longitudinally 
 afterwards is a matter which varies equally in both. Link says further, that it wholly 
 or partially withers with the flower (he should have said with the fruit or male flower), 
 and, indeed, falls off; a peculiarity which it shares with all annual stems (e. g. with 
 Aquilegia, Aconitum, umbelliferous plants, &?.), which therefore does not distin- 
 guish it. 
 
306 MORPHOLOGY. 
 
 inflorescences in particular families, to investigate minutely their com- 
 position from simple inflorescences ; and it is found more pleasant to make 
 a collective word, which may then be defined a little closer (although 
 very superficially) by a few adjectives. To this want of profundity we 
 owe the catalogue of sins of synonymy* ; since in the total want of 
 scientific ground for such modes of naming, every one has an equal right 
 to assert his imaginary wisdom. 
 
 140, Both peduncle and pedicel may fall off soon after the 
 development of the flower (p. caducus), e. g. the male flowers of 
 Salix, &c., or with the ripe fruit (p. deciduus), e. g. in Cerasus 
 avium ; or remain upon the axis after the ripening of the fruit 
 and scattering of the seed (p. persistens), e. g. Aquilegia vulgaris ; 
 or even become altered in various ways by growth, during the 
 ripening of the fruit (p. excrescens), e. g. Anacardium, Hovenia 
 dulcis, &c. 
 
 That each part of a plant may endure for a shorter or longer period, 
 may remain in connection with the entire structure for a shorter or 
 longer time, and undergo alteration in various ways subsequently to its 
 first appearance, is not peculiar to the peduncle and pedicel ; and, instead 
 of saying this once and for all, it is superfluously repeated for every part 
 in botanical manuals, as though there were a lack of matter. In the 
 study of the inflorescence, however, a special import has been at- 
 tached to this universal property, and the spica and amentum have been 
 distinguished according to it. The three first conditions do not belong 
 at all to morphology, but are vital phenomena ; the last is referable to the 
 morphology of the axial organs, not of the inflorescence. But I was 
 obliged to mention the matter here to prevent obscurity in the following 
 review of the kinds of inflorescence usually admitted. 
 
 141. It is dependent on some peculiarities connected with the 
 vitality of the plant, the causes of which are unfortunately still 
 quite unknown to us, and can only be perceived as special proper- 
 ties, that sometimes this, sometimes that, portion of the whole plant, 
 but in a specifically regular course, is advanced in growth and 
 development toward perfection. This is seen in the flower-buds, 
 which open and blow in regular procession, according to definite 
 laws. On the simple axis only, the following conditions occur : 
 
 1. The unfolding of the flowers follows the order of their age. 
 The older flowers, lying undermost, bloom first ; and the upper ones 
 gradually follow. This is termed a centripetal inflorescence (in- 
 
 florescentia centripeta). It occurs in Philadelphus, Isotoma axillaris. 
 
 2. The unfolding of the flowers follows the reverse order, so 
 that the upper and latest-formed buds open first, and the older 
 ones follow in regular course. This is termed a centrifugal in- 
 florescence (iiifl. centrifuga)-, it occurs in Clematis integrifolia, 
 Saxifraga, &c. 
 
 * The v;inity of wishing to be referred to is the parent of most useless words ; and 
 this disease will not come to an end until the catalogue of synonymes is understood to 
 be a botanical pillory, wherein a man becomes abased lower for every time he stands in 
 it : then people will be careful of making new words, without sufficient scientific 
 grounds. Of such men as Robert Brown I am not afraid ; for those people always 
 make the most new words who are least capable of doing actual work in science. 
 
PHANEROGAMIA : FLOWERS. 307 
 
 3. The blooming follows no such simple order; it may com- 
 mence in the centre, and proceed both upwards and downwards 
 simultaneously, as in the capitula of Dipsacus ; or the upper and 
 middle buds may begin to open simultaneously, and the blooming 
 proceed downward in two divisions, as in Campanula Medium. 
 This may be termed indefinite inflorescence (itifl. vaga). 
 
 In compound axes the same condition occurs with respect to 
 main axes and adventitious axes, and is by no means necessarily 
 uniform with the law for the simple axis. Thus, in most Com- 
 positoe the infl. centripeta frequently occurs in the single capitula ; 
 and infl. centrifuga in the side branches, in relation to one another, 
 as occurs in Centaurea calocephala: in Sanguisorba, on the con- 
 trary, the main capitula, as well as the side branches, exhibit infl. 
 centrifuga. The generality of the LabiattB exhibit in the inflo- 
 rescence of the individual side branches, an infl. centrifuga^ whilst 
 the branches themselves are centripetally developed. 
 
 This relation of condition, as is self-evident, is one altogether foreign 
 to the inflorescence, i. e. the arrangement of the flowers, and belongs to 
 the vital phenomena of the plant as a whole ; unfortunately, however, 
 through want of clear logic, it has become entangled in the study of the 
 inflorescence, and I was therefore obliged to refer to it here. Any brain 
 with a little logic in it, will readily see that the course of the unfolding 
 of the flowers does not possess equal importance with the arrangement 
 of the single flowers, in establishing the various kinds of inflorescence ; 
 but at most may subordinately contribute, in one and the same species of 
 inflorescence, specific distinctions for single groups, genera, or species 
 of plants. 
 
 142. Upon the condition of structure we have here little to 
 say, since this subject was necessarily forestalled in the axis and leaf; 
 and here only relations of position alone come into the question. 
 The bracts and bracteoles are commonly formed of thin- walled 
 cellular tissue, delicate, and often coloured * ; sometimes in entire 
 families of plants, they are perfectly dry and sapless. The vascular 
 bundles of the pedicels sometimes stand in definite proportion to 
 the number of the floral leaves. 
 
 REVIEW OF THE INFLORESCENCE IN GENERAL. 
 
 143. A. The solitary flower, as terminal or axillary flower (fos 
 solitarius, term, vel axilT). The latter may be situated in whorls, 
 and then form a verticil (verticillus). 
 
 B. Simple Inflorescence, 
 a. Inflorescentia centripeta. 
 
 1. The capitulum. The undeveloped axis is here usually en- 
 larged upward, with a fleshy or spongy substance, and the more 
 
 * Coloratns, i. e. of some other colour than green. 
 x 2 
 
308 MORPHOLOGY. 
 
 so if the number of flowers is very great. It may be more mi- 
 nutely designated as simple, discoid, cupulate, lageniform, conical, 
 and cylindrical, as it approaches nearer to one or another. The 
 last form then passes gradually into the spadix. 
 Special varieties are : 
 
 a. The calathium (anthodium Ehrh.,jtf0s compositus Linn.) A 
 many-flowered capitulum, whose single flowers stand in the axils 
 of more or fewer stunted bracts, and are surrounded with one or 
 more circles of sterile bracts, as in the family of the Composite. 
 
 b. The ccenanthium Nees, hypanthodium Link, exactly like 
 the preceding inflorescence, in some Urticeacce. The cup-shape of 
 the peduncle in Ficus is no distinction, since it is wanting in Dor- 
 stenia ; and it exists in some Composites ; the same may be said 
 with regard to the sterile bracts, which are as much stunted in Dor- 
 stenia as they are clearly present in Ficus. 
 
 2. The spike (spica) in very various forms. The kinds are : 
 
 a. The catkin (amentum), distinguished by the fact that it falls 
 off entire or by its imperfect flowers. The male inflorescence of 
 Cupuliferce, Salicacece, Betulinece, and some few other plants. 
 
 b. The spadix. A closely crowded spike, or partially a cylin- 
 drical capitulum with fleshy peduncle; in Aroidece, Maize, and 
 some other Grasses, and in Palms, in the last of which it is often 
 compound (spadix ramosus). 
 
 c. The cone (strobilus or conus). A cylindrical capitulum or 
 solid spike, on which the individual foliar organs become woody 
 scales ; as in the Conifer a, the Casuarinacea, the Betulinece, and 
 some others. 
 
 d. The spikelet (spicula). The simple inflorescence of the 
 Grasses and CyperacecB ; namely, a few-flowered spike, whose 
 flowers have no bracts, surrounded at the basis by one or two 
 sterile bracts (glumce).* 
 
 3. The umbel (umbella) in the Umbelliferce ; when compound 
 termed umbellule (umbellula). 
 
 4. The raceme (racemus) occurs in very different forms ; it is 
 usual to distinguish in it 
 
 a. The corymb (corymbus), a pyramidal raceme. 
 
 j8. Inflorescentia centrifuga. 
 
 5. The cyme or false umbel (cyma), a corymb with inflor. cen- 
 trifuga. 
 
 N. B. That only singular cases are distinguished in these is 
 a proof of the totally unscientific patching together of termino- 
 logy. The compound raceme, the compound umbel, and capitulum, 
 with inflor. centrifuga, are all called a cyme (cyma\ which is con- 
 trary to the commonest scientific laws. DeCandolle has further 
 
 * This, as Link cleverly observed, stands in the same relation to the spike as the 
 ealatlrium to the capitulum. 
 
PHANEROGAMIA : FLOWERS. 309 
 
 applied the term cyme to the inflorescence of the Boraginacece, which, 
 on account of the peculiar manner in which it unrolls itself, he 
 terms cyma scorpioides ; and he adds the fiction, that the under- 
 most, first-blooming flower is really the terminal blossom, and the 
 second, the terminal blossom of side axis, is developed in a dispro- 
 portionate degree, &c. From the rolling up there is just as little 
 to be deduced as from the same phenomenon in the leaves of 
 Ficus and Cycadacece. The position of the bracts, as seen in Ce- 
 rinthe, contradicts this fiction ; and the history of the development, 
 which can alone determine the point, appears to me to prove (I 
 own from a few very imperfect observations) that here a one-sided 
 raceme or spike is present, whose unrolling is only a peculiar 
 situation of the buds. 
 
 C. Once compound Inflorescences. 
 
 a. Pure or homomorphous. 
 a. Inflorescentia centripeta. 
 
 6. The spike of the Grasses (spied). Several spikes united in a 
 spicate arrangement, as in the Grasses ; the component spikes are 
 termed spikelets (spiculce). 
 
 7. The umbel (umbella)\ umbels united in umbels; the com- 
 ponents are termed umbellules (umbellulcB). 
 
 N. B. Sound terminology would have long ago rejected these 
 words, and exchanged them for spica and umbella composita. 
 
 8. The panicle (panicula)\ see No. 11. 
 
 None of the remaining combinations deserve special names, and 
 may probably be classed among those mentioned under 9 and 11. 
 
 b. Inflorescentia centrifuga. 
 
 9. The cyme or false umbel (cyma) ; see No. 5. and No. 14. 
 
 10. The anthela; see No. 16.' 
 
 /3. Mixed or heteromorphous. 
 a. Inflorescentia centrifuga. 
 
 See No. 14. 
 
 b. Inflorescentia centripeta. 
 
 See No. 11. 
 
 D. Many times compound Inflorescences. 
 a. Inflorescentia centripeta. 
 
 1 1. The panicle (panicula). Every many -branched inflores- 
 
 x 3 
 
310 MORPHOLOGY. 
 
 cence; in Grasses universally, and otherwise only in developed 
 pedicels. 
 
 12. The thyrse (thyrsus), a panicle, with very short pedicels; 
 with the exception of Grasses, found almost universally. 
 
 Both terms are applied also to once compound inflorescences. 
 DeCandolle uses the term thyrsus for those in which inflor. cen- 
 trifuga and centripeta are mingled ; others differently ; all arbitra- 
 rily. 
 
 13. The anthurus, an inflorescence that has the kind of aspect of 
 that of the Amaranthus candatm or the Chenopodiacece. 
 
 b. Inflorescentia centrifuga. 
 
 14. The cyme (cyma), also in manifold combinations, in which, 
 however, we do not consider whether the side ramifications follow 
 the inflor. centripeta or centrifuga in longer pedicels. 
 
 15. The bunch (fasciculus), a manifold compound cyme, with 
 short pedicels, and rather crowded. 
 
 16. The Anthela, all kinds of inflorescences in the Juncece and 
 Cyperacecs. 
 
 17. The glomerule (glomerulus), many inflorescences that ap- 
 pear almost like a capitulum, and consist only of ill-formed, im- 
 perfect flowers, as in some Chenopodiacece, Urticacece, and Juncacece. 
 
 I leave every one with thinking faculties to draw for himself the sad 
 conclusions which the preceding survey affords ; and I think that I have 
 not to defend myself to any one who is acquainted with our literature, 
 against the charge that the foregoing is a frivolous vagary of my 
 humour. Roper first attempted a scientific development of the inflo- 
 rescence. No one that I know of has followed him, except Lindley. 
 Physiologists seem not to have accounted it of sufficient importance. 
 Systematists have too much to do with their herbaria, and it is much 
 easier to coin a new word than to study minutely the progressive de- 
 velopment through a large series of plants. For the sake of those unac- 
 quainted with these matters I will insert the following examples: In 
 Lotus corniculatus : Koch (Syn. Fl. Germ.), a capitulum, Kunth (Fl. 
 Berol.), an umbella, Reichenbach (Fl. Excurs.), actually & fasciculus. To 
 Eriophnrum vaginatum Kunth gives a spica ; Koch, a spicula. For Cla- 
 dium Mariscus Kunth has umbellce axillares et terminates ; Koch, Anthelce 
 axillares et termin. ; Reichenbach, cymce A. et t. ; in Isolepis supina : Koch 
 spiculis in fasciculum aggregatis ; Kunth, spicis conglomeratis. I have 
 here omitted the French and English botanists, or the matter would 
 have been still more glaring. 
 
 I have also omitted the great crowd of synonymes as altogether use- 
 less, and even only introduced the more useful of the names of peculiar 
 inflorescences : otherwise I must have written a whole book upon them, 
 and truly one upon empty words, 
 
 II. Of the Parts of the Flower at the Time of Blooming. 
 
 144. The flower originates from a bud (gemma, here commonly 
 termed alabastrus), and is nothing more than a particular modifi- 
 
FHANEROGAMIA : FLOWERS. 311 
 
 cation in the perfecting of the parts contained in the bud ; namely, 
 the several foliar organs and internodes. It has been already 
 shown, that only two essential processes of development, and from 
 those only two essential organs, as fundamental organs, can exist 
 in the plant ; namely, the axis and leaf. All the several parts of 
 the flower must, therefore, be referable to these fundamental organs, 
 and be traced back to them. Since Goethe's time, this tracing 
 back has been termed the Metamorphosis of plants. Originally, 
 this mode of considering the flower rested solely on comparative 
 morphology, and the observation of cases in which the interrup- 
 tion of the usual processes of development, in some or all parts of 
 the flower, caused those parts to reassume forms in which it was 
 not difficult to recognise the nature of the fundamental organ from 
 which they had been produced. This latter has been termed re- 
 trogressive metamorphosis ; as examples of it, we may mention the 
 different monstrosities, the doubling of a flower through the transi- 
 tion of the stamens into petals, the transition of the petals and 
 sepals into the common leaves of the plant, &c. This mode of 
 establishing the foundations of the doctrine of metamorphosis has, 
 however, two essential faults : since, in the first place, it seeks to 
 obtain individual facts by means of hypotheses and comparisons ; 
 while, secondly, its progress depends entirely upon favourable cir- 
 cumstances. The only correct and sure ground on which to rest 
 this doctrine, is the history of development, and this, only quite 
 recently recognised, is as yet pursued by few investigators ; hence 
 the doctrine as a whole still exhibits many deficiencies, imperfec- 
 tions, and uncertainties. 
 
 The doctrine of the metamorphosis of plants is still partially treated 
 as a special section of Botany, although it is in fact no other than an 
 isolated fragmentary application of the only really scientific principle 
 AV Inch botany can at present possess; namely, that of progressive de- 
 velopment. By most persons, however, the matter was long, by some 
 even still, regarded as an agreeable fantasy, playing round science ; the 
 blame of this rested partly upon the mariner in which Metamorphosis 
 was introduced into science. 
 
 Even Linnaeus had a presentiment of something of the kind, and in 
 his Prolepsis Plantarum (Amcenit. Academ. vol. vi. p. 324.) carried it 
 out in such a way, that, starting from the consideration of a perennial 
 plant with regular periodicity of vegetation (as in our forest trees), he 
 explained the collective floral parts from the bracts onward, as the col- 
 lective foliar product of a five-year old shoot, which, by anticipation 
 and modification, was developed in one year. This view is, in the first 
 place, taken from the most limited point possible from the examination 
 of a plant of our climate ; and, secondly, imagined and carried out with 
 great want of clearness. Up to the formation of the flower in the axil 
 of the bract, the matter holds, perhaps ; but from thence the explanation 
 is restricted to the laying down of his untenable, and, in the highest 
 degree, superficial anatomical notions as to the connection of the floral 
 parts with the elements of the stem ; and only in a few very indefinite 
 words is it indicated of every floral part, that it (for instance, the stamen) 
 
 x 4 
 
3 1 2 MORPHOLOGY. 
 
 corresponds to the axillary bud of the preceding (the petal), and no at- 
 tempt is made to elucidate how it happens that the axillary bud of the 
 calyx appears only as one leaf (petal), and yet developes its axillary bud 
 at once, which again is stunted to a single leaf; finally, the usual al- 
 ternate position of the floral parts, directly contradicting the whole fiction, 
 is not entered into at all. 
 
 C. Fr. Wolff (Theoria Generations, 1764) opened the true and only 
 path by which this doctrine can be carried through, in making good the 
 study of development as the true principle in Botany, as in other sci- 
 ences. He erred, certainly, in particular conclusions ; for instance, in 
 determining the stamens to be modified axillary buds of the petals. But 
 all his intelligent activity remained altogether lost to Botany, a fact 
 readily explained by the scientific spirit of those days. * 
 
 Long after Wolff, Goethe wrote his " Versuch, die Metamorphose der 
 Pflanzen zu erklaren," (Gotha, 1790), in which he correctly explained 
 most of the floral parts, up to the carpellary leaves, as foliar -organs. 
 With his method of mere comparisons and references to monstrosities, 
 he could not, of course, pronounce any thing original and profound as to 
 the structure of the germen. There he introduced, from Schelling's 
 doctrines, the fantastic comparison with an alternating contraction and 
 expansion, from which, in connection with a gradual refinement, pro- 
 ceeded the difference of the parts of the flower. This last was soon 
 dropped. Goethe found little hearing at first in Botany, especially in 
 Germany where the very stupidest materialism of the Linnsean school 
 prevailed ; Jussieu and listen first mentioned his ideas in scientific Bo- 
 tany. But it was DeCandolle (Organographie, Paris, 1827) who first 
 called general attention to this branch (or rather main trunk) of Botany, 
 and thus the so-called metamorphosis of plants gradually came to its 
 place as a special chapter in the revision of the science. Wolff's ideas 
 were not indicated by a single syllable, at most he was cited with philo- 
 logical profundity as Goethe's predecessor, and thus the whole doctrine, 
 in the absence of the only correct method, remained without any essen- 
 tial influence for the advancement of Botany. As to the import of 
 calyx, corolla, stamen, and carpel as foliar organs all, except a few 
 heretics, were soon agreed. The seed-buds (ovules) were left to origi- 
 nate as buds on the borders of the carpellary leaves, and no great trouble 
 was taken about the thousand contradictions which lay close at hand. 
 The particular families, more complicated in their structure, the pistils 
 of which could not so readily be referred to carpellary leaves, &c., then 
 
 * Even now but few botanists have an idea of the importance of the history of 
 development ; and while animal physiology progresses with wonderful rapidity through 
 the constant application of the correct method while in it every rising difference of 
 opinion soon becomes obliterated, because the principle, as to the correctness of which 
 all are agreed, the skill in manipulation, which every one must acquire as an indispen- 
 sable preparation for profound study, causes every question to be quickly and univer- 
 sally decided Botany remains hopelessly behind all the sciences. Endless contests 
 about the commonest things consume the best time, and the science moves not ; because 
 most botanists either place side by side, as of equal value, or make selections from, 
 without judgment (and take therefore, according to accident, sometimes untruth, some- 
 times truth), all that is given them by the few inquirers who have taken a higher path. 
 As to critical re-investigation, it is not to be thought of by most. The most important 
 organ in Phanerogamous plants is the anther : how many botanists are there who know 
 the structure of an anther perfectly from their own experience? Hence we find in the 
 books of botanists of the greatest reputation, things stated about the anthers which 
 truly are not a whit better than if J. Miiller were to describe the human lungs as 
 simple sacs. 
 
PHANEROGAMIA: FLOWERS. 313 
 
 became the tilting-ground for what were in part most adventurous 
 fantasies and fictions. The unfortunate seed which Goethe sowed, 
 sprang up with sad rapidity ; and next to Schellingism, we owe it to 
 him * that, in Botany, whims of the imagination have taken the place of 
 earnest and acute scientific investigation. In that unbounded region 
 every individual's imagination had naturally equal right ; there was a 
 total want of any scientific principle which should undertake the deci- 
 sion between differing opinions of any method, the recognised accuracy 
 of which could give security for the results of an investigation. 
 
 I have striven, in my methodological introduction, to develope such a 
 principle for Botany, out of the contemplation of its object ; and I here 
 once more express my firm conviction, that without rigid carrying 
 through of the investigation of development, in the total as in the sin- 
 gular, Botany is, and will remain, an unscientific game of purely arbi- 
 trary arrangement and combination of uncomprehended forms. In spite 
 of our 'by far less difficult problem, Zoology has far outstripped us, and 
 has shown us the road which properly she should have learned from us. 
 "We must follow behind, if every botanist does not in time become red 
 with shame, who takes in hand a work of Miiller, Schwann, Reichert, 
 Baer, Rathke, Siebold, Wagner, and all the hundred others, by the side 
 of whom we can scarce place half a dozen. 
 
 Following Robert Brown, I first sought to apply the investigation of 
 development to the discovery of the structure of flowers. In this man- 
 ner I found the explanation of the flower of the Grasses, the Carices, the 
 composition of the involucre in Euphorbia, &. c. With my deceased friend 
 Vogel, I published the first perfect history of development of the flower 
 of a Leguminosa. After a considerable time some botanists followed 
 
 * Perhaps a part of the blame rests upon an innocent encouragement, expressed in a 
 friendly manner, in a letter of A. von Humboldt, who certainly did not mean what 
 Goethe understood him to do, at a time when, from his total want of mathematical ex- 
 perience and knowledge, he made such a poor figure in science with his theory of colour. 
 Goethe said (Contribution to Morphology, Stuttgard and Tubingen, 1817, p. 122.) : 
 " Humboldt sends me his work with a flattering picture, by which he indicates that poetry 
 may indeed attain to lifting the veil of Nature ; and if he admits it, who will deny it ? " 
 Humboldt certainly meant no more by this than that a poet, who by his inmost nature is 
 led to it, may, in particular cases, conceive the universal (that is, the universal human), 
 and even may succeed, by the contemplation of Nature alone, in finding a happy 
 thought, without that thought itself being already science, and without admitting the 
 possibility of its becoming an integrant part of it until further carried out and inves- 
 tigated. The mistaken meaning which Goethe attributed to the words, that a poetic 
 treatment of nature could be placed on a level, or even preferred, to the rigidly scien- 
 tific, could not have existed in Humboldt's mind. But it happened just at a time 
 when the misty fanaticism of Schelling's " Philosophy of Nature," built on the same 
 want of psychological investigation, stirred up together imagination and intellect, musings 
 and thought, poetry and science, into a mixture as distasteful to the true poet as to the 
 clear thinker. This has brought much trouble upon us in science, and, especially in 
 Botany, caused a gnawing disease of development. Zoology soon recovered from this 
 fever, since it had at that time already developed abundance of healthy juices ; but 
 Botany, which then was staggering about as the melancholy Linnaan skeleton, had 
 longer to suffer ; since, judging from the preceding condition, the ruddy hue of fever 
 was taken for a sign of health. Poetry and science are two regions distinct in their 
 inmost essence, which both lose their whole value when they are intermingled. A 
 poetical treatment of science, and especially of philosophy, the most strict of all sciences, 
 is as repugnant and distasteful to the clearly educated mind, as if one should strike a 
 bargain, order a coat, or call a servant in a poetical speech. A learned poem is empty 
 versified prose a remnant of the barbarism of the middle ages poetical science 
 is a troubled mysticism of a cloudy fanatic, of whom, indeed, in the imperfect educa- 
 tion of our thinking powers in youth, there will long exist instances. 
 
314 MORPHOLOGY. 
 
 me, and have in part confirmed the correctness of my views. The first 
 was Geleznoff in Tradescantia virginica (Bull, de la Soc. Imp. des Nat. 
 de Moscau, torn. xvi. 1843). He was still doubtful whether the stamens 
 did not arise earlier than the corolla. Duchartre spoke more decidedly 
 on this point, with regard to the Malvacea (Compte rendu, 1844, seance 
 18 Mars), and the PrimulacecB (ibid, seance, 18 Juin). On the other hand, 
 Barneoud confirmed my observations completely, through the investiga- 
 tion of the PlantaginacecB and Plumb aginacece (Compte rendu, 1844, 
 30 Juli). Strangely, he says *, that the course of development of the 
 flower follows, against my theory (!), from without inwards, which on 
 account of the figures given by Vogel and myself, cannot be excused, 
 even on the plea of ignorance of the German language. 
 
 It has often been attempted to develope the morphological laws of the 
 structure of flowers from monstrous formations. I believe that this 
 attempt is altogether faulty, even presupposes a total ignorance of the 
 value and import of the progressive development. If up to this point 
 one must reject every application of the analogy of animals to plants, it 
 were yet very desirable that most botanists should go through a thorough 
 course of zoological physiology, so that they might, at least in some de- 
 gree, learn method in the treatment of organic bodies. Whoever has 
 traced the course of development of even a couple of only rather difficult 
 flowers, will have certainly become convinced that every conclusion from 
 the developed flower as to its regular rudiments, and the import of its 
 parts, must inevitably be faulty, and that monstrosities, double and pro- 
 liferous flowers, such as are transformed into leaves, &c., require eluci- 
 dation by the history of development just as much as the normally 
 formed flower itself. Even Mohl might have spared himself his so 
 acutely carried out examination of Poa vivipara, and the explanation of 
 the flower of Grasses deduced from it (Botan. Zeit. b. iii. p. 33), if he 
 had only convinced himself, in the flower of a single Grass or of a single 
 Carex, how by a subsequent one-sided development, the most perfect 
 symmetry becomes wholly hidden. I have thought myself obliged, 
 especially for a better understanding of the importance of the course of 
 development, to care for it in publishing several of the more difficult or 
 more instructive instances in the accompanying plates ; namely, in Plate 
 III. the course of development of the leaf of Pisum sativum, of the 
 flower of Agrostis alba, of Carex Lagopodioides and Ccmna exigua ; 
 and in Plates IV. and V. a more complete illustration of the development 
 of the flower of Passiflora princeps. 
 
 145. In Phanerogamic flowers the following parts are distin- 
 guished, proceeding from without in wards: 1. The floral envelopes, as 
 the external calyx (epicalyx), of which the parts are leaves (phi/lla); 
 the calyx, the parts of which are sepals ; the corolla, the separate 
 portions of which are petals; or, instead of these three, the perianth 
 (periantliiurn), whose separate parts are leaves (phylla): 2. The sta- 
 mens (stami7ia), around and within which some stunted acces- 
 sory foliar organs appear under very various names : and, lastly, 
 3. In the centre of the flower, the pistil (pistillum), the separate 
 foliar organs of which are carpels (carpella}. In the stamens the 
 lower thread-like portion, which is termed the filament (filamen- 
 
 * At least in the extract in the Botanische Zeitung, 1845, p. 115. 
 
PHANEROGAMIA : FLOWERS. 315 
 
 turn), is distinguished from the upper thick and hollow part, contain- 
 ing the dust (pollen), called the anther (anther a). In the pistil, 
 the lower part surrounding the seed-buds (gemmulcK) is called the 
 germen*; the upper free part, which is usually covered with 
 papilla, is termed the stigma, and between these two frequently 
 a stalk-like elongation of the germen occurs, called the style. 
 
 The flower of Phanerogamia is the only physiologically deter- 
 minate organ of the plant, since it contains the apparatus for the 
 regular propagation. But to this only two forms contribute: 
 namely, the stamens, as generators and receptacles of the pollen ; 
 and the seed-bud, as the place in which the pollen is developed 
 into the embryo. All the remaining parts of the flower : namely, 
 the envelopes of the whole perianth, the calyx, and corolla, the 
 receptacles containing the seed-bud (the germens, styles, and 
 stigma), are not, in a physiological sense, essential, and they may 
 be absent, without the flower losing its correspondence to the 
 character by which a flower is defined. 
 
 In the correct (morphological) view of the flower, there is no 
 distinction between essential and inessential forms, and, therefore, 
 it is necessarily more proper to divide into axial and foliar or- 
 gans. The following relations of condition must be borne in 
 mind : The axis and its modifications are the basis of the flower, 
 because to them the foliar organs are attached. Attached to the 
 outer part of the axis of the flower occur several forms of true 
 foliar organs, the floral envelopes, accessory leaflets, and stamens. 
 The innermost part is occupied by organs which are formed from 
 true axial organs, or an intimate blending of these with foliar 
 organs, which are termed the female apparatus, or, better, the ru- 
 diment of the fruit. At the same time, the parts of the flower 
 are usefully grouped together and treated generally, according to 
 the relations of number and position, as well as of duration ; thus 
 we obtain this plan for our following investigations : 
 
 A. The axial organs of the flower. 
 
 B. The number, relative position, and duration of the parts of 
 the flower. 
 
 C. The true foliar organs of the flower. 
 
 a. The floral envelopes. 
 
 b. The stamens. 
 
 * The term hitherto most frequently applied to the seed-bud is ovule. In the first 
 volume of the first edition of this work I proposed that botanists should agree to 
 banish from their science all expressions which have a definite signification in Zoology, 
 so that for the future we might avoid the continual confusion which so readily arises 
 through the conceptions obscurely introduced from that science. With pleasure I saw 
 that a better man than myself, A. Endlicher, had been before me in this in his " En- 
 chiridion Botanicum," and throwing aside the term ovulum, had substituted for it 
 gemmula ; and, instead of the customary expression ovarium, had used the old word 
 germen for the lowest portion of the pistil. I follow him here, and believe that I have 
 translated the word gemmula tolerably closely by seed-bud (Samenknospe) ; on the other 
 hand, I retain, from the many expressions substituted for the usual name of placenta for 
 the part bearing the seed (Satnentrager), the term spermophorum in preference to tropho- 
 spermium, which is grammatically incorrect in its construction, and, signifying more, is 
 not so applicable to the purpose. 
 
316 MORPHOLOGY. 
 
 c. The accessory foliar organs. 
 D. The rudimentary fruit. 
 
 a. Of the pistil. 
 
 b. Of the spermophore. 
 
 c. Of the seed-buds. 
 
 Hitherto the anthers have been called the male organs of a plant 
 (with the superfluous collective term andrceceum) ; the seed-buds 
 and their receptacle the pistil, the female parts (together the 
 gynoBceum). A flower that contains both parts is termed herma- 
 phrodite (flos hermaphroditus) ; flowers that contain only one of 
 those kinds of organs, are termed unisexual flowers (flores unisexu- 
 aleSy diclini). When, in the last case, male and female flowers (mas 
 etfemina) appear on the same individual plant, such plant is termed 
 monoecious (planta monoicd)', when they appear on separate indi- 
 viduals, the plant is termed dio3cious ( planta dioicd). An inflores- 
 cence which contains both male and female flowers, also is termed 
 inflorescentia androgyna. Here again it must be distinguished 
 whether the male and female blooms are formed upon different 
 plans, as in the Cupuliferce (true diclines); or whether, through the 
 suppression of one or other part, a pseudo-diclinous condition 
 appears in a flower formed on the plan of a hermaphrodite. This 
 latter condition, which is never found to run through all the 
 examples of any species of plant, brings monoecious and dioecious 
 species into hermaphrodite genera, and suggested to Linnaeus the 
 establishment of his twenty-third class, Polygamia, where in one 
 and the same species male, female, and hennophrodite flowers are 
 present. 
 
 Very incorrectly, the pistil, as the receptacle of the seed-buds, and as 
 the apparatus to facilitate impregnation, is usually counted among the 
 essential parts of the flower ; for it may be 
 absent as well as the floral envelopes, as in iso 
 
 the Coniferce, Cycadacece, and Loranthacece, 
 which have a naked seed-bud. The simplest 
 form of the flower is that in which only a 
 few foliar organs are converted into anthers, 
 and between them the simple extremity 
 of the axis displays itself as the simplest 
 form of seed-bud. "We might reckon as 
 exactly such an ideal flower (primary flower) 
 that of Viscum album (fig. 180.), were not the 
 true condition interfered with here by the 
 fact, that some examples constantly develope 
 only anthers, the seed-bud not being perfected 
 for its function; whilst upon others the axis 
 alone is perfected into the seed-bud in its 
 most simple form, and the four foliar or- 
 gans persist around it in the condition of 
 leaves. Further, I have to observe, with respect to Viscum, that there is 
 
 lso Viscum album. Vertical section of the female flower, a , Leaves of the floral 
 envelope ; b, naked seed-bud, consisting solely of the naked nucleus, and formed from 
 
PHANEROGAMIA I FLOWERS. 317 
 
 not yet any distinction or division of the axis as pedicel from the axis as 
 seed-bud. The axis terminates immediately in the 
 flower, with a scarcely evident rounding of the I80u 
 
 extremity, and all that gives it peculiar import to 
 the seed-bud, namely, the formation of the embryo- 
 sac, as well as the subsequent development of the 
 embryo, is carried on in that part of the axis beneath 
 the flower, therefore in the pedicel. The term 
 gemmula infer a would in fact be applicable here. 
 Amongst the Coniferce, the female flower of Taxus 
 (fig. 180a.) is an example of the simplest structure; 
 here, again, we see nothing of floral envelopes or 
 seed-vessels, but the seed-bud no longer exists in the simplest form, as a 
 naked nucleus (nucleus nudus) ; it has a coat (in(egumentum), but no ger- 
 men, and therefore it is still always a naked seed-bud (gemmula nuda)* 
 
 The distribution into essential and unessential parts of the flower is, 
 according to my manner of treating the matter, entirely useless. For 
 the morphological consideration of the plant each organ is equally essen- 
 tial, as a definite expression of the form-creating power of the plant, and 
 it is in this point of view unimportant, whether or not the part fulfil 
 some determinate function, or what this be. In the morphological treat- 
 ment of the flower the only correct division is into axial and foliar or- 
 gans ; but I must not carry out this reform with unvarying strictness, 
 lest I depart too far from the old beaten track, and thus, perhaps, become, 
 if not incomprehensible, yet apparently too difficult, although in fact the 
 development of the flower would thus become far more simple, and be 
 freed from innumerable, otherwise inevitable, repetitions. In the almost 
 total neglect, too, of investigation of development, any other than the 
 usual mode of treatment has been hitherto impossible. 
 
 There are a few more points to notice. Since the time of Linnaeus it 
 has been usual to class the nectaries with the parts of the flower charac- 
 terised by the secretion of a fluid containing much sugar. This charac- 
 teristic was subsequently laid aside and more regard paid to its external 
 form, so that at last all possible things have been gathered together under 
 this name. If we would really comprehend the structure of the flower, 
 
 * Link (Linnasa, vol. xv. 1841 (!), p. 482.), with the appearance of great acute- 
 ness, remarks, against Robert Brown's view of the structure of the Coniferous flower, 
 " Si ad micropylen apertam respicis semen nudum dicere poteris, si vero ad integu- 
 menta (ex quo stigmata duo excedunt) tectum erit." Had Link more than hastily 
 skimmed the writings of Robert Brown, Brogniart, and Mirbel, he would have known 
 that they very strictly distinguish a gemmula nuda from a nucleus nudus. According to 
 the common use of language, an organ is nudus which wants the immediately succeeding 
 covering ; the nucleus, therefore, is nudus without the integumentum ; the gemmula, without 
 the germen. Semen means nucleus and coats together, and can only be called naked 
 when no pericarpium exists ; but it is the gemmula which is under consideration here : 
 the micropyle is a part of the coat of the seed-bud; the stigma, a part of the pistil. 
 Either the integument of the nucleus in the Conifers is a coat of the seed-bud then 
 it is absurd to talk of a stigma, or it is a germen, and then no micropyle exists. But 
 I must return to this hereafter. 
 
 the somewhat hemispherical projecting extremity of the stem ; c, pith, within the 
 middle expanded portion of which some cells are transformed into embryo-sacs; d, circle 
 of vascular bundles ; e, bark ; f, epidermis. 
 
 I80a Taxus baccata. Vertical section of the seed-bud, a, Base and point of attach- 
 ment of the seed-bud ; 6, nucleus ; c, embryo-sac ; d, simple integument ; e, large cells of 
 the endosperm (corpuscula, Robt. Brown); g, micropyle; A, rudiment of the coat of 
 the seed. 
 
318 MORPHOLOGY. 
 
 we must distinguish first of all axial and foliar organs, and then in- 
 dependent organs and mere appendages and excrescences of particular 
 organs. In all these parts it may, and sometimes does, happen, that a 
 part of the surface does not develope epidermis, and secretes a sac- 
 charine or often other kind of juice. Neither the wholly subordinate 
 and always accidental condition of structure, nor the function, and this 
 least of all, justifies the assumption of its being a special organ. To 
 define nectaries according to form has not been attempted, and would, 
 indeed, be an impossibility. I reject the term from morphology, as alto- 
 gether useless. 
 
 A. OF THE AXIAL ORGANS OF THE FLOWER. 
 
 146. There are very few flowers of so simple a structure that 
 they consist only of one simple essential part, so that no formation 
 of internodes is possible within the flower ; and the extremity of 
 the pedicels immediately supports the floral parts existing. This 
 is the case in the male flower of the Euphorbia, where the end 
 of a pedicel bears one single stamen ; also in the male flower of 
 the Abietinece, where one single foliar organ, converted into a 
 stamen, constitutes the entire flower : it is the case in the female 
 flower Taxus, where the small pedicel, clothed with bracts, ter- 
 minates immediately in the naked seed -bud. In the generality of 
 flowers, however, several parts are united which do not stand at 
 equal heights on the axis, and thus more or fewer internodes take 
 part in the structure of the flower. The original condition of the 
 internodes, the undeveloped, is here also most frequently perma- 
 nent ; and the pedicel, after the detachment of all the parts of 
 the flower, frequently ends in a small, slightly thickened knot, 
 which represents the collective internodes of the flower in undeve- 
 loped condition, the simple base or receptacle of the flower (torus). 
 Examples in which individual internodes become elongated are 
 rather rare. I am not acquainted with any case where this occurs 
 between the floral envelopes, but in some families they are elon- 
 gated between the inner floral envelopes and the stamens (andro- 
 phorum), and between the stamens and the gerinen (gynophorum). 
 The latter is generally termed germen stipitatum. There are 
 examples of both in the Passiflorce and the Capparidece. 
 
 A considerably longer part, without elongation of the indi- 
 vidual intern odes, frequently occurs as a gynophore in flowers 
 which contain many germens (as in the Rosacece, the Ranuncu- 
 lacece, Magnoliacece, &c. Again, the gynophore is often presented 
 as a hemispherical or cushion-like part, as in some other Rosacecs 
 and RanunculacecB ; a very rare form of it is that of a reversed 
 cone, which bears the germens upon a base turned upward, as in 
 Nelumbium. In the rarest instances, with the exception of this 
 case, the axis of the flower is elongated within the floral parts, 
 even without ending as a germen ; but this does sometimes occur 
 as in the male flowers of some Palms and other plants ; for ex- 
 
PHANEROGAMIA: FLOWERS. 319 
 
 ample, Charn&dorea, where the points of the petals unite with the 
 apex of the axis of the flower which passes up through them.* 
 
 In very crowded inflorescences, the torus of an axillary bud deve- 
 lopes obliquely, and rises up on one side, especially beneath the ger- 
 men, so as to appear as a part of its side-wall ; this happens with 
 most of the Grasses. A similar circumstance, arising from a similar 
 cause, happens when many single germens are present in one 
 flower, by the division of the torus, which forms the basis of each 
 of those germens, and thus assumes the appearance of forming a 
 part of the wall of the germen (as in Potamogeton and Dryadece). 
 
 But the development of the internodes into a disc, or in a hollow 
 cup, is far more frequent in the flower. If the collective inter- 
 nodes of the flower form a hollow body, or even a cylindrical 
 elongated tube, which encloses only seed-buds, and bears all the 
 floral parts upon its upper edge, all this is the so-called inferior 
 germen, or ovary (germen inferum). 
 
 Every other similar expansion of the internodes of the flowers 
 which does not immediately bear seed-buds, is called the disc 
 (discus). This may be situated beneath the rudiment of the fruit 
 (discus hypogynus), and then may be flat, as in Potentilla and 
 Fragaria ; or cup-shaped, as in Rosa, Populus (mas), &c. This 
 latter may be free (Rosa), or may be blended with the germen 
 situated inside it (Pyrus), or it may pass off from the middle of 
 the (half-inferior) germen (discus perigynus), as in many Myrtacece ; 
 or, lastly, it may rise above the (inferior) germen, and stand upon it 
 (discus epigynus). Here it is very rarely (or never ?) flat, but funnel- 
 shaped, as in Godetia ; in the form of a long tube, as in (Enothera ; 
 or resembling a style, as in the Orchidacece and Aristolochiacece. In 
 these cases, the foliar organs of the flower may be situated in very 
 different places. Usually, indeed, they collectively form a zone 
 around the edge of the flat or concave discs ; then the discs may 
 be said to correspond to as many discs, lying one above the other, 
 as there are internodes implied by the number of foliar organs. 
 Frequently the true foliar organs stand around the edge of the 
 disc; and upon its inner or upper surface the germens are ar- 
 ranged in one or more circles (as in Rosa, Punica, Onagracece). 
 More rarely the floral envelopes alone stand on the border, while 
 the stamens are then at a distance from them, upon an internal 
 prolongation of the disc, as in the Orchidacece. 
 
 The disc is by no means always regularly developed, but some- 
 times enlarged at one side only, whereby the whole flower appears 
 oblique, thus in Reseda. The most remarkable structure is in 
 Pelargonium, where the disc forms a cavity to one side of the 
 peduncle, and in Tropaolum, where the spur is formed solely by 
 the disc. 
 
 * Here, and in some similar cases, this portion of the axis is falsely called an abortive 
 germen. The germen in these cases is usually composed of carpels, and these never 
 exist in an abortive condition. The spermophore differs from the axis solely through 
 the presence of the seed-buds, and therefore neither does it exist here. 
 
320 
 
 MORPHOLOGY. 
 
 There are but few special observations to be made respecting 
 the structure of the internodes of the flower ; it is in general like 
 that of annual steins ; but it must be remarked that they often 
 possess fewer vascular bundles, and these of simpler development. 
 It is more particularly to be mentioned, that the internodes (as 
 also some of the foliar organs) within the flower, frequently do 
 
 183 
 
 c. 184 
 
 185 
 
 186 
 
 181 Echinops ruthenica. A capitolum with flower-buds (a), in vertical section. The 
 shady part is the axial organ (the peduncle). 
 
 }si Ranunculus procerus, A flower in vertical section, a, Calyx ; 6, corolla ; c, sta- 
 mens ; d, carpels. The shaded part is the axial organ (peduncle, torus). 
 
 183 Ephemerum Matthioli. A flower, in vertical section, a, Calyx ; b, corolla ; c, sta- 
 mens ; d, carpels, forming the germen, pistil, and stigma (which is cut off) ; e, seed- 
 bud. The shaded part is the axial organ (spermophore). 
 
 184 Helianthus annuus. A capitulum in vertical section, a, Leaves of the invo- 
 lucre; 6, bracts (pa/e) ; c, flowers. The shaded part is the axial organ (discoid 
 peduncle). 
 
 183 Geum rivale. Flower in vertical section. a, Calyx ; b, corolla ; c, stamens ; 
 d, carpels. The shaded part is the axial organ (discoid receptacle-disc), and in its 
 centre a gynophore. 
 
 186 Arisarum australe. Pistil in vertical section, a, Carpels, forming the side walls 
 and covering of the germen, the style, and the stigma ; b, seed-buds. The shaded part 
 is the axial organ (discoid spermophore), forming at the same time the base of the 
 germen. 
 
PHANEROGAMIA : FLOWERS. 
 
 321 
 
 not have the epidermis developed, but, instead of this, a delicate, 
 soft, cellular tissue, somewhat yellowish in colour, and often con- 
 taining a sugary secretion, forms the investment of the surface 
 (Nectariuni). 
 
 187 
 
 189 
 
 188 
 
 191 
 
 192 
 
 187 Sonchus asper. A capitulura past flowering, in vertical section, a, Involucral 
 leaves ; b, half-ripe fruits, crowned with the hair-like calyx (pappus). The shaded part 
 is the axial organ (cup-shaped, concave peduncle). 
 
 188 Dryas octopetala. Flower in vertical section, a, Calyx ; 6, corolla ; c, stamens ; 
 d, carpels. The shaded part is the axial organ (cup-shaped, concave receptacle- 
 disc). 
 
 189 Heuchera villosa. Flower in vertical section, a, Calyx ; 6, corolla ; c, stamens ; 
 d, carpels, forming the covering of the germen and the style ; e, seed-buds. The 
 shaded part is the axial organ, forming the base and side-walls of the germen and a 
 narrow perigynous disc. 
 
 180 Ficus carica. Capitulum in vertical section, a, Leaves of the proper involucre ; 
 6, flowers ; c, leaves of the outer involucre. The shaded part is the axial organ (vase- 
 shaped peduncle). 
 
 191 Rosa davurica. Flower in vertical section, a, Calyx ; b, corolla ; c, stamens ; 
 d, carpels. The shaded part is the axial organ (vase-shaped receptacle-disc). 
 
 IM Leucojiun vernum. Flower in vertical section, a, Calyx ; b, petals ; c, stamens ; 
 d, carpels, at present only forming the style and stigma ; e, seed-buds. The shaded part 
 is the axial organ (an inferior germen). 
 
322 
 
 MORPHOLOGY. 
 
 With the so crowded structures and the many blendings of organs in 
 the flower, it was not easy to comprehend clearly the conditions de- 
 scribed in the paragraphs ; and of all the parts of the flower, these 
 structures have been the latest that we have come to understand. It 
 seems easiest to comprehend them when we place in parallel rows, side 
 by side, the various forms which the a*is assumes, as has been done in the 
 accompanying figures (figs. 181 192.). We here trace the axis from a 
 simple round swelling, through the flat disc, the concave disc, and until it 
 reaches the form of a vase, and this in three parallel series ; the first bear- 
 ing the entire blossom (figs. 181. 184. 187. 190.) ; another bearing ger- 
 mens, that is, carpels and seed-buds (figs. 182. 185. 188. 191.); and a third 
 simply bearing seed-buds, or immediately surrounding the cavity in 
 which the seed-buds occur (figs. 183. 186. 189. 192.). I know of no 
 form which would carry the first series further ; on the other hand, 
 the second and third are not properly completed without figs. 193. and 
 194. In the first of these (fig. 192.) the cup- shaped disk is carried up be- 
 
 193 
 
 194 
 
 yond the upper part of a vase-shaped closed axial organ, in the form of 
 a new disc. By the extension of the same in fig. 194., on the contrary, 
 the part, which in the remaining members of the series is always formed 
 of the foliar organs, is here drawn within the circle of the axial 
 
 198 Godetia Lefimanniana. Flower in vertical section, upper part. The shaded part 
 is the axial organ. From a to b is the inferior germen (fig. 192.); from b to c is the 
 superior cup-shaped disc (fig. 188.). This superior disc exhibits elegant projecting 
 portions, quite similar in kind to those on the inferior disc of Passiflora, only less deve- 
 loped. (See Plate III.) 
 
 194 Epipactis latifolia. Vertical section through the flower, a, External ; I, internal 
 leaves of the perianth ; c, stamens; e, seed-huds; x, stigma. The shaded part is the 
 axial organ ; the under part, up to the insertion of a and b, is the inferior gerinen ; 
 the upper part is originally an androphore, then a gynophore ; but the carpels are 
 wholly abortive, and the axis itself forms the style with these last parts above a 
 and b 
 
PHANEROGAMIA : FLOWERS. 323 
 
 organs, namely, the style and stigma. Then, to create all possible 
 combinations, comes the interesting structure of Siphonodon celastri- 
 neus, described by Griffiths in the Calcutta Journal, where the carpels 
 form the cavity of the germen and the canal of the style ; while the 
 axial organ forms the spermophore, the conducting cellular tissue, and 
 the large umbrella-shaped stigma. 
 
 All those structures grouped together under the name of discs in 
 the paragraphs are doubtless of the same nature ; the development 
 distinctly shows them to be flat or concave expansions of the internodes 
 entering into the flower ; sufficient analogies to which occur in the flat un- 
 doubted internodes of many Compositas (e. g., Helianthus, fig. 184.), in 
 the hollow ones of Ficus (fig. 190.), and so forth. The assertion of the 
 axial nature of all the structures mentioned is, in remarkable manner, 
 inductively proved by the following considerations ; that one leaf 
 actually springs from another, grows forth from it, contradicts the 
 definition, and is therefore impossible. The assumption of a calyx- 
 tube, therefore, of blended foliar organs in the Onagracece, Rosacece, 
 &c., from which free petals should spring, was altogether an uncon- 
 sidered and absurd fiction. An axial structure must necessarily have 
 been presupposed here ; and then it was completely unwarrantable, and 
 clumsy prolixity, to superadd an imagined coherence of sepals into a 
 tube, and adherence of this tube to the discoid receptacle, for instance, 
 in Rosa (fig. 191.), Geum (fig. 185.), &c. (while not the most distant 
 attempt to demonstrate such a condition was thought of). In these 
 cases (the so-called Calyciflorce) the sepals are no more grown together 
 than the petals, and they stand quite free upon the border of the in- 
 ferior (fig. 185.), surrounding (figs. 188. 191.), or superior disc. But 
 the course of development speaks with equal decision in favour of 
 the view propounded in the paragraphs, since often the structures, and 
 especially the inferior germen, exist complete, or almost so, and at least 
 clearly perceptible, before even a trace of the leaves which grow out 
 of them is evident. (See, in regard to this, the development of the flower 
 of Canna exigua, Plate III., with the explanation.) 
 
 In all discs, the sudden change of texture, and commonly also a dis- 
 tinctly projecting rim, show the boundary of the disc, and the point of 
 connection between it and the foliar organs standing upon it ; and by 
 these marks, in the generality of Calyctflorce, the calyx is characterised 
 as composed of free foliar organs "not coherent by growth. I recall 
 it to recollection here that, in these forms of the axis, the middle of the 
 lower or outer surface corresponds to the lowest portions of the axis, 
 the lower or outer and the upper or inner surfaces, together, to the sides of 
 the axis, and the central point of the upper or inner surface to the apex 
 of the axis. On this axis the individual foliar organs, or circles of 
 leaves, may be very variously arranged, as is seen by-comparing together 
 figs. 188. 191. 193. It is not necessary that they should be all attached 
 around in one zone, for in the discoid axis a condition is possible 
 which, as in the elongation of the axis, separates the individual foliar 
 organs or circles from one another, and corresponds to one or more 
 developed internodes. It is usual for all internodes of the flower to 
 concur in the formation of the discs where this exists ; but there are 
 cases where this is not so, and where the different internodes assume 
 very different forms. Thus the Rosacece are divided pretty strictly into 
 two groups, according as the disc is quite flat or concave (Rosa, San- 
 yuisorbca, figs. 188. 191.), or the internodes between calyx and stamens 
 
 v 2 
 
324 MORPHOLOGY. 
 
 flat, and those between the germens hemispherical or conical, convex 
 (the remaining Itosacece, fig. 185.). Yet more striking is the difference 
 in Passiflora, where a flat disc bears upon its edge the calyx and corolla, 
 whilst the internode between this and the stamens is elongated in its 
 upper part, and that between the stamens and the germens in its whole 
 extent (Plate IV.). 
 
 Sometimes individual internodes of the flower appear strikingly 
 developed ; this most frequently occurs in the gynophore, in the Labia- 
 tce and Boraginacece, as a thick fleshy disc (gynobasis) ; in the Malvacece 
 as a thick, conical body, bearing the circle of germens; in Ranuriculacea 
 (e. g., Myosurus) and in Magnoliacece as a long, almost cylindrical,, organ.* 
 
 No word has been so falsely used as the word discus ; all the peculiar 
 organs found in the flower, which could not be reduced to the four 
 common forms calyx, corolla, stamen, or pistil have been heaped 
 together under the term discus. Thus in the Thymeleacece decided, even 
 perfectly free, foliar organs ; in the Scrophularinecp, and allied families, 
 a circle of coherent foliar organs (termed also annulus hypogynus) ; 
 in the UmbellifercB, the somewhat fleshly and succulently developed 
 lower part of the carpels (as discus epigynus) ; and the like. An infinity 
 of special conditions still remain to be 'investigated and explained; I 
 can only offer the few which I have had time to examine ; a complete 
 working out of these conditions would be a most meritorious task, and 
 would be of infinite assistance in the recognition of natural affinities ; 
 but one must not restrict oneself to calling a discus every yellow and 
 rather succulent body one finds in the flower. 
 
 I cannot repress here a teleological observation, which I own is not 
 scientific. We do find the discoid and cup-like form in other axial 
 organs, but nowhere so frequently as in the internodes of the flower : 
 this is, however, unquestionably the simplest means to produce a con- 
 dition of things favourable to a great multiplicity of structures, without 
 injury to the dimensional connection and apparent individuality and 
 completeness of the flower. 
 
 B. NUMBER, RELATIVE POSITION, AND DURATION OF THE PARTS OF 
 
 THE FLOWER. 
 
 147. It is very rarely that a flower consists of one part only, 
 as in the male flowers of Euphorbia^, Lemna, and Wolffia, which 
 are formed of one foliar organ, the anther ; or the female flower 
 of Taxus, which is formed of one axial organ, the seed-bud. 
 Usually more parts unite to form a flower : thus the female flower 
 of most of the Aroidece consists of one or more seed-buds, and a 
 carpel surrounding them. The male flower of the Salicinecs con- 
 sists of a scale-like disk and several stamens. In the generality of 
 cases, male and female organs are both present in the same flower : 
 they are seldom naked, as in Hippuris, but usually surrounded by 
 floral envelopes. 
 
 * Analogous to the disc in the Boragineae and Labiate, the axis in the Crucifera 
 and Alsineas forms tumefactions on the base of the stamens, which surround the bottom 
 of the pistil as little scales or a little cup, and are usually described as inferior glands, 
 because they often secrete sweet viscid fluid through the epithelium, which remains 
 very delicate. 
 
 f Here the single stamen (foliar organ) stands exactly on the middle and the end 
 of the little pedicel. A complete history of the development is still a desideratum. 
 
PHANEROGAMIA: FLOWERS, 325 
 
 In axillary flowers, those parts which are turned towards the 
 peduncle are termed the upper, and those turned towards the 
 bract, where it is present, the lower. Some plants exhibit the 
 peculiarity, that the pedicel, until the time of the blooming, makes 
 a half turn (analogously to the twining stem), and it may be the true 
 pedicel, as in Calceolaria and some Orchidacece ; or the inferior germ, 
 as in most of the Orchidacece. By this curve, the upper parts of such 
 a flower (in those plants the lip) become apparently the under ; and 
 such flowers are termed flores resupinati. The term is sometimes 
 falsely applied to those Orchidacece in which no such twisting takes 
 place, but in which the lip stands regularly as the upper part of 
 the flower, as, for example, in Epipogium. 
 
 The individual organs of the flower taken generally, according 
 to the common view, and known by collective names, may originally 
 consist either of one piece or of more than one : in the first case 
 they are paries monomerce ; in the second case paries di- 9 tri-, or 
 polymercs. In the latter case the parts may be entirely separated 
 and independent of one another, or they may be grown together in 
 various ways. These coherent sets were formerly also called partes 
 monomerce. De Candolle better termed them partes gamomerce ; 
 as, for example, Hemerocallis = perianthium gamo- (mono-) phyllum, 
 hexamerum ; Salvia corolla gamo- (rnono-) petala pentamera ; Rosa 
 corolla pentapetala, &c. 
 
 The coherence occurs here in the same manner as in the stem- 
 leaves, but, on account of the crowded position in the flower- 
 bud, much more frequently. It happens either so that a single 
 foliar organ grows together by its edges into a tubular or cup-like 
 organ, as, for example, occurs frequently in the so-called mono- 
 merous floral envelope (bracteole) ; or that several foliar organs 
 grow together by their edges : this commonly affects all the edges 
 of a circle of leaves, but sometimes two edges remain ununited, 
 as with the calyx of Gentiana lutea. So, again, this process is 
 usually simultaneous in development at all the edges of a circle ; 
 but it sometimes happens very much later a. on two uppermost 
 leaf-edges, whereby the single-lipped forms arise, as in the corolla 
 of Teucrium and t\\Q fares ligulati of the Composites; or, b. with 
 each pair of leaf-edges at the side of the leaf-circle, whereby the 
 two lipped forms (part, bilabiatce) of descriptive botany arise. 
 Another kind of blending also occurs in the flower, of which I 
 know no example in the stem-leaves, and only one in the bracts 
 and bracteoles, namely, the cupula of the Cupulifera, this is the 
 blending together of two or more circles, as in the two circles of 
 the floral envelopes of many Liliacece ; or in these and the two 
 circles of stamens, in the circle of petals and stamens, in the 
 Labiates, &c. ; and in general in all flowers to which arc ascribed 
 stamina perianthio vel corolla (not calyci) inserta. 
 
 The coherence of the stamens of one or more circles has been 
 well termed, since Linnaeus' time, fraternity ((idclphia), and, 
 according to the number of brotherhoods in a flower, mon- 
 
 v 3 
 
326 MORPHOLOGY. 
 
 adelphia, diadelphia, polyadelphia. When the foliar organs of the 
 flower are coherent, the blended part is termed the tube (tubus 
 perianthii, calycis, corolla, &c.); the free parts, the limb (limbus)', 
 and the boundary of the two, the throat (faux). One of the most 
 striking examples of coherence, which also has no analogue in the 
 stem-leaves, is found in the blending of the foliar organs of the 
 flower at the point only, the union never extending further ; so that 
 the foliar organs are connected above, but free below, as in the 
 corolla of the male flowers of Chamcedorea, Casuarina, and in the 
 androphore of Symphyonema montamim (?).* 
 
 Abortion in the flower has the same and simple meaning which 
 I have explained at length in the case of the foliaceous organs ; 
 namely, that some part present in the rudimentary condition is 
 arrested in development, and during the gradual perfecting of the 
 flower, and thus at last retires from observation. The assumption 
 of any other kind of abortion has no place in natural science ; it is 
 a mere dream of the imagination. So soon as the individual parts 
 of a flower become distinct members, the foliar organs appear ar- 
 ranged around an ideal and real axis of the flower (the axial organs 
 of the flower), and in the rudimentary condition always regularly. 
 Through subsequent unequal development of the single parts the 
 flower frequently becomes symmetrical, or, as it is called, irregular. 
 This irregularity is always such, that the upper part of a flower 
 becomes developed differently from the under. Such irregularity 
 very seldom affects the germen, which almost universally remains 
 regular, even in symmetrical flowers ; yet there are cases in which 
 this is the onlv symmetrical part, as in many of the Scrophulariacece, 
 AcanthacecB, and Cryptocoryne spiralis. If the symmetrical flower, 
 with or without coherence of its parts, is divided into two halves, 
 an upper and under, developed in different ways, they are generally 
 termed bilabiate ; but if only one single foliar organ is deve- 
 loped in an aberrant form, that leaf acquires the name of labellum, 
 or lip. Rare, indeed, are the cases where the entire flower is 
 unsymmetrical, as in Goodyera discolor. 
 
 It is not possible to state, in general terms, the number 
 of parts which may unite to form, a flower. We find, of foliar 
 organs alone, sometimes so many as fifty or sixty united in one 
 flower. Certain combinations, on the contrary, are rarely met 
 with : I know of no monomerous flower possessed of double floral 
 envelopes. When the various parts of the flower are present 
 in large numbers, these arise universally, in one or more circles 
 (whorls), at the same height on the axis, and at the same time. 
 When circles containing members of equal number follow in suc- 
 cession, the members of the one circle usually stand opposite the 
 interspaces between the members of the preceding circle (the circles 
 and their members alternating) ; they seldom stand precisely before 
 
 * Other conditions, such as the connection of the points of the two outer petals in 
 the Fumariacea, of the anthers in the Composite, &c. do not belong here. These are 
 glued together by a fluid secretion. 
 
PIIANEROGAMIA : FLOWERS. 327 
 
 them (the circles and their members opposite). But it by no 
 means is to be assumed that the members of each circle are always 
 of equal number in a flower. The number of members often in- 
 creases up to the stamens, and from thence diminishes : it is rare 
 for the circle of the carpel to contain the greatest number, as in 
 the Malopea and Maluacece. The generality of Monocotyledons with 
 perfect individual flowers* have regular hornomerous circles through 
 the entire flower : in the Dicotyledons this is relatively rarer ; the 
 outermost and innermost circles have usually fewer members. 
 Again, respecting the number of circles which follow one another, 
 no general statement of importance can be given. Seven different 
 forms of foliar organs may possibly exist in the same flower, 
 namely, the epicalyx, calyx, corolla, accessory corolla, the stamens, 
 accessory stamens, and the carpels ; yet I know no flower in which 
 all occur in conjunction. All these foliar organs may be pre- 
 sent in one or more circles, with the exception of the epicalyx, 
 in which I know no example of a double circle. Perianth, calyx, 
 corolla, accessory corolla, and carpels occur in one, or more rarely 
 in two circles. Stamens may be present in one, two, three, or 
 possibly even four circles ; more circles than this are not exhi- 
 bited in the normal condition of the flower. If the number is 
 increased, which seldom happens, except in stamens and carpels, 
 as in the Ranunculacecs and Dryadece, the Magnoliacecs, &c., they 
 stand no longer in circles, but in a spiral. In Monocotyledons 
 with perfect individualized flowers, with the single exception of 
 some ScitaminecB, five trimerous circles of foliar organs of the 
 flower appear to be formed in those where a second circle of petals 
 exists. The greatest multiplicity of forms occurs in the Dicoty- 
 ledons. Lavatera, for example, has an epicalyx, calyx, corolla, 
 stamens, and carpels in five circles, with increasing numbers of 
 members ; those of the calyx and corolla alone are equal. Gnidia 
 virescens has perianth, stamens, accessory stamens, and carpels, but 
 in eight circles, which are throughout composed of two members 
 each. It is by no means necessary that all the parts of a circle of 
 floral foliar organs should be ultimately developed in the same 
 manner ; and many floral structures which have hitherto been ap- 
 parently inexplicable may probably, by keeping this truth in mind, 
 and following out the history of the development, be readily traced 
 back to the original type. 
 
 The duration of the individual parts of the flower is very various ; 
 the axial organs, so far as they support the rudiment of the fruit, 
 or aid in its formation, persist naturally, at least until the ripening 
 of the seed, then fall away with it ; or if it becomes disengaged 
 from them, die away with the remainder of the plant. When 
 axes bear only male organs or flowers, their duration is different ; 
 sometimes they are cast off at a true articulation, sometimes they 
 remain upon the parent plant, and gradually die away. The 
 
 * Perhaps the Grasses and Cyperacece alone excepted, in which only one carpel 
 
 k- 1 c f c 
 
 Y 4 
 
328 MORPHOLOGY. 
 
 foliar organs of the flower are equally various in their duration. 
 Perianth, corolla, and accessory corolla commonly perish soon after 
 the perfecting of the flower ; either they are cast off by true dis- 
 articulation, or they wither upon the parent plant. The epicalyx 
 and calyx frequently share the fate of the axial organs supporting 
 the rudiments of the fruit ; the carpels almost invariably. The 
 carpels are rarely destroyed before the perfecting of the seed, as 
 in Leontice and, according to Robert Brown, in Peliosanthes Tlieta. 
 The stamens die away mostly immediately after the dispersion of 
 the pollen ; either they are cast off, or they dry up and die away 
 within the flower. 
 
 The terminology in use is as follows : those parts which fail 
 away immediately, when their perfect formation is but scarcely 
 completed, are termed caducous or fugacious (paries caducce); 
 those which endure somewhat longer are termed, if they are cast 
 off by disarticulation, deciduous (partes deciduce) ; if they retain 
 their position and die by gradual withering and drying up, mar- 
 cescent (partes marccscentes) ; those parts which remain long, still 
 vegetating, are termed persistent (partes persistentes) ; if they 
 change their forms by further growth, they are termed excrescent 
 ( partes excrescentes). 
 
 In what has just been said there are three points to which I must draw 
 especial attention, because they have most important influence on the 
 mode of observation of the entire flower. They are by no means new 
 facts, but their importance has not hitherto been properly recognised. 
 
 a. The first relates to the position of the parts of the flower. I will 
 not enter here into the very acute theories of Schimper, but confine 
 myself singly to the true observation of Nature. She gives us two dis- 
 tinctly separate conditions ; namely, the origin of the foliar organs of 
 the individual members in closed circles, in which all the individual 
 parts appear simultaneously and at the same elevation upon the axis.* 
 Where this condition obtains, the individual parts of the several circles 
 alternate with each other, without one established exception that I know 
 of; and where this does not occur in the perfect flower, an inter- 
 mediate circle has always failed to develope, or parts have been esteemed 
 independent which are not so in fact, as in Potamogeton, where the 
 stamens are said to be opposite to the leaves of the perianth ; but the 
 so-styled perigonial leaves are only crest-like expansions of the con- 
 nectives of the anthers, and not independent foliar organs. Probably 
 exactly the same condition occurs in the Proteacece, an account of the 
 development of which I have been unable to obtain. But I must observe 
 that many of my Investigations do not lead in the same direction. I 
 may not pass over here the condition that in few- (two-) membered circles, 
 as in the Tkymelacece, every two-and-two circles approach together, and 
 alternate in pairs, although observation proves that here originally four- 
 membered circles are by no means present. All these plants belong to 
 those which in descriptive botany are spoken of as definite parts (partes 
 definite) ; and it is easy, by means of the equal number of members of a 
 
 * Examples of this are furnished by all Lih'acece, IridetE, Palma, Grasses with 3- 
 merous ; the Lnbiatce, BoraginecE, Composite, Campanulacece, with 5-merous ; many 
 ScrophularinitB with 4-merous ; the Berberidete with 3-merous ; and the Thymeleacece 
 with 2-merous circles. 
 
PHANEROGAMIA : FLOWERS. 
 
 329 
 
 circle that belong to one and the same part of the flower, as, for instance, 
 the stamens, to reckon up the amount even for the greater number. 
 
 Close to those just named comes another condition, though far more 
 rarely ; where, namely the individual parts of the flower, either through 
 the entire flower* or from the stamens forward, as in the Ranunculacece, 
 or the carpels, as in the Dryadece, arise, one after another, in a spiral 
 around an axis then mostly very much developed, and thus become 
 perfected in succession. Here it is never specifically determinate, but 
 only individually, with which members of the spiral, another form of 
 the foliar organ shall enter, for instance, the stamens be converted 
 into carpels ; nor what shall be the greater number of foliar organs 
 contained in the spiral ; consequently, shall complete the entire flower. 
 The plants here referred to are properly characterised as possessing 
 indefinite parts (partibus indefinite). In this way the said expressions 
 of descriptive botany, which had been selected through a distinctly-felt 
 necessity, and by a practical perception of nature, acquire, through the 
 investigation of development, a rigid, scientific meaning which they 
 really did not possess before, since no one could rightly say what paries 
 definite and indefinite actually were. 
 
 b. The second point to which I desire to draw attention is the varied 
 development of the members of one and the same circle, in which they 
 assume forms such, that we are tempted to separate them entirely from 
 the circles to which they belong ; where, for instance, in the corollary 
 circles some leaves become, if we may so say it, stamens ; and in the 
 staminal circles some become petals, accessory petals, or accessory stamens; 
 or, in the carpellary circles, some become stamens, and some accessory 
 stamens. One of the most striking examples 
 of this is offered by the fourth and inner- 
 most tri-merous circle of Canna (fig. 195.). 
 Properly all three parts should become car- 
 pels, and form the style ; but one alone is folded 
 in to form the style ; a second becomes the 
 stamen ; and the third is wholly abortive, but 
 exists in the tolerably large bud on a small 
 scale, not very easy to represent. (See Plate III. 
 fig. 12., with the explanation.) 
 
 Many of the Orchidacece furnish known 
 examples of the same fact, in which only one 
 or two leaves of the innermost circle but one 
 become stamens ; whilst one or two, if they are 
 not totally abortive, develope merely into small 
 scales or glands. I may add, that something 
 similar occurs in the generality of the Scita- 
 minece, but I have not had opportunity to 
 follow out fully the history of the development. 
 The Balsaminece may, perhaps, be explicable 
 in the same way, but I have not yet succeeded 
 in detecting their earliest conditions with suf- 
 ficient clearness. When the entire bud has 
 reached only the length of from one-eighth to 
 one-sixth of a line, the flower already has its 
 contour almost as irregular as subsequently. 
 
 * Although I cannot bring forward any certain example of this, probably in the 
 
 species of l\f<iynli<i and some l\<n/Kcu/ftcc, especially the Ainmniii'ir. 
 
 195 Canna exigua, developed flower, a. Inferior get men ; />, calyx ; c, external, and 
 </, inner circle of the corolla ; e, stamen* ; e', style. 
 
 1P5 
 
 ail- 
 
330 MORPHOLOGY. 
 
 The PolygalacecB are also referable here, although I have not yet suc- 
 ceeded in finding out the earliest structure of the flower. The earliest 
 condition of the bud which I have yet been able to arrive at, exhibits five 
 free foliar organs in one circle, and within that, apparently placed in 
 another circle, five other leaves, at that time also entirely free ; of these 
 the undermost becomes the pitcher-shaped, fringed petal ; the two upper- 
 most the bilobed petals ; the two remaining side leaves are four-lobed ; 
 and each of these lobes is a perfect anther. The question remains to be 
 solved whether this entire inner circle in truth originated as a penta- 
 merous circle, whose two side members each represent a four-lobed 
 stamen, since there is no other way of reducing the flower to regu- 
 larity ; or whether abortion had already occurred at a very early period. 
 
 c. The third point to which I wish particularly to draw attention is, 
 that all foliar organs of the flower, though they may subsequently 
 unite in growth, first arise entirely free parts ; and if they belong to one 
 circle, they are, at their earliest rudiments, and for some longer or 
 shorter time after, exactly like each other ; so that the coherence of these 
 several members, and their symmetrical development, is a later process. 
 I have been able readily to trace the most irregular flowers up to the 
 condition of bud in reference to this ; as, for instance, the flowers of the 
 LeguminoscB, of the Labiates, the Scrophulariacece, and the species of 
 Aconitum, and these fully established the laws laid down here. One of 
 the most remarkable instances in this respect occurred in the stem of an 
 Orobanche, which had not yet risen above ground, and which I came 
 upon by happy chance, in digging for another plant. This exhibited 
 such surprising regularity in tetra-merous circles distinctly alternating 
 with each other, that nothing could appear more elegant. I have not 
 yet succeeded in following out the perfect history of the development of 
 the very irregular flowers. 
 
 I refer again to the flower of the Grasses (see Plate III. figs. 21 23., 
 with the explanation, of Agrostis alba), and the Carices (see Plate III. 
 figs. 24 26., with the explanation, of Carex lagopodioides.) 
 
 C. OF THE TRUE FOLIAR ORGANS OF THE FLOWER. 
 
 a. Of the floral Envelopes. 
 
 148. As among the floral envelopes are usually reckoned the 
 perianth, the calyx, and the corolla, I also include the epicalyx 
 here, and I circumscribe the term perianth in the narrowest 
 sense, so that under it only those foliar organs fall, which, at 
 least two in number, are applied closely to the flower, and upon 
 one level ; so that all individual foliar organs on the axis of the 
 flower, which only enclose stamens or germens, are to be termed 
 bracts. All these bracts have this in common, that they are merely 
 foliar organs peculiarly modified ; and, consequently, all the pecu- 
 liarities of form which occur in the latter naturally appear in 
 the former also. The few distinctions depend upon what here 
 follows : 
 
 As for all other foliar organs, so also for these all forms are 
 
PHANEROGAMIA : FLOWERS. 331 
 
 possible ; but it is not often that the leaves of the floral envelopes 
 have great thickness ; they are almost always more or less flat. But 
 the forms analogous to the pitchers or pouches are here frequent, much 
 more so than is the case with the stem-leaves ; and these are termed, 
 according to their various resemblances to objects, cup-shaped, as 
 the lower petal of Polygala ; hood-like, as in the upper leaf of the 
 perianth of Aconitum ; and So on. If a long sac-like appendage * is 
 formed at the basis of a perianthial leaf expanded above, the un- 
 happily-chosen term spur (calcar) is applied, as in Orchis, Del- 
 phinium, Fumaria, &c. The formation of the spur is frequently 
 conjoined with the formation of a symmetrical flower, where 
 one upper or lower foliar organ forms a spur. The flattened, 
 expanded form, which is connected with the axis by a linear pro- 
 longation, frequently occurs in the sepals (?). This expanded 
 surface is termed the limb or blade of the leaf (lamina) ; the nar- 
 rowed base is not termed petiole but claw (unyuis). True articu- 
 lation is frequent between the floral envelopes and the axis, but it 
 never occurs in the continuity of these leaves (?) ; therefore there 
 are no true compound perianthial leaves, though a simply divided 
 limb is frequent, as the petala palmatifida in Reseda, the petala 
 pinnatifida in Scfiizopetalum, &c. An indication of true articulation 
 may probably be afforded in the separation of the upper part of the 
 tube of the flower in Mirabilis, of the calyx of the Datura, from 
 the lower, and in some similar cases. 
 
 True stipules are not met with in the floral envelopes, but 
 appendages analogous to the ligula appear, to which, indeed, a part 
 of the structure described as the corona belongs. As in the Nar- 
 cissus and the Lychnis, the scales of the throat of the Boraginece 
 also belong here. These parts are formed in very various fashions 
 on the floral envelopes, and such appendages are sometimes exhi- 
 bited standing upon the surface of the foliar organ, in three or more 
 rows, one above another. Almost all forms which descriptive 
 botany recognises as corona and accessory corolla (paracorolhi) 
 belong here, in particular a part of those elegant forms exhibited in 
 the Stapelice and the Passiflorece ; so also do a portion of the so-termed 
 nectaria, as, for example, in the petals of Ranunculus. All these 
 are mere dependant appendages of the foliar organs, which are 
 developed originally simple and flat, all these parts being produced 
 from them subsequently. Coherence and abortion have been 
 already treated of. Here, also, occurs the one-sided development 
 of a foliar organ: this is seen frequently in the petals of the 
 ApocynacecR ( Vinca, Nerium, and Cerbera). 
 
 The collective form of one or more circles, whether coherent with 
 each other or not, is more accurately designated according to fur- 
 ther peculiarities, as tubular (tubulosuin), bell-shaped (campanu- 
 latum), funnel-shaped (infundibuliforme), salver-shaped (liypocra- 
 teriforme), rotate (rotatam), &c. 
 
 * Exactly analogous to the pouch or pitcher in Dischidia Rajfleslana and davata. 
 
332 MORPHOLOGY. 
 
 More will be said respecting this structure when we come 
 to speak of the different kinds of floral envelopes. 
 
 Merely a few points require special notice here, because the principal 
 facts are self-evident, as mere analogical application of what has been 
 explained of the foliar organ in general. 
 
 In the first place, some further remarks are necessary on the dis- 
 tinction between perianth and involucre. Both are undoubtedly 
 foliar organs on the axis itself; each foliar organ may be adherent 
 at its borders or free ; both may be green, brightly coloured, tough 
 or delicate, like all foliar organs. The bracts may stand at various 
 distances from the so-called parts of the flower ; consequently, there is no 
 distinction to be made between a one-leaved perianth and a bract, if we 
 do not pay attention to the number of foliar organs arising on a level 
 (in one circle) on the floral axis. Thus, and so alone, we acquire a per- 
 fectly strict and easily-maintained distinction for scientific description, if 
 we only reckon anything as belonging to the floral envelopes when it 
 consists of at least two foliar organs situated on a level, and call 
 every other merely single foliar organ of the flower a bract. In this 
 way we have a bracteola urceolata in Humulus and Cannabis, whereby 
 in each case they are not so far removed, according to the usual mode of 
 judging, from the true Urticacece, from which they are not to be separated 
 at all, as when a perianthium is ascribed to them. The distinction 
 between Salicacece and Cupuliferce is easily described ; although these 
 plants are of very simple structure, they exhibit a manifest advance in 
 the perfection of the flower. In the Salicacece the flower possesses no 
 foliar organs ; the glandula hypogyna in Salix, the so-called perian- 
 thium of Populus, are, according to their development, merely discs 
 (axial organs). In the Cupuliferce a perfect superior perianth exists ; I 
 have not yet become acquainted with the development of the Betulacece. 
 This much is certain, the axils of the bracteal scales of the catkin do not 
 bear single flowers but inflorescences (capitula), which distinguishes 
 them widely from the Salicacece ; but observation of the development can 
 alone decide as to the import of the foliar organs which exist here. In the 
 female flowers they are apparently bracts (not bracteoles), in the, male of 
 Betula the same, but in Alnus perianthial leaves. In the Myricacece and 
 Casuarinacece distinct di-merous circles of floral envelopes occur. The 
 Piperacece, including Saururus * f have the so-called naked flowers 
 (without any envelopes) in the axils of bracts. Among the Monoco- 
 tyledons the Orontiacece have a distinct perianth. Among the Naiadece, 
 Aponogeton and Ouvirandra have some coloured organs on the flower, 
 the nature of which cannot be determined for want of investigation of 
 development ; the scales of Potamogeton are nothing more than a scale- 
 like crest on the connective of the anther. None of the others have any 
 envelopes ; in Zarnichellia the female flowers are enclosed by a single 
 delicate bract f (spatha hyalina). 
 
 * The Sauruace<e, as I have elsewhere observed, are not a distinct family, but a 
 strange mixture of Monocotyledonous and Dicotyledonous plants, which has originated 
 from imperfect knowledge ; Aponogeton and Otivirandrn are true Naiadce ; Saururus is 
 only generically distinct from Piper and Peperomia ; Houttuynia I do not know, there- 
 fore I cannot say whether it alone will justify the establishment of a special family. 
 
 f The same botanists, who would of course admit that we can only speak of an her- 
 maphrodite flower when stamens and germens are inclosed in one and the same set of 
 envelopes, write coolly, Zarnichellia : flos liermaphroditus ; stamen unicum stipuhe op- 
 pnsitum, germina quatuor perianthio inclusa. See Nees ab JCsenbeck, Genera Plantnrum 
 Flor. Germanice. 
 
PHANEROGAMIA : FLOWERS. 
 
 333 
 
 It is indeed striking that (if my ignorance is not to blame) we have 
 no example of a compound leaf in the floral envelopes, not even in such 
 a way that a single articulation exists, as in Citrus, in the continuity of 
 the same leaf. On the other hand, forms which are relatively rare in 
 the stem-leaves occur here very frequently ; for instance, the hollow ones. 
 
 A different and here especially attractive interest attaches to the dis- 
 tinct separation from the really independent foliar organs, of parts, 
 which, though they appear in such striking and odd forms, are but ap- 
 pendages, and therefore portions of other organs. The terms corona, 
 accessory corolla, nectary, &c., have hitherto been applied by botanists 
 to the most different parts, with a truly inexcusable superficiality ; and 
 how little is dreamt in general of a scientific treatment of the matter, is 
 seen in an expression of Link (I. c. ii. 145.), where he says of the ac- 
 cessory corolla of the Passifloreacce, " We have no double forms by 
 means of which to determine the true nature of this part." A simple 
 examination of the young buds suffices to show that the various filaments 
 and other appendages become developed out from already perfectly- 
 formed foliar organs, consequently the former cannot be independent 
 organs (see PL IV., with the explanation). Double forms, through which 
 Link, for instance, decides upon the nature of the corona in Narcissus 
 (196, h.\ give no results whatever, since the double form is always 
 
 196 
 
 196 Narcissus Icetus. Flower, a, Peduncle ; b, spathe ; c, bud ; d, pedicel ; e, inferior 
 germen ; f, tube of the perianth ; g, limb of the perianth, appearing like six free 
 leaves; h, corona, formed of six coherent ligules of the perianthial leaves. 
 
334 MORPHOLOGY. 
 
 a monstrosity, fin aberration from the normal course of development ; 
 and there exists no principle here, by which to judge how far the plant 
 deviates from its type to produce new forms, or how far the usual form 
 is to be carried back to simpler elements. Assuming that the coronet 
 of Narcissus consists of independent foliar organs blended with the 
 leaves of the perianth, may not they be multiplied in the doubling of 
 the flower as well as the others, and, since their adherence to the peri- 
 anthial leaves is merely a characteristic of the special nature of the 
 flower, be isolated from each other and become blended one to each peri- 
 anthial leaf? Monstrosities prove nothing at all here, but merely render 
 probable ; the only perfectly sure decision is to be obtained here, as every- 
 where, by tracing the development. In the paragraphs I have connected all 
 these appendages to the analogy with the ligule, which is certainly war- 
 ranted by the development for some forms, e. g. Narcissus, Silene, &c. 
 In others, indeed, no such analogy exists, as in the Passifloracea ; in very 
 many forms we have no accurate investigations whatever, as in Par- 
 nassia and in the Stapelice. The fleshy portions of the latter form the 
 transition to the thick fleshy papillce, such as occur, for instance, in 
 such strange forms in the labellum of the Orchidacece ( Oncidium) ; on the 
 other hand, the filiform appendages of Passiflora, which indeed belong 
 partly to the disc, are more nearly allied to those tufts of hair occurring 
 in more definite places, and with more definite colour and form, which 
 are called beards (barba), for instance, on three of the perianthial leaves 
 of Iris. 
 
 Finally, I will observe, that I have referred to the terms employed to 
 describe the total form of the floral envelopes, as of general application, 
 although most of them are only mentioned in isolated special cases, with- 
 out involving any thing at all specific for one or other kind of floral 
 envelope. Most of the words are very readily understood, some more 
 difficult ; e. g. hypocrateriforme, which will not be easily understood by 
 any one who has not seen in old collections or old paintings the form of 
 a flat plate supported on a long stem, on which wine-glasses were placed 
 in the middle ages ; floral envelopes are called rotate when they expand 
 the separate organs equally or almost equally from the point of attach- 
 ment in one plane. It also appears to me to be a mistake when a part of 
 these expressions are applied solely to floral envelopes when the leaves 
 are coherent, which merely gives rise to the necessity of imagining a 
 new word for the condition with free leaves. What it is here required to 
 name is the general contour, and therefore it is no more necessary to 
 regard the subordinate divisions in these, than in the subdivided flat 
 organs, such as the lobed and pinnatifid leaves. In rotate, salver- 
 shaped, &c. corollas, however, the limb is always divided, which never 
 is the case in a wheel or salver ; and in this mode of naming we cannot 
 convey ideas of degrees of more or less, so that in the corolla of Lychnis 
 and Dianthus the words corolla (pentapetala) hypocrateriformis an- 
 fivver the purpose very well. 
 
 149. Five kinds of floral envelopes are distinguished. When 
 all the foliar organs are similarly or nearly similarly developed 
 in a circle of one evident form, colour, and structure, they are 
 described under the general name of perianth, the single organs of 
 which are called perianthial leaves. If in the floral envelopes of 
 one flower we can distinguish two circles differing in form, colour, 
 
PHANEROGAMIA : FLOWERS. 335 
 
 and structure, the outer is named the calyx, its component organs 
 being sepals ; while the inner is termed the corolla, its single parts 
 petals. Then, if three circles of forms are distinguishable, the 
 outermost is called the epicatyx, the leaves of which may be deno- 
 minated phylla. When, between the simple or manifold floral 
 envelopes and the stamens, other independent foliar organs occur, 
 which exhibit a structure very imperfect and abnormal com- 
 pared with the true envelopes, these are called a paracorolla, of 
 which it will be necessary to speak further on, among the accessory 
 parts of the flower. 
 
 It would be vain to seek in most of our botanical works for an ex- 
 planation of what really is the distinction between the separate kinds of 
 floral envelopes. Here, as almost everywhere else, botanists are careless 
 about scientific treatment, about strictly defined conceptions. The in- 
 dividual forms are taken up diagrammatically, the internal unity not 
 perceived, because no correct method is used, and thence the accurate 
 comprehension of the external distinctions in the phenomena also be- 
 comes impossible. How childish are the many contests we have had as to 
 whether a plant had a calyx, a corolla, or a perianth ; people had forgotten 
 that for the decision of this point it was first necessary to examine 
 whether nature does generally exhibit these three kinds of foliar or- 
 gans as different, and if so, how nature (not we with our fancies) dis- 
 tinguishes the parts. In nature we find the distinction so, and in no 
 other manner, as I have given it in the paragraph, since all floral 
 envelopes consist of foliar organs, in which a countless multitude of 
 varieties of form, colour, and structure are equally possible. Where all 
 the parts are developed alike, they are consequently only like parts, to 
 be named with one word, undoubtedly the simplest and most natural 
 condition ; where, on the other hand, differences manifest themselves, 
 the subdivision thus produced may be distinguished by the application 
 of different names, which at the same time are only valid when the dif 
 ferences actually exist, and none of which are ever to be used where 
 nature herself has not made a distinction. It is therefore a funda- 
 mental error when Kunth (Handb. der Botanik, 81.) carries over the 
 term calyx to the perianth, since it is not the calyx, but calyx and co- 
 rolla together ; which correspond to the perianth, and it is an empty, 
 groundless fiction to say that when only one set of similar envelopes 
 exists, the corolla is always wanting. Lindley (Introduction to Botany, 
 llth ed. 136.) has comprehended the conditions most correctly and clearly 
 on the whole, but errs when he speaks of calyx and corolla in the IA- 
 liacece ; here nothing is to be founded on the number of circles, other- 
 wise the Thymelacece would also have calyx and corolla, and a new 
 word would be required for the Berberacece, since these have four circles 
 of floral envelopes. How far very many botanists still are from having, 
 I will not say a deep insight into the nature of plants, but merely a con- 
 ception of the primary principles of the frue^study of nature, is shown 
 by a remarkable expression of Ach. Richard. He says : " The floral 
 
 envelopes are somewhat modified l?aves It is often difficult 
 
 not to regard them as one and the same -organ. Meanwhile botanists 
 ltd re agreed, in order to facilitate the establishment of the generic cha- 
 racters of plants, to regard them, in consideration of their position and 
 purpose, as altogether different from the organs with which they at the 
 
336 MORPHOLOGY. 
 
 same time agree in internal structure." Such a convention among 
 botanists, did it actually rxi>t, would be. a foolish agreement to obscure, 
 nature instead (!' comprehending her better. As 1 have, before said, wo 
 do not make the forms with our ideas, but receive them from nature; 
 and our object is to learn to understand nature, to divide where, she 
 divides, and to leave united what she herself does not distinguish. If, 
 then, nature herself exhibits to us a certain complication of foliar 
 organs united into one general form, and thus separating themselves 
 from the. other foliar organs, on this account, and not in consequence. 
 of a convention altOg6th6T valueless for the perception of nature, do \ve 
 distinguish the Moral envelopes as special organs. On that point, how- 
 ever, whereon the concurrence of botanists has to decide, namely, what 
 word shall be applied to denominate the organ distinguished by nature, 
 they have not, Unfortunately, coiiie to an agreement, just from the fact 
 that they are altogether destitute of the correct principle of investi- 
 gation. That nature gives us flowers in definite general form, in the 
 J'lKUH'rui/iinnd, is certain ; and just as certain is it that these flowers 
 frequently consist, externally of one or more eircles of foliar organs 
 not essentially altered; that when many of these foliar organs are 
 present, these are developed either similarly or dissimilarly; that they 
 are sometimes all green, sometimes all bright-coloured, sometimes partly 
 green, sometimes partly bright-coloured: which are all i'acts, not derived 
 from us, but from nature. When these, variations have to be named, 
 and this is in general an arbitrary matter, the certainty of scientific 
 language requires an universal agreement, from which variety and the, 
 desire of novelty of the individual, cannot detach itself without stepping 
 as a direct stumbling-block into the path of science. These terms must 
 not be. SO chosen that like things have different names, dilferent things 
 like names. If the outer circle of ditl'erent foliar organs is called a 
 calyx, several circles of similar organs must not receive the same name. 
 The first thing is to find out what forms nature gives us ; the second is to 
 give these names ; and here scientific language demands, for its safety, 
 the most rigid logical consequence. 
 
 What Ach. Richard says about the floral envelopes of Monocotyledons 
 is scarcely grounded on even the most superficial observation, but rather 
 a pure arbitrary invention, to support his equally arbitrary subdivision 
 of the Moral envelopes. He says, " Although the six segments of the floral 
 envelopes of the Monocotyledons stand in two rows, yet they form only 
 a single circle on the summit of the pedicel which bean them ; that is, 
 they have only one common point of origin on the receptacle, and 
 evidently all six develope from the outer parts of the pedicel." In these 
 last words it is evident that Linna-us's fancy of the import of the bark, 
 liber, wood, and pith, in the origin of the parts of the (lower, was in view, 
 and yet with ridiculous want of consistency ; since Richard himself 
 explains all floral envelopes, therefore also the corolla, as foliar or- 
 gans, and all foliar organs arise on the stem in the very same way, 
 and not some from the outer and others from the inner parts. I will not 
 refer to the course of development here, which at once shows how 
 groundless Richard's assertion is; it is sufficient to call to recollection a 
 Commclina or a Tradescantia, where three and three floral envelopes 
 originate as evidently at dilferent heights upon the receptacle, as can be 
 the case in any calyx and corolla of a Dicotyledonous plant. 
 
 What causes the greatest ditliculty in the accurate and certain applica- 
 tion of names is what has to be understood as similar and dissimilar. 
 
PHANEROGAMJA : FLOWERS. 337 
 
 Mere, as in all cases where a purely empirical matter is in question, it is 
 infinitely difficult to express in words what a single glance at nature 
 establishes with facility. In point of fact, nature is not indeed so 
 changeable and undefined as might appear at the first glance, for it is our 
 imperfect perception that produces the indeterminateneas in nature. With 
 a complete and profound knowledge of all plants, it would be easy enough, 
 even by a simple sign, without the application of our so uncertain ter- 
 minological instrument, to characterise a given flower intuitively; but 
 for this is required a knowledge of the laws of the structure of forms, of 
 which we have not yet even a presentiment. For the present we must 
 make use of various external aids, but select these in such a manner 
 that tiny may put no compulsion upon nature, but leave the path open 
 to progress in the science. This is only possible by a construction of the 
 definition from actual experience, instead of out of a pretended theory 
 which cannot exist at present ; and, further, by rigid logical classifica- 
 tion of the definitions according to their relative value and dependance 
 upon each other. In the Phanerogamous plant we have, in this way, the 
 axis and leaf as the primarily defined differences; subordinate to this 
 division come the distinctions founded on progressive development and 
 position, therefore on time and space, as the most universal ; then we 
 arrive at the conditions of form, structure, and colour, which are neither to 
 be evolved from the nature of the plant at present, nor have any relation 
 to primary intuitions, therefore can only be empirically comprehended 
 through experience, and must be described with aesthetic clearness. 
 Thus the conception of similarity admits of no general definition in 
 regard to the floral envelopes, but requires actual demonstration; and 
 here we are destitute of the comprehensive knowledge of all cases from 
 which the more general or more restricted importance of the individual 
 characters might with certainty be deduced. Here we must confine 
 ourselves almost entirely to certain groups of plants, within the limits of 
 which an example does not readily lead to error. If we take, for instance, 
 n corolla only symmetrically developed, e. g. a Pea flower, a striking differ- 
 ence among the separate foliar organs cannot be denied; nevertheless 
 they have a certain agreement in colour and texture, which determines us 
 to recognise I hem as similarly developed. How, in most Orchidacea, the 
 lip differs in form and colour from the rest of the perianthial leaves, and 
 yet there is something in its texture in which we perceive it to be similar 
 to them. Colour and texture agree almost perfectly in the calyx and 
 corolla of Ranunculus acris, and yet we distinguish here two dissimilar 
 structures, according to form. Structure, colour, and even almost form, 
 are exceedingly similar in the Moral envelopes of the Amarantacece, and 
 nevertheless we separate, directly we see them, the corolla from the 
 calyx (the inner two of the three so-called bracteoles), &c. From these 
 causes we can, in (leneral Botany, in regard to very many conditions, 
 only indicate the directions in which the study of these has advanced ; 
 and instruction in these tilings must be given by pointing them out in 
 actual specimens ; more special explanations are only possible in Special 
 IJotany, in reference to particular groups of plants, and the attempt to 
 gather them into generalities leads to endless complexity and useless 
 time-wasting repetitions. 
 
 1 have included the epicalyx among the floral envelopes; and, true to 
 the fundamental axiom, that what nature unites man may not divide, I also 
 
 z 
 
338 MORPHOLOGY. 
 
 reckon among these the outermost circle of leaves, closely applied to the 
 flower, and so gathered together as to form a collective object in the flowers 
 of Dipsacete, in many Malvacece, Passiftoracece, &c. Many persons, in 
 defiance of all correct modes of naming, call these involucrum or involu- 
 cellum in the Dicotyledons, spatha in the Monocotyledons terms which 
 were originally applied to bracts, or a circle of bracts surrounding an 
 inflorescence, and are in the highest degree unsuitable ; and even in- 
 clude here parts which cannot be called anything but calyx without 
 a complete confusion of terminology as, for instance, the outermost 
 circle of floral envelopes in Scitaminece, &c. The only parts which can 
 be confounded with the epicalyx, and to which it naturally forms the 
 transition, are bracteoles upon the pedicel ; but of course, where nature 
 has not united them in definite form and arrangement to the flower, as 
 in the plants mentioned, no epicalyx exists, but merely bracteoles. It is 
 indeed very difficult to draw a line here, as in the distinction between 
 flos pedicellatus and t /?os sessilis, since it is not an absolute difference, but 
 merely a question of more or less that has to be decided on. It is again 
 a point, where the more refined cultivation of the perceptive faculty, 
 where the tact of the inquirer can alone give a correct determination, if 
 we do not agree to arbitrary absolute measurement, which would be ex- 
 ceedingly useless, since in difference of size of flowers that very absolute 
 measure, for instance a line, becomes relative. In some flowers, as in 
 Parietaria, a line is an enormous deal ; in others, such as Datura or 
 Brugmansia, &c., nothing at all. Where, as in Passiflora, elongated 
 internodes occur within the undoubted flower, it would be the readiest 
 expedient to measure ; but this is rarely the case, and therefore this best 
 expedient admits of only limited application. On the whole, a doubtful 
 case will rarely occur, if a man endeavour, with a genuine and refined 
 feeling for truth, to understand nature, and not try to adapt this to his 
 own preconceived opinions. 
 
 The epicalyx, as I define it, may co-exist both with a true calyx and 
 with the perianth, but, in the latter case, only where it is separated from 
 the perianth by the inferior germen, since otherwise there is no cause why 
 it should not be called the calyx, as, for instance, in the Amarantacece.* 
 
 The paraeorolla may also exist in the perianth, but it is always suffi- 
 ciently characterised by the aberrant structure of its foliaceous portions, 
 so that it cannot be confounded with the corolla, and the perianth taken 
 for a calyx. 
 
 150, The perianth consists, according to the preceding consi- 
 derations, of one or more circles of leaves, which are developed so 
 as to be similar in colour, form, and structure. The following 
 series of its forms may be more minutely characterised. 
 
 The individual foliar organs are always (?) expanded in a flat- 
 tened form, seldom divided into limb and claw, and, at least when 
 
 * In almost all descriptions of the Amarantacece, one reads fiores tribracteati . That 
 one of these leaves belongs to a totally different axis, namely, the peduncle, is wholly 
 ignored here. In the Polycnemece, however, where exactly identical parts exist, and only 
 one leaf, namely, the only true bract, is green, we find, fiores quia in axilla fnlii ses- 
 siles bibracteati. If an Amarantaceotis plant should occur with coloured bract and 
 green calyx, it would probably run, flores quia in axillis foliorum duorum sesaiks uni- 
 bracteati ! ! How shall we describe this sort of thing adequately ? 
 
PHANEROGAMIA: FLOWERS. 339 
 
 they are not coherent, usually oval or lanceolate. They may be green, 
 as in the male flower of the Urticacece, or of various colours, as in 
 Thymelacece ; they may be firm and solid, and that especially when 
 green, as in Elaagnacea ; or of delicate texture, as in Aristolo- 
 chiacecB ; or they may be developed as delicate sapless scales 
 (paleci), or bristles and hair, as in the Typhacea and Cyperacece. The 
 perianth is almost universally regular, rarely (in some Ranunculacece 
 and Orchidacece) symmetrical; in these cases never (?) two-lipped, but 
 often with one lip, as in the Orchidacece. This is then not infre- 
 quently developed hollow (cucullatum in Aconitum, calcaratum in 
 Orchidaccce), and it is commonly the uppermost leaf of the perianth. 
 Its foliaceous portions may be free, as in Juncacece ; or coherent, as 
 in Funkia, Hemerocallis, &c. ; they may consist of one circle, as 
 in Urticacece, or of more, as in Liliacece. The parts are frequently 
 blended with the stamens : in the coherent perianth the tube 
 is sometimes straight, as in Narcissus ; sometimes curved, as in 
 Aristolochia. The mouth is mostly naked ; sometimes, but seldom, 
 as is the case in Narcissus, furnished with appendages which 
 form a corona, which, however, are rare in the perianth, and 
 in free foliar organs only (?) occur on the lip : the inner circle 
 often has a beard. 
 
 According to the definition that has been given of the perianth (196.), 
 it cannot be questioned that in some families, as, for instance, the 
 Rosacece (in its widest sense) and in the Ranunculacece (fig. 197), 
 
 we may sometimes have a peri- 
 
 197 anth, and sometimes calyx and co- 
 
 rolla. But when the matter is cor- 
 rectly considered, this is of no im- 
 portance, since the unity of the type 
 depends not upon the names we give 
 things, which are merely to express 
 our experiences, but upon the gene- 
 ral structure of the plants, which 
 ever is and must be subject to a 
 multitude of specific modifications 
 and changes. Floral envelopes are 
 only foliar organs, and the character 
 of any particular group of plants 
 seldom rests only upon their peculiar formation. The attentive ob- 
 server of nature easily traces the relation in certain vegetable groups, 
 but this relation is unaffected by the terms with which we may choose to 
 characterise the groups briefly ; and on account of our deficient know- 
 ledge of the vegetable world, it is most difficult always to apply the 
 correct expressions. The history of the development can alone help us 
 here, for the unity of the group always lies in certain forms of the process of 
 development ; and here we are scarcely on the threshold of our science. 
 
 197 Aconitum napeUus. A, Flower: a to e, five perianthial leaves ; e, hood -shaped ; 
 /, g, A, three bracteoles. JB, Leaf of the accessory corolla. 
 
 z 2 
 
340 
 
 MORPHOLOGY. 
 
 198 
 
 The perianth of the female flower of 
 Carex is peculiar ; it is originally three- 
 leaved, but one leaf very soon ceases 
 to grow, whilst the others, developing 
 disproportionately, unite by their edges 
 and enclose the stunted leaf, and thus 
 form the tubular envelope of the ger- 
 men, which has been termed utriculus, 
 cupula, &c. (See Plate in., figs, 24. 26., 
 with the explanation.) The perianth 
 of the Grasses is similar (fig. 198.) ; 
 it originally consists of three leaves, of 
 which one (palea exterior) is excessively 
 developed, and encloses the other two, 
 which soon cohere and grow imperfectly 
 into a membranous structure (palea 
 superior binervis. (Plate III., fig. 21 
 23., and explanation.) 
 
 The structure of perianthial leaves is, on the whole, that of very 
 simple leaves, which exhibit no special peculiarities, particularly if 
 they are green. The ramifications of the vascular bundles are 
 therefore simple, the separation into an upper and under paren- 
 chyma layer is seldom exhibited ; but the epidermis usually. In 
 the coloured and delicate parts the cells of the parenchyma contain 
 colouring matter. In general the parenchyma is very loose and 
 almost spongy, with homogeneous, transparent fluid contents, and 
 large intercellular cavities filled with air ; hence the white colour. 
 The epidermis is less developed in coloured leaves, and more 
 resembles the structure of epithelium ; stomata are sometimes pre- 
 sent, especially upon the under surface, but the epidermal cells of 
 the upper surface are often raised in shorter or longer papillae, which 
 give the upper surface the peculiar velvet-like appearance. It is 
 very frequent here to find the secreted layer of the epidermis 
 (cuticle) regularly and delicately striated (aciculatus), which cer- 
 tainly contributes to heighten the brilliancy of the colour, and 
 perhaps, by its effect upon the rays of light, to the production and 
 modification of the peculiar tints. 
 
 Occasionally, especially at the base of hollow forms, no epidermis 
 is produced at certain points, and the parenchyma assumes a pecu- 
 liar structure, to perform the function of secretion of a juice con- 
 taining much sugar ; as, for instance, the nectary at the base of the 
 perianthial leaves of Fritillaria, very various parts on the labellum 
 of the Orchidacece, &c. In rare cases the texture is hard and almost 
 
 198 Phalaris cceruhscens . A, Spikelet : a and b, spathe, formed of two bracteae (valvce 
 glumce, Auct. ) ; c and d, one free and two coherent perianthial leaves (palece, Auct. ) ; 
 e e e, three stamens ; /; a stigma. B, The two coherent perianthial leaves, with two 
 nerves (palea superior, Auct. ). C, Pistil, surrounded at the base by two weakly coherent 
 accessory petals : h A, (squamulce, Auct. ) ; g, germen ; /, one stigma ; the other is cut of 
 
PHANEROGAMIA : FLOWERS. 341 
 
 woody from the interspersion of many thickened, porous paren- 
 chyma cells, as in the species of Banksia and Dryandra (?). In 
 paleaceous perianths, the spiral and other vessels are not found 
 in the usually simple vascular bundles, and in hair-like perianths 
 even the vascular bundles themselves are wanting. 
 
 151. The calyx only exists when a corolla occurs with it; it 
 therefore can never be confounded with it. It is always the external 
 of two dissimilar sets of envelopes. Its series of forms very much 
 resemble those of the perianth; perhaps it is not so frequently 
 delicate in structure and colour (as in the Scitaminece, Musacece, 
 Butomacece, Ranunculus, Trop&olum, &c.). Usually it consists of 
 one circle of sepals, more rarely of two (as in the JBerberidacece). 
 These sepals are always very simple, oval, or lanceolate, seldom 
 pinnatifid, very frequently broad at the base and tapering to a 
 point, or very small (denies calycis obsoleti) ; sometimes they appear 
 only as dry scales, or as tufts of hair (the pappus of the Composites). 
 Appendages seldom occur upon the sepals, but they are frequently 
 of hollow or concave form. The number of the sepals in each 
 circle is in Monocotyledons frequently three, more rarely four or 
 two ; in the Dicotyledons it is most frequently five, but also two, 
 three, or four (and, perhaps, sometimes more). Coherence of the 
 sepals with one another may occur in every way, but, so far as 
 my knowledge extends, never with the corolla and stamens, nor 
 with the germens ; that which is so called being quite an other 
 condition (which has been already explained ( 146.) as the in- 
 ferior germen). Both in free and in coherent sepals, regularity and 
 symmetry are met with, the latter often exhibit the bilabiate 
 structures. 
 
 That which has been said of the structure of the perianth applies 
 also to the calyx, only that here green foliar sepals are the more 
 frequent. 
 
 The definition of the calyx, rightly comprehended, presents no diffi- 
 culty whatever, and it is only necessary to give a few examples to guide 
 in observation. For this purpose we select the three-leaved calyx of 
 Canna exigua (fig. 195.), the four- leaved calyx of 1 satis tinctoria 
 (fig. 199.), the coherent form of Salvia patula (fig. 200.), and the un- 
 developed one (pappus) of Actinomeris alferntfolia (fig. 201.). The 
 development of the calyx, so far as it appears necessary, is exhibited in 
 Plate IV. in Passiftora princeps. 
 
 152. The corolla, which only exists as the inner set of floral 
 envelopes accompanying a calyx, may be compared to a very deli- 
 cate and coloured perianth. So far as my knowledge extends, no true 
 corolla occurs perfectly green and resembling the leaves ; its series 
 of forms is greater than that of any other of the floral envelopes. 
 In the Monocotyledons it presents in general only simple, round, 
 oval, or lanceolate leaves, very seldom having claws. In the Dico- 
 
 z B 
 
342 
 
 199 
 
 MORPHOLOGY. 
 200 
 
 202 
 
 tyledons the forms are infinite, as are also the variety and splendour 
 of the colour. The following are the main points : 
 
 The individual petal exhibits, on a reduced scale and in a deli- 
 cate condition, almost every variety of form of the leaf, with the 
 exception of the truly compound. Concave forms are here frequent, 
 such as the hood-shaped, pitcher-shaped, or spurred petals, &c. ; 
 these latter very often on individual petals of an otherwise regular 
 corolla (as, for instance, in Fumaria). Fringed and feathered 
 forms, as well as variously lobed petals, are also by no means rare. 
 The limb and the claw are often clearly to be distinguished. Parts 
 analogous to the ligule, and every imaginable form of appendage, 
 with the exception only of the stipules, occur frequently, and cha- 
 racterise genera and families. 
 
 On this account it is indispensable to distinguish the simple 
 appendages of the petals from the independent foliar organs. 
 To the former belong the scales (fornices) of the Boraginacece, the 
 scales of the corona of the Silenece, the formations generally 
 
 99 Canna exigua. Developed flower. , Inferior germen , b, calyx ; c, external, and 
 d, internal circle of the perianth ; e, stamens ; e', style. 
 
 * Isatis tinctoria. Flower, a, Four-leaved calyx; b, four-leaved corolla; c, six 
 stamens ; d, pistil. 
 
 801 Salvia patula. Flower, e, Five-membered coherent bilabiate calyx ; a, upper lip 
 of the 5-merous coherent bilabiate corolla, formed of two leaves; c, d, lower lip, 
 formed of three leaves, a central and two lateral ones; b, style and bifid stigma. 
 
 2 Actinomeris alternifolia. Single flower, e, Bract (palea, Auct. ); f, inferior ger- 
 inen ; d, stunted calyx, originally five-membered (hairy crown, pappus, Auct.) ; c, tubular 
 corolla, formed of five coherent petals ; 6, tube of the five cohering anthers ; a, style 
 with two stigmas. 
 
PHANEROGAMIA : FLOWERS. 343 
 
 described as corona? in the Stapelics and some other Asclepiadecea, 
 the nectaria of Ranunculus, Parnassia, &c. 
 
 The corolla consists of one circle, rarely of two (three series in 
 Berberis) or more (four series in Nymphcea). In Monocoty- 
 ledons the number of members is equal to those of the calyx ; 
 in Dicotyledons, the number of five in a circle predominates, though 
 it is sometimes composed of two, of four, or of greater number (in 
 Dryas) (?). The number of members is equal to that of the calyx, 
 or greater ; very rarely indeed is it smaller ; this last case occurs 
 with Hibiscus. Suppression is not infrequent, and sometimes 
 involves all the foliar organs of a corolla at once (for instance, in 
 the summer flowers of many species of Viola, in Lepidum ruderale, 
 and some species of Acer). The coherence of organs in every way 
 is still more frequent ; never, indeed, with the calyx or the germens, 
 but frequently with the stamens. 
 
 The corolla, whether with free or with coherent petals, may be 
 regular or only symmetrical. In the latter the bilabiate formation 
 is the most frequent, especially in five-membered circles, in such 
 a way that, according as the odd petal is on the upper or the under 
 side of the flower, the upper lip consists of three or of two petals. 
 In the latter case these two are very often little or not at all 
 coherent, as in Teucrium, the so-called radiated flowers of the 
 Composites (floribus ligulatis vel radiatis). Peculiar forms of sym- 
 metrical flowers are, for instance : the personate flowers (corolla 
 personata\ in which the upper petals of a coherent corolla are so 
 curved inwards that they close the entrance of the tube (as in 
 Antirrhinum) : the incurved portion is termed the palate (palatum)\ 
 the true bilabiate or mouth-like corolla (corolla ringens), in the 
 Labiates, in which the two petals forming the upper lip often 
 present a concave form overhanging the lower lip, termed galea ; 
 the so-called papilionaceous flowers of the Leguminosce, in which 
 the uppermost leaf, which is broad and large, surpassing the others, 
 is termed the standard (vexillum), whilst the lateral petals, as wings 
 (alee), are usually dissimilarly developed, and the two undermost, 
 very frequently coherent, also developed unequally at the two 
 sides, approach each other in a concave form, so as to form the 
 keel (carina). Sometimes all the petals of the papilionaceous 
 flowers become coherent at the lower part, and form a tube, as in 
 Trifolium; or individual petals are abortive, &c. The most irre- 
 gular of all the forms have hitherto received no names ; such as 
 appear, for instance, in the Potygalaceae, the Balsaminacece, Tro- 
 pceolacece, &c. 
 
 All that has been said respecting the structure of the perianth 
 holds good of the structure of the corolla, except that this is 
 more delicate. The contents of the cells vary very much in colouring 
 matter, and their distribution in groups is sometimes very remark- 
 able. Very dense texture, in consequence of the presence of much- 
 thickened porous cells, as in the Amarantacea, is infrequent. 
 
 z 4 
 
344 
 
 MORPHOLOGY. 
 
 203 
 
 204 
 
 The structure of the epidermis, and its development into pa- 
 pillae, hairs, &c., is very manifold. Development into surfaces 
 secreting nectar, both at the bottom of concavities and upon the 
 appendages, is especially common. The petals also occasionally 
 secrete a viscous substance, in consequence of which they adhere 
 together, as happens at the points of the inner petals of the 
 Fumariacece. I know of no other remarkable condition requiring 
 notice. 
 
 I will here present merely a few examples of the forms described in 
 the foregoing paragraphs, exhibiting the tetra-merous, cruciate corolla 
 (fig. 200.), the bilabiate (fig. 201.), the tubular (fig. 202.), the papi- 
 lionaceous (fig. 203.), 
 and the many-leaved 
 cup-shaped (fig. 204.). 
 The development of 
 the regular corolla of 
 Passiflora princeps 
 is given in Plate 
 IV. 
 
 From the multi- 
 plicity of its forms 
 and the variety of its 
 colours, the corolla has in all times at- 
 tracted attention, and so, from the earliest 
 period of the scientific study of Botany, 
 much, perhaps too much, relative stress 
 has been laid upon the knowledge of it, 
 whilst the other parts of the plant have 
 been comparatively neglected. That, in the 
 general destination of the vegetable world 
 to favour pre-eminently brilliant and varied 
 play of forms, and thus to become the richly 
 decorated garment of the geologically naked 
 and poverty-stricken earth, the organ espe- 
 cially devoted to the production of this wealth of form should express the 
 essential character of individual groups, genera, and even species of 
 plants, is of course to be expected ; but it is still even only a part of a 
 number of organs of equal importance, and in the scientific view of plants 
 the corolla must be considered even as a subordinate part, because we 
 are wholly ignorant of the laws of the production of form, and by giving 
 it a partial pre-eminence we should deviate most widely from our aim. 
 In General Botany there is particular necessity merely to indicate the 
 points of view from which one has to observe the infinite abundance 
 of specialities ; and this I have endeavoured to do in the paragraphs. 
 To go further into the structure of the corolla of particular groups I 
 consider to be a mistake, and in the highest degree confusing to the 
 
 101 Lathyrus odoratus- Flower. A, a, Penta-merous coherent calyx, surrounding a 
 5-merous irregular papilionaceous corolla ; 6, upper petal (standard, vexillum) ; c, d, 
 and B, two lateral petals (wings, /) ; e and C, two lower petals, coherent at the 
 lower border (together the keel, carina). 
 
 m Malva miniata. Flower, a, Three-leaved cpicalyx ; b, 5-merous coherent calyx ; 
 c, five-leaved corolla. 
 
PHANEROGAMIA : FLOWERS. 345 
 
 learner. The elucidation of these specialities belongs to Special Botany, 
 where, however, the development of the characters of families must be 
 carried out much farther than is done in the present barren summary of 
 the equally barren descriptions of genera. 
 
 I have nothing more to add to what has been said in the paragraphs. 
 
 153. The epicalyx is exhibited when three several series of 
 foliar organs are distinguishable in the floral envelopes, and 
 it is the outermost of these. There are not many plants which 
 possess an epicalyx; still fewer are the families in which it is 
 constantly presented. In form and structure it much resembles 
 the calyx. It occurs with free leaves, as in Passiflora ; and co- 
 herent leaves, as in Lavatera. Its leaves are seldom delicate like 
 those of the corolla, but are often dry and membranous, as in 
 Scabiosa, but generally green and leafy, as in the Malvaceae and 
 Dryadeoz. 
 
 Since all floral envelopes are but foliar organs peculiarly modified, 
 and since the bracteoles situated on the floral axis below the flower may 
 assume almost all those modifications, so naturally we cannot set a 
 boundary to the flower below by means of the definition, where such a 
 boundary is not presented to us by nature. In the families of the Mal- 
 v#me(fig.204.), Dipsacece, and PassifloracfZ, certain circles of organs are 
 united into a collective form outside the calyx, and evidentlv in a very 
 close relation to the flower ; and these therefore, no less than the calyx, 
 deserve to be accepted and characterised as one special form of the floral 
 envelopes. In all families with dispersed leaves, no doubt can exist as 
 to the distinction between bracteoles and epicalyx, if the latter be de- 
 scribed as one leaf circle close outside the calyx or spiral. In a ver- 
 ticillate arrangement of the leaves, the distinction might be more dif- 
 ficult; but I am not acquainted with any such case. 
 
 Some Botanists have imagined that they have cleverly explained the 
 epicalyx of the Dryadece, as, for instance, it appears in Potentilla, 
 where they have deduced it from the coherent stipules of the calicine 
 leaves. Such false ideas and false explanations are the inevitable con- 
 sequences of the perverse method of guessing instead of investigating. 
 The epicalyx of Potentilla and its allies is a true leaf circle, and, as is 
 self-evident, the first which is formed on the entire flower, and the sepals 
 arise subsequently and higher upon the axis as the second circle of 
 leaves. 
 
 b. Of the Stamens. 
 
 154. The stamen is doubtless a true foliar organ, and of all 
 the foliar organs of the flower is that which exhibits forms the most 
 analogous to the stem leaf. 
 
 It is the only foliar organ of the flower which is not merely 
 defined morphologically by its form and position, but also phy- 
 siologically determined by the importance of its peculiar structure 
 to the formation of the spore, here called the pollen. The law 
 here is: Where no pollen is formed, there is no stamen. The 
 
346 MORPHOLOGY. 
 
 terms stamina abortiva and stamina castrata have no meaning. 
 In that relation it corresponds completely to the sporophyll of the 
 cryptogamic stem plants, and the forms there exhibited as ty- 
 pical of classes are here again manifested to characterise families 
 or genera. 
 
 We find here the sporophyll of most Ferns, developing a number 
 of capsules (here termed cells, or loculi), out of the under face of 
 the leaf, in the Cycadacea. In many Coniferous plants, only a few, 
 long and tubular loculi are formed on the under surface (as in 
 Cunninghamia). In Juniperus, Cupressus, &c., the stamens can- 
 not be distinguished at all from the sporophyll of the Equisetacece ; 
 and we find in Humirium and Glossarrhen, where, however, two 
 loculi are presented instead of one, an analogy with the sporophyll 
 of the Lycopodiacea, where a capsule is formed on the upper 
 surface of the base of a flat foliar organ. But the stamen 
 usually corresponds to the sporophyll of the other Ferns, in which 
 only the petiole and mid-nerve of the leaf are perfected, at the 
 sides of which the parenchyma merely forms the loculi. The 
 structure, however, corresponds not to the much divided Fern 
 leaf, but usually to a simple flat leaf, with a petiole. Then it 
 exhibits an attenuated basis (the petiole is here termed Jilamenf), 
 and an upper broader part, the blade of the leaf (here termed 
 antherd). In the anther, we further distinguish a middle part (the 
 mid-nerve of the leaf, here termed the connectwum) from the 
 lateral parts, the chambers (loculi or thecce) which appear at the 
 summit, the edges, the upper or under surface of the connective as 
 globular, oval, or long cylindrical projections ; besides these, the 
 original edge of the leaf as a longitudinal furrow (rima longitu- 
 dinalis]. Finally, in many stamens the entire leaf substance, in 
 analogy with the so-called sessile leaf, is applied to the formation 
 of pollen-chambers (anther a sessilis). 
 
 Each stamen originates as a leaf, runs at first through a similar 
 series of forms, and its subsequent peculiar appearance is merely a 
 result of its special mode of development, which may be traced, 
 not merely ideally, but mostly really, in the progressive develop- 
 ment, to a few simple fundamental types. Besides the cryptogamic 
 type, above followed out in the families of the Cycadacece and Coni- 
 ferce, a Phanerogamic type is also to be traced ; which essentially 
 consists in the circumstance, that, independently of the presence of 
 the filament, a flat leaf is so developed that its mid-rib becomes the 
 connective, its edge the longitudinal furrow, its parenchyma swells 
 out on both sides of the connective, in which then, through the 
 formation of the finally free pollen-grains, one (as in Abies and the 
 Asclepiadacece) or commonly two thecae are commonly formed on 
 each side. This type doubtless lies at the base of all Phanerogamic 
 stamens, if we except Najas, Caulina, and some Aracea (of which 
 I do not know the history of development). All further peculiar- 
 ities concern either the development of the theca3 on one side alone 
 
PHANEKOGAMIA : FLOWERS. 347 
 
 (as in Canna and Salvia), or the excessive development of the 
 connective, either altogether, so that the thecae are more or less 
 removed from each other (as in Lacistema and Sfalvia), or at its base 
 (as in Stachys sylvatica), at its upper part (as in Berberis and 
 Humirium), or on the under surface, so that the thecae have the 
 appearance of lying upon the upper surface (anther & anticce, introrsce), 
 or on the superior surface, so that they have the appearance of 
 lying upon the under surface (anther ce posticce, extrorsce) ; or several 
 of these modes of excessive and disproportionate development may 
 occur together. Further, we find very irregular development of 
 the connective, and of the thecae dependent upon it ; for instance, 
 in the serpentine form (in many of the CucurbitacecR\ the thecae 
 rolled inwards like the Corinthian volute, in Phitydrum, &c., all 
 originally starting from the same structure, and only gradually 
 assuming these forms. Besides the forms already mentioned, other 
 irregular growths of the connective are presented, especially upon 
 the under surface, where they assume strange forms of spurs, hoods, 
 &c., as in Asclepias, &c. : all these varieties are generally thrown 
 into a heap with things of the most different nature, under the 
 name of corona. On the thecae also occur, sometimes in the upper 
 and sometimes in the under part, processes and appendages of very 
 various kinds (as in the Ericaceae). The connective expands in a 
 very peculiar manner on the back of the anther, beyond it, but pro- 
 jecting especially above and below, and encasing it as a coat, as 
 in many of the Apocynacece. 
 
 Many varieties occur in the mode of union of the anther with 
 the filament ; sometimes no filament is formed. When it exists, it 
 sometimes again merges into the connective, which appears some- 
 what broader than it, and the base of which is not surpassed by 
 the base of the loculi; or the latter grow further out beyond it, 
 so that the filament seems to be inserted between the thecae corre- 
 sponding to the folium cordatum or sagittatum ; or the thecae are 
 developed out in a similar manner beyond the base of the connec- 
 tive, and become blended in the course of their formation, corre- 
 sponding to the folium peltatum : this is termed anthera dor so affixa, 
 or, as it is usually unsteady upon the slender filament, anthera versa- 
 tilis. Again, the filament corresponding to the petiole offers a mul- 
 titude of varieties ; sometimes it is linear or flat (band-like), or may 
 be developed thick and fleshy, exhibiting all kinds of appendages 
 both upon its upper and under side, and especially such as corre- 
 spond to appendages on the leaves : thus, for example, like the 
 ligule (in Cuscuta and some species of Zygophyllum) ; and in par- 
 ticular appendages corresponding to the stipules (as in many 
 Lauracece, Amarantacece, and species of Allium, Alyssum, and 
 Campanula)., which is the more remarkable, since no other foliar 
 organ of the flower exhibits anything similar. 
 
 A true articulation in the continuity of the same stamen I have 
 nowhere found ; in the Composites, it is certain that no such thing 
 
348 MORPHOLOGY. 
 
 exists. Coherence of every kind occurs here ; the stamens some- 
 times become blended in the entire length ; or the filaments cohere 
 in part or entirely ; the filament with the perianth or the corolla. 
 Coherence of their stipules also occurs, as in the Amarantacece. 
 
 "We have here again a few points to bring forward, which require a 
 more minute exposition in order to establish an accurate comprehension 
 of the stamen. 
 
 In the first place, I must discuss the proper definition of the stamen. 
 In this matter I need spend no more words than are necessary to say 
 that it is a modified leaf, since all Botanists whose opinion is of the 
 slightest consequence are now agreed upon this point : but this does 
 not do much for the formation of the definition ; we have such a multi- 
 tude of kinds of foliar organs, which comprehend the whole region of 
 possibility of conditions of position, form, colour, and structure, that it is 
 necessary at once to draw a line between the stamens and all other forms. 
 As a foliar organ of the flower, its definition is not determined, since 
 the sphere is infinitely great here. According to the principle which I 
 have placed at the very beginning of the whole study, namely, the mor- 
 phological mode of treatment, there are only two possible ways of defin- 
 ing accurately, viz. according to the external and internal forms, or ac- 
 cording to the condition of structure. According to the outward form, the 
 externally visible anther-cell, and according to the structure, the develop- 
 ment of the pollen, are undoubtedly the characteristics which define the 
 stamen as such : both are so intimately connected that it is unimportant 
 which character is taken. If this character be passed over, scarcely 
 any stamen can be distinguished from the accessory foliar organs of 
 the flower ; many for example, the outer stamens of Nymph&a, the 
 stamens of Canna not in any way from petals, &c. And, therefore, 
 the definition must be thus taken : a stamen is a foliar organ of the flower 
 which develops anther-cells, and contains within these pollen. By such a 
 definition we acquire a safe basis for the comprehension of the flower, 
 and the accurate description of the forms. Nothing which does not 
 correspond to this definition (and no other is possible) is a stamen. On 
 such grounds, therefore, it is altogether incorrect and superfluous to 
 speak of castrated or abortive stamens, i. e. of stamens which are not 
 stamens at all. An imperfect perception of the nature of the flower as 
 a whole, lies at the bottom of such expressions. This consists of foliar 
 organs (and axial organs) variously modified, some of which must 
 be stamens (or seed-buds), or the definition of a flower cannot be 
 retained. But the essential nature of the flower does not by any means 
 determine how many foliar organs shall be developed into stamens. 
 Even in particular groups of plants no law can be deduced, seeing that 
 nature forms sometimes one way and sometimes another ; but what lies at 
 the basis of the groups, as types, are definite conditions of development, 
 through which are conditioned the number and arrangement of the foliar 
 organs, but not particular modifications of them. These latter are, 
 perhaps, of quite subordinate importance, and may alter in genera and 
 species, nay, even in mere varieties, sportive forms, and monstrosities. 
 What I have particularly to do here, is to reject the anthropomorphic 
 preconceptions of certain ideal types, which float between us and nature, 
 and sometimes perfectly, sometimes imperfectly, attain to a likeness of 
 her ; which, however, we entirely carry over into nature, instead of 
 obtaining from her, and which at best can serve but as a make-shift, 
 
PHANEROGAMIA : FLOWERS. 349 
 
 until the correct expression of the real common character of a group of 
 forms is discovered. This expression can, and will, only be given by 
 the history of development ; and if we wish to understand ourselves and 
 nature, we must now unconditionally give up that clumsy method of 
 preconception. And thus we must establish and maintain in the special 
 case, that nothing which has not an anther-cell and pollen is a stamen, but 
 another form of the foliar organs of the flower, which we are by no 
 means entitled to refer to that particular form. If we take the Comme- 
 linacece as an example, it is part of their general character to develop 
 five tri-merous circles of foliar organs in the flower; the particular 
 group is characterised by the development of the two outer into 
 calyx and corolla, of the innermost into a germen ; but it lies in the 
 character of the family that the two intermediate are sometimes all, 
 sometimes partly, developed into stamens, and that in the latter case 
 the remaining foliar organs assume peculiar forms, which however are 
 not stamens. Now, these six organs are all called stamens, and it is 
 added that the anthers (consequently the sole exclusive character of the 
 stamens) are wanting ; in this the character of the family is main- 
 tained for all: but does the similarity in different plants lie in our 
 imperfect mode of description, or is it not rather in the plant itself? 
 If the latter were not the case, all our systems would be but a childish 
 game with our words. Such a mode of describing a family is therefore 
 entirely superfluous, so soon as the character of the family has been 
 correctly unfolded. In this example the reference is to the analogous 
 position in different genera, and the position in one and the same circle, 
 from which it is presupposed that all its foliar organs must be de- 
 veloped in a similar manner. But the last is just as much as the first, 
 an empty prejudice ; here there is, indeed, some loop-hole to creep out 
 at, since the accessory stamens which are formed are by no means so 
 strictly characterised organs as to make the term stamina castrata at 
 once evidently inapplicable ; but in Canna exigua (see Plate III., figs. 
 ]2 20.) we have the most striking instance of the entire perversity of 
 this mode of conception, where, in the inner circle of leaves, one is 
 abortive, one becomes the stamen, and one the style. If this circle of 
 leaves were described either as a staminal circle or a carpellary circle, a 
 monstrous Phanerogamous plant would be produced, in which was typi- 
 cally suppressed an organ without possessing which it cannot be a Pha- 
 nerogamic plant at all. 
 
 I next turn to the analogy of the stamen with the sporophyll of the 
 higher Cryptogamia. An unprejudiced examination renders it manifest 
 that the latter is a true foliar organ, in which determinate cells become 
 parent-cells, which, after the formation of four spores, are dissolved, so that 
 the spores, in their peculiar form of simple cells, invested by a peculiar 
 secreted layer, lie free in certain cavities of the leaf previously filled by 
 the parent-cells, and, by the regular rending of the walls of these cavities 
 through desiccation, become scattered. We find this structure per- 
 fectly identical in the phanerogamous anther. I have, in earlier pages, 
 as well as in the paragraphs, remarked upon the analogies, which may be 
 carried out even into individual cases, between the sporophyll and the 
 stamens, more particularly in the Cycadacece and Coniferte. We are 
 unfortunately destitute of any account of the development of the stamens 
 of the Cycadacece; but, familiar with the development of other forms, we 
 may tolerably safely come to a conclusion in this case. In Cycas, on a woody 
 axis with abbreviated internodes, we find a number of foliar organs, 
 
350 MORPHOLOGY. 
 
 on the back of which arise a number of little cellular masses, and these 
 become (sessile) capsules in which the pollen grains are developed. 
 That the foliar organ is here developed into a woody scale is an 
 inessential matter of subordinate importance. A similar structure would 
 not be impossible in a Fern, but would merely give a generic distinc- 
 tion. Thus, in Cycas we have all the essential characters of the sporo- 
 phyll of the Fern ; and Cycas would be a Fern, if a strict boundary were 
 not drawn by the peculiarity of the development of the spore (or pollen 
 grain) into a plant. In the same way, and in a still higher degree, holds 
 the analogy between the stamen of Taxus and the sporophyll ofEquisetum. 
 Disregarding the remnants of the parent-cell, which in the latter adhere 
 to the spore, not even a generic distinction could be drawn between the 
 two structures, if the development of the pollen grain in the seed-bud in 
 Taxus did not again enter into the question. The capsule at the base 
 of the leaf of Lycopodium also corresponds naturally to the three anther- 
 cells of the base of the leaf in Cunninghamia sinensis, Rich. That the 
 latter are formed on the under, the former on the upper, surface of the 
 leaf, can make no essential distinction with the frequent exchange from 
 anthera antica to a. postica in the same family. If we then trace the 
 stamens from Cycas through Zamia, Araucaria, Agathis, Cunning- 
 hamia, and those of Taxus through Juniperus, Thuja, and Phyllocla-r 
 dus to Pinus, we find in both series a gradual transition to a simple 
 form, which then becomes the fundamental type for all the rest of the 
 Phanerogamia, and may at once, by comparison, but more safely still by 
 following out the development, be traced back in a definite manner to the 
 modified stem -leaf. This phanerogamic type consists merely of this: 
 that the two lateral halves of a leaf, at the sides of the mid-rib (the con- 
 nective), develope into chambers, in which two groups of parent-cells, 
 separated by a layer of cellular tissue, form pollen, so that every anther 
 is typically an anthera bilocularis, quadrilocellata. I shall have to speak 
 more at length regarding the apparent deviations from this structure in 
 the following paragraphs ; in this we have merely to do with the definition 
 of the idea and the external form. 
 
 The last point requiring notice relates to the differences of the external 
 form of the stamen. I have here, as in all other cases, confined myself 
 to the indication of the outline of the directions which these subordinate 
 variations of form may take. Here, again, the different denominations 
 of the forms are not signs of different ideas, but serve for empirical 
 description, and therefore are to be understood as pictorial expressions, 
 according to the meaning of the words ; they are therefore by no means 
 fixed things in the science, but undergo constant extension and correc- 
 tion, as the art of observation and empirically describing, in science in 
 general, becomes developed, or as an individual gifted with a special talent 
 for this advances it. No Botanist is tied down to such terms as cucullus, 
 calcar, appendix, &c., when once he hits upon an expression which 
 describes these forms more aptly, and in accordance with the impression 
 they make ; and no confusion in science can arise from this. It does, 
 indeed, bring confusion into science, and makes a scientific unity in 
 nature altogether impossible, when a Botanist applies the same terms to 
 fundamental and derivative forms ; for instance, to actually independent 
 foliar organs and to their appendages, since here the question is no 
 longer a more or less perfect success in conveying the impression, but a 
 confusion of the definitions deduced from the essential nature of the 
 object. 
 
PHANEROGAMIA : FLOWERS. 351 
 
 For my purpose it is merely important to indicate how the different 
 derivative modes of appearance are connected with the fundamental 
 organ, the leaf, and its forms, and originate therefrom, not merely 
 according to the idea, since that is of no use to the unity in nature, but 
 in real metamorphosis, through gradually increased development of this 
 or that region, or this or that portion of the cellular tissue. We must 
 especially look to the most multiform development of the connective, 
 from which arise forms that, when perfect, appear altogether incapable 
 of being referred to the fundamental form of the modified leaf, and yet, 
 when the development is traced, are easily deduced from it. Celsia 
 cretica may serve as an example, in which the stamen is perfectly 
 regular in the very young bud, and consists of a filament which passes 
 above into a narrow connective, bearing two longish anther-cells on its 
 two borders ; the connective gradually expands in its lower part, and 
 particularly on one side ; thus the base of one anther- cell becomes 
 gradually removed from the base of the other, and so far that, since the 
 summits of the chambers always remain in contact (they merge into one 
 here, of which hereafter), in the fully developed stamen the two anther- 
 cells lie in a straight line, and it appears as though only one cell existed 
 on one side of the connective. In a similar manner the strangest forms, 
 as in the Cucurbitacece and Philydracece, are readily referred to the fun- 
 damental form, when we trace back their gradual development. 
 
 It is most remarkable that, with all the other great similarity of the 
 conditions of form of the normal leaf, no true articulation in the con- 
 tinuity of the staminal leaf occurs. Herberts, usually named as an 
 example of this, I have neglected to examine. In the Composites there 
 exists merely a very gradually appearing difference in the cellular tissue 
 at determinate points, which, far from corresponding to an articulation, 
 depends, on the contrary, on a somewhat increased thickening of the 
 cell-walls. In Mahernia and Vinca there is no trace of an articulation. 
 Never, so far as I have yet been able to examine, does there exist an 
 articulation between anther and filament. The latter is, indeed, when 
 it passes into the anther, often very thin, readily bent, and readily torn 
 away ; but there is never a layer of cellular tissue formed differently, 
 breaking the continuity of the structure ; the anther and filament never 
 separate spontaneously here. 
 
 On the other hand, the stipulary structures are very perfectly developed, 
 and exhibit forms which are often enough mistaken. They appear most 
 remarkably in the Amarantacece. Nothing is more easy than to trace 
 out the origin of the pretended corona from the blending of the stipules 
 of the stamens in this family, and the perfect forms exhibit every pos- 
 sible transitional condition. The unscientific inconsequence of descrip- 
 tive terminology is here again most strikingly manifest. So long as 
 the stipules are only partly blended, the terms are : filamento trifido 
 lobo media antherifero ; if they are wholly coherent, the two blended 
 lobes are called stamina sterilia ; if they are diverted to the inner side, 
 so as to escape a superficial examination, as in Celosia, it is even written 
 staminodia nulla. 
 
 155. The condition of structure plays a very important part in 
 the nature of the stamens. The filament, when present, and its 
 appendages, have almost always the structure of petals, consisting 
 of very delicate cellular tissue, filled sometimes with coloured, but 
 more frequently with colourless sap, and having large intercellular 
 
352 MORPHOLOGY. 
 
 spaces, filled with air, which gives them a snow-white appearance. 
 The appendages of the filament and the connective exhibit like 
 characters. A simple vascular bundle usually runs through the 
 filament and the connective ; but not unfrequently the vessels are 
 wanting, as in the case of the Amarantacea. The vascular bundles 
 are never ramified, excepting in the case of the lobed or pinnate 
 stamens, and then a bundle enters each lobe. The epidermis is 
 here, as in the petals, an intermediate structure between epidermis 
 and epithelium; it presents sometimes, though seldom, stomates, 
 and frequently regular, elegant, and partially brightly coloured 
 hairs. 
 
 In the Apocynacece, a little group of hairs is exhibited beneath 
 the anther, upon the upper surface of the filament, in which a quan- 
 tity of viscid matter is secreted, so that by these adhesive tufts of 
 hair the stamens adhere firmly to the large stigmatic body, and 
 thus render spontaneous fertilisation impossible, since the surface 
 destined to receive the pollen is below the point where the stamens 
 and stigmatic body are connected. The anthers also sometimes 
 secrete a viscid substance, by means of which they adhere amongst 
 themselves, as in the Composites (here it is perhaps formed by the 
 solution of the secreted layer of epidermis), or they cleave to the 
 body of the stigma, as happens in some of the Apocynacea. 
 
 The development of the epidermis into surfaces secreting nectar 
 is also frequent here, especially on the appendages at the bottom of 
 concave forms, at the points of the stipules of the Lauracea, &c. 
 
 Far more important is the structure of the anther. Originally 
 this is formed of quite uniform, delicate-walled cellular tissue ; 
 soon, however, after the loculi become externally characterised as 
 incipient expansions, two layers may be distinguished in the 
 cellular tissue, namely, that which is destined to form the walls of 
 the thecae, and that which is appropriated to the formation of the 
 parent-cells of the pollen. Between these exists another thin layer 
 of cells, which at the time of the perfect formation of the pollen 
 becomes dissolved and absorbed, so as to ensure for the pollen the 
 free space requisite. In all three layers a constant development of 
 cells within cells goes on until the completion of the entire organ, 
 whereby the volume is increased, and the form of the anther, which 
 was developed in its regular manner as a leaf from the axis, is 
 perfected, but not changed. The outer layer of cellular tissue 
 originally clothed with a layer of epithelium, developes this into 
 a structure intermediate between epithelium and epidermis, not 
 unfrequently provided with stomates. The connective sometimes 
 exhibits hairs, the theca3 seldom. Sometimes the epidermal layer 
 is thickened at its outer edge by the presence of a layer of cells 
 elongated perpendicularly to the surface, so that it forms a pro- 
 jecting border (as in Gladiolus, Cassia, Passiflora, &c.) Perhaps, 
 with the sole (?) exception of plants flowering under water, one or 
 more layers of spiral fibrous cells exist in all anthers, but in 
 various modes of arrangement. Usually only one or two layers of 
 
PHANEROGAMIA : FLOWERS. 
 
 353 
 
 cells, which form the substance of the walls of the thecse, beneath 
 the epidermis, are developed in this way ; more rarely, merely the 
 epidermis ; or, again, the entire parenchyma of the anthers, with 
 the exception of the epidermis and the vascular bundles, is the 
 connective. 
 
 To illustrate what has been stated in the foregoing paragraphs, I will 
 here introduce figures of the stamen of Euphorbia (fig. 205. A), with 
 the cross section of the anther (fig. 205. #), and a cross section of the 
 anther of Neottia picta (fig. 206.). 
 
 205 
 
 2O6 
 
 207 
 
 The connection of the anthers in the Composites, is usually very in- 
 correctly termed blending. In its early state, each anther possesses its 
 own perfect epidermis ; and at a later pe- 
 riod the cells of the different anthers are 
 only found adhering to one another on 
 account of secreted matter (fig. 207.), and 
 not truly confluent with one another. 
 
 I have nothing further to add upon the 
 structure of the filament ; this part of the 
 stamen is indeed the least important : but 
 I have other observations to offer on the 
 structure of the anther ; and I beg further 
 to refer the reader, for elucidation, to 
 Plate IV., with its explanation. 
 
 In that form of the anther which occurs 
 
 205 Euphorbia Lathyris. A, Male flower : a, anther, consisting of two halves (thec<e\ 
 which retreat from each other in the lower part, and leave the connective free ; b, fila- 
 ment ; c, pedicel. B, Cross-section through the anther : on each side of the thick 
 connective are two loculi, separated by a septum. 
 
 06 Neottia picta. Cross-section through an unopened anther. A, Connective. J9, The 
 halves of the anther, or thecac : a, vascular bundle of the connective ; b, epidermis ; 
 c, walls of the four loculi (cT), formed of spiral fibrous cells : the loculi are arranged in 
 pairs, which are divided by the cellular tissue of the partition- wall (septum} ; e, the 
 place where the septum separates from the walls, and where this splits, thus throwing 
 the loculi open. 
 
 207 Actinomerts alternifnlia. Cross-section through a flower-bud (r, of natural size), 
 
 A A 
 
354 MORPHOLOGY. 
 
 most frequently, two simple perpendicular rows of cells are very early 
 distinguishable in each theca, from which the pollen is developed. The 
 remaining cellular tissue of the anther may be divided into three groups : 
 1. That forming the connective and the septa between the fore and 
 hinder loculi ; 2. That forming the outer walls of the cellular tissue 
 forming the thecae ; and 3., That lining the thecse, subsequently ab- 
 sorbed, and mostly elongated in a radial direction. Of these different 
 cellular tissues, only the two last portions (2. and 3.) progress in deve- 
 lopment by independent cell formation, after the staminal leaf is put 
 forth from the axis. The cellular tissue of the connective once existing 
 in its rudiments does not multiply its cells, but only expands those which 
 are already present, and changes them in manifold ways. The distri- 
 bution of the cells originally formed in the anther among these three 
 groups exhibits great varieties. Sometimes the largest portion of the 
 original or fundamental cells (as occurs in Berberis vulgaris], and some- 
 times the smallest portion of them (as in Trop&olvm minus\ are employed 
 in the formation of the connective. In consequence of such arrange- 
 ment, the thecse exhibit varieties of form, either appearing as four 
 cylindrical cavities (as in Tropceolum minus and Sparganium simplex}, 
 or as four scarcely concave, very shallow cavities (as in Berberis} ; or, 
 as is very frequent, as cavities somewhat deeper, but strongly inclined 
 together at the sides. In the last case, the septum often enters, as a 
 ridge, very deeply into the cavity ; as is seen in Canna and many other 
 of the Scitaminece ; for instance, Cosfus and Calathea, in almost all the 
 Solanacece, &c. ; and, in less striking degree, in Ctrbcra Thevetia ; and, 
 inconsiderably, in Gentiana lutea. 
 
 The common supposition, that these projecting ridges are the ru- 
 diments of new septa, involves the false presupposition that the septa 
 in general grow from the connective out into the loculi ; but. in fact, 
 they exist earlier than the loculi, and are merely the remnants of the 
 parenchyma which has not been converted into pollen. The common 
 statement, that the thecae have grown to the connective, arises from an 
 equally false perception of the natural condition. In the transitory 
 cellular tissue of the third group, the newly arising cells are both radially 
 and tangentially arranged ; in the cellular tissue of the walls, on the 
 contrary, of the second group, they are only tangental ; by which means 
 the walls expand towards the surface, and the thecae enlarge, and con- 
 tinually acquire greater capacity, as the gradual development of the 
 pollen demands. Hence it happens, also, that the little furrow which in 
 the rudiment of the anther is actually the edge of the leaf, at a later 
 period forms the bottom of a deeper furrow, since, as the edge of the 
 septum, it cannot follow that expansion. 
 
 Towards the time of the completion of the development of the anther, 
 a part of the cellular tissue of those plants flowering above water is con- 
 verted into spiral-fibrous or porous cells (see fig. 206. d) ; which cells, or 
 how many, are thus converted, is matter of the greatest variety. Some- 
 times the change only occurs in the epidermis alone remaining of the 
 outer walls, as in Lupinus ; more commonly, however, this remains 
 unchanged, and one (e. g. Composited) or more (many Liliacecc) layers of 
 the outer walls beneath the epidermis become spiral-fibrous cells, usually 
 
 The five lobes of the apex of the corolla are applied together by their edges, surround- 
 ing five stamens which alternate with them, the transversely-cut anthers of which are 
 only in contact by the posterior loculus of each side, which adhere together. Within 
 are exhibited the two arms of the style in cross-section. 
 
PIANEROGAMIA : FLOWERS. 355 
 
 extending to the entire expansion of the outer wall of the anther, some- 
 times scarcely to half of it, on each side of the longitudinal furrow. 
 Sometimes this spiral-fibrous layer extends under the epidermis, over 
 the anterior surface of the connective (as in Pachysandra procumbens), 
 or over the posterior surface (as in Hyoscyamus orientalis\ or over 
 both (as in Gentiana lutea and Erythrcea). Sometimes such a layer 
 lines each loculus on all sides (as in Strelitzia farinosa and Hippuris 
 vulgaris), either leaving the septum free or actually forming it ; some- 
 times a layer extends round each pair of loculi lying on one side, with 
 an unaltered septum (as in Calathea flavescens), or making a curve in 
 it, without entirely metamorphosing it (as in Costus speciosus]. Finally, 
 in very rare cases, all the cellular tissue, even up to the vascular bundle of 
 the connective, is converted into spiral-fibrous tissue. This multiformity, 
 left unnoticed by Purkinje*, shows the manifest inapplicability of the 
 terms proposed by him exothecium for the epidermis, endothecium for the 
 spiral-fibrous layer. The walls of the small loculi of Cycas revoluta are 
 formed entirely of a thick porous cellular tissue. In the Composite the 
 connective is formed of elegant porous cells, as are the generality of the 
 crest-dike appendages of the anthers (e. g. in the Centaurece). 
 
 The formation of the pollen takes place in the following manner : 
 in the interior of each rudimentary loculus a process of develop- 
 ment commences within a soft row of cells, through which, in the 
 common form of the anther, a cylindrical string of cells, more or 
 less in number, the parent-cells, are gradually formed. In each 
 parent-cell the granular mucilaginous contents divide, simultane- 
 ously with the appearance of a cytoblast, into four portions, which 
 quickly become clothed by four cellular membranes ; or it may be 
 that originally two such cells are formed, and within these again 
 other two in each. These cells enclosed within the parent-cells 
 are special parent-cells. Then, by means of the secretion of a 
 gelatinous layer over the internal surface, these parent-cells and 
 special parent-cells become very much thickened, and a simple cell 
 (the pollen-cell) is produced simultaneously in each special parent- 
 cell. This, in all plants except those flowering under water, se- 
 cretes upon its outer surface one or more layers, forming the exter- 
 nal pollen membrane, which assume, in some fcases, peculiar and 
 remarkable forms. During this last perfecting of the pollen, the 
 parent-cells and the special parent-cells are dissolved and absorbed. 
 In many Monocotyledons, especially Liliacece, the product of the so- 
 lution of the parent-cells is a clear or dark yellow 7 fluid, of gluti- 
 nous or oleaginous (?) nature, which adheres to the external pollen 
 membrane. In the Onagracece, in the parent-cells or special parent- 
 cells (as in the Equisetacea), a spiral thickening layer is formed, 
 which is not dissolved with them, but adheres in long threads to 
 the perfect pollen granules. A part of the product of the solu- 
 tion of these cells is frequently viscid, and glues the four pollen 
 granules belonging to one parent- cell firmly together (pollen quater- 
 narium) ; sometimes it unites only two (in Podostemon), and some- 
 times a greater number of granules, (in some Acacias, for instance, 
 
 * De Cellulis Antherarum Fibrosis. Breslau. 
 A A 2 
 
356 MORPHOLOGY. 
 
 A. lophantha). In the Orchidacea, the entire product of the solution 
 of the parent-cells and special parent-cells is viscid, and glues all 
 the pollen granules in a mass, and is easily recognised between 
 them, as a tough substance, capable of being drawn out in threads. In 
 the Asclepiadacea it appears that only the parent-cells are absorbed, 
 and that at a very early period ; the special parent-cells are not ab- 
 sorbed at all, but adhere closely to one another, and so form, out of 
 the whole mass of pollen a loculus, or small cellular body, which 
 appears clothed with a special membrane, since in the outermost 
 layer of the special parent-cells no pollen granules are developed. 
 Probably there exists in all the cells, from the parent-cells to the 
 pollen granules, a circulation of sap (in the latter most certainly, 
 in the young condition), the currents of which form reticulations on 
 the cell-wall. 
 
 I have, in the preceding account, given the history of the develop- 
 ment of the pollen, essentially in accordance with the excellent investi- 
 gations of Nageli*, as I have nothing more complete of my own to 
 oppose to it. Let Plate IV. and the explanation be compared with the 
 preceding. I by no means suppose that what has been said will be found 
 the complete settlement of the entire matter, and I cannot withold some 
 thoughts which strike me with regard to the formation of the cells. 
 There are two difficulties which certainly nowhere oppose so great a bar- 
 rier to the completion of investigation as here ; namely, the attainment of 
 perfect stages of development, and the correct arrangement of them in 
 their proper series. I will offer the following objections to Nageli. I 
 will first mention that I have convinced myself, both in the parent-cells 
 and the special parent-cells (in the cases of Pepo, Passiflora princeps, 
 and Arum maculatum), and also in the young pollen-ceH'(in the cases of 
 Lupinus, Larix, Pinus alba, Juniperus, Richardia cethiopica, Arum ma- 
 culatum, and Fritillaria imperialist that the cytoblast is clearly to be 
 recognised as parietal (sometimes even in the pollen-cell which has 
 sent a tube into the nuclear papilla of the seed-bud). In Fritillaria, two 
 kinds of cytoblasts are easily to be distinguished, those which give the 
 origin to the pollen-cells, and lie embedded in the walls, and those 
 which form later in the pollen-cells and here, as is not rare in the 
 pollen-grain generally, give origin to a transitory process of cell-forma- 
 tion.f A second point, wich appears to me important, is that I have 
 frequently observed, between the period of the existence of the empty 
 parent-cells and their regular division into two or four special parent- 
 cells, free cytoblasts floating among the granular contents of the parent- 
 cells (Passiflora princeps), and I have seen also this accompanied by very 
 delicate young cells with cytoblasts on the walls (in Passiflora princeps, 
 Pepo, and Rhipsalis salicornioides). In the last-named plant I ob- 
 served all the transitional stages between free cytoblasts and the perfect 
 formation of the special parent-cells (or the pollen-cells ?) ; in other 
 plants I have not yet succeeded in such complete observation. Finally, 
 I must observe that the entire assumption of special parent-cells appears 
 to me questionable. It is no matter of doubt that in the stage near ma- 
 turation, each pollen-cell appears surrounded by a tolerably thick gela- 
 
 * Contributions to the History of Development of the Pollen of the Phanerogamia 
 (Zur Entwick. des Pollens, &c.). Zurich, 1842. 
 
 f Nageli, loc. cit. pp. 20, 21. j Meyen, Physiologic, vol. iii. p. 186. 
 
PHANEKOGAMIA : FLOWERS. 357 
 
 tinous membrane ; and that each four lie thus in a thicker gelatinous 
 parent-cell, which is manifestly such from its origin. But the so-called 
 special parent-cells are not easily distinguished either from the parent- 
 cell, or from one another, or from the enclosed pollen granules at this 
 period. Their origin may, indeed, be other than that assigned by Na- 
 geli. The following appears to be equally probable. In the parent-cell 
 are formed, according to the laws of development, four pollen-cells ; 
 whilst these expand, the granular contents of the parent cell are gradu- 
 ally dissolved into gelatine, in which the pollen-cells then lie imbedded. 
 By this pressure of the expanding pollen-cells, a portion of the gelatinous 
 substance is thickened or condensed into a membrane around and enclos- 
 ing each, and thus forms the so-named special parent-cells. 
 
 Where, on the contrary, the parent-cells first divide into two cells, 
 two special parent-cells are really formed, but in the same manner as I 
 have just described of the pollen-cells ; and in each of these special parent- 
 cells two pollen-cells are formed in the same way. It would be in har- 
 mony with this that a distinct pollen binarium occurs, as in the Podo- 
 stemacece, which indicates the closer relation of the pollen-cells. Only 
 continued and careful investigation can decide whether Nageli's excellent 
 observations, as he has related them, are to be regarded as complete, or, 
 according to the hypothesis I have given, to be brought into agreement 
 with other processes of cell-formation. 
 
 On the other matters mentioned in the paragraphs, I have only to add 
 that I have found Nageli's observations respecting the order in which the 
 parent-cells and the special parent-cells are dissolved, and upon the ex- 
 ternal pollen membrane, a secreted product of the pollen-cells, perfectly 
 correct. 
 
 The perfect pollen granule consists, as has been said, of the essential 
 pollen-cell, which in plants flowering above the water is clothed with 
 a peculiar secreted layer. This always forms an uniform membrane 
 lying immediately upon the pollen-cell, not unfrequently in a double 
 layer, on which usually appear all kinds of strange projections (the 
 first product of the secretion). Most frequently these little ridge-like 
 projections are connected together in a reticulated form, and often 
 give the external membrane the deceptive appearance of being com- 
 posed of cells, which the history of development proves not to be the 
 fact. The spaces between the meshes of this net are frequently partly 
 filled with transparent jelly (in Iris and Passiflord). Sometimes 
 these articularly- connected ridges present very regular, definite 
 areas, giving, in the excessively varied form and arrangement of the 
 pollen grains, the most elegant and beautiful appearance : this is 
 especially the case in the Passiflorce. Sometimes, again, the pro- 
 jections appear as minute points, cones, papillae, curves, or like little 
 towers, either scattered upon the surface or very regularly arranged 
 there (e. g., most elegantly in many of the Composites, Scorzonera, 
 Tragopogon, &c.). The substance of this secreted layer is usually 
 yellowish, more rarely tinted with green, blue, or red, and by con- 
 centrated sulphuric acid it is only very slowly destroyed (requiring 
 one or two days), and during this the acid often gives it a 
 Burgundy-red colour. 
 
 In all pollen granules the external pollen membrane exhibit? 
 
 A A 3 
 
358 MORPHOLOGY. 
 
 certain places, either like slits or in well-marked circles, where it is 
 either entirely wanting, or becomes so exceedingly thin as to escape 
 the eye. The number and arrangement of these places is very 
 different ; thus the generality of Monocotyledonous pollen granules 
 have only a longitudinal slit (as in Lilium) ; some Dicotyledons 
 have very many (as Poly gala) \ the generality of Dicotyledonous 
 pollen granules have three circles uniformly distributed at their 
 equators (as in Centaur ecs), or four placed towards the angles of the 
 tetrahedron, or they have a large number (as Polemonium cmruleum 
 and Ipom&a purpurea). These openings are not always free, but 
 sometimes covered by a lid-like portion of the secreted layer, which 
 is entirely separated from the rest of the membrane (as in Pepo). 
 
 The contents of the pollen-cells are originally almost purely 
 granular, with a small quantity of fluid; by degrees, however, the 
 granules are dissolved, and the thin contents become watery and 
 almost transparent, whilst the granules, still remaining undissolved, 
 appear as globules of mucilage. Towards the time of the matura- 
 tion of the pollen granules, these increase in size, and other small 
 granules appear amongst them of some undetermined substance, 
 coloured yellow by iodine (Inuline ?), and minute globules of oil ; 
 very frequently, also, starch granules, in greater or smaller num- 
 ber, sometimes of peculiar form (e. g., in the Onagrace&\ and always 
 differing much in size in the same pollen granule. By their presence 
 the fluid becomes more concentrated, losing water and acquiring an 
 extraordinary endosmotic power, even towards acids, on the appli- 
 cation of which it expands, the pollen-cell bursts, and its contents, 
 being protruded, coagulate into the form of an intestine. The 
 pollen granule, which towards the close of its development is very 
 much expanded, contracts again a little when quite mature, on 
 account of the loss of the water, and forms considerable folds in 
 the direction of the slits or pores, which are again effaced by the 
 absorption of water. The movement of the contents in reticularly- 
 connected currents has ceased in all the mature pollen granules 
 (with the single exception, as yet known, of the long cylindrical 
 pollen granule of Zostera marina) ; but instead of this, the various 
 granular contents of the pollen-cell exhibit active molecular motion : 
 this is often seen while the contents are still within the pollen-cell, 
 and always after they are expelled, even in the pollen of old speci- 
 mens in herbaria, and after the operation of tincture of iodine. 
 
 We have received from Fritsche, in his work on the Pollen, published 
 in St. Petersburg!! in 1837, a collection of most careful and accurate in- 
 vestigations respecting the condition of the external pollen membrane in 
 its perfect state, to which I must here refer. In some plants he distin- 
 
 fuished three several layers in the outer membrane of the pollen granule, 
 do not think myself obliged to accept his terminology, since it is not 
 in accordance with the most recent investigations. Here the pollen-cell 
 arid the secreted layer are opposed to each other ; this last may be single, 
 or it may be divided into three layers, but it is always opposed to the 
 pollen-cell merely as a single whole. The individual layers, however, 
 
PHANEROGAMIA: FLOWERS. 359 
 
 when they are present, are best defined as first, second, and third layers. 
 That the external pollen membrane never consists of cells, will be self- 
 evident after the manner of its origin is known ; but Meyen had already 
 corrected this error, which arises from the very deceptive appearances. 
 
 The doctrine of vegetable spermatozoa is now, I hope, gradually dying 
 away. A man must be blinded indeed by old prejudices if he will con- 
 tinue, after the very complete investigations of Mohl, to hold the remote 
 analogies between the antheridia and the anther. I have already shown 
 that in Phanerogamia the representatives of these are to be sought in a 
 very different place. The granules (generally starch) taken for sper- 
 matozoa have, indeed, lost their life in Fritsche's tincture of iodine, since 
 their evidently purely physical molecular movement remained unde- 
 stroyed. 
 
 It appears to me altogether superfluous to enter further upon this 
 point; Meyen * gives the whole literature, which has now merely a his- 
 torical value. Fritsche f has completely settled the matter, and every 
 unprejudiced observer may convince himself with ease of the completely 
 untenable nature of the wonders formerly spun out, especially by Meyen. 
 The confirmatory observations of Nageli on this point are also of great 
 value. | 
 
 At a determined time the thecae of all anthers open in one fashion 
 or other, in order to permit the dispersion of the pollen, just like 
 the sporocarps of Cryptogamia. The manner in which this takes 
 place varies very much. The thecae of the anthers of the Cycadacece, 
 which are small in size, two or four in number, and united into a 
 little oval, capsular form, are rent open by a longitudinal slit ; the 
 thecae of Juniperus, Taxus, and their allies, open exactly like the 
 sporocarps of Equisetum. I am unacquainted with the manner in 
 which the anthers of most of the exotic Coniferce burst. In our 
 native Abies (Pinus and Larix ?), and in all the Asclepiadacece, only 
 one loculus is formed at each side of the connective, both open, 
 whilst the wall is torn away in the middle line from the connective, 
 therefore with two longitudinal slits, one for each loculus. The 
 outer wall of the loculus, which thus becomes disengaged, and 
 which is dry and elastic, is termed the valve (valvulct) ; and because 
 only two valvular are to be distinguished, only one long cleft is 
 spoken of, anthera rima loncfitudinali unica dehiscens. 
 
 In many Caladiece, in Ceratopkyllum, and other plants, at the time 
 of the ripening of the pollen, a canal is formed (by destruction of 
 the cellular tissue ?) to the summit of the anther, through which 
 
 * Physiologic, vol. iii. pp. 178 196. 
 
 f Loc. cit. supra. 
 
 | Gottsche (on Haplomitrium Hookeri, Act. A. L. C. N. C. xx. i. p. 804.) has 
 a strange polemic against me, referring what I say regarding the contents of the pollen 
 of Phanerogamia to the contents of the antheridia of the Cryptoyamia, because he cannot 
 overcome the prejudice that the anthers of the Phanerofjamia and the antheridia of the 
 Cryptogamia are the same organs. He is guided here solely hy the word anther ; and 
 this very mistaken argument may show to him, as an example, how wrong he is in 
 saying, at p. 297., that by the term antheridium he knows neither more nor less than 
 by the term anther. Of course, one understands more by it : the different word tells 
 us that we have to do with a different thing, and must not mingle matters which are 
 not the same. The whole argument is the more strange, since I myself had published, 
 at least long before Gottsche, some contributions to the knowledge pf the spiral fila- 
 ments in the antheridia of the Mosses and Liverworts, and their motion. 
 
 A A 4 
 
360 MORPHOLOGY. 
 
 the pollen is emitted (anther a poro dehiscens). In almost all the 
 rest of the Monocotyledons and Dicotyledons, the basis of the 
 structure is the origination of two loculi on either side of the 
 connective ; this then forms the septum between the two halves of 
 the anther, a layer of cellular tissue running from this towards the 
 two sides divides each half into a fore and hinder loculus. Rarely 
 (as in Viscum) cross partitions form additional horizontal septa. 
 In the Piperacece, Malvaceae, Solanacece, Cucurbitacece, and perhaps 
 some other families, the two fore and hinder loculi become blended 
 into one at the summit of the anther ; if, then, through great ex- 
 pansion of the connective, the bases of the two halves of the anther 
 are gradually brought into straight, or almost straight lines (as in 
 Peperomia), we have an anther really, though scarcely apparently, 
 formed of two thecae, from which the case (frequent in the Scitami- 
 nece) where only two loculi are formed on one side of the connective 
 (the anthera dimidiata), must be carefully distinguished. The part 
 of the wall which extends between the connective and the septum 
 is also always termed the valve. Most of the varieties which are 
 commonly distinguished in the anthers depend, in the first place, 
 upon the spreading out of the thecae through the expansion of the 
 connective, and the time and manner of the disengagement of 
 the valves. They commonly remain attached to the connective, 
 and whilst yet connected together tear themselves away from the 
 septum, which is thus, either in part or entirely, destroyed (the 
 anthera bilocularis of descriptive botany). Sometimes the disrup- 
 tion happens later, and they separate almost simultaneously from 
 each other, as in Tetratheca (anthera quadrilocularis). The sepa- 
 ration of the valves from each other usually begins above. If it be 
 confined to a small portion of their length, as in many Grasses and 
 in the Ericaceae, the anther is termed anthera poro (spurio) dehiscens ; 
 if the separation extends to the whole length, the anther is said to 
 be utrinque rima longitudinali dehiscens. Very rarly the valves sepa- 
 rate, connected together all round, or upon the anterior side of the 
 connective (the anthera unilocularis of descriptive botany): this 
 characterises the family of the Epacridacece. A very aberrant struc- 
 ture occurs in two families very far removed from each other, 
 namely, the Berber 'acece and the Laur acece. In these two the valves 
 become free in the entire circumference, with the exception of one 
 small point at the summit of the loculus, and curl back from below 
 upwards (anthera valvulis dehiscens). In the Lauracece the additional 
 peculiarity occurs, that of the four original rudimentary loculi, the 
 two hinder ones either shrivel away, or the loculi become so dis- 
 placed by the unequal expansion of the connective, that at last, 
 instead of lying one in front of the other, one is placed on the top 
 of the other. 
 
 It is a proof of the dreamy spirit which prevails in our science, that, 
 even with respect to superficial knowledge of the structure of this most 
 important of the organs, the anther, the truth has not yet been arrived 
 at. It is, in fact, no better than if zoologists should be yet engaged in 
 
PHANEROGAMIA : FLOWERS. 
 
 361 
 
 contending, whether the human heart contains four chambers or only 
 one, and how little skill is required to make a transverse section of an 
 anther in a rather young bud ! In the Composites (fig. 206.), there are 
 four-celled anthers in which the valves of the hinder loculi are glued 
 together, and commonly burst open at each side by a longitudinal slit. 
 
 Almost every patch of turf affords material for the investigation of 
 this condition in Bellis perennis : in the Zinnias, Sun-flowers, &c., 
 merely a tolerable lens is required to make the matter out readily, and yet 
 in so simple a thing as this Link says * : " Originally the anthers are 
 closed, and exhibit a five- (instead of twenty-) chambered tube, then 
 the inner borders (which are these?) separate, and the tube becomes 
 one-chambered." I think it would be impossible to find a notion more 
 contradictory of nature, and to represent it more confusedly. 
 
 The anthers of most plants, as has been said, have originally four 
 loculi, not, as is usually said, on account of the incurvation of the 
 borders of the valves, but because they secrete four cords of cellular 
 tissue for the formation of the pollen. From this rule the (Enotherece, 
 in particular, do not deviate, though Link ascribes to them anthers with 
 only two loculi from the very first. So also the anthers of Malvacece 
 are not one-celled on each side, but two-celled. Still less are the anthers 
 of the Balsaminece altogether and in every case one-celled, as Link 
 says f, but perfectly four-celled. Of Canna, he says, the anthers ap- 
 pear to be contracted from a two-celled anther, as the suture is com- 
 pound. The fact is, that in Canna, Maranta, Calathea, Phrynium, 
 &c., the anther is perfected only on one side of the connective, but here 
 regularly two-celled, with a perfectly simple and usual suture, and a 
 septum which, according to specific variations, projects more or less, as 
 a ridge into the theca ; in the Scitaminece, in the strictest sense (R. 
 Brown), on the contrary, two loculi are perfected on each side of the 
 connective, and in these also the septum projects inwards into the thecse, 
 sometimes more (Hedychium coccineum), sometimes less (Curcuma aro- 
 ma tied}. The remarkable structure of the valves in the Lauracece (and 
 in the Berberacece it is similar) may readily be understood from fig. 208. 
 
 208 
 
 Elem. Phil. Bot. ed. 2. p. 179. 
 
 f Loc. cit. 
 
 08 Laurus carolinensis. A, Stamen of the outer circle : a, filament ; b, anterior and 
 lower c, upper and posterior pollen-chambers (loculi) ; d, the glands analogous to 
 stipules. B, Stamen of the inner circle ; o, filament ; , l w er posterior ; , upper 
 anterior loculi of the loculi. C, Cross-section of the anther (B) in the level of . 
 A Cross-section of the same in the level of 2". 
 
362 
 
 MORPHOLOGY. 
 
 I will now call attention to some peculiarities of the family of the 
 Orchidacete, which have hitherto remained wholly unexplained. The least 
 remarkable of these is, that the pollen is often formed in more than four 
 (eight to sixteen) different portions, and therefore more than the usual 
 fourloculi exist ; as in Calanthe, Bletia, &c. : the most usual arrangement 
 is, however, that in which the anther is regularly four-celled ; particularly 
 in all the Ophrydece (fig. 209.), in which the pollen mass of each cell, 
 from causes unknown to me, becomes divided into many small ridge- 
 shaped pieces (fig. 210.), which are arranged around one large central 
 
 209 
 
 mass of that viscid substance already mentioned above. It not unfre- 
 quently happens that the cellular tissue appointed for the formation of 
 the pollen forms a secretion continued as a narrow process into the at- 
 tenuated base of the anther, sometimes also curving round forward from 
 the broad base, and then ascending into the substance of the valve, as 
 in Epidendrum cochleatum ; sometimes the connective of the anther is 
 continued forward over the stigma, as a pointed process, the rostellum ; 
 that cellular tissue sometimes extends up into this. All this cellular 
 tissue, however, subsequently commonly becomes changed into viscine, 
 and then it forms the tail-like appendage known as the caudicula (figs. 
 210. A. b. 211. f.) on the pollen mass. At the lower edge of the anther, 
 commonly glandularly thickened at this point (fig. 209. c.\ or of the ros- 
 tellum (fig. 211. <?.), are exhibited frequently at an early period, beneath 
 
 SOD o rc Jii s militaris. The organs of generation of a bud about two-thirds long, after 
 the removal of the perianth. The germen is cut away, as also the lip, so that we can 
 see the edge and the entrance to the cavity of the spur of the lip, the inferior part of 
 which is also removed, a, Connective of the anther ; b 6, the two halves of the anther ; 
 c, the receptacle, still covered by the membrane (the bursicvla) ; d, the inferior part of 
 the anther-cell, wherein the caudiculus is situated ; e e, the two accessory stamens ; f, the 
 stigmatic surface. The arrow in the direction from x to y shows the direction of the 
 section which fig. 211. represents. 
 
 2!0 Orchis Morio. A, Pollen mass from one half of the anther : a , the two lobes of 
 the mass, corresponding to the two loculi of one side ; b, the caudiculis ; c, the reti- 
 nacula. The lobes (a a) are divided into many wedge-shaped portions : one of them is 
 much magnified in B, and in itself again consists of groups of pollen granules, united 
 in fours. 
 
 811 Orchis niilitafis. Longitudinal section through the central part of the organs of 
 
PHANEEOGAMIA : FLOWERS, 363 
 
 the epidermis (here termed the peach, bursicula) (figs. 209. c. 211. /*.), 
 one or two small groups of cells which become filled with viscine, and 
 are in part dissolved into it (figs. 211.*. 210. c.). The membrane covering 
 them is gradually decomposed, and they then lie free, and are termed 
 the retinacula (fig. 210. b. c.) ; if the epidermal membrane becomes de- 
 composed very early, they are termed retinacula nuda. In the last case, 
 the cellular tissue which separates the point of the caudicula from the 
 retinaculum is also decomposed at the same time, and thus caudicula 
 and retinaculum come into union (this also, therefore, happens before 
 the anther opens). In the first case, on the contrary, the two are fre- 
 quently separated, but so placed, that as the anther opens, the very 
 slightest movement of the pollen mass brings the point of the caudicula 
 into contact with the then always bare retinaculum, so that they adhere 
 together. It is perfectly easy to follow this process in the last- mentioned 
 case, in Orchis militaris, and especially easy in the very long rostellum 
 of the Neottiece. Gymnadenia albida and conopsea offer good ex- 
 am pies of the other case. The Orchidece diandra and the Aposta- 
 sies exhibit none of these remarkable peculiarities, having their anthers 
 regular, and pollen granules which do not adhere together. 
 
 I have never yet succeeded in penetrating the very first stages of the 
 formation of the flower ; the little I have seen in Orchis latifolia and 
 Cypripedium Calceolus gives me ground to presume that only three 
 stamens are ever formed in rudiment, of which, in Cypripedium, one is 
 developed in a foliaceous form, whilst in the rest of the Orckidacece, two 
 are abortive, or appear as two little fleshy scales, which, in consequence 
 of the one-sided, excessive development of the upper floral envelopes 
 (the labellum), are pushed to the side of the single developed stamen. 
 
 The most incomprehensible structure of the anther, if I have seen it 
 in the true light, occurs in Caulinia. Here, both in male and female, a 
 bracteole is developed into a pitcher-shaped organ, which in the female 
 is two-lobed above, resembling a germen with two stigmata ; in the male 
 splits up in the upper part on one side, imitating a perianth. 
 
 On the little conical body which is embraced by each bracteole, an 
 envelope is formed, in both sexes, in the manner hereafter to be de- 
 scribed in the seed-bud ; and at this time it is impossible to determine 
 whether mas or "femina is being formed ; but then they begin to deviate, 
 and in the femina the seed-bud produces a second integument, and becomes 
 inverted, whilst in the mas the cone grows up into a large nucleus ; and 
 while this becomes invested by the envelope until only gradually a little 
 canal remains at the summit, it is entirely (?) converted into pollen, which 
 then finds an outlet by that opening at the apex. Finally, Brosimum Ali- 
 castrurn also appears to possess a most aberrant formation of anther. 
 The beautiful representations of this in our Botanical works look strik- 
 ingly like elegant, newly-turned chessmen ; and without knowing the 
 structure in nature, one may assert that the pictures have little resem- 
 blance thereto. 
 
 generation, in the direction of the arrow (#, y) in fig. 209. a, b, Lower part of the left 
 half of the anther ; c, epidermis ; d, parenchyma of the walls ; e, pollen mass ; f, cau- 
 dicula ; g, point of the rostellum, here very short, h, epidermis (bursicula) ; i, reti- 
 naculum; k, part of the bursicula, which is subsequently dissolved, so that the retiniculum, 
 now free, comes in contact with the candicula, also set free by tho bursting of the 
 anther; /, loose, easily separable cellular tissue; i, outer surface of the conducting 
 cellular tissue (the stigma) ; w, parenchyma of the disc, forming a style. 
 
364 MOKPHOLOGY. 
 
 c. The accessory foliar Organs of the Flower. 
 
 156. Besides those parts of the flower of which we have 
 already spoken, other foliar organs are frequently met with, 
 which, considering their simple structure (scales of varying degrees 
 of thickness) or very aberrant shape, may be regarded as parts of 
 the flower but partially developed. According to their position, 
 I distinguish two forms : 1st, from the outermost floral envelopes 
 to the outermost circle, exclusively, in which stamens are deve- 
 loped, the accessory corolla or paracorolla, and its accessory petals 
 or parapetala; and, 2dly, from that circle, inclusively, to the gernien, 
 the accessory stamens, or parastemones. 
 
 The accessory corolla consists sometimes of scales, which are 
 either thin and leaflike or thick and fleshy, with their margins 
 sometimes entire, sometimes divided, as in the Grasses, the inner 
 tri-merous circle of foliar organs, of which one member is com- 
 monly abortive : in Vallisneria the three little scales. More fre- 
 quently the accessory corolla exhibits very peculiar aberrant forms, 
 which may present the forms of the floral envelopes in miniature, 
 and often distorted, as in the long, thin foliaceous organs in the 
 flower of Aconitum, which imitate a long-clawed, spurred peri- 
 anthial leaf, the horn-shaped accessory petals of Helleborus, Trol- 
 lius, Nigella, &c., the extraordinary little, mostly boat-shaped 
 leaflets of the Loasacecs. I am unacquainted with any instance in 
 which the members of the accessory corolla are coherent. The 
 structure is either very simple, as in the generality of scales, which 
 consist merely of delicate cellular tissue ; or it resembles that of the 
 floral envelopes and its appendages. The secretion of nectar at 
 given places is very frequent here, especially in concave forms. 
 
 Accessory stamens occur in two ways either as perfectly free 
 foliar organs, or wholly coherent. a. In the first case they 
 are more or less similar in form to the stamens, and often, espe- 
 cially if (as in Chelone and Scrophularia) they belong to a circle, 
 of which some members are developed to stamens, they are formed 
 exactly like a filament without its anther, as in many Geraniacece : 
 sometimes they are also scale-like here, as in Veronica, where they 
 represent two parts of the four-membered staminal circle.* When 
 they form a proper circle by themselves, they are usually developed 
 as small scales, as in Pimelea, Gnidia, &c. 
 
 b. In the second case, they mostly constitute the so-called in- 
 ferior ring (annulus hypoyynus\ and are then usually thick, fleshy, 
 and juicy, as in Daphne, Celosia^[, and Trapa. Sometimes this 
 ring is lobed, so as to exhibit the number of its members clearly, 
 as in the generality of the Ericaceae : in Chrysosplenium it is eight- 
 lobed ; in Cobcea scandens and Convolvulus five-lobed ; or indis- 
 
 * This condition also appears to exist in Lathraa and Orobanche. 
 f In which this ring has hitherto been wholly overlooked. 
 
PHANEROGAMIA : FLOWERS. 
 
 365 
 
 tinctly (as in the whole family of Scrophulariacea). In its fully- 
 formed condition, however, it is more frequently quite uniform, as 
 in Ruellia formosa, Calystegia, and many Polemoniacece. It some- 
 times, also, shares the symmetry of the flower, as in Gesneria and 
 Pedicular is. 
 
 In the matters treated of in the preceding paragraphs, an indescribable 
 confusion prevails, which results from a total neglect of the development. 
 To settle this question at once, is beyond the power of an individual ; 
 and it is a subject for research in the highest degree serviceable, and yet 
 by no means of great difficulty, by as comprehensive as possible mono- 
 graphic examination of these structures, and an exhibition of their 
 nature founded on the development, to establish at least a temporary 
 basis, from which then further advance may be made. In the foregoing 
 sections I have only been able to give indications. These structures, as 
 well as the entire series of independent appendages of the floral enve- 
 lopes and stamens, and a portion of the peculiar forms of the axial organ 
 of the flower, are almost all described under the same names, sometimes 
 as paracorolla, with its subdivisions, corona, fornix, cuculli, cylindrus, 
 &c., sometimes as discus or nectaria, sometimes as staminodia, &c. ; and 
 the question never being mooted, whether parts offering similar appear- 
 ances may not have very various origin, and what ? I have endeavoured 
 to establish the definition of the accessory corolla in contradistinction to 
 the floral envelopes, and thus to render possible a simple and consequent 
 terminology. 
 
 For the elucidation of the matter, I give some examples. 
 
 In the Ranunculacece (Helleborece), I term the external leaves of the 
 floral envelopes the perianth (fig. 212, A. a. b. c. d. e.), and the inner 
 ones, which are always diverse in form, and often dwindled in develop- 
 ment, the accessory corolla (fig. 212, B.). So I term the palea3 of the 
 Grasses the perianth (fig. 213, A. c. d. B.}, and the scales (squamulce, 
 Rob. Br.) I term the accessory corolla (fig. 213, C. h. h.). From these 
 
 213 
 
 A, Flower : a to e, five perianthial leaves j e, hood shaped ; 
 
 B, Accessory petal. 
 
 Phalaris ccerulescens. A, Spikelet : o and 6, spathe formed of two bractea (ra/r<c 
 gluma, Auct.) ; c, d, one free and two coherent perianthial leaves (palea, Auct. ); 
 
 912 Aconitum napellus. 
 f, g, h, three hracteoles. 
 
366 
 
 MORPHOLOGY. 
 
 must be carefully distinguished all those dependent organs which have 
 also been termed the accessory corolla, as, for example, the corona of 
 the Narcissus (fig. 214, h.), and the so-called accessory corolla of the 
 
 214 
 
 Asclepiadacetz, which are for the most part only remarkable forms of the 
 filament and the connective of the stamens (see fig. 220.). 
 
 All the remaining foliar organs of the flower, from the outermost 
 circle in which the stamens are developed, to the germen, may be embraced 
 under the general term of accessory stamens. A definitive separation 
 of them is impossible, since their forms are continually passing into one 
 another. The scales in the flower of Pimelea (fig. 215.) may serve as 
 an example. 
 
 Here the history of the development is still too imperfect, especially 
 in the forms which produce the so-called inferior annulus, to allow 
 of our distinguishing those arising from a circle of leaves from those 
 which are a simple extension of the floral axis. In the first case, 
 
 e e e, three stamens ; /, a stigma. , The two coherent perianthial leaves, with two 
 nerves (palea superior, Auct. ). C, Pistil, surrounded at the base by the two weakly 
 coherent accessory petals : h h, squamulee, Auct. ; g, germen ; /, one stigma ; the other 
 is cut off. 
 
 J14 Narcissus l&tus. Flower, a, Peduncle ; b, spathe ; c, bud ; d, pedicel ; e, inferior 
 germen ; f, tube of the perianth ; g, limb of the perianth, appearing as six free leaves ; 
 h, corona, formed of six coherent ligules of the perianthial leaves. 
 
PHANEROGAMIA : FLOWERS. 
 
 367 
 
 215 
 
 the individual rudiments of the leaves are formed 
 quite separately, and always before the carpels : 
 it is by a later process that they become blended 
 together into a ring. In the second case, the 
 ring, or discus, originates at once as a perfectly 
 uniform whole, and always after the appearance 
 of the carpels, by a simple extension of the axis 
 already existing, though this may not itself 
 bear foliar organs on this part (as in Reseda). 
 This last case exists in the Boraginece and La- 
 biatce, in the discus (the so-called gynobasis}. 
 Trapa, Convolvulus, and the family of the Scro- 
 phnlarice, offer good examples of the first case. But 
 in these another difficulty presents itself, which 
 it will require the most comprehensive examin- 
 ation to conquer; namely, in these there appears 
 to occur either a division into two groups, of 
 which one has four-membered and the other five- 
 membered circles in the flower, or they are both 
 four-membered, and the perfect floral parts of 
 the one group only appear five-membered be- 
 cause the individual members of the same are unequally developed : 
 thus one leaf of the innermost circle will form the unilateral disc, while 
 the other three become stamens, and with one or two leaves of the next 
 circle form the four or five stamens, &c. My investigations of Pedi- 
 cularis and Orobanche have led me to this conclusion : the original 
 and always four-divided type is distinctly present in Veronica, in which 
 the two leaves of the innermost circle form stamens, and the two others 
 an unilateral disc*: similar conditions also occur in the allied families ; 
 and a more close investigation would include the Acanthacece, the Pe- 
 dalinece, &c., within the circle of investigation. 
 
 D. THE RUDIMENTS OF THE 
 
 157. The seed-bud, which is the only essential part of the 
 rudiment of the fruit, may be either naked, or enclosed in a re- 
 ceptacle, which last is termed the pistil. When it is present it 
 consists of two parts; a cavity which encloses the seed- bud, the 
 germen ; and an external opening peculiarly modified, the stigma : 
 sometimes the germen is elongated beneath the stigma into a 
 longer or shorter tube, termed the style. The seed-buds are 
 attached, at determinate places, in the germen, where a part is 
 often so characterised as to be particularly distinguished as a 
 peculiar organ. This part is called the spermophore. For the 
 
 * In Calceolaria there are only two tetra-merous circles, the outer of which becomes 
 calyx, while in the inner the upper and lower leaf become corolla, and the two side 
 ones stamens. 
 
 215 Pimelea decussata. A, Longitudinal section through the flower : a, pedicel ; 
 6, tube ; c, limb of the perianth ; d, two stamens; e, accessory stamens ; /, style ; g, ger- 
 men with the seed-bud. B, An accessory stamen, much magnified. 
 
368 MORPHOLOGY. 
 
 better comprehension of the conditions and of their internal 
 connections, I will proceed with the consideration of them in the 
 following order : 
 
 a. The Pistil. 
 
 b. The Spermophore. 
 
 c. The Seed-bud. 
 
 a. Of the Pistil 
 
 158. To the pistil I only refer those parts which contain ac- 
 tual cavities, in which one or more seed-buds are subsequently 
 developed. In this sense of the word, the pistil is absolutely 
 wanting in the Conifera, the Cycadacea, and the Loranthacece. 
 According to the fundamental organs of which the pistil is formed, 
 three principal kinds are to be distinguished. These are the true 
 superior pistil (pistillum superum), the inferior germen (germen 
 inferum), and the stem-pistil (p. cauligenum). The first is formed 
 from one or more foliar organs ; the second, in its lower parts, 
 from the pedicels, in its upper part frequently from foliar 
 organs ; the third originates entirely from axial organs, above and 
 internal to the floral envelopes. A foliar organ, in so far as it 
 contributes to the formation of the pistil, is termed a carpel (car- 
 pelluni). The following cases merit a more detailed explanation. 
 
 I. Of the superior Pistil. The pistil formed from a carpel 
 originates as a leaf, which, in the first instance, expands like a 
 leaf; then. its edges gradually grow together from below upwards; 
 the lower (vaginal) portion, by growing together, becomes a hollow 
 body, and forms the germen ; the upper part, not grown together, 
 but expanded free, forms the stigma ; the intermediate portion (the 
 petiole), when present, growing together into a tube, communi- 
 cating with the germen and opening externally at the beginning 
 of the stigma, forms the style (as in the Zea Mays). When 
 formed in this manner, the whole is a simple, one-mernbered pistil 
 (p. simplex monomerum). In this case, the germen is one- celled 
 only (germen uniloculare). In some cases, by a cellular growth 
 from the inner surface of the surrounding walls of the germen, 
 false septa are formed ; these are spurious dissepiments (dissepimenta 
 spuria)) by which the gefrmen is divided into spurious compart- 
 ments (germen spurie pluriloculare) 9 as in the Aracece. 
 
 If the pistil is composed from several carpels, these may form 
 
 a. Either into pistils, in the manner just described, and remain 
 separate = the multiple, monomerous pistil ( p. plura, monomer a), 
 or, standing in one or more circles *, become coherent with one 
 
 * Lindley's explanation of the structure of the fruit of Diplophractum (Elements of 
 Botany, 1841, p. 503.} appears to me very adventurous; at any rate we have as yet 
 no accurate knowledge of the germen at the period of flowering, and therefore the 
 whole is at present altogether hypothetical. It seems much more probable to me that 
 the five inner chambers are by no means fruit-cells, but produced in a similar way to 
 the five exterior empty colls in Nigella. 
 
PHANEROGAMIA : FLOWERS. 369 
 
 another, by the outer surfaces which are in contact. Thus is 
 formed an apparently simple but many-membered pistil (p. sim- 
 plex, polymernm). This coherence may extend to the entire pistil, 
 as in Apocynacece ; or it may only extend to the germen and style ; 
 or only to the germen itself; from which may proceed either a 
 simple germen, with a simple style and several stigmas (as in 
 Geraniacece), or no styles but several stigmas (as in Phytolacca), 
 or a simple germen with several pistils and several stigmas (as in 
 Buxus). It is very unusual for the germens and pistils to remain 
 separated, and only the stigmas to be coherent ; but this occurs in 
 the Asclepiadacece. In all these cases, the germen is called many- 
 celled (plurilocularis). The cells (loculd) are divided by septa 
 (dissepimenta) 9 which, by reason of their origin, are double, and 
 of course alternate with the carpels, and, consequently, with the 
 stigmas. Occasionally the production of false partitions occurs 
 here by the growth inward of cellular tissue, as in the Labiates 
 and Boraginacece, where the really two-celled germen becomes 
 spuriously four-celled by means of such spurious dissepiments. 
 
 b. Or the carpels may become united together by their edges, 
 so that they form a simple, many-membered germen, a style with 
 a simple tube, and a simple or multifold stigma (p. simplex, poly- 
 merum}. This pistil has, however, here only one cell like the one- 
 membered (imiloculare). Spurious dissepiments seldom exist here ; 
 these generally, perhaps exclusively, originate in a peculiar deve- 
 lopment of the spermophore, as in the Cruciferce, in which the 
 course of development is easy to follow. 
 
 II. Of the false inferior Germen. With the formation of 
 a concave disc, it sometimes occurs that the several simple, 
 monomerous, superior germens which it surrounds, become not 
 only blended together, but with the disc, and so present one 
 uniform mass, which supports the remaining parts of the flower, 
 and from which the styles and stigmas project to greater or less 
 extent. This occurs in the Pomece, where only one circle of 
 germens exists, and in the Granatecs, where two circles stand to- 
 gether. This structure is altogether different from the true 
 inferior germen. In the former the individual germens are formed 
 from foliar organs, and blended with the axial organ ; but in 
 the latter it is a true form of the axis which exclusively con- 
 stitutes the germen. 
 
 III. Of the inferior Germen. In a large number of families, the 
 collective internodes from the calyx to the carpels expand into a 
 hollow, cup-shaped, or even tubular body, which bears upon its 
 borders all the rest of the floral parts, and on its inner surface de- 
 velopes the seed-buds, and thus becomes the germen. The carpels, 
 when they are blended with one another at their edges, form only 
 the upper covering of the cavity of the germen the style, when 
 it is present, and with their free extremities they form the stigmas. 
 But their share in the formation of the germen varies greatly. If 
 
 B B 
 
370 MORPHOLOGY. 
 
 the inferior germen is only a shallow excavation, as in Saxifra- 
 gacecs and Myrtacece, the part which the foliar organs play in the 
 formation of the cavity is very important (germen semiinferum) ; 
 if the germen is already, by the form of the iriternodes, closed at 
 the upper part, as in the Onagracece, then they only form the styles 
 and the stigmas. If, however, as not unfrequently happens, the 
 tube formed of the internodes is elongated above the floral en- 
 velopes, a false style is produced, formed from the internodes, 
 which then commonly bears the stamens ; and the carpels remain 
 only as small scales, forming the stigma ; or they are entirely 
 wanting. This is the structure in the Orchidacecs and Aristolo- 
 chiacea ; and it is strikingly exhibited in the StylidiacecB. In these 
 germens no false dissepiments can be naturally formed ; but the 
 spermophore frequently forms false septa, and indeed, I believe, 
 with few exceptions, opposite to the carpels, and therefore to the 
 stigmas. 
 
 IV. Of the superior Stem-germen. In Passiflora the superior 
 germen originates from a cup-shaped axis, at whose edges the car- 
 pels arise, which form styles and stigma. 
 
 Y. Of the Stem-pistil. In the Leguminosce and LiliacecB, and 
 perhaps in some other families, the extremity of the axis within the 
 other floral parts is gradually developed to one or more flat leaf- 
 like stems. These contribute to the formation of a pistil exactly 
 like true leaves. The seed-buds are formed on the incurved 
 borders below, whilst the upper part is gradually developed to 
 styles and stigmas. 
 
 In the foregoing exposition of the origin of the germen, two essential 
 points must be dwelt upon. The first is the formation of it from very 
 different parts. It is around this subject particularly that the morpho- 
 logy of plants has hitherto groped in complete darkness, and it could do 
 no other while men were content to labour upon the detail, without any 
 principle of investigation to ensure certain results. The history of de- 
 velopment can alone be our guide here, and will lead us to infallible 
 conclusions so soon as it is generally recognised in its true light. Here 
 I have, of course, been able to give but a small contribution, since a 
 whole science is beyond the power of any individual, much more mine, 
 Of anterior labours on this point, I found none ; and much, an infinite 
 amount, still remains to be investigated. The following axioms form the 
 ground-work here : A normal bud and a leaf never originate regularly 
 on or out of a leaf in the Phanerogamia, but from an axial structure ; 
 where, therefore, normal buds or leaves originate, the foundation from 
 which they arise must be an axial organ. An organ which, from its 
 first origin, is single and undivided, can only be explained as a com- 
 bination of many parts by visionary speculation, not by healthy inquiry 
 into nature. Undoubted axial organs occur in the so-called ibliaceous 
 form (e.g., Phyllanthus), bearing buds upon their margins. Undoubted 
 axial organs form flat laminae, concave lamina, and even long, hollow, 
 flask-shaped forms, almost closed at the summit (e. g., Ficus). If, then, 
 we examine the inferior germens of Iridacece, Onagracete, Composites, &c. 
 in course of formation, we always find that the cavity of the germen is 
 
PHANEROGAMIA : FLOWERS. 
 
 371 
 
 formed simultaneously with, often even earlier than, the outer envelopes 
 of the flower, that in the border of the most distinctly formed germen 
 originate by degrees the succeeding envelopes, stamens, and carpels ; 
 that the last, in particular, are frequently not formed until the germen 
 is quite perfect, and even the seed-buds present in it in a rudimentary 
 condition. For those, therefore, who have traced but a few develop- 
 ments in nature, there can be no doubt here, that the entire inferior 
 germen is developed from a cup-shaped axis. In exactly the same man- 
 ner, any one may attain conviction that the style, in the true Gynandria, 
 the Orchidacece, Aristolochiacece, and Stylidiacece, is equally an axial 
 structure. For if it be recalled to mind that in the disc and cup-shaped 
 axes, the upper or inner surface is the organically higher part, and the 
 centre of the disc the highest point of the axis, it becomes easy to refer 
 those abnormal phenomena to well-known and commonplace structures. 
 In the Onagracece, for instance (fig. 216.), the entire outer surface of the 
 cavity of the germen (a 6), and the so-called tube of the calyx up to 
 the free lobes (b c\ correspond to the pedicel : next follow the inter- 
 nodes between calyx and stamens, which are not elongated ; the inner 
 surface of the so-called tube of the calyx up to the style corresponds to 
 the internode between stamens and carpels, which is elongated, as in 
 some degree in Cleome: lastly, the inner surface of the cavity of the 
 germen corresponds to an elongated axial structure contained within 
 the carpels, therefore to the so called spermophorum centrale liberum. 
 In Orchis (fig. 217.), Aristolochia, and Stylidium, the external surface 
 
 2] 6 
 
 217 
 
 * See Plate III. figs. 18 22., with the explanation. 
 
 810 Godetia Lehmanniana. Longitudinal section of the flower. The shaded portion 
 is the axial organ, and from a to & the inferior germen (fig. 215.); from b to c, the 
 superior cup-shaped disc (fig. 211.). This superior disc exhibits projections and orna- 
 mental markings, which are developed exactly in the same way, only in a less degree, 
 as on the inferior disc of Passi flora. (See Plate IV.) 
 
 817 Epipactis lati folia. Longitudinal section of the flower, n, Outer, ft, inner peri- 
 
 BB 2 
 
372 MORPHOLOGY. 
 
 of the germinal cavity corresponds to the pedicel ; the border of it is the 
 undeveloped internode between the inner and outer circles of floral en- 
 velopes in Orchis and Stylidium (in Aristolochia only one circle exists). 
 The outer surface of the hollow columella corresponds, in all these, to 
 the developed internode between the inner floral envelopes and the 
 stamen, such as occurs, for instance, in Passiflora ; the border of the 
 columella is the undeveloped internode between stamens and carpels, and 
 the inner surface of the columella is the lower part destitute of seed- 
 buds, of the central spermophore, as it occurs in some measure in the 
 Primulacece. In the same way the history of development leads to the 
 conclusion that the germen of Passiflora is a stem-organ, since the 
 cavity of the germen is indicated before the stamens show themselves, 
 and exists, distinctly formed, before the appearance of the carpels. (See 
 Plate IV., with the explanation.) 
 
 Less easy and certain is the decision of the question of the origin of 
 the stem-pistil ; especially difficult must it be to become accustomed to 
 regard it in this point of view, to those who are still trammelled by the 
 common prejudice set up without any investigation, and therefore wholly 
 unfounded, that every pistil must be formed of carpels. When a con- 
 viction has been arrived at of the correctness of the preceding expo- 
 sition, and it is seen that even here, in the inferior germen, the most 
 essential part, the germen, is always, and the style often, formed out of 
 axial organs, the notion will be more readily accepted that the superior 
 pistil may also possibly be wholly composed of axial organs. The fol- 
 lowing axioms will serve as a point of departure : Axis and leaf are not 
 distinguishable by any difference of external form, but by their peculiar 
 process of development ; in the leaf the apex is formed first, the base 
 last ; in the axis the contrary is the universal rule. That which regu- 
 larly produces normal buds is not a leaf but an axial organ. Obser- 
 vation gives us the following facts : In some pistils, for instance, in 
 Cruciferce and Fumariacece *, the stigma is perfected first, then the style, 
 next the germen, and last of all in this, on special organs distinct from 
 the carpels, the seed-buds ; in others, as in the Leguminosa, the Liliacece, 
 the germen is formed first, and in this the seed-buds, on the borders of 
 the plates, appearing like carpels ; then the style grows up ; and at the 
 very last the apex developes into the peculiar form of the stigma. If 
 we apply to this the criterion which we have for the distinction of stem 
 and leaf, the first mode of development corresponds to a foliar, and 
 the last to an axial, organ ; and so long as a logical consistency is re- 
 garded as the only means to maintain the secure advance of science 
 against mere playing with words, we must, in the present condition of 
 observation, regard the pistils in question as formed from axial organs. 
 Probably very many families belong here, especially the Ranunculacece, 
 on which, in the absence of complete investigation, I will not venture to 
 judge. The most interesting deviation from the structure, hitherto 
 regarded as normal, occurs in a plant, Siphonodon celastrineus, described 
 
 * Especially adapted, on account of their remarkably formed stigma. 
 
 anthial leaves (half removed) ; c, stamens ; e, seed-buds ; x, stigma. The shaded 
 portion is the axial organ, and up to the point of junction of a and b constitutes the 
 inferior germen : above this, at first an androphore, then a gynophore. The carpels, 
 however, are wholly abortive ; and the axial organ itself forms the style, with the two 
 last-named parts above a and b. 
 
PHANEROGAMIA : FLOWERS. 
 
 373 
 
 218 
 
 by Griffith.* I think one may 
 obtain the clearest idea of the 
 pistil of this plant f by imagin- 
 ing the pistil of a Malvaceous 
 plant, e. g., Lavatera (fig. 
 218.), with the whole of the 
 stigmas (q) abbreviated to little 
 teeth, and the conical extremity 
 of the axis elongated like a 
 pedicel beyond the stigmas, and 
 then spreading out like an 
 umbrella. Here the carpels 
 form the germen and tube of 
 the style, while the axis is at 
 once central spermophore, con- 
 ducting tissue and stigma. 
 
 The result of all these dis- 
 cussions is that the germen, 
 style, and stigma are by no 
 means definite fundamental 
 organs of the plant, but dif- 
 ferent modes of appearance, 
 sometimes of the axial, some- 
 times of the foliar, organs. 
 But the said parts are decidedly 
 inessential portions of the 
 flower, since they may be 
 wholly absent, and therefore 
 there is no thorough unity to 
 be looked for here. On the 
 other hand, the properly es- 
 sential organs of the flower are different as fundamental organs. The 
 stamens are always (only in Najas it is still doubtful) foliar organs ; 
 the seed-bud, and the part on which it is borne, the spermophore, also 
 constantly axial organs. The whole terminology must therefore really 
 be reconstructed, since germen, style, and stigma, as definite organs, 
 must be excluded. If we name every exclusively axial organ which 
 bears seed-buds spermophore, in plants with inferior germens no ger- 
 men exists, but merely a cup-shaped spermophore, a style and stigma 
 perhaps, or merely a stigma; in the plants with a stem-pistil there is 
 nothing but a false pistil, that is, a spermophore in the form of a pistil. 
 We shall hereafter find the scales of the Abietinece to be analogues of 
 these. It is also easy to see, that in a complete carrying out of such 
 
 * Calcutta Journal of Nat. Hist. vol. iv. p. 150, et seq. 
 
 f I only know the description, and have not seen the figures given by Griffith. 
 
 2:8 Lavatera sanvitellensis. Longitudinal section of the flower, a, Pith ; b, epider- 
 mis ; c, cortical layer ; d, vascular bundle of the pedicel (e) ; d, f, g, remains of the 
 removed epicalyx, calyx, corolla, and stamens; h, peculiar spongy cellular tissue of the 
 receptacle ; i, k, I, m, external and internal integument, nucleus, and embryo-sac of the 
 seed-bud ; n, flat hemispherical extremity of the axis in the flower ; p, lower, q, inter- 
 mediate, r, upper part of the carpels, forming the cavity of the germen, style, and 
 stigmas ; s, conducting tissue, on which the pollen tube passes down into the common 
 space (o), from whence it penetrates into the separate cells of the germen, right and left 
 of the spermophore, which is here an immediate prolongation of the axis. 
 
 BBS 
 
374 MORPHOLOGY. 
 
 investigations through all parts of the flower, many at present doubt- 
 ful * alliances of the families of plants will take a very diiferent order ; 
 many certain ones be more accurately established and expressed. 
 
 The second point which it is here essential to make good, and the in- 
 fluence of which in the theory of reproduction is of the most decided im- 
 portance, relates to the connection of the cavity of the germen with the 
 external air through the canal of the style. That any one has opinions 
 on reproduction, deserving even the slightest attention, nay, that any one 
 can institute researches into reproduction with a hope of any useful result, 
 who has not previously become quite clear in this point, is to me as 
 plain, as in Zoology, the necessity of the previous inquiry whether a 
 free passage exists between ovary and uterus, and between these and 
 the external sexual parts. That " laisser-faire" folks, who on this point 
 have not even once attempted to establish their opinions through original 
 investigation, should undertake to discuss the theory of reproduction, and 
 even to set up new theories, persons who are at the same time skilful 
 observers, such as Hartig*, proves how sad the condition of science 
 actually is, how little the generality of men have yet comprehended the 
 true character of a scientific examination of organic bodies. That this 
 reproach applies to botanists generally, and not to individuals, is evident 
 from the acceptance which such essays meet with. If a zoologist were 
 to set up a new theory of reproduction, and in it to assert that the 
 uterus is a sac closed in on all sides, all zoologists would laugh and cast 
 the treatise aside without further notice. Botanists in general have not 
 even advanced so far as to see how indispensible the settlement of such 
 a question is, and thus such treatises circulate, are copied, half-compre- 
 hended, used as materials from whence to spin out new fantasies, and 
 the science remains ever at the same low point, around which it revolves 
 in an eternal circle. Men like Robert Brown, Mirbel, Brongniart and 
 Meyen, write altogether for oblivion, because they find no public which 
 is capable of estimating their labours ; since a man may talk well about 
 many things, but has a scientific judgment only on such objects as he 
 is acquainted with through his own researches ; and how many among the 
 hundreds of German botanists may there be, who have even once at- 
 tempted to form an independent opinion of the nature of the organs of 
 propagation of plants by the investigation of their development on only 
 one single plant ? Would it, in these days, be forgiven a zoologist not 
 to have himself once made the complete course of development of a 
 chicken, or some other animal, an object of his investigation? a subject 
 which is so difficult, that the history of development of a germen appears 
 as mere child's play beside it. 
 
 When the formation of any germen whatsoever is traced, it is seen in 
 every case, from whatever fundamental organs it may have originated, 
 that the cavity of the germen is always open to the external air, either 
 immediately, if only a stigma (stigma sessile) exist, or through the canal 
 of the style, which is indeed merely a prolongation of the cavity of the 
 germen ; since the parts from which the pistil is produced are always 
 formed as flat structures. In monomerous pistils, the margins become 
 applied together and blended, from below upward, so as to form a con- 
 tinuous tube, open above ; in pistils composed of a number of parts, these 
 
 * Ho\v little is as yet certain in this respect is shown by every new systematic work 
 that appears : every one throws the families together in a different way, into a self-styled 
 thoroughly Natural system. 
 
 j- New Theory of Impregnation, &c. Brunswick, 1842, p. 7. 
 
PHANEROGAMIA : FLOWERS. 375 
 
 become applied together and blended at their margins, forming, in like 
 manner, a tube open at the summit ; in both cases the lower part of the 
 cavity of the germen usually begins to enlarge at a subsequent period. 
 In inferior germens the carpels form, in the same way, a tube* communi- 
 cating with the cavity of the germen. With the exception of iheAsclepi- 
 udacece and Apocynacece, there is probably not one single family in which 
 the original canal of the style and the orifice at the stigma becomes ac- 
 tually grown up ; in most, this canal may be seen in the perfect pistil 
 as a tube, with a not inconsiderable cavity, and traced into the cavity of 
 the germen. In the others, no such empty space containing only air 
 can of course be distinguished ; but it nevertheless exists, and is merely 
 rendered indistinct by a peculiar modification of the cellular tissue which 
 lines it, of which I shall have to speak hereafter. As I have said, I 
 know of no exception. Most Monocotyledons which I have examined 
 have an entirely open tube in the style ; among the Dicotyledons, e. g. in 
 Viola, Euphorbia, Ricinus, Phytolacca, most Malvacece, Cruciferce, it is 
 the same. In the Orchidacece, the tube, which is open and proportion- 
 ately very wide before the germen is perfect, certainly appears closed at 
 the epoch of flowering ; but it is not so in fact. Even in the Proteacece, 
 to which, I think, Treviranus even denied a stigmatic surface, the canal 
 may be clearly demonstrated. 
 
 In conclusion, I will add a few observations on some less essential 
 modifications in the form of the pistil and its parts. All here turns upon 
 the point which I have placed at the threshold of the whole subject 
 of Morphology, that the dimensions never determine the definition of 
 an organ : that, therefore, the said three parts of the pistil may occur 
 filiform, flattened, thickened, or globular (capitate), is self-evident. 
 Thence, globular (capitate), leaf-like, flat (and then with entire or va- 
 riously divided borders), or funnel-shaped, filiform, &c. stigmas, are 
 almost equally frequent ; the style is of course usually filiform, but in 
 the Malvaceae, for example, conical f, in Iris and Canna petaloid. The 
 forms of the cavity of the germen are infinitely varied ; generally, how- 
 ever, globular, ovate, or longish. One peculiar form may be briefly men- 
 tioned. When a many-membered pistil is closed up at an early period 
 and the germens, chiefly at the lower parts, and this toward one side, ex- 
 pand, this portion advances, bulging over the point of departure of the 
 style, so that the latter appears to arise, not from the summit but from 
 the side, or even from the base of the germen ; where several blended 
 carpels have been developed in this way, the style appears to arise be- 
 tween them from the receptacle : this is called a stylus gynobasicus, which 
 however, is not distinguished in any respect from the stylus lateralis and 
 basilaris of some Ranunculacece and Rosacece. 
 
 * I will here, in passing, remark that the style is never a continuation of the mathe- 
 matical axis of the flower, as Link says (El. Phil. Bot. ed. 2. p. 217.) but always a 
 prolongation of the wall of the cavity of the germen proceeding out from it. The 
 investigation of every course of development of the germen proves the contrary. Just 
 as little does any process of the axis exist in the Geraniacece (Link, ibid.): the five 
 germens originate at once, separate and free, and become blended together ; no other 
 organ whatever appears among them. A hundred similar observations might be made, 
 since the old ones have done their best to leave the younger the whole harvest of 
 discovery undiminished, without our acquiring a right to be proud of our skill. We 
 do now what should have been done long ago, we look into things instead of making 
 words. 
 
 f A childish game at making words has here invented the superfluous name of 
 morliolus for the stylo. 
 
 B B 4 
 
376 MORPHOLOGY. 
 
 The structure of some Malvacece also deserves remark (Malva, Al- 
 thcea, Lavatera (fig. 218.), Malope, &c.). Here the axis of the flower 
 forms a conical or flat hemispherical body (fig. 218. n.) (gynophorum) 
 in the middle of it, on which a whorl of carpels (fig. 218. q) is produced 
 in (in most) a simple circle, or tortuously alternating up and down 
 (Malope\ in the axils of which one or two seed-buds are developed 
 (fig. 218. ik Im.) The carpels with their lower parts (218. p) embrace 
 the seed- buds on the outside and laterally, and are blended together so 
 far by the outer surfaces of their incurved borders ; a higher part of the 
 carpels (fig. 218. from the seed-bud to s o) (growing together in the same 
 way) forms a half canal, the lower open side of which rests upon the 
 spermophore ; lastly, in the upper portion, the carpels become par- 
 tially blended together by their borders, and thus form one canal of the 
 style (fig. 218. from s to a little below t\ and remain partly free, forming 
 the stigmas (fig. 218. t.) Here then is a perfectly free communication 
 from the exterior to the seed-buds, which is scarcely anywhere so easy to 
 trace as here. It is inconceivable to me how Hartig can say, " There 
 are cases in which the ovules do not lie in the interior of the canal of the 
 style enlarged into a seminal cavity, but are perfectly closed up by 
 masses of cells, in which, in some measure, a parietas (? ! !) extrauterina 
 takes place, as in the Malvacea, the Cruciferce, Campamdacece, and 
 many other plants, in which no connection of the ovarian cavity with 
 the stigma by special conducting tissue ever exists." In the Campanu- 
 lacece and Cruciferce even, it is certainly anything but difficult to trace 
 the canal from the stigma to the cavity of the germen ; but in the Mal- 
 vacece Hartig must know, that he has either not investigated the matter 
 at all, or in the most superficial manner possible. 
 
 Symmetrical forms also occur in the pistil, although more rarely than 
 in the floral envelopes. Thus, the germens on the spadix of Crypto- 
 coryne spiralis are formed so obliquely, that almost the whole circum- 
 ference is formed on one side only ; and the stigmas, instead of lying 
 opposite the base, are pressed quite close to the spadix, which give rise 
 to a completely false idea of the condition of organisation. Other ex- 
 amples are afforded by the Scrophulariacece and allied families, &c. A 
 strange, hitherto unmentioned form of the germen is exhibited by Ce- 
 losia ; here, when the long style is cut away, the germen has exactly the 
 form of a perfect Agaric ; the stipe contains the funiculi of the (numerous) 
 seed-buds, the pileus the seed-buds themselves. 
 
 159. The structure of the pistil differs with the different 
 modes of its origin, and still more in reference to specific peculiari- 
 ties. Like every newly-formed part of a plant, it consists origin- 
 ally of uniform, delicate parenchyma, in which an epithelium on 
 both the outer and inner surfaces is distinguishable. Gradually, but 
 sometimes not till a late period, or in certain cases not at all, the 
 vascular bundles are organised from the parenchyma ; in the single 
 carpel there is usually one main bundle, corresponding with the 
 central rib of the leaf, and two others at the edges of the leaf; 
 in many-membered one-celled germens, the latter are frequently 
 wanting. In rare cases the vascular bundles are ramified in the same 
 way as in the leaf, which indeed is the natural consequence of their 
 morphological import, since germen and style correspond to the 
 vagina and petioles, which are generally traversed by only one, or a 
 
PHANEROGAMIA : FLOWERS. 377 
 
 few parallel vascular bundles. The stigma, on the other hand, 
 corresponds to the lamina, and is so imperfectly developed that in 
 most instances it contains no vascular bundles. In a few cases 
 interesting modifications of cellular tissue are presented in the in- 
 terior of the germen ; yet oil-passages ( Umbelliferce), milk-vessels, 
 and cells containing crystals, &c., occur here and there. The exter- 
 nal epithelium of the outer surface is commonly soon changed into 
 epidermis, which often exhibits stomates, and under this the paren- 
 chyma is somewhat lax and almost spongy. The surface of the 
 germen exhibits all the various appendages of young epidermis, 
 hairs, prickles, glands, &c. The style is sometimes clothed with 
 hairs, which are termed collecting hairs (pili collector es\ because 
 the pollen remains attached to them. The peculiar hairs upon the 
 styles of some of the Campanulacea are worthy of attention ; they 
 have already been spoken of (29.). They have served as the 
 basis for many fanciful notions. The formation of the epithe- 
 lium of the inner surface is more important ; it is sometimes deve- 
 loped with the next subsequent layers into a true epidermis, 
 but only in the cavity of the germen (rarely, as in Passiflora and 
 some Cruciferce, furnished with stomata). On the stigma it is 
 converted, either partially or entirely, into papillae, as it also is 
 sometimes in the canal of the style, if this is distinctly hollow , 
 and in the cavity of the germen along the spermophores, as far as 
 the seed-buds, where the papillae frequently become long hairs. 
 All these papillae commonly secrete at the time of the perfecting of 
 the pistils an adhesive substance, containing gum or sugar, the stig- 
 matic fluid. A similar substance is frequently secreted in the 
 intercellular spaces of the cellular layers lying immediately beneath 
 the epithelium of the stigma and the styles, and often so copiously 
 that the cells are loosened from their union with one another, and 
 lie loosely imbedded in this mucilaginous, semi-fluid matter. The 
 process may be easily followed in the Orchidacece and the Onagracece. 
 The epithelium generally, so soon as it becomes papillose, together 
 with all the cellular tissue and the secreted matter, is termed con- 
 ducting cellular tissue (tela conductrix, conductor fructificationis, Hor- 
 kel; tissu conducteur, Brongniart). In rare cases, in the Asclepiada- 
 cecB and Apocynacece, where the upper opening of the canal of the 
 style is perfectly closed, a conducting cellular tissue of this kind is 
 formed through the thickness of the wall to the outer surface. In 
 the Asclepiadacece a peculiar secretion is presented at the five angles 
 of the great body formed by the blending of the stigmas, from which 
 proceed five glandular, scarcely organised structures, each with 
 two arms, coated with viscine, and, as has already been noticed, 
 receive the pollen masses at the time of the dehiscence of the an- 
 thers. 
 
 Of the last-mentioned matters, the structure of the conducting cellular 
 tissue only is of essential importance. But this again gives striking evi- 
 dence of how vague and obscure all investigations and so-called theories 
 remain, when they are not based on the history of development. Brong- 
 
378 MORPHOLOGY. 
 
 mart long since mentioned, that in several plants the stigma is clothed by 
 a structureless pellicle (cuticula), as, for instance, in Nuphar, Nyctago, 
 and Hibiscus. Here he erred on account of examining the stigmas too 
 late, after the secreted viscid matter had become solidified : at the time 
 when the flower opens this imaginary pellicle is a thickish and amor- 
 phous fluid. In most plants, however, Brongniart had recognised the 
 real nature of it, although he had not observed its gradual formation as a 
 secretion from the neighbouring cells. Quite recently, Hartig has, from 
 the most imperfect observation of this substance, built up a comprehen- 
 sive so-called theory, including not merely impregnation, but even cell- 
 formation, which, in reality, contains nothing but imperfect observations, 
 and these inaccurately interpreted. His whole edifice, built on such 
 weak foundations, falls in, the moment one carefully traces the develop- 
 ment of one single germen and its parts. 
 
 The fluid which here becomes so important, is really nothing but the 
 intercellular substance treated of in an earlier part of this work, which is 
 only distinguished here by being much more watery, and, as it dries 
 slowly, remaining longer in the fluid condition in which it is secreted. 
 If, for example, the stigmatic papillae be observed in a perfect bud of 
 Iris florentina, these are found to be longish, very delicate cells, the 
 contents of the usual kind, with some starch granules actively circulating 
 in currents distributed over the walls. Alcohol and acids coagulate the 
 contents, as in all fresh, vegetating cells, and, as in all cells containing much 
 mucus, the contents of the cells contract into the middle of the cell in a 
 tubular form ; no internal membrane can be spoken of here.* In the 
 opening flower we find a slight secretion of mucilaginous fluid upon the 
 apex of the papilla ; this gradually increases till it forms a little cap, 
 completely enclosing the apex, and by degrees extending down until 
 it entirely covers the papilla : this is Hartig's external membrane. If 
 the papilla; are not much developed, as in the plants named by Brong- 
 niart, the secretions of the separate cells flow together, and then thus 
 form an unorganised layer on the surface of the stigma ; and even over 
 the whole wall of the canal of the style. This is the cuticula of Brong- 
 niart and Hartig, which, however, is in the earliest stage a tough, adhe- 
 sive fluid, which may be' drawn out in threads, and no membrane ; and 
 may be distinctly recognised as a secretion by its origin. In all essential 
 points it is identical with the secretion of the epidermis, and is only dis- 
 tinguished, apparently, by its chemical composition, since it contains 
 more gum and sugar, while that presents more of gelatine, and often 
 wax and resin. It is also very different in chemical nature in different 
 
 * Hartig assumes that there are three membranes to the stigmatic papillse. Of the 
 outer I will speak presently ; the intermediate one is the true cell-membrane, but the 
 internal does not exist at all, and is only the appearance above mentioned. In his 
 " Lehrbuch der Pflanzenkunde, Heft. 4.," Hartig has applied this perverse notion also to 
 the epidermis of plants ; but, from more complete ignorance of the course of develop- 
 ment, made still greater confusion. I have already remarked on the point, that in 
 gelatinous thickening-layers, deposited gradually in the interior of the cell, the inner- 
 most is often less soluble than the rest, and, indeed, quite naturally, from the same 
 reason as the outer layer of the starch granule is less soluble than the inner, because 
 the matters contained in the cell, wax, albumen, &c , impregnate this layer, with which 
 they are always in contact. In the cases of the epidermal cell brought forward by 
 Hartig, the outer membrane is the actually original cell-membrane ; all the rest are 
 subsequently deposited layers of increment, of which the innermost is merely less solu- 
 ble on account of the matters which have penetrated it, and naturally behaves in a 
 <lififerent way from the rest to solvents and reagents. 
 
PHANEROGAMIA : FLOWERS. 379 
 
 plants ; often quite a thin fluid, as, for instance, in the LemnacecB, where 
 it appears to be little more than a concentrated solution of oxalate of 
 lime (?) with a little gum and sugar ; it is thickest and most tenacious 
 (and probably contains gelatine) in Nuphar, where it very quickly dries 
 up into a thick and very tough membrane. When the secretion is not 
 confined to the surface, but extends to the intercellular passages and 
 spaces of the nearest layers of cells, the secreted substance seems to be 
 always identical. Through this secretion the individual cells, which in 
 the first instance form a solid tissue, become completely isolated from 
 each other. 
 
 These cells* lying beneath the epidermis are usually of a long spindle- 
 shape (e. g. Orchidacece, Onagracece), and about four or five times as broad 
 as the pollen-tubes, hereafter to be spoken of. In the Cucurbitacece, they 
 are very little roundish cells; in the Campanulacece and some others, rather 
 long, but seldom exceed half a French line, and are always distinguish- 
 able from the pollen-tubes by their twice or three times greater diameter. 
 They have been sometimes called mucous tubes, because, by imperfect 
 observations, they have been confounded with the "mucous tubes" of 
 Robert Brown, to be mentioned hereafter, with which they have nothing 
 to do. 
 
 Some of the more remarkable forms of the conducting tissue have 
 received special names, which are in the highest degree superfluous. 
 Thus, in the Plumbaginece, a little cord of such tissue, which has been 
 called an embolus, extends from the internal orifice of the canal of the 
 style to the exostome, lying close beneath. In Linum, Euphorbia, and 
 JRicinuSj the papillae of this tissue are very long and capillary, and extend 
 in a close body over the exostome and into it. They are of a splendid 
 red colour near this in Ricinus. Mirbel first represented them (as well as 
 the embolus just spoken of) in Euphorbia, much too stiffly and twisted 
 like a solid body, which he called an eteignoir. Similar tissue of a beautiful 
 golden yellow occurs in Phytolacca, and in almost all the Portulacece 
 the micropyle is densely covered up by long, capillary, conducting cel- 
 lular tissue. 
 
 I will describe rather more fully the most wonderful structure of the 
 Asclepiadacece and Apocynacece, which has ever been a crux botanophi- 
 lorum, and in which no one has given any useful observations but Robert 
 Brown, f because he was the only one who looked into the mode of the 
 formation of the parts. I have industriously investigated all the plants 
 of this kind that I could obtain, but can, at most, only add in little de- 
 tail points to Robert Brown's excellent essay. In the rudiment of the 
 flower originate two little foliaceous (?) organs, which curve towards 
 each other, and each separately has its margins blended, so that they form 
 two straight tubes. In most Apocynacece they grow together at a very 
 early period ; in few, as in Apocynum, they remain free in the lower 
 part. The upper part, on the contrary, which soon becomes thickened 
 and fleshy, and soon greatly exceeds the lower part in volume, becomes 
 blended into one in both families, so perfectly that at a later epoch the 
 
 * The epithelial cells are mostly of different form from those lying beneath them, 
 and may be distinctly made out in the earlier stages. By the solution of the cells, the 
 epithelial cells are also scattered through the mucilaginous fluid, and can only be dis- 
 covered singly with some difficulty. 
 
 j- How, after Robert Brown's researches, any one can bring forward such clumsy 
 ideas, in the spirit of the last century, as Link (1. c. vol. ii. p. 231. ), is truly only ex- 
 plicable in one way, that the profound study of foreign researches does not yet lie in 
 the spirit of our Botany. 
 
380 
 
 MORPHOLOGY. 
 
 former line of demarcation cannot be defined in the homogeneous tissue, 
 While the lower part is thus gradually developed into the gerinen and a 
 short style, while the spermophore and seed-buds are perfected, a peculiar 
 change takes place in the upper part ; the originally open canal grows up 
 completely without leaving a trace in the interior.* The whole body 
 acquires the specific form, which in the Apocynacece is usually a short 
 cylinder, running up into a cone above ; in the Asclepiadacece commonly 
 a short pentagonal prism, also ending in a cone at the top. 
 
 1. In the Apocy nacece (fig. 219) there is produced, on or somewhat be- 
 yond the lower or upper edge of the cylinder, a membranous, longer ( Vincd) 
 or shorter (Apocynum, fig. 219.) projecting, often wavingly- toothed (Cer- 
 
 219 
 
 hero) border ; above this border, or in the indentations of it, or on peculiar 
 tufts of hair, according to specific differences, begins then the secretion 
 of viscine, through which the tufts of hair and projections on the filaments 
 and the bases of the anthers become firmly glued to the stigmatic body. 
 Over the whole body a distinct epidermis has been gradually perfected, 
 excepting close beneath the border (or in Vinca just above it?). Here, 
 on the other hand, begins the secretion of the stigmatic fluid (g), and 
 this is produced in curved streaks through the whole thickness of the 
 stigmatic body (#, A), as far as the cavity of the style, and so forms a con- 
 ducting cellular tissue, which breaks through the original carpel (?) and 
 thus reaches the cavity of the germen. 
 
 2. In the Asclepiadacece (fig. 220.) a pretty thick epidermis is likewise 
 formed over the entire stigmatic body. At its five angles it assumes a 
 
 * Two point-like excavations are frequently seen on the upper surface, traces of the 
 confluent canal, e. g. in the Stapelice. 
 
 819 Apocynum androsecmifolium, A, Stamen, seen on the inside : a, filament ; b, cell of 
 anther ; c c c, connective, elongated into a point above, expanded into a kind of mantle 
 at the sides and below ; d, tuft of hairs, between which the viscine is secreted by which 
 the stamen becomes glued to the stigmatic body. B, A longitudinal section through 
 the stigmatic body and a stamen : a, filament ; b, anther ; c, connective ; d, tuft of hair 
 adhering to the stigmatic body ; e, glandular corpuscle, which lies on the distinct epi- 
 dermis (z) of the stigmatic body ; /, vascular bundle, on the outer side of which ran 
 the original (now obliterated) canal of the style ; </, h, conducting cellular tissue, which 
 has been formed from the original canal of the style (from h downward), out through 
 the thickness of the carpel (from h upward), and at g constitutes a stigmatic surface. 
 
PHANEROGAM I A : FLOWERS. 
 
 210 
 
 381 
 
 peculiar form, the cells elongating very much perpendicularly to the 
 surface (the same occurs at five points above the border in Apocynum). 
 Immediately beneath these five places five points remain without ac- 
 quiring a perfect epidermis, while five cords of conducting tissue are 
 formed from them into the canal of the style, in the same way as in the 
 
 K0 A, 23, C, Asclepias syriaca. A, Completely expanded flower : a, sepals ; b, petals ; 
 c, stamens. J?, The same seen from above : a, hood-like appendages on the back of the 
 anther ; b, wing-like appendages of the anther, which, retracted, form a kind of little 
 box ; d, crest-like elongation of the anther, which lies fast upon the stigmatic body (/) ; 
 e, gland-like bodies, which, five in number, alternate with the five stamens, and adhere 
 to the epidermis of the stigmatic body. C, Part of the organs of propagation from a 
 very small bud : a, hood ; b, spur projecting from it ; c, e,f, as before. 
 
 !i D, E, F. Gomphocarpus fruticosus A, Longitudinal section through the organs 
 of propagation of a very young bud : the section goes between the two germens, and 
 on the right side between two stamens, and divides in half the stigmatic body above a 
 stamen on the left, and on the right the tubes formed by the confluent filaments, 
 a, Germen ; b, style ; c, half the stigmatic body ; d, filament of the divided stamen ; 
 e, vascular bundle of the same ; /, half an anther ; g, divided staminal tube ; /<, wing- 
 like appendage of the anther, so far as it forms the box-like body; i, half the gland-like 
 body lying in the dense epidermis, which is remarkably thickened below it, and appear- 
 ing as an immediate prolongation upward of the wing-like appendage of the anther. 
 E, The pistil extracted free : a, two germens ; b, two styles ; c, a stigmatic body, on 
 which three gland-like bodies are visible. F, Gland-like bodies (a), with the three 
 arms (6) and the pollen-masses (r) appended to them, from a perfectly developed 
 flower. 
 
382 MORPHOLOGY. 
 
 ApocynacecB. In those five places lying above the five points, where the 
 epidermis is peculiarly modified, now very soon begins, in the Asclepia- 
 dacece and in Apocynum, the secretion of a peculiar, viscine-like, adhesive 
 substance, and very different forms appear ; in Apocynum forming five 
 little depressed, roundish cushions ; in the Asclepiadacece exhibiting a 
 rather longish body forked in the middle, and, when quite perfect, fur- 
 nished with two arms going from the upper or lower end, which in the 
 different species and genera manifest many small, inessential differences. 
 This body is merely adherent to the subjacent, remarkably sharply and 
 distinctly-developed epidermis ; originally green, it gradually becomes 
 yellow, and at last of a dull brown. Its structure is but very indistinctly 
 cellular, perhaps not at all. Its origin is as yet by no means made out, 
 for the investigation is the most difficult I know. From some original 
 observations on Gomphocarpus and Hoy a, I am inclined to conclude that 
 the outermost borders of the wing-like appendages of the anthers are 
 formed rudimentarily very early here, become firmly adherent and sub- 
 sequently torn away from the anthers, so that each body originates from 
 the cohesion of two fragments of two different anthers. So much is cer- 
 tain, that they are never organically united with the angles of the stig- 
 matic body, for the epidermis,, which was distinctly formed before their first 
 appearance, runs on quite uniformly and uninjured, beneath them. 
 They could, at most, in opposition to the above notion, be regarded 
 as semi-organised secreting points. At the time of the dehiscence of 
 the anthers they always lie in such a manner that one, mostly the upper 
 (in the Stapelice^ the lower) end of the pollen mass must at once come 
 into contact with one arm of this body, and there adhere. Another point 
 which I have been equally unable to decide is, whether the five cords 
 of conducting tissue enter the two styles unequally divided (in two and 
 three), or whether they unite just before into a circle, which is then dis- 
 tributed in two equal portions in the styles. 
 
 b. Of the Spermophore (Placenta). 
 
 160. Since the seed-bud corresponds to a bud which arises 
 immediately from a stem, it follows that the spermophore does 
 not always exist as a special organ : when, for instance, the axial 
 organ from which the seed-bud springs is already defined and 
 named on other grounds. In this case, the spermophore is 
 nothing more than the region in which the seed- buds are attached, 
 and, in the simplest case, this may be limited to the basilar 
 surface of one single seed-bud ; as, for example, in Taxus. But 
 those places on an axial structure on which seed-buds are borne 
 may be formed into such projecting processes that they may be 
 well distinguished as peculiar parts of this axial organ* ; or a 
 particular part of the axis, which is in no other way defined as an 
 organ, may be exclusively devoted to the production of seed-buds. 
 In this way we obtain the following varieties : 
 
 a. Spermophore as a simple region of another organ ; 
 
 * Somewhat as in the projecting ridges on the stem of Echinocactus and Melo- 
 eactus. 
 
PHANEROGAMIA : FLOWERS. 383 
 
 b. Spermophore as a distinguishable part of an independent 
 organ ; 
 
 c. Spermophore as an independent organ. 
 
 We have now to compare these with the different conditions 
 and the various forms of the germen. 
 
 1. Where the pistil is entirely wanting, as in the Cycadacece, 
 Coniferce, and Loranthacece, we have as yet, unfortunately, so little 
 material toward the history of the development, that we can only 
 venture to make explanatory guesses under the guidance of laws* 
 discovered in plants which have been well investigated. According 
 to these the matter stands as follows : 
 
 a. We find the naked seed-buds, as the immediate termination 
 of the floral axis, without distinguishable Spermophore in Taxus, 
 Ephedra, Podocarpus, Dacrydium, and the Loranthacece. 
 
 b. In the axil of a bract (in Pinus, Larix, Abies, and Gingko), 
 or without any bract (as in Zamia, Araucaria, and Agathis), a 
 twig is formed which, as independent Spermophore, bears the seed- 
 bud. In CycaS) this Spermophore is flat, and bears many seed-buds 
 on its margins ; scale-like, and bearing one (in Agathis and Arau- 
 caria), or two (in Zamia, Pinus, Larix, and Abies) seed-buds upon 
 its upper surface ; or branched like a stem, and bearing one seed- 
 bud upon the point of each twig (as in Gingko). 
 
 Respecting the remaining Coniferce, and especially the group of 
 the Cupressinece, for example Juniperus, Cupressus, Thuja, &c., I 
 will not venture even to express a supposition, in the absence of a 
 history of the development or sufficient analogies. 
 
 2. In the superior germens an axial organ must always project 
 into the carpels in the Spermophore. 
 
 3. In germens that are either half or wholly inferior, the floral 
 axis itself, in the form of the inferior germen, is always the sper- 
 mophore. 
 
 4. In the superior stem-germen and stem-pistil it is always the 
 floral axis which bears the seed-bud. In the first, three prominent 
 ridges are developed as spermophores ; in the second, the seed-buds 
 are formed on the edges of the flat expanded branches, curved in a 
 little toward the interior. These edges may here form merely a 
 slight prominence (spermophorum parietale of the Leguminoscs), or 
 they may extend quite across the cavity, becoming blended by 
 their meeting surfaces, so that the two seed-bud-bearing edges are 
 placed in the inner angle of each compartment (gemmulce angulo 
 loculorum inferno affixes; as in the Liliacece). 
 
 5. Besides these cases a condition, which seems quite abnormal, 
 sometimes occurs, in which the entire surface of the septum is 
 covered with seed-buds ; as in Butomus, Hydrocharis, Stratiotes, 
 Nymphaa, and Nuphar. 
 
 These are all the varieties with which I am acquainted in the 
 
 * Of the family just named, I have as yet only followed the development of Abies 
 Taxus, and l r iscnm so perfectly as to leave no further doubt. 
 
384 
 
 MORPHOLOGY. 
 
 formation of the spermophore. For the purposes of description 
 they may be simply classed as follows (fig. 221.) : 
 
 A. A seed-bud in each germen. 
 
 a. Attached at the base (gemmula basilaris), Composites. 
 
 b. Suspended (gemmula pendula), Typliacea. 
 
 c. Attached to the wall (g. lateralis), Graminece. 
 
 d. Depending from a free central spermophore (//. e spermophoro 
 centrali libero pendula), Plumbaginacece. 
 
 B. More than one seed-bud in each germen. 
 
 e. Attached to a free central spermophore (g. spermophoro cen- 
 trali libero affixce), Primulacce. 
 
 f. Attached in an angle of the compartment of the germen 
 (g. angulo interno loculorum affixes), Iridacece. 
 
 g. Attached to the parietal spermophore (y. spermophoro pa- 
 rietali affixes), Orchidacece. 
 
 There are some further general remarks to be made upon its 
 form. The free spermophore may, like the axis, present various 
 shapes ; it may be conical, spherical, and pedicellate, cylin- 
 drical, prismatic, winged, &c. The adherent spermophore, so 
 soon as it is to be distinguished as a projecting ridge, may be 
 simple or split into two lamella?, which are often very broad (as in 
 Begonia and Gesneracece ; spermophorum bilamellatum, bifidum) ; 
 each of these lamella may again be divided, so that the sper- 
 mophore may have four seed-bearing edges ; as in Mariynia 
 diandra. The structure in the Cucurbitacece is peculiar ; in these 
 the parietal spermophore, extending in as far as the axis, here 
 become split into two lamina? ; these lamina?, consisting of the two 
 spermophores applied together, turn back again to the wall of the 
 cavity of the germen ; thus a new spurious septum is formed in 
 the compartments already formed by spurious septa, and then 
 each curves once more to its own side in the secondary com- 
 partment, and produces the seed-buds on the free edges. 
 
 It may be originally a thin plate, the edge of which becomes 
 thickened into a border, and this again may be angular or winged, 
 &c. It is, moreover, by no means unusual for the substance of the 
 spermophore to be much distended between the seed-buds, so that 
 they are seated on, or imbedded in, little heaps of the parenchyma, 
 as is very frequently the case in the Primulacece. 
 
 As to its structure, it is usually composed of delicate walled 
 
PHANEROOAMIA: FLOWERS. 385 
 
 cellular tissue, covered with epithelium ; and only when it occurs 
 naked (as in the Conffera), of tough, porous, woody cells, clothed 
 with epidermis. According to its form, it is traversed by one or 
 more vascular bundles, like a simply-formed axis ; and these 
 usually give off as many side branches as there are seed-buds 
 present ; the seed-buds may be destitute of vascular bundles, as is 
 the case in the Orchidacece, &c. Sometimes the internal portion 
 consists of very lax, spongy, cellular tissue, with large intercellular 
 spaces ; as in some Cruciferce, Capsella, &c. 
 
 I will here add some few observations, and in these take the sections 
 given in the paragraphs separately. 
 
 Obs. 1. Robert Brown had already shown incontestibly, from the 
 structure of the seed-buds, that the Conifer & and Cycadacece have naked 
 seed-buds. The investigation of development, in which an integument 
 is very easily distinguished from a germen, confirmed this truth. But 
 this great observer had not gone beyond this, and therefore took the 
 certainly leaflike scale for an open carpel the more readily, that at that 
 time the view was universally received that seed-buds were formed on 
 the borders of foliar organs. But so soon as the history of develop- 
 ment had shown beyond doubt that, at least in a great number of 
 plants, the seed-buds cannot have their origin from a foliar organ, but are 
 borne immediately by the axis*, this old prejudice lost all value; and 
 the question now arose for every single group of plants : Is the part 
 which bears the seed-bud an axial or a foliar organ ? Whence shall 
 we now take the ground of distinction ? The following expresses the 
 train of thought : 1. In the regular course of vegetation a normal bud 
 never arises according to law at a definite place on a leaf: when buds 
 arise according to law at definite places, the base is always an axis. All 
 cases which are brought forward in opposition to this are occurrences 
 which happen under conditions foreign to the normal vegetation of the 
 plant, but on this alone may we build any theory. 2. Throughout the 
 whole vegetable kingdom no simple leaf is ever formed in the axil of 
 another leaf; that which arises in an axil is always an axial organ with 
 more or less perfect leaves. 3. Leaf and axis cannot in any way be 
 distinguished by external form, but only and solely by the process of 
 development ; therefore, as to the foliar or axial nature of a doubtful 
 organ, the only means of decision, besides the 1st and 2nd analogies just 
 mentioned, is the history of development ; but this latter gives the safest 
 conclusion. 
 
 Now, we find in Abies that in the axil of a foliar organ exists 
 another organ, which is formed exactly like an axial organ, and subse- 
 quently has buds (seed-buds) developed upon it. This organ is conse- 
 quently not a carpel but a free spermophore. Having obtained this 
 result with certainty, we may now judge with greater confidence in the 
 other Coniferce and Cycadacece. Accordingly, the female flower of Cycas 
 and Abies are only distinguished by the fact, that in the former the 
 spermophore bears several unreversed seed-buds. Here it is pre-sup- 
 posed that it also arises from the axil of a leaf, which, unfortunately, 
 has not been noticed by any botanist who has had the opportunity. 
 
 * Of these, with easily traceable development, may be given Taxus and Viscum, from 
 which we may venture to assert a similar origin of the seed-bud in Ephedra, Podocarpus, 
 Dacrydium, and in the rest of the LaranthaceeB. 
 
 c c 
 
386 MOKPHOLOGY. 
 
 Obs. 2. The following cases are possible here :. 
 
 a. The floral axis, as terminal shoot, itself bears one seed-bud, either 
 without being distinguishable in the cavity of the germen as a special 
 organ (spermophore) (gemmicula basilaris, e. g. Zea Mays), or elongated 
 into the cavity as a free central spermophore (gemmula ex apice sper- 
 mophori centralis liberi filiformis pendula, e. g. Statice). 
 
 b. The floral axis, more or less elongated into the cavity of the germen 
 as a central spermophore, bears the seed-buds as lateral buds (gemmula 
 angulo interno loculorum affixce, in part, and the spermophorum centrale 
 of descriptive botany, e. g. Ericacece) ; if there are not more seed-buds 
 than carpels, the former appear as axillary buds of the latter (e. g. Lava- 
 tera), otherwise they have no supporting leaves (e. g. Labiatce and 
 Boraginacece). If the borders of the carpels do not turn inward and 
 become blended with the spermophore, the latter stands free in the 
 midst of the cavity (spermophorum centrale liberum, e. g. in the 
 Primulacece). 
 
 c. The floral axis is ramified in the cavity of the germen, und the 
 shoots (axillary shoots of the carpels) curve immediately from their 
 origin toward the side, and become blended with the margins of the two 
 carpels on their inner side, as parietal spermophores, bearing the seed- 
 buds as lateral buds (spermophora parietalia, e. g. in Resedacece and 
 Cruciferce). Here the spermophores may be so uniformly blended with 
 the carpels as to be indistinguishable as special organs, or they may 
 project by the seed-bud-bearing margin into the cavity, and even meet 
 in its axis, thus forming spurious central spermophores, or, lastly, may 
 expand as a naked lamella between the seed-buds, come in contact in the 
 interior of the cavity, here unite with one another, and form false 
 septa (e. g. in the Cruciferce). 
 
 In the case of the superior germen, we find a great number of plants 
 in which the immediate origin of the seed-buds, as true axial organs, 
 follows at once from their position, and this is decisively confirmed by 
 the history of development. I here name only the following plants*, in 
 which I have myself observed the development, and for which I can 
 therefore answer: Amarantacece, Ardisiacece, Aponogeton, Arum., Am- 
 brosinia Bassii, Berberacece, Cyperacece, Chenopodiacece, Caulinia, Calla 
 palustris, Cryptocoryne spiralis, Caladii spec., Ericacece, Globularia, Ora- 
 minece, lllecebracece, Lemnacece, Linacece, Malvacece, Melianthus major, 
 Myricacece, Najas, Nyctaginacece, Orontium aquaticum, Primulacece, 
 Plumb aginacece, Polygonacece, Portulacece, Piperacece, Pistiacece, Poly- 
 gala, Plantago, Sauromatum guttatum, Trapa natans, Urtica, and some 
 others presently to be mentioned. Such a series cannot certainly be 
 explained as isolated exceptions, but allows us to conclude the existence 
 of such a wide prevalence of a law, that, moreover, presumption does 
 not speak in favour of the formation of the spermophore out of the 
 border of a leaf, but against it, especially when it is remembered that 
 many families, genera, and species allied to those named, admit of being 
 added to them by analogy, at first sight, and with certainty, in particular 
 all plants, without exception, with spermophorum centrale liberum or 
 gemmulis basilaribus. To this may be added the plants in which the 
 seed-bud is nothing in the world else than the axillary bud of the carpel- 
 lary leaf, of which I can name the following : Alisma, Dryadece, Euphor~ 
 
 * In very uniform families I have always examined several genera ; in genera, a few 
 species. 
 
PHANEROGAMIA : FLOWERS. 387 
 
 bid, Limnanthes Douglasii, Lttzula, Malvacece loculis I-ovulatis, Mercu- 
 rialis, Phytolacca decandra, Sagittaria, Tropceolacece, Triglochin. The 
 said plants comprehend the cases named under a. and b. For the case 
 of c. speaks the entire course of development in the Cruciferce ; in the 
 Resedacece, however, both this and the most beautiful retrograde meta- 
 morphoses in all conceivable intermediate stages, which occur frequently 
 enough in gardens in Reseda alba. A great many cases of course remain 
 undecided, in which I can only assume the axial structure of the spermo- 
 phore : on these, future investigations of the development can alone 
 decide ; hitherto my time has not been sufficient to work up more 
 material. 
 
 Here, again, the following varieties occur ; namely, the true central 
 spermophore, blended with true septa (in Solanacece, Acanthacece, &c.), 
 the spurious central spermophore formed out of the parietal spermo- 
 phore, which projects in as far as the axis of the cavity of the germen, 
 which thus becomes spuriously many-celled. The latter two cases are 
 frequent. 
 
 In regard to the gemmula basilaris I will once more mention that the 
 unilateral development of the receptacle often makes the spermophore 
 appear like part of the wall of the cavity of the germen, which, in fact, 
 is only the bottom of it, and that, hence, seed-buds may also be spurie 
 laterales, which really are basilares ; this is especially the case in all 
 Grasses, Potamogetons, and perhaps in many others, of which we are at 
 present ignorant of the course of development. 
 
 Obs. 3. Persons may think what they will of the nature of the inferior 
 and half-inferior germen s, but there are cases here beyond doubt, where 
 position and course of development demonstrate the seed-bud to be an 
 immediate prolongation of the axis. Here are included, above all, the 
 extensive family of Composite, which, comprehending a tenth of the 
 whole Phanerogamic vegetation, give no little weight to the idea of the 
 universal law of the formation of the spermophore out of the axis. I 
 will further name, from my own researches, iheJuglandacece, Elceagnacece, 
 Lonicerece, Rubiacece, and Peliosanthes Teta. In none of these can any 
 tolerably accurate observer doubt that the spermophore is an immediate 
 prolongation of the floral axis, and itself an axial organ. The same 
 result is obtained from the investigation of the development of the 
 Myrtacece. 
 
 If, however, the development of an inferior germen is accurately 
 traced, not the smallest doubt remains that this itself is also merely an 
 axial organ ; and in the parietal formation of the spermophore it is 
 equally certain, where the carpels do not even apparently project into 
 the cavity of the germen, that the seed-buds are seated on an axial organ. 
 In order to comprehend the spurious central spermophore, it must be 
 called to mind that the inner surface of a cup-shaped axial organ corre- 
 sponds to its sides in the usual condition ; now if these exhibit projecting 
 ribs, on which the buds are seated, somewhat as in Echinocactus, in the 
 concave shape these ribs must project inwards, and the carpels above 
 may be blended with these projections of the axis running upwards, like 
 the so-called folium decurrens with those running downwards. On the 
 other hand, it must be recollected that these projections (which form the 
 spurious septa and bear the seed-buds) are perpendicular from the 
 margin of the cavity of the germen to its base : this direction, however, 
 corresponds to that from below upwards in the usual condition of the 
 
 c c 2 
 
388 MORPHOLOGY. 
 
 axis, and no leaf is ever attached to an axis in this way, but always in 
 the transverse direction : already from this it follows that these projec- 
 tions cannot be leaves. Finally, if the wing of the axis in the folium 
 decurrcns is assumed to be a real foliar part, the analogy would be 
 inapplicable here, since the direction, if from the margin of a hollow 
 axis to the bottom of its cavity, corresponds to the direction from below 
 upwards : now we really know the so-called decurrent leaves, but leaves 
 running up a stem are unheard of. Thus the assumption of the form- 
 ation of the spermophore from the axis appears to be unexceptionably 
 established for this section. The conditions which occur may be 
 arranged according to the following review : 
 
 a. The terminal bud, therefore the innermost and lowest part of the 
 cavity of the germen, may develope as seed-bud (gemmula basilaris unica 
 in g ermine infero, e. g. in the Composite), or the axis may rise up again 
 in the cavity of the germen, and bear the seed-buds as lateral buds 
 (spermophorum centrale in germine infero, e. g. in the Myrtacece). 
 
 b. The internal surface of the cavity of the germen bears the seed- 
 buds in as many lines as there are carpels, without further marking of 
 the spermophores (spermophora parietalia). 
 
 c. From the internal surface of the cavity of the germen project as 
 many ridges, in the same arrangement, the free angles of which bear the 
 seed-buds (spermophora parietalia, e. g. Orchidacece). 
 
 d. The projecting ridges become so broad that they meet in the axis 
 of the cavity of the germen, and thus form spurious septa ; then their 
 borders split into two layers, which, somewhat recurved, project into the 
 two contiguous cells, and each bears seed-buds in its free angle (gemmulce 
 in angulo loculorum interno affixes, e. g. Iridacea). 
 
 Obs. 4. Here 1 have nothing to add, but only to direct attention to 
 what has been said regarding the germen. If I was right then, the 
 matter here is self-evident. 
 
 Obs. 5. On the cases here brought forward I will not venture to 
 judge, because I do not know the complete course of development. In 
 an earlier work (yet trammelled by the spirit of the old school in which 
 I learnt) I have helped myself out with analogies and guesses, which I 
 here expressly recall. True observation and investigation of nature 
 have shown me how this road can never lead to safe conclusions, and in 
 most cases does lead to error, since, to use analogy, we must first have 
 higher principles of unity and universal laws ; and these are just what 
 we as yet are destitute of, and can never be gained in the manner in 
 which it has been attempted hitherto. Therefore, I prefer rather to 
 confess my ignorance, where I know myself not to be warranted by a 
 complete knowledge of the development, than to think only of the 
 present, and purchase the distant possibility of being held an acute 
 observer of nature, with the much closer probability of a most wretched 
 blunder. 
 
 Finally, I have a few general remarks to subjoin. It is a frequent 
 phenomenon for the seed-buds to be seated on two- or many-budded linear 
 spermophores, and since in these cases just as many spermophores as 
 carpels, therefore twice as many rows of seed-buds, exist, this condition 
 has much contributed to nourish the prejudice that the seed-buds arise in 
 rows from the margins of the carpels. With the countless instances of 
 a different kind of structure of the spermophore, the correctness of this 
 relation admitted, the matter would not be of great importance. But 
 we have quite a different explanation afforded us of the bi-seriality of the 
 
PHANEROGAMIA : FLOWERS. 389 
 
 seed-buds, which especially prevails in the cases where the spermophore 
 is central, or belongs to the inferior germinal cavity ; if we here put out 
 of view the metamorphosis of the fundamental organ, and continue the 
 arrangement of the carpellary leaves in equal-membered alternating 
 circles, we obtain, with two carpels four-ranked, with three six-ranked 
 leaves, therefore four or six rows of axillary buds. By the conversion 
 of the axis into the spermophore the regular rows of buds are pressed 
 nearer together in pairs. If we examine, in this respect, Tillandsia 
 amcena, we find really six spermophores, which are approximated in 
 pairs, but neither so morphologically nor anatomically connected as to 
 justify us in regarding them as three two-leaved organs. 
 
 Where, however, the spermophores are to be regarded as lateral 
 branches of the floral axis, whether in germens formed of carpels or in the 
 stem-pistil, we must always look upon them as flat shoots folded together, 
 which then, somewhat like the flat shoots of Phyllanthus, bear two 
 rows of buds. 
 
 On the structure of the spermophore I have no additional remarks to 
 offer, since no especially striking conditions are known to me. 
 
 c. Of the Seed-bud (Ovule). 
 
 161. Every seed-bud (gemmuld) appears at its first origin as a 
 email roundish papilla at the extremity of an axis (terminal shoot) 
 within the flower ; as such it is an erect, straight seed-bud (aemmula 
 erecta, atropa). It consists simply of the nucleus (nucleus, chorion 
 [Malpighi], perisperma [Treviranus], lamande [Brongniart], tercine 
 [Mir Del]), without special integument (nucleus nudus). On this 
 seed-bud are to be distinguished the base (when it does not gradually 
 pass into the axis of which it forms the extremity) at the point of 
 attachment of the seed-bud (hilus, umbilicus), and the apex as 
 nuclear papilla (mammilla nuclei, mamelon tf impregnation [Brongn.] ). 
 The seed-bud seldom persists in this simple condition, as in the 
 LoranthacecK. It usually changes, partly by the formation of the 
 integuments of the bud, and partly by the peculiarity of its modes 
 of development, which may in general be termed curvatures. 
 
 At a greater or less distance beneath the apex of the seed-bud 
 there arises simultaneously on the whole circumference a circular 
 fold, which gradually rises over the nucleus and closes in it above, 
 leaving only a small orifice. If this development is permanent (as 
 in Taxus and the Piperacece), this envelope is termed a simple bud- 
 integument (integumentum simplex) ; the upper opening is called the 
 micropyle, and the part where the bud-integument and nucleus are 
 confluent is called the base of the bud (chalaza). The point of 
 attachment is here precisely defined, as in the former case. Below 
 the first circular fold, of which we have spoken, a second is often 
 formed, which encases the first as the first encases the seed-bud. 
 The first is then styled the inner bud- integument (integumentum 
 primum internum, membrana internet [Robert Brown], teamen 
 [Brongniart], secondine [Mirbel]). The other is the second or outer 
 
 c c 3 
 
390 MOKPHOLOGY. 
 
 bud-integument (integumentum secundum externum, testa [Robert 
 Brown, Brongniart], primine [Mirbel]). Then the orifice of the outer 
 integument is known as the exostome (exostomium), that of the inner as 
 the endostome (endostomium). If beneath the entire seed-bud there 
 yet remains a free, distinguishable piece of the axis, this is termed the 
 gemmophore (funiculus). The seed-bud is found in this state of 
 development in, for example, Hydrocharidea, with the exception of 
 Stratiotes, in many Aracece, in the Polygonacece, &c. 
 
 This form of seed-bud is modified in many ways by means of the 
 curvatures above mentioned. 
 
 1. The funiculus is much elongated, the nuclear papilla bends 
 downwards, and thus the side either of the naked nucleus or of the 
 simple or of the external bud-integument turned towards the funi- 
 culus, becomes gradually blended with it. In the perfect seed-bud 
 the nuclear papilla then lies close to the point of attachment, the 
 chalaza opposite to the point of attachment, and the line from the 
 centre of the chalaza through the middle of the nucleus is straight. 
 Such a seed-bud is termed re versed (gemmula anatropa]\ the adherent 
 part of the funiculus is termed the raphe. This appears to be the 
 most frequent form ; it occurs in the naked nuclei * of Hippuris and 
 fiubiacece, in the simple bud-integument of the Composite, in the 
 double bud-integument of the Liliacece, &c. 
 
 If the blending of the funiculus with the bud-integument only 
 affects the lower part of the seed-bud, so that a considerable part of 
 the apex (the upper half) is left free, the seed-bud is said to be half 
 reversed (gemmula hemianatropa), as, for instance, in Meconostigma 
 and many Aracece. If the funiculus is then very short and scarcely 
 perceptible (g. sessilis), the seed-bud appears as if attached by the 
 centre (medio affixa, peltata). 
 
 2. The two sides of the seed-bud are unequally developed ; one 
 remains almost totally at a stand-still, whilst the other is exceedingly 
 increased, and in the perfect seed-bud constitutes almost the entire 
 circumference of the seed-bud. The point of attachment and 
 chalaza are here almost coincident ; the nuclear papilla lies near the 
 first, and a line drawn from the centre of the chalaza through the 
 centre of the nucleus to the point of the nuclear papilla is a curved 
 line ; such a seed-bud is termed a curved seed-bud (gemmula 
 campylotropa). 
 
 I am not acquainted with any example of this in the naked 
 nucleus. Datura may be cited as an example in the simple bud- 
 integument, and in the double bud-integument instances are offered 
 
 * Robert Brown also enumerates the Apocynacece and Asclepiadacece here. I have already 
 said that the Apocynacece have a simple integument ; but, more recently, I have convinced 
 myself that in the Asclepiadacece, also, a very minute nucleus is enclosed in a thick 
 integument at a very early period. . Jn both families the nucleus is displaced by the 
 embryo-sac long before impregnation ; but the micropyle canal, which may be detected 
 long before the flowering period, proves beyond a doubt the existence of an integu- 
 ment. 
 
PHANEROGAMIA : FLOWERS. 391 
 
 by many Solanece, the generality of the Grasses, the Silenacece, and 
 the Cruciferce. 
 
 3. The conjunction of the circumstances described under 1. and 
 2. produces a form in which exists a short raphe ; hence the chalaza 
 and point of attachment do not coincide, while at the same time one 
 side of the seed- bud remains undeveloped, so that here also a line 
 drawn from the chalaza through the centre of the nucleus up to 
 the nuclear papilla is curved. This form is termed semi-curved 
 seed-bud (gemmula hemitropa) : as accompanying the simple 
 bud-integument it is peculiar to the Labiates and Boragi7iaceae, as 
 accompanying the double bud-integument, to the Leguminosa. 
 
 4. When a seed-bud is very much elongated, a curve is formed 
 in its middle during its development, so that it appears curved in a 
 horse-shoe form. Here the point of attachment and the chalaza 
 coincide ; the nuclear papilla and the point of attachment lie side by 
 side. A line drawn through the middle of the nucleus is curved, 
 but the two sides of the seed-bud are parallel and equally developed. 
 If the seed-bud is confluent in the curvature, it is called an arched 
 seed-bud (gemmula camptotropa\ as in the Potamogeton and Gal- 
 phimia ; if it is not confluent, it is called a horse-shoe-formed seed- 
 bud (g. lycotropd] : according to Griesbach this occurs in many 
 Malpighiacece. 
 
 5. In some few cases, after the formation of -the seed-bud is 
 complete, an additional bud-integument is produced, which more or 
 less entirely envelopes the seed-bud : this is termed an arillus 
 (in Hellenia ccerulea) ; it of course bears no part in the curvatures, 
 which are complete at the period of its origin. 
 
 Malpighi, in his immortal works, laid the foundation for the study of 
 the structure of the vegetable seed-bud ; but his successors added nothing, 
 and neither used nor understood what he had taught them. Treviranus, 
 in his account of the development of the embryo, certainly did nothing to 
 advance the knowledge of the structure of the seed-bud ; he did not follow 
 up that which Malpighi had done, and he overlooked that very important 
 part of the seed-bud, the embryo-sac. It was Robert Brown who, in 
 1826*, first gave the true history of an unimpregnated seed-bud in 
 Kingia australis. Brongniart f gave some useful contributions. Mirbel J 
 subsequently investigated the history of the unimpregnated seed-bud, in 
 which he gave most interesting explanations, but promulgated a totally 
 incorrect view of the formation of the integuments, which, although long 
 since refuted by Robert Brown and Fritsche, is set forth, i. e. copied, 
 still in Link's Elem. Phil. Bot., ed. 2, vol. ii. p. 79, and even in much more 
 recent works, easy as it is to make the observation in any Lily or 
 Passion-flower, since nothing more is required than a simple microscope, 
 magnifying some twenty times, and a couple of not particularly fine cross- 
 
 * King's Voyage, Appendix, " Botany." London, 1826. 
 
 f Mem. sur la Generation et le Developpement de 1'Embryon dans les Vegetaux 
 Phanerogames. Paris, 1827. 
 
 \ Rech. sur la Struct, et les Devel. de I'Ovule Veget, lu a 1'Acad. des So., Dec. 
 1828, et Add. aux Nouv. Recherches, &c., lu a 1'Ac des Sc., Dec. 1829. 
 
 c c 4 
 
392 MOKPHOLOGY. 
 
 sections from a young germen. Robert Brown * was here again the first 
 to strike out the true path, and showed, contrary to Mirbel's view, that 
 the original nucleus of the seed-bud does not open at the apex and allow 
 first the internal integument and then the true nucleus to grow forth 
 (hence Mirbel's mistaken application of the numbers in his names primine 
 and secundine), but that the inner and then the outer coat originate as 
 circular folds on the base of the originally solid nucleus, and gradually 
 envelope it. Fritsche's * observations did at least put the incorrectness 
 of Mirbel's views beyond doubt, if his own idea of the mode of formation 
 of the integuments was not wholly in accordance with the simple opera- 
 tions of nature. 
 
 Brown, in his first works, has assumed the continual presence of two 
 integuments. Brongniart pointed out that seed-buds with one integument 
 undoubtedly occur. In Robert Brown's Treatise upon the Fecundation 
 of the Orchidacece, he called attention to the fact of the occurrence of the 
 naked seed-bud, after Mirbel had correctly developed the most important 
 curvatures presented by the seed-bud. 
 
 Excepting Fritsche, who at the time of his writing was in St. Peters- 
 burgh, not a single German botanist has done anything on this weighty 
 point of our subject, not even so much as to re-examine the re- 
 searches of the distinguished Frenchman and Englishman ; and we find, 
 in consequence, even up to the most recent dates, the false views of 
 Mirbel, and these often sadly disfigured, copied without reflection. 
 
 Using the observations of these men, I have made a large series of 
 investigations upon the development of the unimpregnated seed-bud in 
 plants of the most different families; and I have succeeded in verifying the 
 laws which had been laid down, modifying them in some subordinate 
 matters, and discovering a great body of facts, which are related in my 
 two treatises, " Einige Blicke auf die Entwicklungsgeschichte, &c.," 
 Wiegmann's Archiv., 1837, i, 289, and " Ueber Bildung des Eichens, &c.," 
 Act. A. C. L. C. N. C., vol. xix. P. I., p. 29. I have stated the main 
 points in the paragraphs. For the history of the development of a 
 reversed seed-bud with two integuments I refer to Plate IV., with 
 its explanation. I will now add a few remarks of subordinate im- 
 portance. 
 
 The above-mentioned varieties of the seed-bud which arises from its 
 curvature are only the main types, and by no means embrace all possible 
 diversities ; nay, are only arbitrary distinctions, since between each of 
 those named occur intermediate forms which are difficult to reduce. No 
 definite laws, therefore, can be laid down for the occurrence of particular 
 forms, any more than for the number of integuments. Usually the same 
 form is constant in the same family, yet it does sometimes exhibit 
 deviations ; this, however, less in Dycotyledons than in Monocotyledons : 
 amongst the last, the family of the Aracece especially exhibits an endless 
 variety of forms of seed-bud. In order to aid the comprehension of the 
 various forms of seed-buds, and to lead to the examination in actual 
 specimens, I here offer some examples arranged as systematically as 
 is possible. The seed-buds are exhibited cut accurately in half by a 
 successful longitudinal section : 
 
 * Observations on the Organs and Mode of Fecundation in Orehidacea and dsclepi- 
 dacete. Condon, 1831. 
 
 f Wiegmann's Archiv, 1835, vol. ii. p. 229. 
 
PHANEROGAMIA : FLOWEK8. 
 
 393 
 
 1. Seed-bads not curved, as naked nuclei (fig. 222. b\ or with one 
 (fig. 223.) or with two integuments (fig. 224). 
 
 222 
 
 ctT 
 
 2. Reversed seed-buds, as naked nuclei (fig. 225.), or with one (fig, 226.) 
 or with two integuments (fig. 227.). 
 
 227 
 
 229 
 
 3. Half-reversed seed-buds, with peltate mode of attachment (fig. 228.) 
 and erect (fig. 229.). 
 
 *** Viscum album. Longitudinal section through the female flower, a, Point of 
 attachment (hilum) and chalaza ; b, end of the floral axis as seed-bud, forming a straight 
 naked nucleus ; c, boundary of the pith in the pedicel, in which the embryo-sacs are 
 also developed (two are shown in the figure) ; x, floral envelopes. 
 
 223 Taxus baccata. Longitudinal section through the seed-bud, a, Hilum and cha- 
 laza ; b, nucleus ; c, embryo-sac ; d, simple integument ; e, large cells of the endosperm 
 (corpuscula Robt. Brown); g, micropyle ; and A, rudiments of the arillus. 
 
 i24 Polygonum divaricatum. Seed-bud in longitudinal section, a, Hilum and cha- 
 laza ; 6, nucleus ; c, embryo-sac ; d, inner, and /, outer integument ; g, micropyle. 
 
 KS Hippuris vulgaris. Seed-bud in longitudinal section, a, Hilum ; 6, naked nu- 
 cleus ; c, embryo-sac ; g, nuclear papilla ; h, chalaza ; r, raphe. 
 
 26 Adoxa Moschatellina. Seed-bud in longitudinal section, a, Hilum ; b, nucleus ; 
 c, embryo-sac ; rf, simple integument ; g, micropyle ; h, chalaza ; r, raphe. 
 
 47 Cucurbita Pepo. Seed-bud in longitudinal section, some time after impregnation, 
 a, Hilum ; 6, nucleus ; c, embryo-sac ; d, inner, and /, outer integument ; g, micropyle ; 
 h, chalaza ; r, raphe. 
 
 8i8 Lemna trisulca. Seed-bud in longitudinal section. a, Hilum ; b, nucleus ; 
 c, embryo-sac ; rf, inner, and f, outer integuments ; g, micropyle ; h, chalaza ; 
 r, raphe. 
 
 829 Meconostigma pinnatijidum. Seed-bud in longitudinal section. a, Spermophore, 
 funiculus, and hilum ; b, nucleus ; c, embryo-sac ; d, inner, and /, outer integuments ; 
 g, micropyle : A, chalaza ; r, raphe. 
 
394 
 
 MORPHOLOGY. 
 
 4. Curved seed-bud, as naked nucleus (fig. 230.), with one (fig. 231.) 
 or with two integuments (fig. 232.). 
 
 232 
 
 230 
 
 5. Semi-curved seed-bud, with one (fig. 233. ) or with two integuments 
 (fig. 234.). 
 
 6. Arched seed-bud, with two integuments (fig. 235.). 
 
 235 
 
 233 
 
 234 
 
 7. Reversed seed -bud, with two integuments and an arillus (fig. 236.). 
 
 8. Doubly-curved seed-bud, with two integuments (fig. 237.). 
 
 9. Wholly abnormal, spirally-curved seed-bud, with two integuments 
 (fig. 238.). 
 
 880 Galium Aparine. Seed-bud in longitudinal section, a, Hilum and chalaza ; 
 6, naked nucleus ; c, embryo-sac ; g, papilla of the nucleus. 
 
 231 Datura Stramonium, a, h, Hilum and chalaza ; 6, nucleus (as a nuclear membrane) ; 
 c, embryo-sac ; d, simple integument ; g, micropyle. 
 
 232 Spergula pentandra. Seed-bud in longitudinal section, a, h, Hilum and cha- 
 laza ; b, nucleus ; c, embryo-sac ; c?, inner, and f, outer integument ; g, micropyle. 
 
 233 Salvia officinalis. Seed- bud in longitudinal section. a, Hilum; b, nucleus; 
 c, embryo-sac ; d, simple integument ; g, micropyle ; h, chalaza ; r, raphe. 
 
 234 Colutea arborescens. Seed-bud in longitudinal section, a, Hilum ; b, nucleus ; 
 c, embryo-sac ; d, inner, and f t outer integument ; g, micropyle ; A, chalaza ; r, raphe. 
 
 235 Galphimia mollis. Seed-bud in longitudinal section a, Funiculus and hilum ; 
 A, chalaza; b, nucleus ; c, embryo-sac ; d, inner, and/, outer integument; g, micro- 
 pyle. 
 
PHANEROGAMIA: FLOWERS. 
 897 
 
 395 
 
 236 
 
 238 
 
 In the formation of the integuments, the conditions and relations of 
 the individual parts particularly deserve a closer investigation. 
 
 In the first place, I must remark that the term nucleus, as used in con- 
 tradistinction to the integuments, designates only that portion of the ori- 
 ginal little conical body, which, in the beginning above the integuments, 
 becomes covered up by these, and to which the micropyle canal leads. The 
 relative size and the form of this nucleus are very various ; it usually 
 forms a small ovate body, being thicker above the base, and then gra- 
 dually narrowed towards its summit (fig. 239.) ; but it is also frequently 
 a long cylinder (in many Scrophulariacce, as, for example, Pedicularis 
 (fig. 240.) ; frequently, it is a mere blunt cone (as, in Podostemon\ or a 
 hemisphere (as in Convolvulus, fig. 241.), or even little more than a mere 
 point to which the micropyle canal leads, whereby alone such a seed-bud 
 is distinguished from a naked nucleus (for example, in Scabiosa, fig. 242.). 
 
 239 
 
 240 
 
 241 
 
 242 
 
 J 
 
 836 Hellenia carulea. A, Seed-bud before impregnation : x, thickened border of the 
 exostome. #, The same in longitudinal section : a, funiculus and hilum ; b, nucleus ; 
 c, embryo-sac ; d, inner, and /, outer integument ; g, micropyle ; h, chalaza ; r, raphe ; 
 k, arillus. 
 
 837 Scleranthus perennis. Seed-bud in longitudinal section, a, Funiculus and hilum ; 
 6, nucleus; c, embryo-sac; d, inner, and/, outer integument; g, micropyle; h, chalaza. 
 
 838 Lathraa sqnainaria. Seed-bud in longitudinal section, a, Hilum ; b, nucleus 
 (as a nuclear membrane) ; c, embryo-sac, with its appendices; d, simple integument; 
 g, micropyle ; h, chalaza. 
 
 239 Lilium spec. Seed. bud in longitudinal section, c, Nucleus ; m, nuclear papilla; 
 g, micropyle. 
 
 840 Pedicularis palustris. Seed-bud in longitudinal section, c, Nucleus ; m, nuclear 
 papilla ; g, micropyle. 
 
 811 Calystegia septum. Seed-bud in longitudinal section, c, m, Nucleus and nuclear 
 papilla ; g, micropyle. 
 
 848 Scabiosa atropurpurea. Seed-bud in longitudinal section, c, m, .Nucleus and 
 nuclear papilla ; g, micropyle. 
 
396 MORPHOLOGY. 
 
 No law can at present be laid down concerning the number of in- 
 teguments, except that, so far as my observation extends, all Monocoty- 
 ledons, without exception, possess two integuments, whilst in Dicotyledons 
 we find sometimes two, sometimes one, and sometimes none at all. 
 Speaking generally, we may say that in monopetalous plants the form- 
 ation of one, and in polypetalous two integuments, are the more frequent. 
 The total absence of integuments is the least frequent condition. 
 
 In the RanunculacecB one and two integuments occur in the same 
 family ; and, as I believe, in the same genus Delphinium, of which most 
 species have two, but D. tricorne and chilense only one integument. 
 Otherwise, so far as my knowledge extends, the number of integuments 
 in the same family is a very constant character. A certain recognition 
 of the very earliest conditions of the seed-bud is a matter of great dif- 
 ficulty in some plants, easy as it is in others ; and the actual size of the 
 parts to be investigated is by no means the cause of this. One of the 
 smallest seed-buds and germens is, for example, presented by Urtica 
 dioica, and yet this is one of the cases in which it can be traced ; the 
 isolation of a germen, and a slight pressure with a glass plate, suffice to 
 make all clear. The difficulty is much more frequently caused by a 
 very dense (preventing transparency) or very loose (interfering with 
 certainty of the section) structure ; by the form of the seed-bud (as in 
 the Asclepiadacece) rendering the section of the seed-bud in symmetrical 
 halves difficult ; by the unsymmetrical arrangement, which renders the 
 precise section into two halves, an impossibility (for instance, in Ve- 
 ronica serpyllifolid} ; by the nature of the contents of the cellular tissue 
 destroying the transparency, and especially by the presence of much 
 hairy structure from which the air can scarcely be disengaged, which 
 makes observation impossible, and, even when the air is driven out, con- 
 fuses the appearances by the irregular superposition. We often hear 
 the following reasoning : " Since a matter could not be observed in such 
 and such larger parts of plants, it is unlikely that any one has ob- 
 served it in much smaller ones." My certain conclusion from this is, 
 that he who thus argues has made but very superficial ob- 
 servations. Taught by experience, I, on the contrary, now 
 frequently seek in preference the smaller plants, because 
 they are often the most advantageous for investigation on 
 account of needing no preparation. Water plants are es- 
 pecially to be recommended for most investigations, since 
 their usually watery and transparent parenchyma greatly 
 favours observation. These are unfortunately too little cul- 
 tivated in our botanical gardens. 
 
 The common form of the papilla of the nucleus is that of 
 a roundish hemispherical body (fig. 239. m) ; sometimes it 
 is drawn out cylindrically, and then somewhat enlarged again 
 at its extremity, as, for example, in the naked nucleus of 
 Loranthus, where the point of the nucleus resembles a style 
 in form (fig. 243. g). 
 
 Another point worthy of attention is the formation of the 
 micropyle : this is commonly only a simple canal, the length 
 of which is dependent merely upon the thickness of the integuments ; 
 sometimes, however, it is a large opening, from which the inner parts 
 
 843 Loranthus Deppeanus. Part of the flower in longitudinal section, a, Pedicel , 
 c, embryo-sac ; o, n, floral envelopes and stamens, cut off; g, nuclear papilla, elongated 
 so as to resemble a style. 
 
PHANEROGAMIA : FLOWERS. 
 
 397 
 
 project out more or less. This is often most striking in the external 
 integument, which frequently leaves fully the half of the seed-bud un- 
 covered, as in Zea, Coix, Panicum (fig. 244.). According to Brown, 
 a similar condition occurs in the species of Banksia and some of those 
 of Dryandra ; however, from investigations made upon fresh flowering 
 examples of Banksia insularis and media, I believe that I have a right 
 to assert distinctly the contrary. On the other hand, I have examined 
 an undetermined Banksia from the Berlin botanical gardens, in which 
 it was certainly as Robert Brown states ; but the seed-buds were sus- 
 pended and half-reversed, whilst, with the two species of Banksia just 
 mentioned, the seed-buds were erect and quite reversed. A remarkable 
 form occurs in some Abietinece ; for instance, in Abies (fig. 245. <?.) and 
 
 245 
 
 at A 
 
 Larix, in which the micropyle is extended into two lobes, papillose, and 
 secretes a fluid ; and thus, from its similarity to a stigma, has been the 
 greatest prop of the opinion that the integument is a germen. It is 
 very common for the inner integument to project beyond the outer one, 
 or at least to have its free border uncovered and lying in one plane with 
 the outer integument. Where this occurs, it is common also to find 
 the part of the inner integument forming the endostome swollen, so as 
 to appear somewhat constricted by the rest. In Aracetz, Liliacece 
 (fig. 246.), &c., this is very frequent. Occasionally, but less frequently, 
 the exostome is swollen in a similar way : this occurs, however, in many 
 Euphorbiacece, (fig. 247.), (the so-called caruncula of the seed), as Mirbel 
 has shown. 
 
 247 
 
 244 Panicum miliacewn. Seed-bud in longitudinal section, a, h, Hilum and chalaza ; 
 6, nucleus ; c, embryo-sac ; d, inner, and/; outer integument, tbe last leaving tlie great 
 part of the first uncovered ; y, micropyle. 
 
 245 Abies excdsa. Longitudinal section through the seed-bud, with the upper part of 
 the micropyle (g) uninjured, a, A, Hilum and chalaza ; 6, nucleus ; c, embryo sac ; 
 d, simple integument. 
 
 *" Trillium erectum. Seed-bud in longitudinal section. a, Hilum; 6, nucleus; 
 c, embryo-sac ; d, inner, and /, outer integument ; g, micropyle, formed solely by the 
 inner integument ; h, chalaza. 
 
 * 47 Euphorbia pallida. Seed-bud in longitudinal section, a, Hilum ; 6, nucleus ; 
 
398 
 
 MORPHOLOGY. 
 
 One of the rarest phenomena is that in which the formation of the 
 outer integument begins higher up upon the seed-bud than the inner, 
 so that the upper half of the nucleus is covered with two integuments, 
 and the lower part only by a very thick, simple one, as is the case in the 
 Tropaolacece (fig. 248.). A similar result occurs in Ricinus (fig. 249.) 
 
 249 
 
 248 
 
 through the opposite process : here the outer integument commences 
 much lower down than the inner one, and the upper part of the seed-bud 
 exhibits two integuments, the under part only one, which is the external 
 one. 
 
 In the presence of integuments, the relation of the chalaza to the rest 
 of the seed-bud, which consists of nucleus and coats, varies exceedingly. 
 The chalaza is usually confined to a small point at the base of the ovate 
 nucleus ; in the conical nucleus it occupies a greater portion, and in some 
 plants ( Canna), and even some families ( CompositcB\ 
 it takes up half, or more than the half, of the entire 20 
 
 seed-bud. 
 
 Lastly, it is to be mentioned, that on reversed 
 seed-buds a peculiar cellular growth, termed a crista, 
 is not unfrequently developed upon the raphe ; it 
 is sometimes narrow, resembling a cock's comb, 
 as in the species of Corydalis (fig. 250.), sometimes 
 thick and broad, so that the seed-bud itself appears 
 but as a small appendage, as in Aristolochia. Some- 
 times, also, such a growth is formed like a collar 
 around the entire seed-bud, or a part of its basis, as 
 in Hellenia. Again, the funiculus has here and there sometimes peculiar 
 hairy appendages, which often envelope the entire seed-bud, and almost 
 always reach to the micropyle. 
 
 162. The structure of the seed-bud is very simple ; it con- 
 sists of parenchyma and a distinct epithelium ; this latter alone, as a 
 mere fold, frequently forms the inner integument, probably in 
 
 c, embryo-sac ; d, inner, and /, outer integument ; g, micropyle, swollen ; h, chalaza ; 
 r, raphe. 
 
 8-18 Chymocarpus pentaphyllns. Seed-bud in longitudinal section, some time before 
 impregnation, a, Hilum; 6, nucleus ; c, embryo-sac ; d, inner, and f, outer integu- 
 ment ; ff, micropyle ; h, chalaza ; r, raphe. 
 
 249 Hicinus leucocarpus. Seed-bud in longitudinal section, a, Hilum ; b, nucleus ; 
 c, embryo-sac ; d, inner, and /, outer integument ; g, micropyle ; h, chalaza ; r, raphe. 
 
 850 Sanguinaria canadensis. Seed-bud in longitudinal section, some time after im- 
 pregnation, a, Hilum ; b, nucleus ; c, embryo-sac ; d, inner, and f, outer integument ; 
 g, micropyle ; A, chalaza ; r, raphe, with a crest-like excrescence. 
 
PHANEROGAMIA : FLOWERS. 399 
 
 all (?) Monocotyledons. The simple integuments, the outer always 
 and the inner sometimes, in Thymelacea, Lauracece, Euphorbiacece, 
 and Cistacece, are composed of parenchyma, clothed on both surfaces 
 with epithelium. Vessels and vascular bundles are never met with 
 in nuclei or the integuments ; usually, however, a vascular bundle 
 traverses the funiculus and the raphe where they are present, but 
 always terminates in the chalaza, frequently in a clavate group, or 
 in a flat or concave expansion of spiral-fibrous cells. The funi- 
 culus is likewise clothed with epithelium, as an immediate continua- 
 tion of the epithelium of the seed-bud. 
 
 The most important circumstance, however, is the change that 
 takes place in the structure of the nucleus. Originally, this con- 
 sists of a homogeneous, delicate, uniform parenchyma, but soon, and 
 simultaneously with the first appearance of the integuments, one in- 
 dividual cell is excessively distended, displaces gradually more and 
 more of the parenchyma around, which becomes dissolved and 
 absorbed, and forms a cavity in the interior of the nucleus, clothed 
 with a simple, structureless, membrane : this cell is the embryo-sac 
 (sacculus colliquamenti vel satius amnii of Malpighi ; the quintine of 
 Mirbel, the sac embryonnaire of Brongniart.) Its form is very 
 various, usually oval, often a slender filiform cell in the axis of 
 the nucleus, the part towards the point of which is considerably 
 swollen (as in Amygdalus.) Its contents are gum, sugar, or mu- 
 cilage ; very rarely it is gradually filled with cellular tissue before 
 impregnation, as in the Asclepiadacea. In extremely rare cases (so 
 far as is at present known, only in Viscum), two or three embryo- 
 sacs are formed simultaneously. 
 
 The anatomical structure of the seed-bud is extremely simple, and I 
 know of nothing important to be added to the above statements. Link 
 says, " Where the funiculus enters the seed, a variously-shaped body 
 often exists, which originates from the thickened and expanded funi- 
 culus, but clothed with an epidermis, of which the funiculus is destitute." 
 Neither funiculus nor seed-buds or seeds, nor any part of them (with the 
 exception of Canna and Nelumbium), have an epidermis with stomates. 
 The funiculus is clothed by epithelium as well as the' seed-bud (or the 
 seed.) Link cites as an example, the caruncula in Euphorbia (which 
 certainly, as I have already said, does not refer here), but in this very 
 instance no epidermis, nay, even no epithelium, can be distinguished, 
 since it is wholly composed of delicate, transparent, and somewhat elon- 
 gated cells: on the other hand, the short thick funiculus has a most 
 distinct epithelium in this very instance of Euphorbia. 
 
 The only essential anatomical point is the development of one cell of 
 the nucleus into the embryo-sac,* This, so far as I can judge at pre- 
 sent, exists in all Phanerogamia without exception ; I venture to assert, 
 ^at I have examined at least 500 plants of the most diiferent families 
 
 * Link (Elem. Phil. Bot. ed. 2. vol. ii p. 283.) says, " Malpighi's sacculus colliqua- 
 menti, which Robert Brown meant, Mirbel not" Link has not read Mirbel properly : 
 he expressly says, " la quintine est la vesicule de famnios, Malpighi,'' &c. Link further 
 says, " This sac'is filled with cellular tissue." This is untrue of at least one-tenth of the 
 Phanerogam ia. 
 
400 MORPHOLOGY. 
 
 (some 150), and have never failed, at least in earlier stages, to extract 
 the embryo-sac uninjured, or at least in such large pieces that there can 
 be no doubt of its existence. Meyen denies it in the Liliacece ; I have 
 already shown * how only most imperfect investigation is to blame for 
 this. Link (El. Phil. Bot. ed. 2. ii. 283.) confounds every thing, because 
 he evidently has made no thorough investigation himself, and therefore, 
 copying Mirbel, Brown, and Brongriiart, understood nothing of what 
 they said. To enumerate all his errors and blunders here, would lead 
 me too far ; every one who knows the subject may readily compare Link 
 and the authors named, and my explanations. 
 
 The observation is surest in Lilium candidum and most of the Or- 
 chidacece, since every cell of the nucleus has a distinct cytoblast here, 
 therefore that cell also which expands to form the embryo-sac. By this 
 means we are enabled always to recognise the tolerably perfect embryo- 
 sac as a simple cell on account of its cytoblast. The demonstration of 
 the embryo- sac is easiest in Phorminm tenax, Amygdalece, Nympha- 
 acece, and some Cucurbitacece, in which it may be exhibited free without 
 much trouble. The form of the embryo-sac varies very much, partly 
 depending on whether the cell which becomes converted into it lies 
 nearest to the chalaza, the middle of the nucleus or the nuclear papilla. 
 Very frequently it originally extends out into a cylindrical cell lying in 
 the axis of the nucleus, which then becomes gradually widened from the 
 summit (the part next the nuclear papilla) downward to the base ; in 
 some families this expansion is confined to the upper part, so that the 
 lower portion appears like a filiform appendage to a large vesicle (Amyg- 
 dalece t CucurbitacecBj Nymphceacece). 
 
 Great differences are manifested in the extent to which the nucleus is 
 displaced by the embryo-sac. Sometimes the cellular tissue in the 
 middle of the nucleus is connected into a closer and firmer ring around 
 the embryo-sac, then usually also possessed of granular contents in this 
 spot : thence the embryo-sac can only expand above and below this 
 region, and thus acquire a lyrate form. In some families it displaces 
 the nucleus very early, even to the extent of leaving only its epithelial 
 layer, the nuclear membrane (membrana nuclei), which may then be 
 readily overlooked (e. g. in the Composite) ; in others, this remnant of 
 the nucleus becomes also displaced, and then, in the perfect seed-bud, 
 the embryo-sac lies free in the cavity of the integuments (e. g. in the 
 Orchidacece) ; in most of the Leguminosce it does not stop here, but the 
 internal integument becomes absorbed, sometimes from above down- 
 ward, sometimes vice versa ; then a remnant of the cellular tissue of the 
 nucleus sometimes remains upon the chalaza as a little conical body, so 
 far as it surrounds the pointed lower extremity of the embryo-sac, e. g. 
 in Phaseolus. In other families, too, a little papillary group of cellular 
 tissue often occurs in the chalaza, which is persistent, and, since the em- 
 bryo-sac displaces the cellular tissue in the circumference, projects as a 
 little cone, clothed by the embryo-sac into its cavity, e. g. in Hedychium. 
 The most remarkable phenomena occur in the Scrophulariacece : here the 
 simple integument is very thick, the micropyle canal very long, and the 
 nucleus a very slender longer or shorter cone, which is sometimes wholly 
 displaced by the embryo-sac. As soon as this happens the apex of it 
 extends out into the micropyle canal, and expands into a sac, displacing 
 
 * Wiegmann's Archiv, 1839, vol. i. p. 256. ; Schleiden, Beitrage zur Botanik, vol. i. 
 p. 40, et seq. 
 
PHANEROGAM1A : FLOAVERS. 
 
 401 
 
 here a part of the integument (of the micropyle); in Lathraa, which 
 plant has altogether a strangely aberrant form of seed-bud, there is 
 formed, not merely here, but at the opposite extremity, a caecal, sac like 
 appendix (fig. 238.). 
 
 Lastly, in the Santalacece it emerges from and lies quite free outside 
 the micropyle as a sac of varying length.* 
 
 The formation of several embryo-sacs in Viscum, already mentioned, 
 is at present peculiar to it. Meyen has the merit of first directing at- 
 tention to it, and almost completely unfolding the particulars. In the 
 beginning the cellular tissue of the pedicel of Viscum is perfectly homo- 
 geneous ; by degrees an abundance of fluid is secreted between the cells 
 lying in the axis ; they separate from their union, and a kind of cavity 
 is formed in which they lie loose. This I formerlyf, before I had suf- 
 ficient material for the history of development, erroneously stated to be 
 the embryo-sac. Two or three of the loose cells in this cavity then ex- 
 pand into the form of tubes, which gradually displace the others (fig. 222.). 
 All the rest, the gradual formation of cellular tissue, and the subsequent 
 processes in the formation of the embryo, agree perfectly with those of 
 other plants. \ Only in a few cases does the embryo-sac, even at this 
 period, become wholly filled with cellular tissue, but in a great many 
 plants there begins at this time (as always happens later) a process of 
 cell -formation, which constantly commences at the circumference of the 
 cavity, and proceeds inwards ; when a few layers of cellular tissue have 
 been formed in this way upon the periphery, they represent what Mirbel 
 has called the quartine, and from not having completely traced their de- 
 velopment, has described as a fourth integument formed between the 
 nuclear membrane and the embryo-sac. It is not a rare occurrence, and 
 in the very family of Cruciferce cited by Mirbel is easily traced in the 
 way I have described it. There can be no question of integuments here. 
 I will merely remark in passing that every embryo-sac subsequently be- 
 comes gradually filled with cellular tissue, which either becomes wholly 
 displaced by the advance of the embryo or remains as endosperm (al- 
 bumen); whether it appears some- 
 what earlier or later makes no 
 difference. In the Conifer ce cellu- 
 lar tissue is likewise formed in the 
 embryo-sac, which, however, be- 
 comes so arranged that from three 
 to six larger cells immediately 
 beneath the part turned toward 
 the nuclear papilla, and clothed 
 only by the embryo-sac on the out- 
 side, become especially strongly 
 developed. The layer of cellular 
 tissue which bounds these cells 
 acquires an epithelial aspect, so 
 that these cells appear like defi- 
 nitely bounded little sacs (Robert 
 Brown's corpusctifa.) I have 
 
 * Griffith on the Ovule of Santalum, Linn. Trans, vol. xviii. 
 
 t Wiegra. Archiv, 1839, vol. i. p. 212.; Schleiden's Beit, zur Botanik, vol. i. p. 21. 
 pi. 2. fig. 15. 
 
 | Link (Wiegm. Archiv, 1841, vol. i. p. 393.), in opposing DeCaisne's very valua- 
 
 151 4 bits exceha. A, Seed-bud in longitudinal section ; />, nucleus ; r, embryo-sac ; 
 
 D D 
 
 251 
 
402 MORPHOLOGY. 
 
 traced the development of these completely in this way in our indige- 
 nous Conifer ce, particularly in Pi?ii(s, Abies, Larix, Taxus, Thuja, 
 Juniperus, &c. In the young cells in the embryo-sac a circulation with 
 reticular currents very often occurs (e. g. in Ceratophyllum, Nymphtza, 
 Nuphar, Pedicularis, &c.). I have described the peculiar forms of this 
 in Ceratophyllum, at length, in the Linnaen. 
 
 III. Of the Transformation and Development of the Parts of the 
 Flowers into the Fruit. 
 
 163. Through manifold changes the individual parts of the 
 fruit are developed out of the flower. The commencement of all 
 these processes is, however, principally (in the natural conditions of 
 plants, as wild, always?) connected with that circumstance which 
 has hitherto been usually called the fecundation of plants. Here we 
 have nothing to do with the explanation and signification Q$ the phe- 
 nomena therein occurring, but with the morphological develop- 
 ment, which comprehends the four following sections: A. The 
 change of place and development of the pollen to the embryonal 
 globule. B. Development of the embryonal globule into the em- 
 bryo. C. The perfecting of the germen and seed into fruit and 
 seed. D. The phenomena exhibited in the other parts of the 
 flower during these processes. 
 
 A. THE CHANGE OF PLACE AND DEVELOPMENT OF THE POLLEN 
 TO THE KMURYONAL GLOBULE. 
 
 164. As soon as the pollen is completely formed and the cells 
 of the anthers have dehisced, the granules are brought in some 
 mode or other, sooner or later, in the LoranthacecB to the nuclear 
 papilla, in the Conifers and Cycadacece to the micropyle, and in 
 other plants to the stigma; or lastly, in the Asclepiadacece and Apocy- 
 nacece, to the points of the stigmatic body which take the place of the 
 stigma. There the granules lie for a variable time, then swell up 
 somewhat, and the pollen-cell grows out gradually at one point of 
 its periphery into a filiform cell (tubus pollmis, tube pollinique, 
 
 ble (but begun much too late) researches to Meyen's excellent essays, but without en- 
 tering at all into Meyen's facts, says, "If Meyen had continued his researches far 
 enough, he would have seen his error." The very reverse, applied to DeCaisne's, would 
 have been a just criticism. Link imagines that Meyen has not thdught of the peri- 
 carpium, the berry. Has Link here thought of the juicy, berry-like seed of Punica ? 
 As if the pedicel in which an embryo has been formed may not become berry-like and 
 juicy as the pedicel of Anacarditcm, which contains no embryo. 
 
 e, corpuscula (R. Br.); </, simple integument; g, micropyle. D, Upper part of the 
 embryo-sac seen from above : three orifices are perceived, formed of larger cells, cha- 
 racterised by the cytoblasts lying exactly externally. C, Upper part of (he embryo- 
 sac in longitudinal section, c, Embryo-sac; e, corpusculum (R. Br.); another, on the 
 right side, shows through the cellular tissue, which fills the embryo-sac. 
 
PHANEUOGAMIA : FLOWERS. 
 
 403 
 
 252 
 
 boyeau, pollen-tubes, budetti pollinici). In the three first-named fa- 
 milies this penetrates immediately into the nuclear papilla ; in the 
 rest it follows the conducting cellular tissue, sometimes growing 
 forth on its surface, sometimes penetrating through its loosened 
 cells, till it reaches the cavity of the germen, and here penetrates 
 through the micropyle, or immediately into the nuclear papilla 
 of the seed-bud. 
 
 "Whether and how the embryo originates 
 from the pollen-tube is in the first place 
 dependant on the question, whether and 
 how the pollen-tube in each case reaches 
 the micropyle and the papilla of the 
 nucleus ; and it is important for the esta- 
 blishment of the facts to separate the two 
 questions completely from each other. The 
 first question, how the pollen -cell deports 
 itself on the stigma, I believe I may an- 
 swer as in the paragraph, for all Phanero- 
 gamia, without exception ; on this point, I 
 think, the facts now lying before us can 
 leave no doubt ; it were rather to be wished 
 that all our inductions in Botany were as 
 well supported. For the illustration of 
 this process may serve a preparation of 
 Helianthemum denticulatum (fig. 252.), in 
 which plant I have not imfrequently ex- 
 tracted the pollen-tube free, in unbroken 
 continuity from the pollen-grain to the 
 seed-bud. I refer also to Plate IV. figs. 
 1 3., with their explanation. However, 
 it appears to me to be to the purpose to 
 give a review of the observations on which 
 my statements are founded. In the fol- 
 lowing plants of the following families I 
 have traced the pollen-tube from the 
 stigma into the micropyle ; in those marked 
 with an asterisk I have frequent, isolated 
 the pollen-tube, in complete, unbroken 
 continuity from the pollen-granule to the seed-bud. 
 
 Families. 
 
 Abietinece.* 
 Cupressineae.* 
 
 GYMNO8PER1LE, 
 
 Species. 
 
 Larix europaea, Abies pectinata, alba, ex- 
 celsa, Pinus sylvestris, uncinata. 
 
 Taxus baccata. Jnniperus communis, sativa, 
 virginiana, Thuja orientalis, Callitris 
 quadrivalvis. 
 
 fiB Helianthemum rlcnticnfafinn. The pistil, in longitudinal section. a, Germen ; 
 6, style ; c, stigma ; rl, pollen-granules, the tubes of which descend in the germen as far 
 as the seed-buds. 
 
 n i) 2 
 
404 
 
 MORPHOLOGY. 
 
 Families. 
 
 Lemnacese. 
 
 Pistiaceae. 
 
 Aroidese. 
 
 Typhaeese. 
 
 Orontiacese. 
 
 Najadeae. 
 
 Alismacese. 
 Juncea3. 
 Philhydreae. 
 Liliaceae. 
 
 Phormiacese, 
 
 Aloineae. 
 
 Hemerocallideae. 
 
 Asphodeleae. 
 
 Tulipaceae, 
 
 Colchicaceae. 
 Bromeliaceae. 
 Irideae. 
 
 Hydrocharideae. 
 Scitamineas. 
 
 Orchideae. 
 
 Ophrydese. 
 
 Arethusese. 
 
 Neottieae. 
 
 Palm ae. 
 Gramineae. 
 
 Cyperaceae. 
 
 MONOCOTYLEDONE^E. 
 
 Species. 
 
 Leimia gibba, trisulca. 
 
 Pistia commutata, obcordata. 
 
 Ari spec., Cryptocoryne spiralis, Sauro- 
 
 matum guttatum.* 
 Sparganiura natans. 
 Pothos reflexa, Orontium aquaticum.* 
 Zannichellia repens, Potamogeton lucens, 
 
 heterophyllus, Caulinia fragilis, Apono- 
 
 geton distachyon.* 
 Alisma Plantago. 
 Luzula pilosa. 
 Philhydrum lanuginosum. 
 
 Phormium tenax.* 
 
 Gasteria subverrucosa. 
 
 Agapanthus umbellatus, Funkia coerulea. 
 
 Eucomis punctata. 
 
 Tulipa sylvestris*, Breyniana*, Tupistra 
 
 squalida. 
 
 Colchicum autumnale.* 
 Tillandsia amoena. 
 Sisyrinchium anceps, Gladiolus psittaci- 
 
 nus.* 
 
 Stratiotes aloides. 
 Canna Sellowii, Maranta gibba, Hedychiura 
 
 Gardnerianum. 
 
 Orchis morio*, latifolia, palustris. 
 
 Epipactis palustris. 
 
 Neottia picta, Goodyera discolor, Prescotia 
 
 plantaginea. 
 
 Chamaedorea Schiedeana. 
 Zea mays, Phleum pratense, Bromus mollis, 
 
 Elymus arenarius, Secale cereale. 
 Carex acuta.* 
 
 DICOTYLEDONEjE. 
 
 Nympha3acese. 
 Ranunculaceae. 
 
 Papaveraceae. 
 
 Cruciferas. 
 Resedaceae. 
 Passifloreae. 
 Cucurbitaceae. 
 
 Nuphar luteum. 
 
 Thalictrum petaloideum, Aconitum Napel- 
 lus. 
 
 Papaver Rhoeas, Argemone Hunnemanni, 
 Chelidonium majus, Sanguinaria cana- 
 densis, Eschscholzia californica. 
 
 Matthiola incana, Capsella bursa-pastoris. 
 
 Reseda odorata. 
 
 Passi flora princeps. 
 
 Pepo macrocarpus, Momordica Elaterium. 
 
PHANEROGAMIA : FLOWERS. 
 
 405 
 
 DICOTYLEDONS^ (continued). 
 
 Families. 
 Cue teas. 
 Santalacese. 
 Ceratophylleae. 
 Podostemeas. 
 Thymeleae. 
 Phytolaccea3. 
 Polygoneae. 
 Nyctaginese. 
 
 Limnanthaceae. 
 Euphorbiaceas. 
 Cistineaa. 
 
 Linear. 
 
 Tropasoleas. 
 
 Malvacese. 
 
 Sterculiaceas. 
 Rosaceas. 
 Amygdaleas. 
 Leguminosae. 
 
 Illecebreae. 
 
 Scleranthaceas. 
 
 Sileneas. 
 
 Alsinea3. 
 
 Callitrichaceai. 
 
 Portulaceae. 
 
 Staphyleaceae. 
 
 On ag re as. 
 
 Halorageae. 
 
 Trapaceae. 
 
 Loaseas. 
 
 Plumbagine3. 
 
 Rubiaceae. 
 
 Umbelliferae. 
 
 Stylidieae. 
 
 Lentibulariae. 
 
 Violaceae. 
 
 Primulaceas. 
 
 Erieeas. 
 
 Pedalineas. 
 
 Labiatas. 
 
 Boragineae. 
 
 Orobancheaa. 
 
 ScropliularineiC. 
 
 Salpiglossideae. 
 
 Digitaleae. 
 
 Species. 
 
 Cereus grandiflorus. 
 Thesium intermedium, linophyllum. 
 Ceratophyllum demersum, 
 Podostemon ceratophyllum. 
 Daphne Mezereum, alpina. 
 Pliytolacca decandra.* 
 Polygonum orientale, divaricatum. 
 Mirabilis Jalapa, longiflora*, Oxybaphus 
 
 chilensis. 
 
 Lirnnanthes Douglasii. 
 Euphorbia pallida. 
 Helianthemum lasiocarpum *, denticula- 
 
 turn*, inutabile.* 
 Linum pallescens. 
 Tropaaolum majus. 
 
 Hibiscus Trionum, Lavatera thuringiaca. 
 Theobroma Cacao. 
 Rubus caesius. 
 Prunus Armeniaca, Padus. 
 Cicer ^irietinum, Phaseolus vulgaris, Tetra- 
 
 gonolobus purpureus, Baptisia exaltata, 
 
 Lupini spec, 
 Spergula pentandra. 
 Scleranthus perennis. 
 Lychnis dioica, Saponaria officinalis. 
 Alsine media. 
 Callitriche stagnalis. 
 Calandrinia speciosa. 
 Staphylea pinnata. 
 CEnothera Sellowii, viminea, crassipes*, 
 
 Simsiana, rhizocarpa, Epilobium hirsu- 
 
 tum. 
 
 Hippuris vulgaris, Myriophyllum spicatum. 
 Trapa natans. 
 
 Loasa bryonisefolia, Mentzelia hispida. 
 Arrneria vulgaris. 
 Oalium Aparine. 
 Peucedanum officinale. 
 Stylidium adnatum. 
 Pinguicula vulgaris. 
 Viola tricolor. 
 Hottonia palustris. 
 Monotropa Hypopitys. 
 Martynia diandra. 
 Salvia bicolor. 
 
 Echium vulgare, Symphytum officinale, 
 Lathraea Squamaria. 
 
 Salpiglossis hybrida. 
 Chelone rosca. 
 
 D D 3 
 
406 MORPHOLOGY. 
 
 DICOTYLEDON*: M (continued). 
 Families. Species. 
 
 Scropliularineae : 
 
 Rhinanthea?. Pedicularis palustris, Melampyrum pra- 
 
 tense. 
 
 Veroniceas. Veronica hederaefolia, serpyllifolia. 
 Solaneae. Datura Tatula.* 
 Polemoniaceaa. Phlox paniculata. 
 Cuscutaceae. Cuscuta europsea. 
 
 Gentianeaa. Gentiana lutea. 
 
 Apocyneaa. Vinca rosea, minor, Nerium Oleander. 
 
 Asclepiadese. Asclepias pulchra, Cynanchum nigrurn, 
 
 Stapelia deflexa. Asterias. 
 
 Campari ulaceaa. Campanula Medium*, rapunculoides. 
 
 Compositae. Achillea Eupatorium, Hypoehceris radicata, 
 
 Carduus nutans.* 
 
 To the preceding list I must subjoin the following observations : 
 Pistia commutata I examined in dried specimens ; Pistia obcordata, 
 Cryptocoryne spiralis, and Podostemon ceratophyllum in specimens 
 which had been preserved in spirit. Otherwise the list is to be regarded 
 merely as an enumeration of certain examples, since, during the last 
 year or two I have not thought it worth the trouble to continue any 
 longer the formerly rigidly kept list concerning this one fact, which is 
 already put beyond a doubt by it ; and I must have named a great number 
 of additional families and species from memory, which I do not consider 
 to the purpose. The majority of the foregoing observations were made 
 in Berlin, and I made use of my uncle Horkel constantly as a testis 
 omni exceptione major, and therefore most of the facts are to be re- 
 garded as certified by him also, as he has already openly stated.* From 
 other quarters come the following confirmations. In the first place, Rob. 
 Brown for the Asclepiadacece and Orchidacece ; Wydler for the species of 
 Scrophularia, Griffith for the Santalacece. Brongniart's observations 
 also, of the pollen-tube hanging from the micropyles may now be added 
 to these, although he had a different view of their origin ; consequently 
 the families of the Cucurbitacece, Polygonacece, Euphorbiacece and Con- 
 volvulacecB ; further, Amici for Yucca gloriosa and many other plants 
 not specially named by him ; lastly, Meyen must be named, although, 
 in the whole of his somewhat confused exposition of fecundation and 
 formation of embryos, he constantly speaks of the universality of the 
 descent of the pollen-tube, but does not mention one single plant de- 
 finitely in which he had actually observed it : on the other hand, he cites 
 a large number of plants of the above-named families, as well as of some 
 others, in which he had observed the pollen-tube to enter into the mi- 
 cropyle. 
 
 Easy as the observation is in some families, it is very difficult in 
 others ; not only the same circumstances occur here as in the tracing of 
 the canal of the style from the stigma to the cavity of the germen, but 
 it requires very much greater delicacy and skill in manipulation, to lay 
 the conducting tissue bare in large pieces in such a manner that it may 
 be conveniently separated under a simple microscope, and the pollen- 
 tubes be extricated. While in some plants, Orchidacece, Datura, (Eno- 
 
 * Monatsbericbte der Berliner Academic dcr Wissenschaften, Aug. 18:36. 
 
PHANEROGAM! A : FLOWERS. 407 
 
 them, ffelianthemum, (fig. 251.), I pledge myself to lay bare the tube 
 from the stigma to the seed-bud in a few minutes, which plants I select 
 annually for demonstration in my Lectures, in others I have often dis- 
 sected a week, and even a fortnight, from early till late, before I once 
 succeeded in perceiving, with full certainty, the whole course of the 
 pollen-tube. Nay, sometimes my observations have remained quite im- 
 perfect in one year, and only been completed by resuming them in the 
 following. I remark this here, because I find that many imagine the 
 matter to be very easy, and when they have not succeeded in the first 
 attempt, think at once their negative observation has sufficient value to 
 set aside the assertion of others, while it only bears testimony to their 
 want of skill or impatience, and this indeed most decidedly.* The best 
 method of proceeding is to cut from the axis of the entire pistil, with a 
 broad, sharp knife (I always use a razor), a lamella, not too delicate, so 
 that the section may contain part of the stigma and the conducting tissue, 
 as perfect as possible, down to the seed-bud. This section must then be 
 brought under the simple microscope, and the whole of the pollen-tubes 
 present separated with the needle from the cellular tissue on which they 
 lie, beginning at the stigma and proceeding to the seed-buds ; then the 
 funiculus of these is to be cut away from the spermophore, taking care 
 not to cut through the pollen-tubes at the same time, and the attempt 
 made to separate the single tubes from each other until you are 
 guided by one of these to the micropyle. One must frequently be con- 
 tent to perform the operation piecemeal, by examining, one after ano- 
 ther, as long pieces as possible of the conducting tissue, from the stigma 
 to the seed-buds, and thus to make sure of the complete descent of the 
 pollen-tube. The search for and tracing of the tubes is most facilitated, 
 especially in the Dic/wgamece, MonocistcR^ and Diocistce, by applying the 
 pollen of recently-burst anthers to a perfectly developed stigma, and 
 then examining at different periods. The time required to complete the 
 process of growth varies very much : in the style of Cereus grandiflorus, 
 nine inches long, the end of the pollen-tube reaches the seed-bud in a 
 few hours ; in that of Colchicum autumnale, of thirteen inches long, in 
 about twelve hours ; in others it is often weeks before it has traversed 
 the very short distance. Besides, the pollen-granules, which are also 
 often carried to the stigma at different times, do not all grow down 
 simultaneously. Finally, the persistence of the upper end, which still 
 sticks or did stick in the pollen-granule, varies much ; while in some 
 plants the pollen -tube remains perceptible in its whole length for weeks, 
 in others it dies away above almost as fast as it grows below. In plants 
 of which the stigmatic fluid hardens into a kind of membrane, the por- 
 tion of the tube between this membrane and the pollen-granule often 
 remains visible for a long time, while the portion from the membrane to 
 
 * This difficulty in the investigation, which only occurs in certain cases, is by 
 no means the reason why in this, the most important of all studies, from 1823, when 
 the question was raised by Amici's discoveries, to 1842, only five, say five, men can be 
 named who have contributed to its progress : but the usual indifference of most botanists 
 to all deeper and really scientific investigations. How essentially the answering of 
 the whole question is thereby modified, whether the stigma is clothed by a dense, 
 structureless membrane, is evident. Brongniart had asserted the existence of such a 
 membrane in Nympha-a, Hibiscus, and Mirabilis, in 1827: in 1837 Link said, "Accord- 
 ing to Brongniart, it is so." Therefore, during ten years, he had not thought it worth 
 the trouble once to look into these plants, which are everywhere to be found, to confirm 
 or refute Brongniart's opinion. Is anything like tin's really heard of in any other branch 
 of natural science ? 
 
 n r> 4 
 
408 MORPHOLOGY. 
 
 the growing extremity soon decays, e. g. in Nymphaa, Mirabilis, &c. 
 The differences stated render it wholly impossible to give safe indica- 
 tions a priori for all plants. Patience is necessary, not to be frightened 
 by frequent abortive attempts, till we have learned from the plant itself 
 its peculiarity : whoever has not this patience will not do for an inves- 
 tigator of nature. 
 
 Many have referred to another difficulty in the observation of the 
 pollen-tube, which, from my own investigations, cannot at all be considered 
 as such, namely, the possible confusion of the cells with the conducting 
 tissue for the pollen-tubes. I have never yet met with a plant in which 
 such a mistake was possible; the cells of the conducting tissue are 
 always twice or three times as thick as the pollen-tubes of the same 
 plant : in no plant are those cells longer than very much elongated par- 
 enchyma-cells, i. e. about one-tenth of a line, and therefore every pollen- 
 tube may be recognised at once by the continuity of the cavity through 
 longer tracts. The lament over the possibility of that error has arisen 
 solely from very bad methods of investigation. He who takes an 
 impregnated plant, and hastily examines a longitudinal section from the 
 style, may perhaps doubt whether he has an elongated cell or a pollen - 
 tube before him ; but and this is the only proper way he who first 
 traces the development of the pistil in all its parts up to the time of 
 flowering, and then, well acquainted with the existing condition, 
 examines an impregnated pistil, perceives in a moment what new 
 elements have entered into the style, and cannot imagine the possibility 
 of a confusion of the pollen-tubes with the conducting tissue. Lastly, I 
 must confirm the opinion which Horkel has expressed, that Rob. Brown's 
 '* mucous tubes " are nothing else but the pollen-tubes, the connection of 
 which with the pollen-grain is already destroyed. Within a certain 
 time after impregnation all the pollen-tubes of the Orchidacece become 
 mucous tubes, because they begin to decay from without inward. 
 
 Meyen says that he has frequently seen branched pollen-tubes : I have 
 never met with them, but I consider them very possible. Only in the 
 neighbourhood of the seed-bud, or quite inside the micropyle, I have 
 sometimes seen a very short blind lateral branch given off by a pollen- 
 tube, and, in general, the otherwise pretty smooth and cylindrical tubes 
 here very frequently exhibit irregular curves and varicosities. In the 
 earliest stage of formation of the tube, the contents of the pollen-tube 
 usually exhibit an active circulation, which, however, soon ceases ; by 
 degrees the contents becomes concentrated down into the apex of the 
 tube, partly unaltered, partly chemically changed into other matters, 
 often dissolved into a perfectly transparent watery fluid. 
 
 It is well-known that the pollen-granules swell up and burst through 
 endosmose in water, and the coagulating contents are emitted in an 
 intestine -like form, but this has nothing to do with the formation of the 
 tube on the stigma ; on the other hand, true tubes may be obtained from 
 almost every kind of pollen, for clearer observation than is generally 
 possible on those taken from the stigma, by laying them in the sweet 
 juice which is secreted by some plants, e. g. in the nectary of the Crown- 
 imperial, the abundant nectar of Iloya carnosa, &c., or sometimes even 
 merely in sufficiently concentrated solution of sugar or diluted honey. 
 In these it usually is easy to see the circulation of the contents of the 
 pollen-cell in the formation of the tube, first observed by Amici. 
 Without human interference also, pollen-grains, which come accidentally 
 in contact with nectar, readily send out tubes, and we often find at the 
 
PHANEROGAM I A : FLOWERS. 409 
 
 base of the flower a whole mass of confervoid web, which consists of 
 entangled pollen-tubes emitted in this manner. Nay, in the anthers of 
 theAristolochiac(B, which usually secrete some sweet juice, thepolJen not 
 unfrequently emits tubes, which then, as I believe to have seen, come by 
 chance over the border of the anther on to the stigma, and so descend 
 into the cavity of the germen without waiting for the insects which here 
 so abundantly assist. 
 
 History and Criticism. 
 
 In many plants the pollen- tubes are so striking, even by their 
 mass, that, although every possible opinion but the true one was 
 entertained as to the behaviour of the pollen to the stigma, they 
 could not have been wholly overlooked, if it had only happened 
 to the few microscopic observers of the eighteenth century to have 
 examined the localities in which they occur. Horkel (op. cit.) has 
 collected the earliest traces of observation of them : Amici* made 
 the discovery that a tube is emitted by the pollen-granule and penetrates 
 between the papilla of the stigma; and was also the first who traced 
 the pollen-tube from the stigma to the micropyle, probably in Yucca 
 gloriosa.\ In the interval between these observations, however, Brong- 
 niart J had made known his far more comprehensive researches, in which 
 he observed the pollen-tube everywhere on the stigma, and in many 
 plants as torn extremities hanging out from the micropyle. These two 
 torn ends were then united by Rob. Brown (1831, 1832, 1833) in 
 applying Amici's discovery, with his well-known profundity and accuracy, 
 to two of the most widely distinct families, the Asclepiadacece and Orchi- 
 dacecB, and in both he placed the growth of the pollen-tube into the seed - 
 bud beyond doubt. I myself have extended Rob. Brown's observations to 
 a great number of families, and these observations, confirmed by Horkel, 
 were made known by him in the Monthly Report of the Berlin Academy of 
 Sciences, in August 1836, and by me in Wiegmann's Archives for 1837 
 (vol. i. p. 312. et seq.). Horkel's paper appears to have remained wholly 
 unnoticed, and thence many may have thought that they might quietly 
 set aside my observations, to put their crude observations, or often mere 
 opinions, in their place. Nevertheless, I might leave mine to themselves 
 as incontestible, under the aegis of observers like Amici, Rob. Brown, 
 and Horkel. Finally, WydlerJ of Bern observed the descent of the 
 pollen-tube and its entry into the seed-bud iu. several species of Scro- 
 phularia ; and Meyen likewise confirmed the correctness of the existing 
 observations, without specially naming the plants in which he had com- 
 pletely traced the pollen-tube, but giving abundance of matter in the 
 shape of observation of the entry of undoubted pollen-tubes into the 
 micropyle. Thus the fact, that in all Phanerogamia the pollen-tubes 
 descend to the seed-bud was admitted as a law, till recently Hartig^f 
 appears to have intended to upset the whole matter. In the first place, it 
 cannot but awaken a prejudice against his book, that instead of relating 
 unbiassed and accurately-observed facts, he at once spins out a new so- 
 
 * Mem. di See. Ital. v. xix. pp. 253 257. (1823). 
 f Ann ties Sc. Nat. v. xxi. p. 331. (1830). 
 
 \ Mem. sur la Generation et le Developpement de 1'Embryon, &c. Paris, 1827. 
 Observations on the Organs and Mode of fecundation in Orcliideac and A sell? - 
 piadese. London, 1833. 
 
 || Btbliotbeque Univcrs. de Geneve, Oct. 1838. 
 
 f Neue Theorie der Befruchtung der Pllanzen, &c. Brunswick, 1842. 
 
410 MORPHOLOGY. 
 
 styled theory, and, moreover, gives an extensive new terminology. 
 Hartig certainly speaks of many new discoveries, but if one looks into the 
 matter, not one single fact is found which was not better understood before. 
 The complete uselessness of this book to the advancement of our science 
 follows from two circumstances : in the first place, the author's total 
 ignorance of the literature of the subject, of what has been established 
 by those who have worked in the science before him ; in the second 
 place, Hartig evidently has not the necessary skill in manipulation, nor 
 a correct method. Therefore his whole work in fact only says, " I have 
 not succeeded in tracing the pollen-tubes in the generality of plants;" 
 on which it is to be remarked, that he sought partly in the wrong places, 
 and partly (as in the Dichogamous flowers) at the wrong time ; hereupon 
 lie at once assumed a new mode of fecundation, where he saw the pollen- 
 granules lie and dry up, or emit imperfect tubes. Hartig has himself 
 such clear and correct reasoning in his Introduction, that he may be 
 readily confuted by it. He states the question thus : Can the rudiment 
 of the embryo lie sometimes in the pollen-tube, and in others in the 
 gerrnen, in the seed-bud? and with perfect right answers in the negative; 
 since there exist no grounds for assuming such a planless uncertainty in 
 nature. Then Hartig proceeds : If now an undoubted case exists, in 
 which the embryo cannot originate from the pollen-tube, its origin from 
 that is consequently to be universally denied. This is quite right too, 
 only, from the greater value and easier proof of positive assertions, it 
 would be better to state the matter the reverse way. If, namely, the 
 origin of the embryo from the pollen-tube has been observed undoubtedly 
 in but one case, the matter is decided, and all apparently opposing facts 
 fall into the class of imperfect observations. Such cases actually do 
 exist, even if I disregard my own observations, quite clear and admitting 
 of no other signification ; Wydler has furnished in Scrophularia, and 
 Meyen in Fritillaria imperialis, the most complete testimony, and 
 Meyen's observation is especially the more decisive, that he, starting 
 from a pre-conceived notion, neither expected such a result from the 
 investigation, nor could admit it, and therefore took every pains to 
 explain away those facts which he was much too candid to suppress. 
 Thus is the question decided on the ground which Hartig himself has 
 given. He thinks, however, he can give the decision quite the other 
 way, in ignorance of those facts and referring to his observations of 
 Campanula, as he himself owns, the sole sure prop of his different 
 theory. This pillar, however, is very weak ; the peculiar behaviour of 
 the collecting hairs, observed long before his researches, has nothing at 
 nil to do with fecundation, or, at most, only so far that in the retraction 
 of the hairs the greater part of the pollen becomes stripped off them, and 
 thus exposed loose to the wind and insect?, which transport it to the 
 stigma.* The fecundation of the Campanulaccce takes place in quite a 
 different way. By industrious and patient search I have always found 
 the pollen-tubes on the stigma and at the micropyle in the Campanulacece ; 
 in C. Medium and rapimculoides I have traced them the whole way ; in 
 the former it is not even difficult to demonstrate the whole tube in 
 unbroken continuity. I doubt not too, that Hartig, who is earnest and 
 zealous in science, will before long become convinced of the untenable 
 nature of his imaginary theory. I consider it quite superfluous to enter 
 further into Hartig's views, since the whole relates merely to imperfect 
 
 * Wilson (Mohl untl Schlechtenckbl's Bot Zeitg. vol. i. pp. 382. and 870.) lias also 
 shipwrecked his skill in observation on the collecting hairs of the Catnpannlacccc. 
 
PHANEROGAMIA I FLOWERS. 411 
 
 perception of facts long since better understood. Hartig has attempted 
 a rather unfortunate defence of his "theory."* I think that I have 
 wholly settled the matter in my answer.f 
 
 165. The pollen-tube, which has arrived in the seed-bud in 
 the manner above stated, either at once meets the embryo-sac, or 
 penetrates through the intercellular passages of the cellular tissue 
 of the nuclear papilla, which becomes somewhat more lax about 
 this time through a secretion, till it reaches the embryo-sac. 
 
 The next phenomenon is the appearance of the end of the pollen- 
 tube inside the embryo-sac as a cylindrical or ovate utricle of 
 variable length, which has a round closed extremity toward the 
 cavity, and at the apex of the embryo-sac runs up open into the 
 pollen-tube ; the extremity soon swells up, either in such a manner 
 that the utricle produced by it (embryonal vesicle, keimblascheii) 
 consists of the whole of that part of the tube within the embryo- 
 sac, or so that between this utricle and the apex of the embryo-sac 
 there remains a cylindrical piece, of variable length, the embryo- 
 phore (keimtrdger, embryotrager,filamentum suspensorium, filament 
 suspenseur, Mirbel). The cellular tissue is developed in the 
 interior of the pollen-tube, cytoblasts originating and cells being 
 developed from them. Since new cells originate inside these cells, 
 and so forth, the embryonal vesicle, by gradual increase of size 
 and reabsorption of the parent-cells, at last becomes a little globular 
 or ovate cellular corpuscule. The pollen-tube is usually constricted 
 and closed outside the embryo-sac at the same time, and becomes 
 absorbed ; frequently also, especially where an embryophore or 
 suspensor exists, the embryonal vesicle itself becomes constricted 
 and detached, and then lies perfectly free in the apex of the 
 embryo-sac. 
 
 The investigation of the processes described in these paragraphs is 
 without doubt, next to the origin of new cells in crowded parenchyma, 
 the most difficult task in Botany. Since I made those facts known, a 
 great deal has indeed been said on the matter; but of the many hundreds 
 of botanists, only a few have made careful investigations of the kind. 
 The following are the plants in which I have, up to this time, completely 
 examined the formation of the embryonal vesicle from the end of the 
 pollen-tube, in such a manner that I have extracted the already per- 
 fectly distinct embryonal vesicle, perceptible in the embryo-sac, in com- 
 pletely uninjured continuity with pollen-tube, still existing at least outside 
 the nucleus, quite free, and afterwards traced the origin of the em- 
 bryonal gloJDiile, by the formation of cells in the embryonal vesicle : 
 
 Phormium tenax, Eucomis punctata, Sisyrinchium anceps, Stratiotes 
 aloides, Canna Sellowii, Maranta gibber, Orchis Morio (Plate V. figs. 10, 
 11.), latifolia (Plate VI. figs. 1,2.), pahistris, Zca Mays, Nuphar Juteum, 
 Momordica Elaterium (Plate VI. figs. 9 11.), Daphne Mezereum, Phij- 
 tolacca decandra, Polygonum orientate, Mirabilis Jalapa, longifora, 
 
 * Ilartig, Beit, zur Entwicklungsgesohicbte dor PHanzcn. Berlin, 1843. 
 f Die neuern Einwiirfe gcgen meine Lelirc von ck-r Ik-fruchtung, c. Lcipsic, 
 1844. 
 
4 1 2 MORPHOLOGY. 
 
 Limnantkes I}ouglasii t Linum pallescens, Tropceolum maj us, Cicer arie- 
 tinum, Phaseolus vulgaris, (Enothera viminea, crassipes, rhizocarpa 
 (Plate VI. figs. 7, 8.), Martynia diandra (Plate VI. figs, o, 6.), Salvia 
 bicolor (Plate VI. figs. 3, 4.), Lathrcea Squamaria, Veronica hedercRfolia, 
 serpyUifolia, Pedicularis palustris, Cynanclmm nigrum, Campcmula 
 Medium, Tctragonia expansa, Epilobium hirsutum (Plate V. figs. 7, 8.). 
 
 In many of these plants I have laboured in vain for many years ; in 
 some I have oftener succeeded in observing the whole process without 
 the possibility of deception : I have never yet found any plants in which 
 the observation is so easy, that I could say that I could at any time 
 prepare the necessary dissection with certainty ; I have found it easiest 
 in CEnothera, Veronica, Pedicularis, and the Orc/iidacece. If Santalum 
 album were at our command, we should probably have a plant in which 
 we could at any time demonstrate the process with certainty. Perfect 
 confirmation of the main point, namely, the conversion of the end of the 
 pollen-tube into the embryo through internal processes of vegetation, 
 have been furnished by Wydler* in some species of Scrophularia, by 
 Meyen f in Fritillaria imperialis and Tulipa, and by GelesnofFJ in 
 Amygdalus persica, Iberis amara and umbellata. The observation of 
 Meyen is the better evidence that it came certainly quite unsought for ; 
 since it is alone quite sufficient to refute his very artificial, ancl, I will 
 openly confess, to me thoroughly incomprehensible, explanation of his 
 other less perfect observations. The figures 37 43. Plate XIII., from 
 Alsine media, of Meyen, also agree tolerably perfectly with my observa- 
 tions, only I do not rightly know what to make of figures 38 to 41. I 
 must confess that it has hitherto always appeared to me impossible to 
 prepare it free in so early a condition in Alsine media, and these obser- 
 vations do not at all agree with Meyen's explanation ; moreover, figs. 
 21 23. from Draba verna, fig. 34. from Orchis Morio, fig. 44. from 
 Helianthcmum canariense, fig. 48, 49. from the same plant, only the 
 order is evidently different ; fig. 49 is an earlier condition, fig. 48 the 
 commencement of the constriction of the pollen-tube ; lastly, also, 
 (Polyembryonie, &c., Plate I.), from Viscum album, on which I will 
 merely notice that fig. 8. is evidently later impregnated, and an earlier 
 stage of formation than fig. 7., which follows from the fact that the 
 membrane of the embryo-sac is not yet completely absorbed, and there- 
 fore still surrounds the contained cells with a smooth outline. All the 
 rest of Meyen's figures exhibit only later conditions, after the separation 
 of the pollen-tube outside the embryo-sac, often even after the separation 
 of the germinal vesicle inside it. Lastly, Griffith has instituted researches 
 on this process in Santalum album, and indeed earlier, before my obser- 
 vations were made known ; unfortunately, he evidently had not a good 
 microscope at his command, and he is candid enough not to describe, or 
 draw as definitely seen, anything which remained indistinct to him. 
 Santalum album is* certainly a most advantageous plant for these 
 researches. The allied species of Thesium present great difficulty. 
 On the other hand, Martius||, in the year 1844, published the following 
 passage of a letter from Griffith : " A year ago I sent an extended essay 
 
 * Loc. cit. 
 
 f Physiologic, vol. iii. ; and Uebcr den Befruchtungsact und die Polyembrionie, &c. 
 Berlin, 1840. 
 
 J Botan. Zt'itung, vol. i. p. 841. 
 
 On the Ovulum of Santalum album, Trans. Roy. Soc. vol. xviii. 
 
 || Munich gel. Anzeig. No. cxliii. p. 107. 
 
PHANEROGAMIA : FLOWERS. 413 
 
 on fecundation to the Linnaean Society, in which Schleiden's view of the 
 origin of the embryo from the pollen-tube is confirmed. The observa- 
 tions in Santalum are the most sure. In Loranthm the pollen-tubes 
 undoubtedly traverse the whole embryo-sac." 
 
 After this exposition, I must now regard the formation of the embryo 
 from the pollen-tube as completely established, and observations dis- 
 agreeing with this can hereafter only be of value if they at once com- 
 pletely explain the cause how an error, of course not absolutely impossible, 
 could conceivably have arisen in the minds of so various, truth-searching, 
 and, with respect to Meyen in particular, certainly unprejudiced ob- 
 servers. But if science is actually to advance, all boldly-expressed 
 fancies, based on a few imperfect observations, in total ignorance of 
 what has been done before, must be wholly excluded. This especially 
 applies to the trifling, though very pretentiously delivered, new researches 
 of Amici.* It is very sad, that in a whole association of naturalists there 
 was not a single one who had the most distant idea of the imperfection 
 of this essay, or, at all events, expressed it. See my observations on that 
 Essay in the " Flora. "f 
 
 With regard to particular points in the processes described, the fol- 
 lowing questions may yet be raised. In the first place, the mutual 
 behaviour of the embryo-sac and the pollen-tube is by no means perfectly 
 cleared up yet by observation. It remains undecided, in certain cases, 
 whether the membrane of the embryo-sac, which in this way becomes 
 pushed inward and forms an investment over the apex of the pollen- 
 tube, does not subsequently perhaps become dissolved and absorbed, so 
 that the pollen-tube actually penetrates directly into the cavity of the 
 embryo-sac, which is certainly very probable in those plants in which the 
 pollen-tube goes down a disproportionately long way into the embryo- 
 sac, as in many species of Veronica, in the Santalacece, in Marty nia 
 diandra, where it descends almost to the chalaza ; in some, e. g. in Phor- 
 mium tenax, a distinct investment of the pollen-tube clearly remains for 
 a long time. This much is certain, that in all cases where I was certain 
 that the object was still in its natural position, especially where I suc- 
 ceeded in laying bare the apex of the embryo-sac and pollen-tube in the 
 section, without removing them from their proper places in the seed-bud, 
 I saw the membrane of the embryo-sac curve over at the apex, and run 
 inward on the pollen-tube. But it is quite possible that the embryo-sac, 
 originally somewhat pressed inward by the entering pollen-tube, being 
 of course very thin and delicate at this time, sometimes even merely of a 
 gelatinous consistence, may become dissolved gradually from the apex of 
 the pollen-tube, so that the latter shall actually break through it. Such 
 a gradual solution must, at the same time, obliterate every sharply- 
 defined border, which certainly is never seen. It may be, however, that 
 the embryo-sac is only expanded out, so as to become very thin. The 
 possible modifications do not appear to me to be important here, since 
 by the subsequent construction the embryonal vesicle comes also to lie in 
 the cavity of the embryo-sac, and of course, after cell-formation begins, 
 not merely any possible coating of membrane of the embryo-sac, but also 
 the pollen-tube itself, disappears from observation (becomes absorbed). 
 With regard to that, I may remark that the transformation of the ger- 
 minal vesicle into the embryonal globule by the formation of cells within 
 
 * Flora, 1844 and 1845, p. 193. 
 
 t Flora, 1845, pp. 787. and 593. ot seq. 
 
414 MORPHOLOGY. 
 
 cells may always be easily observed. Usually one of the new cells fills 
 up the whole vesicle, and the rest are formed in the suspensor. Some- 
 times (?) several cells combine, simultaneously, to fill the germinal 
 vesicle. Meyen himself has given most beautiful evidences of this in his 
 plates, e. g. Physiologic, vol. iii. PI. XIII. fig. 42., the free cytoblasts 
 in the germinal vesicle ; fig. 43. the young cells with their cytoblasts ; 
 fig. 35., in the uppermost cell of the germinal vescicle, two free cells with 
 their cytoblasts; figs. 11. and 14., free cells with cytoblasts in the ger- 
 minal vesicle. Two other peculiar conditions must also be discussed 
 here. Not unfrequently the pollen-tube swells up before its entry into 
 the embryo-sac (in Ceratophyllum, Taxus, Juniperus), and this expan- 
 sion, lying in the parenchyma of the nucleus, or in the micropyle canal, 
 becomes likewise filled with cells, and remains thus perceptible for a long 
 time (in Cynanchum). In other plants, on the contrary, especially in 
 the Naiadacece and Scitaminece, the pollen-tube forms an expansion 
 inside the embryo-sac, which sometimes resembles a somewhat flattened 
 globule (in Potamogeton, Maranta, Statice], sometimes is a longish 
 cylindrical body (in Tropceoluni) : in the first case the pollen-tube then 
 elongates from the summit of the globule ; in the second, from the side of 
 the cylinder, into a prolongation of various length, and then first swells 
 up to form the germinal vesicle. That expansion also in the interior of 
 the embryo-sac, beneath the germinal vesicle, in general becomes filled 
 with cells, and then remains long perceptible. In Tropceolum, by 
 simultaneous absorption of the investing portion of the integuments of 
 the seed-bud, it even comes to lie free in the cavity of the germen, and 
 grows independently, as a cellular cord, quite round the seed-bud, and is 
 indeed distinctly to be recognised on the ripe seed. 
 
 A remarkable aberration from the usual structure of the embryonal 
 globule, as here sketched, occurs in the Coniferee ; but the investigation 
 of these requires so much skill, patience, and perseverance, that I dare 
 not declare myself content with the year's research I have applied to 
 them. What I have observed is as follows ; and I here beg the reader 
 to recall correctly to recollection the description given above of the seed- 
 bud of the Coniferee. The pollen-granules here, of course, arrive imme- 
 diately upon the naked seed-bud, and from the width of the micropyle 
 usually at once upon the papilla of the nucleus. Here they lie for a 
 variable time, then gradually emit tubes which grow through the paren- 
 chyma in various places. Thus they reach the situations where merely the 
 membrane of the embryo- sac covers the enlarged cells of the endosperm, 
 and penetrate into these, quite filling them up. On the commencement 
 of this last process no doubt can prevail in the abundance of examples of 
 almost all our indigenous Coniferee. In Abies excelsa, Taxus baccata, 
 Juniperus sabina, I succeeded in dissecting out the entire pollen-tube 
 from the papilla of the nucleus to the bottom of the little hole, with the 
 expanded portion accurately filling this. During this process, beneath 
 the said enlarged cells (corpuscula, II. Brown) extends downward to the 
 chalaza a gradual solution and absorption of the parenchyma previously 
 formed here, whereby is formed a cylindrical cavity beneath each of those 
 cells, and only separated from it by the epithelium-like layer of cells 
 which surrounds it. Into this cylindrical cavity the pollen-tube now 
 penetrates, breaking through the wall of the little hole ; but I have only 
 twice succeeded, in Taxus and Juniperus, in dissecting out the pollen-tube 
 in unbroken continuity, and here, also, after it had penetrated a little 
 distance into this cylindrical cavity. My further observations -are still 
 
PIIANEROGAMIA : FLOWERS. 415 
 
 quite imperfect. They show that in those parts of the pollen-tubes which 
 have penetrated into the cylindrical cavity, a process of cell-formation 
 soon begins, so that four cells are formed, which, parallel to the pollen- 
 tube and to each other, extend in a cylindrical form ; then in the free 
 extremity of each another cell is formed (Juniperus communis}, which 
 soon developes into three (?) cells (Abies excelsa\ so that the embryonal 
 globule now consists of twelve cells placed side by side in four rows. The 
 process of multiplication of the cells then advances, and a little papillose, 
 cellular body is formed as embryonal globule, which is seated on a long 
 suspensor composed of four parallel cells. The cells of the latter continue 
 for a long time to expand exclusively in length, and thus acquire a tor- 
 tuous condition in the too short cylindrical cavity. At the place where 
 they come forth from the large cells (corpuscula\ some cells also appear 
 to be formed sometimes, or the neighbouring cells compress the cavity of 
 the pollen-tube together ; in short, there is very soon no further trace of 
 the originally free communication to be discovered. 
 
 Special deviations besides so mentioned I have not yet met with, nor is 
 it probable that differences should occur in the essential particulars when 
 it is remembered that the peculiarities which distinguish the Cryptogamia, 
 Rhizocarpece, and Phanerogamia are far greater than the main points 
 which appear to occur throughout the whole animal kingdom ; yet the 
 Phanerogamia agree so closely in all the rest of their organisation, that 
 it is very improbable that they should exhibit important modifications in 
 so essential a point. In the Plate IV. of this volume I have given a series 
 of the most instructive, and easiest to repeat, observations ; especially in 
 Epilobium angustifoUnm, Orchis latifolia and Morio, Martynia cHandra, 
 Salvia bico/or, (Enothera rhizocarpa, acaulis, and Momordica Elate- 
 rium. I will only add a few words on the preparation of such dissections. 
 If the seed-buds are not very closely enveloped, and immoveable in the 
 germen, I extract them, take them between the thumb and fore-finger in 
 such a manner that with a sharp razor I can cut them accurately in half. 
 To obtain these halves symmetrical, and that the section may hit the 
 micropyle canal, or come near enough to it, I place the seed-bud in the 
 proper position between the fingers, if necessary, with a lens. The two 
 halves thus obtained I place one behind the other, the cut surfaces 
 toward the thumb, between the thumb and finger again, and cut with the 
 razor the thinnest possible slice from the surfaces of the sections. I then 
 bring these two slices under the simple microscope, and dissect the parts 
 with fine needles and knives, if they are not already made evident by the 
 section, which is of course always the best. In one-seeded germens the 
 same may be done if they are very small ; in other cases I at once cut as 
 fine slices as possible, e. g., in the Gourd. 
 
 It is evident that one must always previously study the structure of 
 the unimpregnated seed-bud and germen, and the form of the pollen -tube, 
 and by careful observation make oneself acquainted with the periods of 
 fecundation. Patience and perseverance will always have to be applied as 
 the most important of all means of success. A hundred such slices as I 
 have described may often be made and nothing seen, and perhaps the 
 hundred and first will be so good as at once to complete the investigation. 
 I do not think the method of dissecting off the parts of the seed-bud from 
 without inward, under the simple microscope, advantageous, because 
 much more is destroyed, and in particular displaced, in this than in one 
 simple section made with a sharp instrument. 
 
4 1 6 MORPHOLOGY. 
 
 History. 
 
 We not (.infrequently find examples in Science, of the unprejudiced 
 glance of the first observer divining and expressing the truth, which, 
 however, is naturally at once thrown aside by Science as unfounded and 
 contradicting its temporary laws, till in the end it works back gradually 
 to that first notion, but now consciously, and supported in every way by 
 the true reasons. Thus, if we look to the result now secured as to the 
 origin of the embryo, it is at the bottom exactly the same as that which 
 was asserted more than a hundred years ago by Samuel Morland *, 
 namely, that the pollen-tube descended through the style into the seed-bud 
 and became the embryo. This notion, in its crude form, was contested, 
 and, indeed, at that time, properly, by Vaillant and Patrick Blair. After 
 that, all deeper investigation, such as had been roused by Malpighi, 
 gradually fell asleep ; and when Treviranus f wrote his work on the 
 Development of the Embryo, it was to be considered as a great advance, 
 although he did not go beyond what Malpighi had done, and even 
 did not reach many of the beautiful observations of Malpighi, e. g., 
 the existence of the embryo-sac. The observation of the embryo 
 in its earlier conditions, as the embryonal globule, from which Malpighi 
 and Treviranus started, commenced with Ad. Brongniart (7. c.), and 
 he very nearly completed the matter ; if he had only used the obser- 
 vations of Robert Brown, which soon followed, and by means of these 
 explained his observations on Momordica JElaterium, which only wanted 
 an intermediate stage, easily added hypothetically, he would have dis- 
 covered the origin of the embryo from the pollen tube penetrating into 
 the embryo-sac. Thus the materials stood till IJ brought the matter 
 to a conclusion by my researches. I regard it as wholly superfluous to 
 report on the many opinions of those whose imagination was busier in 
 spinning out their own discoveries, than their hands in dissecting or their 
 eyes in observing accurately people who in all ages have confused 
 natural science instead of advancing it. 
 
 B. THE DEVELOPMENT OF THE EMBRYONAL GLOBULE INTO THE 
 EMBRYO. 
 
 166. The main features of this section have necessarily been 
 already given ( 121.), but this is the place in which to enter into 
 this matter somewhat more specifically ; for this purpose it seems 
 requisite to separate the Monocotyledons from the Dicotyledons, 
 and the Gymnosperms from both. As an universal law, valid for 
 all Phanerogamia., there is only one thing to be expressed, that the 
 part of the embryonal globule corresponding to the point of the 
 pollen-tube always becomes the bud ; the opposite part therefore, of 
 course, that turned toward the apex of the embryo-sac, the nuclear 
 
 Eapilla and rnicropyle, becomes the radicle. The existence of this 
 i\v of position of the radicle in the seed-bud was first stated by 
 Robert Brown. 
 
 * New Observations on the Parts and Use of the Flower in Plants. Phil. Trans., 
 1703. 
 
 f Von der Entwick. des Embryo, &c. Berlin, 1815. 
 
 J Einige Blicke auf die Entwickl. des veg. Organismus, Wiegmann's Archiv, 18:37, 
 vol. i. p. 289. ; Ueber Bildung des Eichens und Entstehung des Embryo, Act. Acad. 
 C. L. C. vol. xix. p. 1. 
 
PHANEROGAMIA : FLOWERS. 
 
 417 
 
 167. 1. Gymnosperms. The process of cell-formation by which 
 the embryonal globule is produced continues on, but in very dif- 
 ferent forms, in different parts of the embryo. The apex of this 
 has acquired, through twelve cells originally formed, a definite form 
 and determinate limits externally, and retains these. At first this 
 end is bluntly rounded off, subsequently from two to twelve folia- 
 ceous organs originate (in such a manner that the extreme point 
 always remains free) simultaneously and in a circle ; in the earliest 
 condition as minute papilla?, standing on the border of the upper 
 convex surface, gradually, however, growing up beyond the point 
 (which always remains free), and then by degrees covering it up by 
 applying themselves more closely together over it : these are the 
 cotyledons or germ-leaves. Very different phenomena are exhibited 
 at the other end : there the process of cell-formation is apparently 
 continued still further on in the suspensor. The extreme cells 
 formed here always become at once more or less elongated, at 
 a somewhat later period curve away from one another, so that the 
 end of the embryo, the radicle, never has a definite boundary, but 
 appears to lose itself among very lax cells. This condition persists 
 until the full development of the embryo, which always passes, 
 through these cells, which constantly appear more lax, almost at 
 once into the four long cells of the suspensor, which remains 
 unchanged to the time of maturation of the seed. The very long 
 suspensor is, moreover, gradually compressed into a coil by the 
 growing onward of the embryo ; it may, however, be disentangled, 
 even in the ripe seed, with some care. 
 
 The preceding exposition is from my own re- 
 searches in our native Coniferce. From the 
 beautiful analyses of the ripe seed of the Cyca- 
 dacece by L. C. Richard *, as well as from the 
 miserable figures by Gaudichaud f, it is cer- 
 tainly similar in this family also, with the dis- 
 tinction that here occur constantly only two co- 
 tyledons, which are blended up to the free points, 
 and only leave a slit on one side for the subse- 
 quent protrusion of the enclosed bud. In Viscum 
 also, according to the excellent researches of 
 De Caisne J, something similar seems to occur in 
 reference to the formation of the radicle. This 
 want of a definite limitation of the radicle essen- 
 tially distinguishes, so far as I know, the Gym- 
 nosporous from all Mono- and Dicotyledonous 
 plants, in which I have never found any thing 
 similar. 
 
 * Commentatio Botanica de Coniferis et Cycadeis, opus posthumum ab Achille 
 Richard in lucem editum. Stuttgardt, 1826. 
 
 f Rech. Gen. sur 1'Organogr. &c. Paris, 1841. 
 
 j Mem. sur le Dev. du Pollen, de 1'Ovule et sur la Structure des Tiges du Gui. 
 Brussels, 1840. 
 
 853 Abies balsaminea; A, Embryo in a very young condition : a, terminal point of the 
 axis, the future terminal bud ; b, border from which the cotyledons subsequently arise ; 
 
 E E 
 
 253 
 
418 MORPHOLOGY. 
 
 168. 2. Monocotyledons. In all the plants of this group which 
 I have 'hitherto examined, the embryonal globule, originating in the 
 way above described, is definitely bounded in its entire circum- 
 ference ; where a striking suspensor exists, the apex of the radicle, 
 which has its outline clearly marked, projects into the cavity of the 
 utricle, the remnant of the pollen-tube which is applied around it. 
 Its form varies, sometimes globular, sometimes ovate, with the 
 narrower end turned, as radicle, towards the micropyle. By the 
 constant .operation of the process of cell-formation, it grows, and 
 is composed of successively more numerous and smaller cells. 
 In the Orchidacea alone it persists in the earliest condition until 
 the ripening of the seed and germination ; in all other plants yet 
 investigated, a cotyledon is formed in the following manner. 
 Somewhat laterally to the apex of the embryo (therefore somewhat 
 below it), a little papilla arises; from the base of this papilla a 
 greater amount of the periphery is gradually included as part of 
 the elevation, till at last a leaflet is formed surrounding the apex 
 (terminal bud) with its base. The terminal bud (plumule) then 
 projects like a papilla from the sheath of this leaf, the margins of 
 which (constantly lower from the axis of the leaf toward the angles) 
 are in contact. Thus far the development of all embryos which I 
 have investigated is exactly similar, at most differing in the fact 
 that the portion of the embryo in the lower half of the cotyledon 
 sometimes attains a very considerable size about this time, some- 
 times merely forms the lower end of the embryo, in the shape of a 
 cone rounded off at the apex. All the further, in outward appear- 
 ances such great variations of Monocotyledonous embryos, are 
 dependant on the unequal development of these parts, which are 
 all alike in the rudimentary condition of the radicle (Naiadece and 
 some other families, which L. C. Richard named embryons macro- 
 podes) or of the cotyledon (in Schcuchzeria, most Aracece), &c. 
 
 In spite of the apparently great variation of the embryo in Monocotyle- 
 donous plants, the manifold forms all start from one element, and have the 
 main point of the development in common. The earliest rudiment here, 
 as in the Dicotyledons, the embryonal globule, developes no further up to 
 the period of germination in the Orchidacece (fig. 254.). In all others the 
 changes above mentioned manifest themselves, and a few examples may 
 illustrate the statement, for which purpose the embryo of Potamogeton 
 
 254 
 
 c, the radical extremity, lost in loose cells. B, A somewhat later condition, in which 
 the individual cotyledons are already distinctly recognisable: a, b, c, as in A. 
 
 844 Neottia picta. Ovate embryo, without a cotyledon. 
 
 155 Potamogeton lucens. A, Embryo : a, radicle ; 6, cotyledon. B, Longitudinal 
 section of the same : a, 6, as in A ; c, slit of the cotyledon, with the plumule. 
 
PHANEROGAMIA : FLOWERS. 
 
 419 
 
 (fig. 255.), with a strikingly developed radical extremity (fig. 255. a.), and 
 the embryo of Scheuchzeria (fig. 256.), with a predominantly developed 
 cotyledon (fig. 256, b.\ appear best fitted. If the radicle is destined to 
 be little or not at all developed subsequently in germination, there are 
 formed already at this period, from the place where the cotyledon is 
 connected with the bud (as the first node of the plant), adventitious 
 roots, which, in the embryonal condition, still remain inside the paren- 
 chyma of the true root (fig. 257, b d.), as in Lemna, Pistia, Graminece, 
 
 256 
 
 257 
 
 260 
 
 ScitaminecB. The vaginal portion of the cotyledon may likewise be- 
 come more or less developed, and wholly, partly, or not at all enclose the 
 terminal bud : in the first case, the borders of the sheath always become 
 blended, so as to leave only a large (Aracetz, 257. A. c. B. c.) or small 
 (Liliacece) slit, which, however, is, in all instances, still perceptible on 
 the ripe embryo ; in the second case, the bud partly projects out from 
 the slit, e. g., Scheuchzeria, some species of Pothos, &c.; the last .case, 
 which is the rarest, occurs in Stratiotcs, Aponogeton (fig. 258, c.), 
 Ouviranda, Orontium aquati- 
 cum, &c. The forms of these 258 
 individual parts are also very 
 various, as in general the or- 
 gans of plants are not bound 
 down to any particular form. 
 Sometimes the cotyledons are 
 developed broad, obconical, on 
 the little conical papilla, e. g., 
 Pothos reflexa (fig. 260.), 
 sometimes umbrella-shaped, or 
 like an Agaric-pileus, as in the 
 Cyperacece (fig. 259.) ; some- 
 times even like a hollow cup, 
 
 856 Scheuchzeria palustris. A, Longitudinal section of the embryo : a, radicle ; 
 
 b, cotyledon ; c, slit of the same, with the plumule. 
 
 257 Pistia obovata. A, Embryo : a, radicle ; 6, cotyledon ; c, slit of the same. 
 B, Longitudinal section of the embryo : a, b, as in A ; c, slit of the cotyledon, with the 
 very simple plumule ; d, adventitious root. 
 
 858 Aponogeton distachyon. Embryo, a, Radicle ; b, cotyledon ; r, free plumule. 
 
 259 Isolepis supina. Longitudinal section of an embryo, , Radicle ; 6. cotyledon ; 
 r, plumule covered by a sheath from cotyledon, and directed downward. 
 
 860 Pothos reflexa. Longitudinal section of an embryo, a, Radicle ; I, cotyledon ; 
 
 c, its slit, with the plumule ; .r, doubtful second bud. 
 
 r. E 2 
 
420 
 
 MORPHOLOGY. 
 
 containing the small quantity of albumen which exists in its cavity, as 
 in Orontium aquaticum (fig. 262.). The radicle is sometimes simply 
 roundly apiculate, sometimes elongate-cylindrical, and then suddenly 
 truncated into a surface occasionally umbilicate in the centre, e. g., 
 Potamogeton (fig. 255.), &c.; sometimes very thick, flat below and at- 
 tenuated above, as it passes into the cotyledon so that the embryo repre- 
 sents an erect cone (in many Palm?, fig. 261.). All these anomalies are 
 
 262 
 
 f c 
 
 easily traced to the fundamental type through the progressive deve- 
 lopment. 
 
 In most of the cases hitherto named, the position of the terminal bud 
 on the ripe embryo is not at all unnatural. Originally occupying the 
 apex of the embryo, it often appears lateral on account of the great 
 mass of the cotyledon, forming an angle with the axis of the latter ; 
 sometimes, however, the cotyledon is so strongly developed that it forms 
 a right angle with its axis (fig. 257.), consequently also with the axis of 
 the radicle, which usually appears as a direct prolongation of the coty- 
 ledon. The structure in Lemnacece is apparently the most aberrant 
 (fig. 263.) ; here the ripe embryo is a large, longish, conical, or ovate 
 mass ; below, at the thicker end, which is turned toward the micropyle, 
 therefore on that account already to be determined as the radical end, a 
 very small transverse slit is exhibited. If a cross section is made 
 through the embryo here, we see that behind this slit the bud, consisting 
 of a flattish rudiment of the stem, lies in such a direction that its axis is 
 almost parallel with that of the cotyledon, and its apex also directed 
 toward the micropyle (fig. 263, C. c.) ; on the other side of the radical 
 
 263 
 
 61 Chamadorea schiedeana. Embryo in longitudinal section, a, Radicle ; b, cotyledon ; 
 c, slit with the plumule. 
 
 68 Orontium aquaticum. A, Embryo : a, radicle ; b, cup-shaped cotyledon ; c, free 
 plumule. J9, The same seen from beneath : c, the point of attachment of the funiculus 
 (hilum). C, Longitudinal section of the same : a, b, c, as in A ; x, the cavity of the 
 cup-shaped cotyledon. 
 
 863 Lemna gibba. A, Very young embryo : , radicle with the torn suspensor ; b, co- 
 
PIIANEROGAMIA : FLOWERS. 
 
 421 
 
 end we then discover, in this transverse section, an adventitious root 
 (fig. 263, C. d.) still buried in the parenchyma, but already perfectly 
 determined, and even provided with a calyptra ; this, also nearly parallel 
 with the axis of the embryo, has its apex turned toward the micropyle ; 
 the axes of the bud and the adventitious root form an angle of scarcely 
 30 with their divergent apices. If we trace the development we see 
 that the bud originally forms the apex of the embryo, and is afterwards 
 gradually thus pushed aside by the growth of the cotyledon. The 
 course of development (which is analogous to that of Cyperacece) I have 
 traced so often in Lemna minor and trisulca, as well as in Telmato- 
 phace gibba, investigated so many ripe seeds of the three said plants, 
 and of Wolffia Delili, that I may venture to declare that nothing at all 
 corresponding, even distantly, to the analysis given by A. Brongniart* 
 occurs in the embryo of the Lemnacece ; how he obtained such strange 
 figures I cannot explain. 
 
 The import of the individual parts of the embryo of Grasses, which 
 formerly gave botanists so much trouble, is exhibited most simply in 
 the course of development. In the Grasses the embryo is originally 
 formed exactly as in other Monocotyledons (fig. 264, A.) ; but the fol- 
 lowing variations subsequently appear. During the formation of the 
 vaginal portion the bud is also considerably developed, and thus that 
 part of the vagina covering it is pushed outward (fig. 264, B.), and 
 a papilliform process is gradually formed over the bud, becoming 
 blended, leaving only a slit : this process is usually regarded as the free 
 bud, not enclosed by the cotyledon (fig. 264, C. e.f.). But if this part t 
 
 264 
 
 * Arch, do Botanique, vol. ii. p. 97. (1833.) 
 
 f Some name it with the superfluous term Coleoptile. 
 
 tyledon ; c, plumule. B> Later condition: a, 6, c, as in A. The radicle is not yet 
 completely rounded ; the suspensor is removed ; the plumule is already partly enclosed 
 in the sheath of the cotyledon, and pushed downward. C, Perfect embryo in longi- 
 tudinal section: a, b, c, as in B; d, rudiment of an adventitious root. D, Perfect 
 embryo in longitudinal section at right angles to the preceding : a, b, c, as in B. 
 
 164 Secale cereale. A, Very young embryo: a, rudimentary plumule; b, cotyledon ; 
 c, radicle. B, Later condition : a, b, c, as in A ; J, the expansion of the scutellum be- 
 ginning ; e, commencement of the formation of the vagina of the cotyledon, which 
 envelopes the plumule. C, Perfect embryo (not so much magnified as in A and .5) : 
 6, c, as in B ; d, cotyledon as scutellum ; e, vaginal part of the cotyledon ; /, slit of the 
 same ; h, /t, h, adventitious roots, still enclosed in the cortical portion. Z), Longitudinal 
 section of the former : a /, as in B and C ; g, adventitious root ; h, investment of it 
 formed by the cortical substance. 
 
422 MORPHOLOGY. 
 
 is now compared with the developed leaf, we find that it exactly cor- 
 responds to the ligule. The cotyledon itself is also developed strangely, 
 expanding out as a flat lamina, not only upward and laterally, but also 
 downward (fig. 264, C. b. d.). Thus is formed the so-called scutellum, 
 to which, on account of its freely projecting bud, covered with an invest- 
 ment from the vagina, and its equally projecting radicle (fig. 264, c.), 
 the embryo appears to be adherent. The radical extremity is finally 
 perfected to a little cone ; as, however, it is never to be developed, the 
 rudiments of several adventitious roots (fig. 264, h.) are formed from 
 the base of the bud, at the point where it is connected with the coty- 
 ledon, therefore from the first node of the plant : these then, lying on 
 the parenchyma of the radicle, appear to be surrounded by a sheath* 
 (fig. 264, D. h.) 9 the true radicle. Then, in addition, it often happens 
 that the cotyledon arises into a kind of collar on both sides of the bud 
 and radicle, and thus more or less completely encloses them again, e. g., 
 in Zea Mays, which has been very incorrectly compared with the true 
 slit of the cotyledon. 
 
 On the whole, abnormal modes of development of the embryo do not 
 appear to occur in such numbers in the Dicotyledons as in the Mono- 
 cotyledons ; the family of the Orontiacece especially certainly furnishes 
 wonderfully rich material for the discovery of most interesting facts ; 
 the forms of the embryos perfectly agree scarcely in any two species 
 of Pothos, and, if I am not very much mistaken, embryos with two or 
 three buds occur, e. g., in Pothos reflexa (fig. 260.) : on this point, how- 
 ever, my knowledge of the development is too imperfect for me to ven- 
 ture to speak. 
 
 History, 
 
 The first to whom we owe minute investigation of the Monocoty- 
 ledonous embryo, was C. L. Richard, in his Analyse du Fruit, 1808; 
 soon after that Robert Brown discovered (Prodr. flor. nov. Holl. 1810) 
 the slit of the cotyledons in the Aracece, Typhacece, and Naiadacece ; 
 he looked upon this, howeVer, as a peculiarity of these families, 
 and all botanists followed him. Mirbelf, in 1829, very indefinitely 
 indicated an analogy of the embryo of the Grasses and Liliacece. 
 Finally, in 1837, I J demonstrated, from the history of development of a 
 great number of Monocotyledonous embryos, not only that the slit of the 
 cotyledon, discovered by Rob. Brown, is universal, but also showed that 
 it must always exist, because it is the result of the true typical develop- 
 ment of the embryo. These observations were soon afterwards con- 
 firmed by Ad. de Jussieu in an interesting treatise, and the analyses 
 of some rarer and very aberrant embryos added. All that Link (El. 
 Phil. Bot.) says about the embryo is wholly worthless, because he evi- 
 dently has not observed the course of development of a single one him- 
 self, and therefore arbitrarily guesses at random of the individual parts 
 of the ripe embryo. 
 
 169. 3. Dicotyledons. The embryonal globule in the Dico- 
 tyledons has sometimes rather a spherical and sometimes rather an 
 ovate form. I cannot decide whether it retains this form until the 
 
 * Some therefore call the true radicle the root-envelope (coleorkiztt\ which is alto- 
 gether superfluous. 
 
 f Mem. de 1'Acad. des Sc. 1836, p. 646. 
 
 f Wiegm. Archiv. 1837, and A. L. C. N. C. vol. xix. p. 1. 
 
 Sur les Embryons Monoc. Ann. des. Sc. Nat. June, 1839. 
 
PHANEROGAMIA : FLOWERS. 423 
 
 ripening of the seed, because I have not been able to pursue the 
 development in those plants to which undivided embryos are 
 usually ascribed (Bertholetia and Lecythis). Wherever I have 
 been able to follow this out, I have found the formation of the 
 cotyledons which I am about to describe ; the genus Cuscuta 
 alone forming an exception to this. In these plants the embryonal 
 globule grows into a longish stem, without any trace of foliar 
 organs except in the (single ?) case of Cuscuta monogyna. In all 
 the remaining cases which I have hitherto been able to investigate, 
 there are formed on the embryonal globule, sometimes leaving free 
 a considerable part of the point in a papillary form, sometimes only 
 a small part of it extending to a few cells, but never occupying 
 the extreme point, two leaves, at first as little lateral papilke, which 
 gradually extend on both sides, embracing between them, with 
 their bases, the point of the embryo as a free bud. This is also 
 considerably developed, and produces sometimes more, sometimes 
 fewer, or occasionally no leaves at all in the embryonal condition. 
 Here, again, the varieties of the perfect embryo depend upon the 
 varied ulterior developments of the individual parts thus formed in 
 a rudimentary condition. 
 
 Sometimes the radical end is disproportionately developed, as in the 
 Pekea and Rhizophora ; sometimes the cotyledons; occasionally, but not 
 frequently, one cotyledon alone is greatly increased, whilst the other 
 makes no advance in growth ; this is the case with Trapa natans, in 
 which I have observed, in an early condition, a large papilliform 
 terminal bud, and at the sides two equal-sized cotyledons (?) ; but I 
 have not been able hitherto, notwithstanding every pains, to discover the 
 intermediate stages between this state and that of the ripe seed. 
 
 Of a large series of interesting conditions, which were in great part 
 observed by Bernhardi (Linnsea, Bd. vii. 572.) in germinating plants, 
 we have unfortunately no history of the development of the embryo. 
 All that is commonly said on that subject is merely idle, useless specula- 
 tion, more calculated to mislead than to enlighten. The cotyledons may 
 be blended, as often occurs; and cotyledons originally equal may be sub- 
 sequently unequally developed. Future minute researches can alone 
 solve the problem here. 
 
 C. DEVELOPMENT OF THE GERMEN AND SEED-BUD TO FRUIT 
 AND SEED. 
 
 170. During the development of the embryo, cellular tissue, if 
 not already existing, is always formed in the embryo-sac, always 
 growing from the walls as well as from the surface of the nascent 
 embryo into the cavity : this is called endosperm. How far this 
 new cellular formation may be carried, how soon and to what 
 extent it may be again displaced by growth of the embryo, vary 
 extremely ; but they are usually constant in each particular family. 
 Thus a considerable portion of this endosperm is still to be recog- 
 nised in the ripe seed in the Liliacea, Palms, Grammcce^ and Cypc- 
 
 F. 4 
 
424 MOKFHOLOGY. 
 
 racece amongst the Monocotyledons, and in the Ranunculacece, 
 Papaveracea, Umbelliferce amongst the Dicotyledons, &c. Even 
 where the embryo-sac is very narrow, such an endosperm is often 
 to be detected in the vicinity of the embryo, as, for instance, in the 
 Nymph&acece and the Hydropeltidece. Very rarely indeed, and, so far 
 as I yet know, only in the Cocoinece among the Palms, the process 
 of cell-formation, starting from the walls of the embryo-sac, forms 
 only a thicker or thinner lining to the cavity, while this is not 
 occupied by the embryo, which is relatively exceedingly small. 
 The cavity in this case still contains, even in the ripe seed, the 
 formative fluid (cytoblastema), together with cell-nuclei and some 
 free cells. This fluid is the so-called milk of the cocoa-nut. 
 
 The ulterior development of the new cellular tissue varies much, 
 sometimes the walls are completely converted into cellulose, some- 
 times they remain in a condition which is at least very little removed 
 from gelatine (as in the species of Cassia), or form various inter- 
 mediate conditions between this, amyloid and cellulose, which in 
 the dry seed are commonly called horny. The cell-walls some- 
 times remain quite thin, sometimes they become porously thickened 
 in various ways : their contents are the usual contents of cells 
 assimilated vegetable matter, in which frequently some one con- 
 stituent particularly preponderates, as oil, starch, &c. Very rarely 
 crystals of oxalate of lime are found in the endosperm (as in Pothos 
 rubricaulis). 
 
 As has been already remarked, the embryo-sac, in its formation, 
 sometimes displaces a greater and sometimes a smaller portion of 
 the nucleus. When a portion remains, two conditions may be 
 distinguished according to the form of the seed-bud. In nuclei 
 with straight axes the embryo-sac grows more or less through the 
 axis of the same, and it is then surrounded by the remaining por- 
 tion of the nucleus (as in Nymph&acece, HydropeltidecB, and Pipe- 
 racece) : on the other hand, where the axes of the nuclei are curved, 
 the embryo-sac only displaces that part of the nucleus correspond- 
 ing to the circumference of the seed-bud, and its persistent part is 
 embraced in annular form by the embryo-sac (as in the Portulacece, 
 Caryopliyllace.ee, &c.) This persistent part of the nucleus is termed 
 perisperm : it consists, so far as I know, only of perfectly developed, 
 thin-walled cells, the contents of which are amylaceous or watery, 
 or consist of the usual assimilated matter. 
 
 In Canna alone the peculiarity exists that the nucleus is very 
 early displaced by the embryo-sac, but the substance of the chalaza 
 remains as perisperm. 
 
 All these masses of cellular tissue are called in descriptive 
 botany, without regard to the manner of their origin, albumen. 
 
 The study of development which arose with the intelligent Italian 
 Malpighi was soon lost in oblivion. Treviranus again revived it, but 
 did not arrive at the recognition of its profound importance as the prin- 
 ciple of the whole science. Robert Brown was the first to demonstrate 
 how, in all matters connected with plants, the history of development 
 
PHANEROGAMIA : FLOWEKS. 
 
 425 
 
 alone can lead to the comprehension of the nature of the plant, and 
 therefore of scientific Botany ; and he it was, especially, who made the 
 first step towards bringing light and order into the theory of the albumen, 
 botanists have allowed it to be told them, and follow the old systems as 
 before. In 1825, Robert Brown showed that two things totally different 
 from each other were confounded together under the term albumen, and 
 demonstrated their simultaneous presence in the NymphceacecB. Eighteen 
 years have passed since that, and not a single botanist has contributed 
 anything to the further development of the subject. Before and after 
 they have talked at random about the nature of things, but investigated 
 nothing ; and the treatises given by Mirbel and Brongniart in 1829-30 
 have been passed over without a trace : and we always find that in the 
 most recent works of renowned botanists, Nymphceacece, &c. are de- 
 scribed as Monocotyledons, and the albumen is mentioned without any re- 
 ference to its origin. My friend Vogel (who too early fell a sacrifice to 
 his zeal for science), with myself, endeavoured, in a memoir on the 
 albumen*, to bring light and order into this subject. In the paragraphs 
 I have given the essential portion of our results : many specialities are 
 also unfolded in that essay, in which we have demonstrated, in an 
 extensive treatise on the albumen of the Leguminosce, that this is a 
 true endosperm, and not, as DeCandolle thought, a thickened inner 
 integument. 
 
 The important conditions may be seen by comparing together the seed 
 of Typha (fig. 265.), where endosperm alone is present ; of Saponaria, 
 (fig. 266.), where only perisperm exists ; and of Nymphcea (fig. 267.), 
 where both occur simultaneously. 
 
 265 
 
 267 
 
 (I 
 
 266 
 
 171. The integuments of the seed-bud, in which I here include 
 the nuclear membrane, are also very variable in their ulterior de- 
 velopment. Sometimes, but extremely rarely, they become wholly 
 
 * Act. Acad. L. C. N. C. vol. xix. pt. ii. I here remark, since the usual title notice 
 of the time of sending in has been omitted by the Editor, that this essay was sent in 
 and received for printing by the Editor in 1838. 
 
 265 Typha latifolia. Fruit in longitudinal section. a, Integument of the fruit ; 
 b, integument of the seed ; c, operculum ; d, endosperm ; e, embryo. 
 
 866 Saponaria officinalis. Seed in longitudinal section, a, h, Ililum and chalaza ; 
 </, coat of the seed ; b, perisperm ; f, embryo. 
 
 * 67 Nymphtea alba. Seed in longitudinal section. a, g, Hilum and micropyle ; 
 h, chalaza ; d, seed-coat and its epidermis ; b, perisperm ; <, endosperm ; f, embryo. 
 
426 MORPHOLOGY. 
 
 absorbed, at least on the outer side, by the pressure of the grow- 
 ing endosperm, so that the endosperm exhibits a convex- concave 
 form, the concavity of which receives the remaining portion within 
 it, whilst the convex surface is quite naked. This remarkable 
 process takes place in that section of the species of Veronica which 
 has been named cochlidiospermce. 
 
 More frequently the integuments remain, at least as a thin 
 pellicle, readily falling into shreds, but adhering to the endosperm, 
 as in many Rubiacece, especially in the Coffee. Usually they form 
 a closed envelope to the perisperm, endosperm, or embryo, according 
 as those parts are present, and they are then termed the seed-coat 
 (episperni). Its cellular tissue gradually produces more or fewer 
 (one to five) layers of cells, developed in various ways. Frequently 
 the entire integument appears as a very thin membrane, especially 
 in one-sided, indehiscent fruits (as in the Grasses). We can usually 
 distinguish several layers. Nothing general can be stated respecting 
 the tracing back of these cellular layers to the integuments or thin 
 parts from which they originate; the history of development of 
 individual families, and even genera, must declare it for each 
 separately. 
 
 In the perfecting of the seed-bud, new vascular bundles are 
 frequently produced in the parenchyma of the single or of the 
 outer integument, in connection with the termination of the vessels 
 of the funiculus, usually running out in elegant radiate forms from 
 it (as in the Hazel Nut, Lemon, &c.). The vascular bundle of the 
 raphe alone is often so prolonged, that it runs simple through the 
 entire circumference of the seed -bud until it reaches the micropyle 
 (as in many Composites). 
 
 It often happens that individual parts of the integument become 
 more developed than the rest ; and here belong, in the first place, 
 those peculiar appendages of the raphe already spoken of, which 
 become still further developed ; or a new excrescence is now pro- 
 duced, usually only from a fold of the epidermis, which now 
 developes into two, rarely three usually vertical lines, into a mem- 
 branous border or wing all round the seed (a/a), or elevated ridges, 
 rising in various ways from the surface of the seed, and, if reticularly 
 connected, often forming little pits between them (as in Scrophula- 
 riacecs). Again, the exostome sometimes produces a peculiar ap- 
 pendage in the form of a papilla (Euphorbiacece), or a tuft of hair 
 (coma) grows out (as in AsdepiadacecR and others), or forms a cup- 
 like excavation with a fringed edge (as in Philadelphus), &c. In the 
 region of the chalaza, also, peculiar modifications of the cells are 
 often exhibited, appearing as papillae, gibbosities, and the like, or 
 as a variously, but often distinctly bounded colouring (as in Abrus 
 precatorius, Erythrina corallodendron, &c.).* 
 
 * Link (Elcm. Phil. Bot. vol. ii. p. 285.) says, very inaccurately, the umbilicus in 
 Abrus precatorius is coloured black. On the umbilicus (hilum) the colour is not deep, 
 as that only occurs on the chalaza, and in Erythrina does not reach the umbilicus at all. 
 
PHANEKOGAMIA : FLOWERS. 427 
 
 Finally, it is to be mentioned, in some plants the endostome (as 
 in Lemnd), in others both the exostome and endostome (as in Pistia), 
 in others, again, the whole of the integuments of the seed, 
 which had previously formed a peculiar circular fold (as in Maranta 
 and the Commelinacece), and, lastly, in Canna, the whole of the inte- 
 guments over a small portion of the periphery of the seed-bud, 
 which become hardened by the thickening of these cells, indepen- 
 dently of all the rest, and easily separable from them, lie as an 
 operculum on the radical end of the embryo, and so are termed the 
 operculum or embryotega. 
 
 I must, alas ! again repeat here, what impresses itself upon the pene- 
 trating inquirer at every step in Botany, that almost all the existing 
 material, from the total want of scientific principles, scarcely carries us 
 beyond the very beginning of science. Scarcely anything can be used, 
 almost every thing is yet to be done, almost every investigation must be 
 recommenced from the very beginning, under an improved method. A 
 greater confusion than that which prevails in the theory of the seed- 
 coats is scarcely conceivable. The most heterogeneous things are thrown 
 together under one name, thoroughly identical ones placed in totally dif- 
 ferent classes of organs ; and there is nothing for it, if we would not 
 make still greater confusion, but to cut the thread altogether and begin 
 over again. The epidermis of the seed, as I have delineated it, is de- 
 scribed sometimes as testa in the Leguminosce and Drosera, sometimes 
 as arillus ; seed-membranes are introduced, as in Canna and the Com- 
 positce, where no true integuments exist. Appendages of the raphe, 
 thickened micropyle, thickening of the funiculus, true arilli, run gaily 
 through one another as caruncula, strophiolus, arillus, and under a 
 dozen other names ; every one has new names in readiness. To observe 
 how the things are formed, what their import is in the plant, few do, 
 and most Botanists let the few like Brongniart, Rob. Brown, Mirbel, 
 and others lie on the shelf. One person cannot help in the matter ; he 
 can only complain, and invoke a better spirit to animate Botanists. 
 
 The whole theory has been constructed hitherto solely according to 
 hypotheses, among which especially the view principally established by 
 Gartner, in his otherwise inestimable work (de fructibus et seminibus 
 plantarum), takes the first rank ; a view totally contradicting nature, that 
 the seed must necessarily be covered by two coats. Whence the law is 
 derived, how it is deduced from the nature of the plant and the seed, no 
 one says ; and yet this prejudice is so firmly adhered to, that even after 
 the works of Rob. Brown, Brongniart, and Mirbel had appeared, very 
 talented persons thought they settled a matter very cleverly when they 
 said, one should not be afraid of the periphrasis, for instance, in Viburnum, 
 but had best give : spermodermis incompleta e tunica simplici formata. 
 I think, however, that one should not be afraid to throw away old pre- 
 judices, without any ground in profound investigation of the nature of the 
 plant, but should say simply epispermium simplex* ; or, for instance in 
 Ricinus and Chelidonium, epispermii stratum medium crustaceum, inter- 
 num membranaceum, whereby it at least remains undecided to which 
 integument the layer named belongs, since in Ricinus the brittle (crus- 
 
 The umbilicus itself, i. e. the point of separation, is never especially coloured, and is 
 only otherwise evident by the shining surface of the torn cellular tissue. 
 * I prefer the older name of C. L. Richard. 
 
428 MORPHOLOGY. 
 
 taceum) is the epidermis of the inner integument, closely connected 
 with the parenchyma of the same, and the membranous layer of the 
 nuclear membrane ; in Chelidonium, on the contrary, the brittle layer is 
 the whole external integument clothed with delicate epidermis, and the 
 membranous layer is the inner integument. In Ricinus, therefore, the 
 outer integument would come in as stratum externum evanescens ; in 
 Chelidonium, the epidermis as stratum membranaceum me.dio arete 
 adhcerens. To make the confusion quite perfect comes next the circum- 
 stance, that the different observers, in the analysis of ripe seeds, have 
 determined the number of coats, in dissections made according to vari- 
 ous methods, or in transverse sections under weaker or stronger magni- 
 fying power, according to the variations of the cells quite undistinguish- 
 able in them : so that a seed has often been determined to have a simple 
 seed-coat, which has two or three ; others actually with a simple mem- 
 brane, favoured with two or three seed-roots, on account of differences 
 in the development of the cells. From the small number of observa- 
 tions which have as yet been published by Brongniart, Mirbel, Brown, 
 and myself, it already follows, with perfect certainty, that every deter- 
 mination of the coats of the ripe seed is altogether useless, if their nature 
 has not been demonstrated by the course of development. 
 
 The case mentioned in the beginning of the paragraphs, of the coch- 
 lidiosperms of the species of Veronica, has appeared to me as yet the 
 most difficult subject of investigation, and I was obliged to take the 
 research up several years, one after another, till I had completed it, 
 since, in addition to all the other abnormalities, totally unsymmetrical 
 formation of the seed-bud occurs, which renders the investigations very 
 much more difficult. 
 
 The most general condition is where the epithelium of the external or 
 the simple integument, or the nuclear coat, is developed in a remarkable 
 manner. Thus, in most plants, especially those which have a hard shin- 
 ing seed (e. g. the Leguminosce), it is converted into a tissue, composed 
 of relatively long prismatic cells, placed perpendicularly to the surface 
 of the seed, and usually much thickened, even to the partial obliteration 
 of their cavities. In other plants, particularly such where the seed, 
 when placed in water, becomes coated with gelatinous matter, it consists 
 of cylindrical cells placed in the same manner, but with thin walls, and 
 densely filled with gelatinous matter (Quinces, Plantaginacece), and which 
 frequently contain elegant spiral fibres (many Polemoniacece and Cucur- 
 bitacetz). Here it is often easy to observe the gradual filling of the cell 
 with starch, the solution of this to gum, and the conversion of this into 
 the very hygroscopic gelatine, while the spiral deposits are simultane- 
 ously formed on the wall.* More frequently that gelatine is wanting, 
 and the cells, less cylindrical in form, project in a papillose manner as 
 hairs, or several unite together as little spines, gibbosities, or ridges, &c., 
 rendering the surface of the seed uneven ; or they form a flat surface, 
 while their walls are thickened by a variety of spiral, reticulate, or 
 porous deposits (in Hydrocharis, most Labiatas, Solanacece, Scrophu- 
 lariacecB). In a few cases these cells develope, in exceeding delicacy, to 
 a large size, and become filled with fluid, so that the seed resembles a 
 berry (in Punica granatum, in Ribes (?) ). Those cases are remarkable 
 in which these cells expand so much in the surface that they necessarily 
 
 * See Miiller's Archiv, 1838, p. 152. ; and Schleiden's Beitriige zur But. vol. i. 
 p. 134. 
 
PHANEROGAMIA : FLOWERS. 429 
 
 become torn from the cells beneath them, and then surround the seed as 
 a loose sac (e. g. in Drosera and Parnassia\ or, transformed in a pe- 
 culiar manner into an elastic tissue, tear open and discharge the seed (in 
 Oxalis). The rest of the tissue of the integument, beneath the epi- 
 dermis just described, is very variously developed. Sometimes next the 
 epidermis is a layer of looser cells, with intercellular passages or spaces 
 (e. g. in Leguminosce\ into which, in the only cases, Canna and Ne- 
 lumbium, where the epidermis exhibits stomates, these latter lead. We 
 usually find next to the epidermis and firmly attached to it, a thin layer 
 of parenchyma (the whole outer integument), and then, distinct from 
 this, a special coat consisting of an extremely delicate layer of cells (the 
 inner integument alone, or with the nuclear coat) : this is the case in 
 most LiliacecB. 
 
 A different formation is not unusually met with, where two integuments 
 exist, and the inner is not formed by a mere fold of the epithelium. Here 
 the epithelium of the inner integument is generally exactly in similar con- 
 ditions to some of those generally described above, while the outer in- 
 tegument becomes gradually suppressed, and falls off in shreds (e. g. in 
 Euphorbiacece), or remains as a thinner envelope (e. g. in Cistacece, 
 Thymelacce, Laurctcece). Elegant spiral thickenings also occur here in 
 the epidermis of the inner integument (Lauracece, Sparrmannia afri- 
 cana (?) and others). 
 
 The occurrence of spiral, reticulated, and porous deposit-layers in 
 the epidermis of the seed is so usual that it is not worth while to 
 enumerate the cases now. A very rich variety of forms is exhibited, 
 for example, in the Scrophulariacece, especially the Verbascece and An- 
 tirrhinece, but almost all the Solanacece, particularly those with a berry- 
 fruit, exhibit sometimes true spiral fibres (e. g. Solanum\ sometimes 
 reticulated thickening (e. g. Datura]. It is most remarkable, however, 
 that this structure of the epidermis occurs extremely rarely in the seed- 
 buds of the Monocotyledons, which almost always have two integuments, 
 and is presented in the Dicotyledons, particularly in the Monopetalce, 
 which usually possess only one integument. 
 
 In the formation of new vascular bundles in the integuments of the 
 seed, I have hitherto found the law almost unexceptionably confirmed, 
 that the vessels are never distributed in the nucleus, or inner integument, 
 but only in the outer, or the simple integument. Treviranus had pre- 
 viously propounded the law opposed to this, that vessels are only formed 
 in the inner integument, because, starting from ripe seeds, he confounded 
 the very hard and thick epidermis of many seeds with their outer inte- 
 gument, and the parenchyma of the same .with their inner integument. 
 Link * has the same incorrect assertion, here doubly wrong, since he dis- 
 tinctly refers the shell of the seed (testa) to the outer integument, and 
 the inner coat (membrana internet) to the inner integument of the seed- 
 bud. 
 
 That the operculum of the radicle (fig. 265. c.) may be formed from 
 very different parts, follows from what has been said in the paragraphs. 
 Mirbel first demonstrated its peculiar development in Commelinacece and 
 Marantacece ; I myself in Canna. 
 
 172. Very important alterations take place in the funiculus 
 also during the development of the embryo. It has been remarked 
 
 * Elem. Phil. Bot. ed. 2. vol. i. p. 285. 
 
430 MORPHOLOGY. 
 
 above, that even before the rudiment of the embryo exists, after 
 the complete formation of the seed-bud a new structure proceeds 
 from the funiculus, very similar to the coats of the seed-bud. But 
 the production of such a structure is much more frequent after the 
 formation of the embryo has begun. It is very various, according 
 as it advances farther or is early arrested in its development (as in 
 most LeguminoscB) ; according as the structure envelopes the whole 
 seed as a continuous coat (in Nymphaa, Passiflora, Taxus), or 
 presents itself in separate lobes and strips, here and there connected 
 together (in Myristica (?) ) ; or, lastly, consists merely of long hairs, 
 which envelop the seed (in Salix) : very various, according as this 
 organ is merely membranous, or dry and fibrous (Nymph&a. Salix) ; 
 fleshy and juicy ( Taxus) ; or, lastly, becomes broken up into iso- 
 lated juicy cells, which surround the seed (Arum., Mamillaria). In 
 this last transformation the conducting tissue and a portion of the 
 inner surface of the cavity of the germen usually take part. The 
 former structures, which all have the same origin, namely, are 
 additional developments of the funiculus, have been partly deno- 
 minated by the name aril (arillus) ; the latter, where the isolated 
 juicy cells no longer betray their origin, as pulp (pulpa). Par- 
 ticular forms, e. g. in Salix, are described as a coma. 
 
 The heterogeneous things which are usually collected under the name 
 arillus pass belief, except with those who know that Botany has 
 hitherto established its definitions almost solely on superficial impressions 
 and external resemblances, or at best on comparisons which, from the 
 want of sure foundations, are valueless. In Zoology the comparative 
 method had still an import, since one organism understood as completely 
 as possible, according to its course of development, the human, could be 
 taken as a basis ; yet the tracing of development has even asserted its 
 right here, and the most recent researches have proved to what mistaken 
 directions and complications mere comparisons may lead in the absence 
 of developmental history. In Botany, on the other hand, when we do 
 not yet understand the structure and development of a single plant com- 
 pletely, such a comparative method is an empty exercise of the wit. 
 There can be no doubt that every contest is childish in which no critical 
 tribunal, no principle for the decision, exists ; that a scientific investi- 
 gation is wholly vain if a principle of truth have not been previously 
 discovered. Botany possesses nothing of the kind. Link (Elem. Phil. 
 Bot. ed. 2. vol. ii. p. 265.) says : " At the place where the funiculus 
 enters the seed a variously-shaped part often occurs, which has origin- 
 ated from the thickened and expanded funiculus, but is invested with 
 an epidermal layer, of which the funiculus is destitute : this is called 
 an aril. It is globular (Euphorbia), a cup with an entire margin (Ana- 
 gallis\ a four-toothed cup (Polygala), a lacerated cup (Myristica)" 
 Mirbel had already shown that the gland in Euphorbia is totally different 
 from an aril, and does not arise from the funiculus at all ; in Anagallis 
 there exists nothing bearing the most distant resemblance to an aril ; in 
 Polygala there is only a rather loose epidermis to the seed : and all these 
 are thrown together by Link. Any one who calls the elastic epidermis 
 of the seed of Oxalis an arillus is just as much and just as little jus- 
 tified as he who chooses to call it epidermis, or even pulp. The strife is 
 
PHANEROGAMIA : FLOWERS. 431 
 
 endless, Science in constant confusion and vacillation, so long as no 
 standard exists by which to estimate the correctness of this or that 
 opinion. Such a standard can only be found in the history of deve- 
 lopment. Organs which have like origin, like laws of development, are 
 alike ; organs of different origin, different. Forms in the perfect con- 
 dition, which may occur in any part, are no characters for the distinction 
 of organs ; but only characters for their sub-division. These are the 
 rules with which the history of development furnishes us, to define 
 every vegetable structure with certainty. But more is required for their 
 application than the meagre examination of a dried plant. 
 
 The formation of the aril and pulp with succulent cellular tissue is 
 very frequent, and the occurrence of lignification is on the whole much 
 more rare in the development of the funiculus ; yet elegant spiral cells 
 occur in the funiculi of some species of Veronica, and the funiculus of 
 the species of Magnolia (which I have unfor- 
 tunately never had an opportunity t of examining) 268 
 is said to consist wholly of spiral-fibrous cells. 
 
 In the perfect aril, which wholly surrounds the 
 seed-bud like an integument (fig. 268. .}, the 
 closed is commonly distinguished from the un- 
 closed : the former never occurs ; where an ac- 
 tually closed structure surrounds the seed, it is un- 
 doubtedly a layer of the seed-coats. In the species 
 of Passiflora particularly, it is always open above. 
 Whether all the^ structures named in 172, those 
 occurring in Evonymus and Myristica, as also those 
 in Solamim, belong here, I will not assert, since I 
 am still ignorant of the history of development.* 
 
 173. In conclusion, we have yet to examine the changes which 
 take place in the germen. The germen grown to the fruit is styled 
 the pericarp (pericarpium). Besides the generally considerable 
 enlargement of the mass, which depends sometimes on the expan- 
 sion of the existing cells, and sometimes on the production of new 
 ones, we have to consider the following points : 
 
 First, the changes in the external parts, since the pistil, as its 
 mass enlarges, often considerably alters in the conditions of its parts. 
 The style, in particular, is usually cast off or dried up as a part of 
 no further use; more rarely it goes on growing, and sometimes 
 acquires a disproportionate size, for instance, in many Geraniacea. 
 The germen also frequently now first produces projecting ridges, 
 warts, gibbosities, or thin membranous appendages (wings). 
 
 The conditions of the interior of the germen now become im- 
 portant. As in the formation of the entire pistil and of the 
 seed-bud to fruit and seed, so, as it would appear, the development 
 
 * We have received an essay from Planchon on the 'arillus (Comptes rendus, Dec. 
 1844), which, from the extract published in the Botanische Zeltung, and his other works, 
 awakens no especial confidence. He asserts particularly, that in Myristica and Euonymus 
 no arillus occurs, but an excrescence of the micropyle, which he calls an arillode. 
 
 868 Passiflora alba. Longitudinal section of the seed. a, Funiculus and hilum ; 
 /, chalaza ; d, external, /, internal layer of the testa ; b, endosperm ; r, embryo ; r, raphe ; 
 *, aril. 
 
432 MORPHOLOGY. 
 
 of the individual parts of the pistil depend almost solely upon the 
 healthy development of the embryo. Hence those cells in which 
 no seed-buds are developed to seed are in like manner arrested in 
 their development, and in the matured fruit are scarcely to be 
 recognised. This non-development of some of the cells appears to 
 be as it were the normal rule in some plants : thus, in many Palms, 
 e. g. Chamcedorea, of three cells one only is commonly developed, 
 whilst the others dwindle away. The same occurs in all Cupuliferce; 
 and the germen of Castanea, with six cells and twelve seed-buds, 
 usually produces a one-celled, one- seeded fruit. In the ripe 
 fruit, therefore, it is always impossible to determine the original 
 number of cells and seed-buds. On the other hand, large air- 
 cavities are not un frequently formed in the wall of the germen, 
 which assume the deceptive appearance of natural cells containing 
 no seeds, as in Nigella. 
 
 Another important matter, moreover, is the development of 
 cellular tissue from the inside of the wall of the cavity of the 
 germen, by which are not unfrequently formed, in long germens 
 (but always subsequent to the origin of the embryo), false septa, 
 which are transverse, and therefore have a direction in which true 
 septa never can occur. The general term for fruits with these false 
 septa is a lomentum; examples of it occur in Raphanus and Orni- 
 thopus. Sometimes this cellular tissue, instead of forming actual 
 false septa, is accumulated thickly between and around the seeds 
 filling the cavity, as in Glaucium, Ceratonia, &c. 
 
 The conditions of structure of the germen are here to be parti- 
 cularly kept in view. 
 
 Through the entire range of Phanerogamic plants, we find the 
 most diversified metamorphoses in the structure of the germen ; on 
 account of which the ripe fruit presents a great multitude of 
 different appearances. So far as my observations extend, two dif- 
 ferent types may be distinguished in the development, according as 
 the layers of cellular tissue of the testa become tougher and firmer 
 from within outwards or from without inwards. In the former, be 
 the morphological import what it may, four several cell-layers are 
 universally to be distinguished, although they sometimes appear 
 more clearly than at others ; namely, the epidermis of the outer 
 surface ; the epithelium of the inner surface ; and between the two 
 an external parenchymatous layer, the cells of which are generally 
 delicate-walled, fleshy, and of simple polyhedral form ; and, finally, 
 of an inner parenchymatous layer, the cells of which are more or 
 less thick, coriaceous, or woody, and always elongated. 
 
 The second type is exhibited in those fruits in which the paren- 
 chyma is developed more or less fleshy and succulent, and frequently 
 toward the interior, where it bounds the fruit-cavity, broken up into 
 isolated cells ; whilst either only the epidermis of the outer surface 
 is very thick, or else some layers of cells thicken beneath it ( Cucur- 
 bitacece), or sometimes acquire even a woody texture (e. g. La- 
 genaria and Crescentia). In the mass of isolated, juicy cells which 
 
PHANEROGAMIA : FLOWERS. 433 
 
 often fill berries, it is no longer possible to determine how much of 
 it belongs to the inner wall of the fruit, how much to the conducting 
 cellular tissue and to the funiculus : the whole mass may in any 
 case be termed pulp. 
 
 Upon the more or less distinct production of the layers of the testa, 
 and upon their varied formation, rest all those varieties of the fruit which 
 strike us on a first impression, and which had received their common 
 distinctive names long before botanists had constructed fruit-systems. 
 Where the layers are clearly distinguished, the epidermis of the surface 
 is seldom particularly striking, the inner epithelium frequently shares 
 the transformation of the inner parenchymatous portion, which varies in 
 its consistence from that of leather up to a stony hardness, sufficient to 
 give out sparks when struck by steel ; but in every condition it consists 
 of thickened cells which are usually porous. Two different conditions 
 may be distinguished in the inner parenchymatous layer : 1st, Where 
 several layers of cells go to its formation, the long-diameter of the cells 
 of one layer is commonly at some angle to those of the next layer (as in 
 Leguminosce, Amygdalece, and almost all capsules) ; 2ndly, Where only 
 one layer is present, the cells are so arranged that five, or six, or more 
 cells, lying parallel, form little plates, from which the layer is so con- 
 structed, like mosaic work, that the long-diameter of the cells of one 
 plate is never in a line with that of those of the next plate (as in Ascle- 
 piadacece and Cruciferce). The epithelium of the inner surface is also 
 sometimes changed into elegant spiral-fibrous cells, as in some Papave- 
 racece (Chelidonium\ in Umbelliferce (Anethum\ &c. ; more rarely it is 
 developed into true epidermis with perfect stomates (as in Reseda, Passi- 
 flora, &c.). The outer layer of parenchyma varies from a leathery con- 
 sistence to the most perfect dissolution into easily compressible, succulent 
 cells, DeCandolle and others have taken pains to trace this layer to the 
 texture of the normal leaf. It appears to me that this is empty trifling. 
 In the first place, it has as little of the structure of a normal leaf as of 
 the form ; secondly, many germens do not arise from foliar organs ; 
 and thirdly, in one and the same strictly-defined and quite natural family, 
 the most essential varieties are found to exist in nearly related genera, as 
 in the Solanacece, where true berries and capsules, and in the Dryadece, 
 where true small berries and achaenia occur. 
 
 In the formation of the berry and the pulp, the origin of cells within 
 cells, &c., may usually be beautifully observed. The parent-cells, how- 
 ever, especially towards the time of the ripening of the fruit, become 
 absorbed before the young cells are firmly united together and sufficiently 
 expanded to become firmly connected with the neighbouring cells when 
 they are set free ; hence they remain lying loose in the abundance of juice 
 which is simultaneously produced. A circulation in reticulated, anasto- 
 mosing currents is exhibited in these isolated cells (in Solanacece, Cac- 
 tacece, and Lonicerece). 
 
 Some very thin- walled germens in Aracece and Naiadacece, as also, in 
 part, in those families whose one-seeded, indehiscent germens are closely 
 united with the external integument of the seed, and thus represent what 
 Linnaeus called naked seeds (e.g. Crraminece, Labiates, Boraginacece, Com- 
 positce, &c.), are in the ripe fruit so compressed and so uniformly 
 developed in all their (few) cell-layers, that they can only be classed by 
 means of analogy with one of the types mentioned. 
 
 The epidermis of the fruit in the occasionally dehiscent fruits exhibits 
 
 F F 
 
434 MORPHOLOGY. 
 
 cells with spiral and reticulated layers of thickening, as, for instance, in the 
 LabiatcB (especially Salvice), and in the Casuarinacece ; and the hairs of 
 the epidermis often exhibit the same, as in some Composite (Senecio and 
 Trichocline\ &c. The most beautiful structures of fibrous cells are 
 formed through the entire tissue of the indehiscent germen, as in the 
 Composites (Picridium) and the Umbelliferce ( Sclerosciadium Prangos). 
 
 174. Similar conditions to those which occur in the bursting of 
 the anthers and in the fall of the leaves are also presented in the 
 fruit, and depend on the same causes, namely, the formation of 
 layers of cellular tissue extremely thin-walled and easily destruc- 
 tible, which is ruptured by the slightest tension arising from the 
 mere weight of the parts, or an unequal contraction of dissimilar 
 layers of cellular tissue. This exists either as a peculiar layer 
 between two differently formed masses of cellular tissue, or forms 
 the external layer of a mass of tissue, itself having thin walls, and 
 lying immediately in contact with some very thick- walled tissue. 
 Whether separations of this kind shall take place, and in what par- 
 ticular situations, are altogether peculiarities of particular species, 
 genera, and families, and are not dependant on any known relation 
 to the nature of the" plant. Hence solutions of continuity arise, 
 sometimes at the place where two originally separate parts (carpels) 
 had become blended in the suture, or else where an undivided whole 
 originally existed *, as in the line corresponding to the mid-rib of a 
 carpel ; sometimes in the direction of the length, as in the examples 
 which have been cited, and sometimes cutting across, as when the 
 entire fruit falls away, or when long fruits break up into separate 
 articulations, &c. ; sometimes only in small portions of the germen, 
 so that it opens by definite orifices. Many fruits are rent open in 
 the most diversified manner by the always unequal drying of the 
 pericarp, on account of the differences of the layers of which it is 
 composed. They may open either, , in individual portions, 
 each closed in itself, and separating either lengthways or crossways 
 (niericarps) ; or, b, in individual flat portions (valves). In the lon- 
 gitudinal division or the formation of valves, there remains besides 
 these parts, in many families, a mass of cellular tissue, usually in the 
 form of a stalk, standing in the midst of the individually separating 
 mericarps, as in the Umbelliferce, the Euphorbiacece, and Geraniacece, 
 or of the separating valves, as in Rhododendron, called the columella. 
 This is merely a separation of originally connected parts, and in 
 none of the cases named is the remaining stalk by any means an 
 internode of the floral axis to which the carpels were attached, but 
 an absolutely independent cellular mass. 
 
 In very many manuals of Botany, we find directions to determine the 
 number of carpels according to the valves of the fruit. How absurd 
 this is, the authors might have known, from the transverse separation 
 of the so-called circumscissile capsule and of the lomentum into separate 
 
 * Here, also, no trouble being felt about the thorough diversity, the line of separa- 
 tion has received the meaningless name of suture. 
 
PHANEROGAMIA : FLOWERS. 435 
 
 pieces, from which two facts it follows that the subsequent separation of 
 the parts is wholly independent of the original composition. But as the 
 word blending has hitherto been applied without any meaning, according 
 to the arbitrary fictions of particular botanists, nothing opposed the 
 equally arbitrary twaddle about the conditions referred to in the para- 
 graph. The kind and manner of these separations has not the slightest 
 connection with the original composition of the germen out of individual 
 parts, carpels, &c., and every conclusion from the number of subse- 
 quent parts as to the number of original constituent portions merely 
 exhibits the total unacquaintance of the concluder with the nature of 
 plants, and of this process in particular. Here, as so frequently in 
 the vegetable organism, in the originally homogeneous cellular tissue, 
 which, where actual blending has taken place, becomes so closely con- 
 nected that the boundary is soon wholly obliterated, layers of a very 
 different kind of cells are developed, which exhibit great diversity, 
 partly in the consistence of the substance forming their walls, partly 
 in the relatively advanced condition of the deposition of thickening 
 matter upon them. Similar cells are generally more firmly adherent 
 to each other than to cells of a dissimilar character, and thence it happens 
 that the different layers separate so readily, as, for instance, in the 
 succulent part of the fruit of the Almond, Plum, Walnut, &c., from 
 the woody. In most cases, however, thin plates of very thin-walled 
 and speedily decaying tissue are formed for this purpose, and are lace- 
 rated by the slightest tension, and thus give rise to a solution of conti- 
 nuity. Even in the situations where originally distinct parts have been 
 blended, the separation seldom (or never ?) happens in such a way that 
 the blended parts become again loosed from one another, but so that the 
 cells are torn and destroyed ; and thus, even in these cases, the circum- 
 stances of the process are by no means arrived at and expressed, when 
 it is said that the valves are the original carpels ; it is here shown, 
 moreover, that all these solutions of continuity, in the entire plant, 
 full under one and the same law, that of the morphologically defined 
 dehiscence, which is wholly different from and independent of the mor- 
 phologically defined formation and connection of organs. 
 
 I will particularly cite the application which has been made of that 
 incorrect view to the -Geraniacece and Umbelliferce. In these the fruit 
 separates into distinct parts from a stalk-like mass of cellular tissue, 
 remaining longest in connection with the summit of this, and, as it 
 were, suspended from it. By the favourite method of guessing, this 
 stalk is explained to be a prolongation of the floral axis, to which the 
 carpellary leaves are attached, and from which they again separate when 
 the fruit is mature. In the first place, it must be observed, that in 
 the Umbelliferce the whole germen is never formed of carpels, but of 
 the axis itself. In the Geraniacece, on the contrary, there are ori- 
 ginally five perfectly free carpels, having no trace of a prolongation of 
 the axis between them, which become blended, and subsequently de- 
 hisce in such a manner that an internal portion of each carpel remains 
 in the axis, while the external portion becomes gradually loosened from 
 below upwards. The internal portion contains a liber-bundle, with the 
 canal of the style. Now in the Umbelliferce two little liber-bundles are 
 found in the middle of the false septum of the germen, which remains, 
 with a portion of their enveloping cells, in the axis of the fruit, while 
 the two portions of the fruit in like manner tear away from them from 
 below upward. Sometimes those liber-bundles separate from each 
 
 F F 2 
 
436 MORPHOLOGY. 
 
 other from above downwards, so that the stalk-like support (carpophore) 
 of the mericarps is bifurcately split above, or is even bipartite from the 
 base. Dehiscences exactly similar to those of the Geraniacece, occur 
 in all the plants in which the valves of the fruit separate from a central 
 columella ; therefore there never is true axial structure in these. Where, 
 for instance, the axis (spermophore) constitutes the element, considerable 
 portions of the carpels always remain connected with the axis, and the 
 separation therefore equally happens within the continuity of one organ, 
 e. g., in Euphorbiacece. 
 
 D. PHENOMENA EXHIBITED IN THE REMAINING PARTS OP THE FLOWER 
 DURING THE FORMATION OF THE FRUIT AND SEED. 
 
 175. Great varieties are exhibited by the remaining parts 
 belonging to the flower during the development of the germen to 
 the fruit. The stamens and petals are soon after the impregnation 
 cast off at their bases by true articulations, or they wither and die 
 away. In rare cases a part of them remain, especially when they 
 are blended together, and become fleshy or woody (as in Mirabilis). 
 The same occurs in the perianth, but this is more frequently per- 
 sistent. When the floral envelopes are partly or wholly persistent, 
 four layers are sometimes formed in them, like the four which are 
 exhibited in the pericarp, whilst this is only developed as a very 
 thin membrane (as in El&agnut\ or they become succulent and 
 form a false berry (as in Morus). The calyx, on the contrary, 
 persists in the generality of plants until the ripening of the fruit, 
 in which it is either little or not at all altered, as in the Pomece ; or 
 becomes large and inflated, and surrounding the fruit (as in Phy- 
 salis, Trifolium fragiferum) ; or, as a pappus, adorns the fruit as a 
 delicate, membranous, or hairy structure, as in the Valerianacecs, the 
 Composites, &c. ; or half of it may be cast off, as in Datura. In 
 many of the cases above named, these parts assume the appear- 
 ance of true fruit, and this is still more frequently the case with 
 the axial organs of the flower : thus in the Strawberry the recep- 
 tacle becomes fleshy, and appears as fruit ; in Hovenia, Semecarpus, 
 and Anacardium the pedicel becomes transformed into an apparent 
 fruit of similar nature. Most frequently, however, it is the con- 
 cave disc of the peduncle which, becoming fleshy, is developed to 
 what is vulgularly called fruit, as in Rosa, Malus, Pyrus, Ficus, 
 &c. Finally, it is to be observed, that, especially in flowers with- 
 out floral envelopes, the bracts and bracteoles grow with the fruit, 
 become woody, and so form false pericarps, as in the Cupuliferce 
 the so-called cupula, and in Betulinece the scales of the catkin. 
 
 I have here merely remarked the existence of the conditions named, 
 since I must return to them when I come to the more minute treatment 
 of the theory of the fruit. As in all other parts of our science, so also 
 with respect to the fruit, we feel the want of scientific definitions ; and a 
 logical arrangement of the characters met with is nowhere less to be 
 thought of than here. When the peasant talks of the edible part of the 
 
PHANEROGAMIA : FLOWERS. 437 
 
 Fig as the fruit, we have nothing to object ; but if the botanist assumes 
 the peasant's style of discrimination, he is far below the peasant : his 
 science should have taught him that edibility is no test of a part being 
 fruit. With the inconsistency thus introduced, a portion of those con- 
 ditions mentioned in the paragraph have been enumerated amongst fruits 
 according to common notions, while, in regard to another portion, it has 
 been correctly noticed that the fruit is surrounded with another part not 
 belonging to it, 
 
 IV. Of the Fruit and the Seed. 
 
 176. Fruit (fructus), in the scientific sense of the term, is the 
 single pistil at the time of the perfect formation of the embryo 
 (the maturity of the seed). The style and stigma, when they still 
 remain, retain their names, but the germen acquires that of peri- 
 carp. In this sense, there are of course some plants which have 
 no fruit, because they are not provided with a germen ; these, 
 therefore, must be described as naked seed-buds, and also naked 
 seeds (semina nuda) : to these belong the Coniferce, Cycadacece, and 
 Loranthacece. But there are also some particular plants in which 
 the germen is easily destroyed, so that the seed-bud is developed 
 in like manner without an envelope to the seed : these, in order 
 to distinguish them from the former, are termed semina denudata 
 (Leontice and Peliosanthes theta). The actual fruits may be divided, 
 according to the analogy of the flower, into naked and covered 
 (fructus nudus etfructus tectus), according as of the entire flower 
 only the germen appears to exist (as in Lilium\ or as this is 
 surrounded by other floral parts (as in Nicandra). According as 
 in a flower one or more pistils are developed, it is distinguished 
 as simple fruit (fructus simplex, as in Nigella) from the multiple 
 fruit (fructus multiplex, as in Ranunculus). Here, also, the ar- 
 rangement of the fruit is to be distinguished just as the inflo- 
 rescence was, and the same terminology may be retained (as fruit 
 spike, fruit capitulum, fruit umbel, &c.) ; or simply, as Linnaeus 
 spoke of the flower of the Composite, so here as a compound fruit 
 (fructus compositus), as in Ananas. 
 
 All that has been said respecting the nature of the individual 
 germen, in reference to its origin, its composition, its interual 
 divisions, &c., holds good of course for each several fruit, unless 
 these conditions have been altered in the subsequent development 
 and progress towards maturity ; in which case such changes, but 
 only such changes, must receive names. 
 
 The fruit may be defined in two ways, either as has been done in the 
 paragraphs, or, as some botanists have attempted, as the whole individual 
 flower at the time when the seed is ripe. It would be quite indifferent, 
 fundamentally, for science, which definition were established, if only one 
 actually were established : but the fact that not one single botanist has 
 carried out the conception of the fruit consistently with his own de- 
 finition has brought such confusion into the theory of the fruit, that, 
 
 F r 3 
 
438 MORPHOLOGY. 
 
 increased still further by the want of knowledge of the germen, and the 
 baseless gossip about explanations of striking phenomena, it has become 
 a crux et horror to all who wish to devote themselves to the study of 
 Botany. 
 
 It appears to me that the definition given in the paragraph, which 
 agrees with that of most botanists, although, indeed, without therefore 
 remaining true to itself, is the most to the purpose for the comprehension 
 of the matter ; besides, we should have no satisfactory word by which to 
 denominate this most essential part of the flower, continuously developed 
 up to the time when the seeds are ripe, if we applied the term fruit to 
 the whole flower at the epoch of maturity. It is indeed self-evident, 
 that botanists who have claims to scientific character may no longer 
 content themselves with statements like " pistillum unicum, stylus nul- 
 lus, stigma simplex" and the like, but that a minute exposition of the 
 rudimentary fruit, according to internal structure, number, and form of 
 seed-buds, &c., is indispensable. Then, however, a quantity of phrases 
 respecting the fruit become superfluous, which were formerly necessary, 
 and are still partially retained from custom. It evidently follows that, 
 putting out of the question the structural conditions, and the newly- 
 formed embryo and endosperm, the construction of the fruit is exactly 
 like that of the rudiment of it, and only requires especial notice when 
 important modifications have occurred through actual abortion of seed- 
 buds and entire cells. 
 
 Two very different points of view must be both established and accu- 
 rately discriminated in the theory of the fruit, namely the scientific 
 condition and the empirical denomination of the fruit. These two so 
 wholly diverse respects have hitherto been completely confounded, and 
 thence in reference to the first far too little, to the second far too much, 
 has been done in the theory of the fruit. Here, also, this complication 
 of aspects has been historically carried forward ; and it is truly now time 
 that we gradually strip off the still adhering egg-shells of newly -hatched 
 science. It is indeed no long time since the more minute observation of 
 the construction of the germen was first commenced ; and so long as this 
 existed merely in rough outlines, much that ought properly to have been 
 previously mentioned necessarily came in as supplementary to the de- 
 scription of the fruit. That such patchwork does not go far, is, I think, 
 sufficiently shown by our systems of fruits with their incompleteness, 
 and yet at the same time with their arid waste of names and synonymes. 
 It is clear, also, that no attempt to understand the fruit from the mere 
 study of the ripe condition can succeed. The fruit is merely the final 
 result of a series of developments of the whole plant, the last product of 
 a great number of factors, and gives no conclusions about what has gone 
 before, about the number and nature of the co-operating factors. Thus 
 it has been attempted to deduce the number of parts forming the germen 
 from the number of valves : it was only necessary to call to mind the 
 capsula circumscissa, the lomentum and legumen, the loculicidal and 
 septifragal dehiscence, to see that original composition and subsequent 
 division stand in no necessary, but at most a very casual, connection. 
 Pains have been taken to refer the separate layers of the pericarp to the 
 layers of a leaf (carpel) : but, disregarding the circumstance that leaves 
 and pericarps do not universally exhibit layers, it is here most erro- 
 neously presupposed that every germen is composed of foliar organs, 
 &c. Now if the construction of the germen has been perfectly under- 
 stood, the gradual process of its development to fruit been comprehended, 
 
PHANEROGAMIA : FLOWERS. 439 
 
 the fruit requires no further explanation, it is self-evident ; the product 
 is always given by the factor, though the reverse never. All that relates 
 to the form and composition of the fruit has, in a correct treatment of 
 the science, been already given under the head of the germen and its 
 developments ; therefore the peculiarity of the fruit does not at all lie 
 there, consequently none of this deserves special nomenclature. That an 
 inferior germen cannot become a superior fruit is self-evident ; and to 
 distinguish the fruit again on this account is wholly superfluous. It is 
 of more importance to state whether cells and seeds become abortive, or 
 whether spurious septa have been formed during the growth of the fruit. 
 On the other hand, the characteristic for the fruit and its essential 
 peculiarity are its structural conditions, and hence these alone merit a 
 peculiar nomenclature ; for instance, the inferior capsule must be dis- 
 tinguished from the inferior berry, but not the inferior from the superior 
 berry, since this latter character has already been given in the germen ; 
 and all that is additional in the fruit is the berry-like development of the 
 parenchymatous layers of the pericarp. 
 
 Nowhere has purely diagrammatic comprehension been so prevalent 
 as in the theory of the fruit ; nowhere have botanists, starting from the 
 language of common life, and merely multiplying the words, taken so 
 little pains to define with scientific strictness ; and hence nowhere does 
 terminology so vacillate among all the definitions as in the fruit. One 
 assumes 10, another 15, a third 20, and another 40 or 50 kinds of fruit; 
 in short, the confusion is indescribable ; and if, according to the best 
 authorities, one explains to the scholar a drupe as a closed fruit, fleshy 
 externally and woody within, a capsule as a dehiscent, dry fruit, he finds, 
 in Reichenbach, for instance, not one single Labiate or Boragineous plant 
 described, since this author ascribes to these four drupes, and the four 
 drupes unite to form a capsule. 
 
 I find the best exposition of this complicated subject in Lindley (Intro- 
 duction to Botany), who has at least sought to let in some light by 
 logical arrangement and strict definitions. Yet it is clear that the 
 existing wilderness of names, thrown together arbitrarily and under no 
 principles, is too much for the most straightforward inclination. The 
 only thing to be done is to throw away the whole mass, and begin the 
 investigation over again. 
 
 We have almost as many systems of fruits as botanical writers. We 
 owe the first thorough research into fruits and seeds to Gartner (De 
 Fructibus et Seminibus Plantarum, Stuttgart, 1788) and L.C.Richard 
 (Analyse du Fruit, Paris, 1808), whose works will remain classic for all 
 time. Subsequently to these, Mirbel, Dumortier, Desvaux, and others 
 have given Systems which, without essentially improving anything, 
 contain an innumerable quantity of new names, even for things long 
 before known and named. 
 
 177. Taking the foregoing for our standard, we have now to 
 follow out particular points in the fruit. 1. We have to examine, 
 as portions of the fruit, the pericarp, the spermophore, the funicu- 
 lus, and the pulp ; then again, the seed, and in this the episperm 
 and the nucleus, and in this the embryo and the albumen. 
 
 2. We have further to take account of the remaining parts that 
 stand in close relation to the fruit, from the bracts up to the parts 
 of the flower : these are accessory organs. 
 
 F F 4 
 
449 MORPHOLOGY. 
 
 3. Lastly, the various kinds of fruits are to be enumerated. 
 
 These matters, for the most part, require only to be generally men- 
 tioned and collected together here, since everything of importance 
 relating to them has already been mentioned in the paragraphs (160 
 175.). 
 
 1. Of the individual Parts of the Fruit. 
 
 178. The pericarp is the transformed germen : sometimes it is 
 united with the other persistent parts of the pistil, style, and 
 stigma. The latter are seldom of particular importance ; and all 
 that need now be said of them is that they have been retained 
 up to this epoch (as in Papaver), or they have become more de- 
 veloped (as in Pulsatilla). The forms of the pericarp are exceed- 
 ingly diversified, but admit of no general definition ; they frequently 
 exhibit hairs, prickles, protuberances, and membranous expansions 
 (alee), prominent ribs (costce or juga\ and pits in their inter- 
 spaces (vallecul(R\ &c. The pericarp essentially determines the 
 varied appearances of the fruit, by its diversity of structure. It 
 has already been mentioned in what various manners the paren- 
 chyma of the germen is developed. In the simplest cases, we find 
 in the mature pericarp only the epidermis of both surfaces, and 
 between these an uniform layer of parenchyma, without vascular 
 bundles (as in the lower Aracece), or traversed by a few simple 
 bundles. In other cases only the epidermis of the external surface 
 is perceptible, whilst the entire parenchyma, with the epidermis of 
 the inner surface, is succulent or fleshy (as in Atropa} ; or it may 
 be, that under the epidermis of the outer surface some layers of 
 cellular tissue are woody, whilst the underlying are fleshy ; in both 
 cases very frequently passing without determined boundary into 
 the pulp. 
 
 In many other cases four layers are distinctly discernible, which 
 have been already characterised ; and since the time of DeCandolle 
 (altogether misunderstanding L. C. Richard, the originator of the 
 division) they have been named, counting from without inward, 
 epicarp, mesocarp, (also sarcocarp, or flesh, caro) ; and the two inner 
 undistinguished coats, the endocarp. Those varieties of structure 
 in the fruit are most important which cause the peculiar solutions 
 of the continuity in the fully mature condition. Hence we obtain 
 two comprehensive classes of fruits, according as their construction 
 causes a separation into individual parts or not. The latter may 
 be termed the berry-like, and the former the capsular. The cap- 
 sular are again divided into two groups, according as the pericarp 
 either opens and suffers the seed to escape capsules with their 
 portions called valves, or separates into individual parts, which do 
 no not again open, but firmly enclose the seed splitting fruits 
 (schizocarps), and their parts called mericarps. The berry-like 
 fruits are also subdivided into three groups, according as the inner 
 
PHANEROGAMIA : FLOWERS. 441 
 
 layers are the more tough and solid, and the outer the more fleshy 
 and juicy stone berries (drupes) ; or the reverse true berries 
 (baccce) ; or, lastly, all the layers appear thin and dry, or leathery 
 (achcRnia). All these forms may, with the germen from which 
 they arise, be superior or inferior, one- or many-celled or one- or 
 many-seeded ; which only require to be noticed when deviations in 
 the structure of the germen have arisen through abortion, being 
 otherwise self-evident. 
 
 a. The capsular fruits occur in the most diverse families. The 
 mode of bursting (dehiscence) is especially to be observed. The 
 simplest process is an apparent wholly irregular tearing open at 
 any place (as in Nicandra) : usually, however, the form of this 
 dehiscence is very regular, even though it may be confined to a 
 small part of the fruit (pericarpium poro dehiscens), as in Papaver, 
 Antirrhinum 9 &c. 
 
 The solution of continuity is either vertical or horizontal: in 
 the latter case, the upper part forms a kind of cover upon the 
 under, and the capsule is termed circumscissile. In the first case, 
 the pericarp, &c. falls away in more or fewer separate pieces, which 
 are termed valves.* In many-celled fruits (a) the valves may 
 
 separate entirely from the persistent septa, as in Cobaa scandens 
 (dehiscentia septifraga) ; or (b) the septa may split into two la- 
 mellae, and each valve may bear one of these lamella? on each of its 
 margins (dehiscentia septicida, valvulce margine septiferce) ; or (c) the 
 septa may remain undivided, adherent to the middle of the valves 
 (dehiscentia loculicida, valvulce medio septiferce). If in any of these 
 kinds of dehiscence a stalk-like mass of cellular tissue remains 
 standing in the axis of the fruit, it is called the columella. 
 
 From what has been said, it is sufficiently evident that these 
 solutions in the continuity are not at all dependant upon the ori- 
 ginal composition. Common Botany, however, assumes such a 
 relation, and therefore applies to the line in the external circum- 
 ference of the pericarp, where the edges of real or pretended 
 carpels have become blended, the term of " dorsal suture," which 
 is only half correct according to this very hypothesis, while the 
 term " ventral suture " designates merely the line where the mar- 
 gins of one and the same carpel or similar part have become blended. 
 
 * Sometimes tough cords of cellular tissue, persistent between each two valves, 
 nected in the stigma above (as in Argemone). I do not find that any special nami 
 
 con- 
 
 name has 
 
 yet been made for these. 
 
442 MORPHOLOGY. 
 
 In the generality of capsular fruits, the above-mentioned four 
 layers of the pericarp may be distinguished from each other ; but 
 they are usually very thin and membranous or leathery, or more 
 rarely woody. 
 
 b. The schizocarps or splitting fruits are usually distinguished 
 chiefly according to the direction in which the cleft occurs. This 
 is either parallel with the axis of the fruit, or perpendicular to it, 
 that is, the solution of continuity is either vertical or transverse. 
 In both, the separate parts are usually only one-seeded. In the 
 first case the separate parts are sometimes named cocci or meri- 
 carps, in the last case joints or articulations ; and they are dis- 
 tinguished, according to the texture of their layers, as dry, coria- 
 ceous, and succulent. The first (the mericarps) are proper to the 
 families Rubiacecs, Euphorbiaceos, Labiates, Boraginacece, Gerani- 
 acece, TropceolacecR, Malvaceae, Umbelliferce, &c. &c. ; the last (the 
 joints) to some of the Leguminoscs and Cruciferce. In the first 
 a columella is not uncommon. 
 
 c. The stone berries, characteristic of the Amygdalece, but also 
 presented in other families, owe their peculiarity to the remarkable 
 diversity in the structure of their layers, and indeed of the paren- 
 chyma layers, the inner of which are always hard, and often 
 woody ; whilst the outer are fleshy or coriaceous : both are de- 
 veloped in a greater thickness than usual. 
 
 d. The true berries, predominating in the families of Grossu- 
 lariacece, Passifloracece, Cucurbitacece, and the Aracece, and occurring 
 occasionally in many other families, depend essentially on the 
 fleshy or juicy texture of the inner layers of the pericarp : this 
 condition often exists to the extent of a dissolution into single cells, 
 tumid with fluid, whilst the external layers are solid, and some- 
 times even woody (as in Lagenaria). 
 
 e. The achaenia, with always thin dry layers, not usually dis- 
 tinguishable, characterise the families of the Grasses, Cyperacece, 
 Cupuliferce, Composites, and Dipsacece, predominate in the Drya- 
 dece and Ranunculacece, and occur singly in other cases. They are 
 one-celled and one-seeded, generally originally, but sometimes (as 
 in the Cupuliferce) through abortion of cells and seed-buds. 
 
 I really believe that the five expressions here given for the nomen- 
 clature of the forms of fruits are perfectly sufficient for the present, if 
 botanists would once begin to seek science in profound knowledge of 
 the vegetable organism, and not in miserable scholastic trifling with the 
 manufacture of Greek and Latin, classic, or even crass, barbaric words. 
 In the enumeration of the particular words now in use, below, I shall 
 have plenty of opportunity for criticism. Here I will merely remark, 
 that the very same botanists who have set up a splendid general Fruit 
 system, often lay aside all these fine words in the special working out of 
 plants, and come off exceedingly well with a very few terms, which is in 
 fact a confession that in the general treatment of the theory of the fruit 
 they have been playing an unaccountably frivolous game with the reader 
 or student. In any case, the manner in which the French in particular 
 have increased nomenclature, is contrary to all laws of a sound termi- 
 
PHANEKOGAMIA : FLOWERS. 443 
 
 nology. Many as there are who praise or condemn Linnasus, call him 
 great or unintelligent, of all these not one has understood him, not one 
 seen what he really attempted and how he attained it. It was a war 
 against the nomenclature, heaping itself up with nothing but substan- 
 tive words, which he began and happily carried through, by which 
 means he, as with a magic touch, opened a thousand entrances into 
 science previously impassable. A second Linnaaus is indeed very de- 
 sirable, and will be made most necessary by those very people who 
 especially pride themselves on being able to look down upon him. The 
 wiser do indeed admire the artifice of Linnaeus, but continue boldly to 
 make names daily, because they are not in a condition to abstract the 
 universal principle from the isolated cases of the application. Here, as 
 everywhere, it is requisite, in the first place, to discover inductively the 
 various genera of the natural ideas, and these alone are to be named 
 with substantives, their species to be separated by the addition of adjec- 
 tives. This assists a rational investigation of nature, and a rational 
 terminology. In all this manufacture of words, we have in fact learned 
 nothing at all about the fruits themselves ; Botanists who have spread 
 themselves out in every new book with twenty or thirty new Greek 
 names, are often so ignorant of the proper object of their research, that 
 they call the epidermis of the fruit of the Labiates a seed-membrane, 
 derive the cross septum of Punica from the disc, &c. ; and, in a word, 
 manifest everywhere that the study of the Greek language has unfor- 
 tunately left them no time to examine deeply into plants. Consequently 
 we possess so few accurate investigations of the fruit, that it will be long 
 before our knowledge of it will be even in the least endurable ; and there- 
 fore we must so much the more content ourselves with the smallest 
 number of names, because a man must know a thing before he names 
 it scientifically. 
 
 179. The nature of the spermophore has been already discussed 
 at length, and but little remains now to be added. In the first 
 place it is to be remarked, that in the dehiscence of the fruit, 
 portions of cellular tissue are separated from the valves or septa, to 
 which the seeds remain suspended, and which have, indeed, been 
 termed spermophores. Here, again, holds good what has been said 
 of these separations in general, that sometimes actually independent 
 organs become solved from their union with others (as in CrucifercB), 
 and sometimes merely pieces of independent organs become de- 
 tached (as in the Asclepiadacea*). 
 
 It has been already observed with respect to the pulp, that on the 
 one hand it passes into the loose cellular tissue of the pericarp in 
 the true berries (as in Solanum), and on the other into the subse- 
 quent products of the funiculus ; namely, into the aril in its widest 
 sense (in Arum), and probably into the true aril (in Ribes ?). 
 
 The funiculus exhibits manifold varieties, which have already been 
 explained, such as hairs, warty expansions among the seeds, mem- 
 branous, continuous, or lobed envelopes of the seed (arils), and so 
 forth. The hairs of the funiculus form one kind of coma ; the other 
 is a development of the episperm at various places, at the micropyle 
 or the chalaza. The wart-like expansions 011 the seed are termed 
 stropldola or caruncula, but have under these names been mixed up 
 
444 MORPHOLOGY. 
 
 with very different things, e. g. processes from the micropyle. The 
 formations of the aril are very various, and differ especially in 
 regard to colour, texture, and cell- contents. 
 
 All the conditions here mentioned have already been explained in 
 previous sections ; here it suffices to notice them again in connection. 
 
 180. The most important part of the whole fruit, as regards 
 the economy of the plant, is the seed (semen), because it encloses 
 the embryo, which is destined to perpetuate the species. The seed 
 may be quite free, without a pericarp, as in the Cycadacece, Coniferce, 
 and Loranthacece. Here the seed assumes quite the appearance of 
 a fruit ; for instance, of a winged achaenium in the Abietinece, of a 
 berry in Viscum, and of a drupe in Cycas, &c. 
 
 In the seed two parts are to be distinguished, the episperm and 
 the nucleus ; the nucleus is either formed solely by the embryo, or 
 by that and the albumen. Then, again, the regions of the seed are 
 distinguished as the base, the part by which it is attached, and the 
 apex, the free point opposite to the former. The position of the 
 seed in the fruit is determined according to the relations of these 
 parts. The fruit is supposed to be erect, its base downward, and 
 the seed, of which the point stands higher than the base, is termed 
 erect, when it is attached at the bottom of the cavity of the fruit ; 
 ascending, when it arises from the lateral wall. Seeds of which the 
 apex is lower than the base are termed suspended or pendulous; if 
 the apex and the base lie on the same level, the seeds are termed 
 horizontal, or 'sometimes indeterminate (vaga). When the line from 
 the base of the seed to the apex forms not the longest but the 
 shortest diameter of the seed, it is styled peltate, or media affixa. 
 In the loose seed, that surface by which it was connected with the 
 funiculus is termed the hilum or umbilicus. 
 
 All these terms would be rendered quite superfluous by the adoption of 
 a better method, since the position of the seed follows from the position 
 of the seed-bud ; but as the generality of our present books do not enter 
 into the structure of the seed-buds in the description of families, much 
 less in the characterisation of particular species, the preceding remarks 
 were required for the comprehension of our existing literature. 
 
 The episperm, as explained above, allows no general reference to 
 the coats of the seed-bud, and, therefore, we can only speak gene- 
 rally of one episperm, and we must characterise the individual cell- 
 layers (strata) more minutely when the history of the development 
 of the particular species, genus, or family is still unknown. The 
 epidermis of the seed may be almost universally distinguished from 
 the episperm with advantage. On its surface are described hairs 
 (issuing from the micropyle in a tuft), as coma, papillae, prickles, 
 ribs, wings, &c., and the regions of the raphe, of the chalaza, arid 
 of the micropyle. 
 
 The old school doctrine, here quite wrong, says that the coat of the seed 
 consists of two membranes, the proper coat of the seed (testa, lorica, 
 
PHANEROGAMIA : FLOWERS. 445 
 
 spermodermis, tunica externa), and the internal membrane (membrana 
 interna, tunica internet, endopleura, tegmen). The first of these is 
 sometimes the outer, sometimes the inner integument, sometimes only the 
 epidermis of the one or the other ; the second is sometimes the outer 
 integument excluding the epidermis, sometimes the inner, and sometimes 
 the nuclear membrane ; and if the epidermis of the outer nuclear mem- 
 brane is developed succulent, DeCandolle has yet a third term, namely, 
 the sarcoderm ; or sometimes the outer, and sometimes the inner coat of 
 the seed may not exist. There have naturally been endless contests 
 whether the vessels run in the outer or inner seed-coats, and more of the 
 like confusions, which necessarily must arise from the unmethodical 
 manner of treating the subject. It has already been observed, that the 
 separate layers of cells of the episperm can only be referred to the 
 integuments of the seed-bud by tracing the development in the individual 
 cases ; when this has not been done, we must be content to describe such 
 layers as are distinguishable, without further talk about their unknown 
 origin. 
 
 The albumen is either endosperm or perisperm, and its texture 
 may be fleshy, horny, or otherwise varied ; if marbled by brown, 
 half-decayed lobes of the episperm, penetrating into its substance, 
 it is said to be ruminated ; its contents are mealy, oily, &c. 
 
 The embryo is mono-, di-, or polycotyledonous, erect, curved, 
 spiral, &c. ; enclosed in albumen, lying at the apex of this (usually 
 falsely called the base), or encircling the albumen (embryo peri- 
 phericus, albumen centrale), &c. Its position in reference to the 
 seed is invariably so determined that the point of the radicle is 
 directed to the micropyle. Through this law the whole of the 
 former temporary terminology has become quite useless, but it 
 is still retained ; it is double : 
 
 270 
 
 1. According to L. C. Richard, the seed, supposed erect upon its 
 base, has, A, an embryo orthotropus or erectus, if the root is directed 
 towards the base ; B, an embryo antitropus or inversus, if it is 
 towards the apex ; (7, an embryo heterotropus or vagus, when it has 
 a direction intermediate between the two; and />, an embryo am- 
 phitropus, when the embryo lies curved into a circle in the seed. 
 
 2. The terminology of older date, still much in use, refers the 
 terms to the unchanged position of the seed in the fruit, supposed 
 to be upright, and it speaks of, A, radicula infera, when it is directed 
 to the base of the pericarp ; B, radicula super a, when it is directed 
 to the apex of the same, and, C, radicula vaga, when it is directed 
 
446 
 
 MORPHOLOGY. 
 
 A 271 
 
 to the side walls. Finally, the forms of the embryo itself have 
 been sufficiently explained in the preceding pages. 
 
 2. Of the accessory Organs of the Fruit. 
 
 181. The parts of the flower external to the germen persist 
 in part until the maturation of the seed, often undergoing many 
 changes, especially as regards their texture, which not infrequently 
 becomes fleshy ; hence they sometimes assume the appearance of 
 fruit (spurious fruit). As examples of this may here be offered the 
 peduncle (in Ficus), the pedicel (in Hovenia dulcis), the bracts (in 
 Ananassa), the perianth (in Morus], the calyx (in Cueubalus bacci- 
 fer\ the corolla (in MirabiUs), the disc (in Rosa), the receptacle 
 (in Fragaria). 
 
 In a similar condition to the close connection in which calyx, corolla, 
 &c., stand to the other organs of the flower, the organs of the nearer 
 (calyx, corolla, perianth, disc, receptacle, &c.) or more distant (pedicel, 
 epicalyx, bracteoles, bracts, peduncle, <fec.) parts of the flower persisting 
 or undergoing further development up to the time when the fruit is 
 mature, come into nearer relation with the fruit. The different points 
 of view under which the forms are conditioned here, have been already 
 explained. The structural conditions are also important here, since fre- 
 quently the most heterogeneous parts undergo transformations which 
 cause them to assume a resemblance to any of the forms of the true 
 fruit. We even find the development of the four layers occurring in the 
 pericarp, expressed in a similar manner here in these parts, for instance, 
 in the perianth of Elaagnus. Where simply the calyx persists, growing 
 in its green condition, and then becoming membranous or thinly woody, 
 no regard has been paid to it, and it is simply called fructus calyce 
 textus, or the flower merely is said to have calyx persistens ; but where 
 a different alteration of the texture has taken place,. and these accessory 
 parts specially enclose the true fruit, a peculiar form of fruit has been 
 made of it, and a technical term soon found ; and thus, with double incon- 
 sistency, the organs become fleshy are made kinds of fruit (the peduncle 
 of Ficus), while those altered in a different way (the peduncle of Urtica) 
 are not : then again, some of them changed into a fleshy condition are 
 described as what they really are, e. g., the fleshy peduncle of Anacar- 
 dium, which no one has proposed to make a special kind of fruit. The 
 whole of the terminology arisen out of these considerations is superfluous, 
 since the further development ought to be always indicated in the de- 
 
FHANEROGAMIA : FLOWERS. 447 
 
 scription of the flower to mnke the fruit comprehensible ; and if we say 
 calyx persisten^ we may just as well say, for instance, in Morus, peri- 
 
 anthium demum carnosum fructus achcenium, by which the 
 
 matter is more clearly and simply characterised than by a new, wholly 
 superfluous, technical word " sorosis" which can certainly only be of 
 use in this one genus ; for in the mass of vain distinctions which have 
 received special names, it is an inconsistency, ridiculous beyond all de- 
 scription, to characterise by one term the fruit of Ananas, an inferior, 
 thin-celled berry ; of Morns, a two-celled (?), by abortion one-celled, 
 thin-walled achsenium ; and of Artocarpus, an originally one-celled, mem- 
 branous pouch. 
 
 For those who define the fruit as the total flower at the epoch when 
 the seed is mature, the matter is equally bad ; what I blame here is 
 merely the ignorance and the inconsistency arising from want of prin- 
 ciples ; since, if the fruits of Morus, Ananassa, and Artocarpus are 
 brought together as a special kind on account of the perianthium de- 
 mum carnosum, the fruits of Hyoscyamus, Nicandra, Physalis, and 
 Atropa must also be jumbled into one kind on account of the calyx 
 persistens demum. lignoso-membranaceus, which no one would agree 
 to do. 
 
 3. Enumeration of the various Forms of Fruit. 
 
 182. 
 
 I. Seed naked (semen nudum). 
 
 A. Seed solitary. 
 
 1. Bacca*, seed inferior, e. g. Viscum. 
 
 2. Sphalerocarpium, seed with a fleshy aril, e. g. Taxus. 
 
 B, Fructifications. 
 
 3. Strobilus, spikes with woody spermophores, e. g. Pinus. 
 
 4. Gal bul us, Capitula with confluent fleshy bracts, e. g. 
 Juniperus. 
 
 II. Simple fruits (fructus simplex). 
 A. Capsule (capsuld). 
 
 t Superior. 
 
 5. Capsula circumscissa. 
 
 6. Utriculus Gartner, No. 5. one-celled, originating from 
 a carpel, few-seeded, e. g. Chenopodium. 
 
 7. Pyxidium, No. 5. one- or many- celled, formed of several 
 carpels, many-seeded, e. g. Hyoscyamus. 
 
 8. Folliculus, one-celled, many-celled, one-valved. Seeds on 
 the two margins of the valve, e. g. P&onia. 
 
 9. Conceptacula, two disunited folliculi with one separating 
 spermophore, e. g. Asclepias. 
 
 10. Legume u, one- celled, 1 , many-seeded, two-valved. 
 Seeds on the two borders of one fissure, e. g. Pisum. 
 
 * The names spread out in the (Italic) type are in tolerably universal use. 
 
448 MORPHOLOGY. 
 
 11. Siliqua, two-celled, two-valved, separating from the 
 persistent spermophore, forming a septum (replum), e. g. 
 Matthiola. 
 
 12. Silicula, a very short siliqua, e. g. Thlapsi. 
 
 13. Ceratium, a siliqua in some Fumariacea and Papaveracece. 
 
 14. Rhegma, elastically two-valved (?) dehiscing from a coin- 
 mella, e. g. Euphorbia. 
 
 15. Capsula, one- or many -celled, many-seeded, dehiscing 
 by valves or pores, Primula, Antirrhinum. 
 
 ft Inferior. 
 
 16. Diplotegia Desvaux, inferior capsule, dehiscing by pores, 
 e. g. Campanula. 
 
 B. Splitting fruits (Schizocarpium). 
 
 17. Cremocarpium (?), in UmbellifercK, Rubiacea. 
 
 a. Mericarpia, the separate parts of the schizocarpium. 
 
 18. Carcerulus, in Tropceolacece, Malvacece. 
 
 19. Ach&nium, in BoraginecB, Labiates. 
 
 C. Stone fruits (drupa). 
 
 20. Drupa, originally one- celled, 1 2- seeded, the meso- 
 carpium fleshy, the endocarpium woody, e. g. Amygdalus. 
 
 21. Try ma, (imagined to be) one-celled by suppression in 
 Juglans. 
 
 D. Berry (bacca). 
 
 22. Bacca, many-celled, inferior, e. g. Ribcs. 
 
 23. Nuculanium, many-celled, superior, e. g. Vitis. 
 
 24. Pepo, one-celled, inferior, e. g. Pepo. 
 
 25. Hesperidium, coriaceous portion strictly separated from 
 the pulp, e. g. Citrus. 
 
 26. Amphisarca, woody toward the exterior, e. g. Crescentia. 
 
 E. Closed fruit (achcsnium). 
 
 27. Achcenium (auctorum), cypsela (Lindley), one-celled, 
 one-seeded, not blended with the seed, e. g. Composites. 
 
 28. Glans, through abortion one-celled, one-seeded, e. g. 
 Corylus. 
 
 29. Caryopsis, one-celled, one-seeded, (imagined to be) 
 blended with the seed, e. g. the Grasses. 
 
 30. Samara, two-celled, winged, e. g. Acer. 
 
 31. Carcerulus, many-celled, not winged, e. g. Tilia. 
 
 III. Multiple fruits (fructus multiplex). 
 
 A. Several achaenia. 
 
 32. Etcerio, if wholly free, e. g. Ranunculus. 
 
 33. Syncarpium, if connected, e. g. Magnolia. 
 
 B. Several berries. 
 
 34. Etario, connected, e. g. Rubus. 
 
 IV. Fructifications (fructus compositus). 
 
 A. Capitula with a flat or cup-shaped, fleshy peduncle. 
 
 35. Syconus, e. g. Ficus, Dorstenia. 
 
 B. Spikes with fleshy bracts and perianths. 
 
 36. Sorosis, e. g. Ananassa, Morus. 
 
PHANEROGAMIA : FLOWERS. 449 
 
 C. a. Spikes with woody bracts. 
 
 37. Strobilus, e. g. Betula. 
 
 b. Spikes with woody bracts and perianths. 
 
 38. Strobilus, e. g. Casuarina. 
 
 V. Spurious fruits (fructus spurius). 
 
 39. Cynarhodon, free, one-seeded achaenia, surrounded by a 
 fleshy disc, e. g. Rosa. 
 
 40. Pom urn, many-seeded acha3nia in one circle, blended 
 with the fleshy disc, e. g. Mains. 
 
 41. Balausta, many-seeded achaenia in two circles, blended 
 with the fleshy disc, e. g. Punica. 
 
 42. Diclesium, achaenia enclosed in a hardened perianth or 
 corolla, e. g. Spinacia, Mirabilis. 
 
 43. Sphalerocarpium, achaenia enclosed in a drupaceous pe- 
 rianth, e. g. Hippophde. 
 
 I did not intend to give a complete enumeration in the paragraphs of 
 all the names of fruits hitherto proposed : many of them would be too 
 much honoured by being named merely to be thrown away. I have 
 here only retained those most in use, and introduced by at least one 
 botanist of consideration (besides the author) ; in the first place, in order 
 to show how they range themselves under those which appear to me fully 
 sufficient for the present, partly to make the beginner at least ac- 
 quainted with the generally accepted words, and partly to allow of connect, 
 ing with them some critical observations on the whole theory of the forms 
 of fruits. I will first endeavour to exhibit, in a brief sketch, howMthe 
 matter has historically developed itself, since only in this way can the 
 total insufficiency of this theory be in some measure comprehended. 
 
 Besides the expressions of common life, which defined useful fruits 
 partly according to their outward, readily perceived differences, partly 
 according to the diversity of the plants called by different names, of which 
 the itself yet unscientific Science took up some, certain other names were 
 very early made, necessarily requisite to denominate things for which 
 common language naturally had no expressions, because they did not 
 immediately serve any of the purposes of life. Thus little juicy fruits 
 were, without distinction, called berries, but malus and pyrus were dis- 
 tinguished as apple and pear : apple, as a kind of fruit, has never been the 
 language of common life. Expressions like acinus, pilula, folliculus, &c., 
 which occur in authors anterior to Linnaeus, were never vernacular 
 words. Up to his time any scientific treatment of the general part of 
 Botany was out of the question ; the forms were conceived diagram- 
 matically, and described somewhat in the same manner. Linnaeus first 
 gave definitions, and an arrangement deduced from a general survey of 
 the conditions known to him. He distinguished the fruit (fructus) from 
 the seed (semen), and combined under the latter head, also, all one- seeded 
 splitting and closed fruits (schizocarps and achaenia, &c.). The former 
 he divided according to its composition from different parts and their 
 structural condition, in which he gave in far too much to the common 
 custom of language, and thus obtained sections of very unequal value. 
 He had no correct principle of division, and, in his imperfect knowledge 
 of the development of the fruit, he could by no means find such. On 
 his foundations others afterwards built, and untenably, since the only 
 
 G G 
 
450 MORPHOLOGY. 
 
 sure ground, accurate knowledge of the unimpregnated germen, was 
 professed by no botanist. The want of a subdivision into classes, 
 orders, genera, and species, deduced from safe inductions, was con- 
 tinually more felt. Linnaeus had placed his forms of fruit side by side 
 as homologous members : the enlarged circuit of knowlege of materials 
 rendered that enumeration of forms insufficient ; and as new peculiar 
 phenomena occurred, new forms with new names were added, without 
 further trouble about the groundwork. This reproach especially applies 
 to that profound observer of individual things, Gartner, the very super- 
 ficial Willdenow, and Link, who always judges from solitary, accidental 
 ideas. In this, as so frequently in his casual notions, Link, of course, 
 has a perfectly correct idea, but usually he wants the scientific earnest- 
 ness to work it thoroughly out. He says, a very mistaken path has 
 been taken in making so many new words for solitary distinctions of 
 fruit, since individual different organs may indeed require especial words, 
 but not their modifications. Nevertheless he receives the whole of 
 the old nomenclature, which, in reference to the number of actual dif- 
 ferences, is partly made up of terms for very inessential modifications, 
 and he adds another new word to it. In the second edition of his Phi- 
 losophia Botanica (vol. ii. p. 253.), he says, Linnaeus, Gartner, and 
 Richard had given so many good descriptions of fruits, with their ter- 
 minology, that he would refrain from all new technical terms, and only 
 add amphispermium as a collective term for achcenium and caryopsis. 
 Nevertheless he made a wholly new definition for achcenium, called the 
 old caryopsis seminium, formed again two species of the new caryopsis, 
 according to characters actually non-existent, and called one carpelletum. 
 Besides these, he speaks only of capsula, pomum, legumen : nothing 
 is said of all the rest of the kinds of fruit ; and it is not stated at all 
 how the introduced expressions are to be applied to siliqua, drupa, 
 bacca, hesperidium, &c. L. C. Richard first (Analyse du Fruit, Paris, 
 1808), and subsequently DeCandolle (Organographie Vegetale, Paris, 
 1827), making use of the knowledge of the structure of the germen by that 
 time collected, sought, with somewhat more philosophic spirit, to give a 
 new basis to the matter. But they remained in the bonds of conven- 
 tionality, and so allowed a number of subordinate conditions to stand as 
 homologous members beside main divisions. L. C. Richard first dis- 
 tinguished the four layers, mentioned above, in the pericarp, namely, 
 the epicarpium and endocarpium, as external and internal epidermis, 
 and the mesocarpium as parenchyma between the two : of this latter, he 
 added, one layer is often separated, which forms the stone in the drupes, 
 &c. He therefore distinguished this layer strictly from the endocarpium, 
 because his distinction depended on minute observation. DeCandolle, 
 however, confused the whole matter again by introducing an imaginary 
 theory, tracing those three layers to the layers of a leaf, to which, from 
 imperfect knowledge of its structure, he ascribed three, and only three, 
 layers. Thus he made the endocarpium the third layer, counting in- 
 wards, and mixed it up with Richard's endocarpium, wholly overlooking 
 the woody layer of Richard's mesocarpium. Thus a pretended theory, 
 without observation, turned an excellent observation into a mass of 
 confusion. DeCandolle did the same with Richard's terminology for 
 the direction of the embryo, which he wholly misunderstood, and con- 
 sequently ascribed a superior radicle to the embryo of Ceratophyllum, 
 nearly a quarter of an inch long, truly easy enough to observe. De- 
 Candolle, indeed, started from the perfectly correct axiom, that the 
 
PHANEROGAMIA : FLOWERS, 451 
 
 fruit must be explained from the construction of the germen, but in 
 the application all went awry again, because he did not understand 
 the structure of the germen itself. Neither he nor any of his fol- 
 lowers had philosophic training enough to abstract the general law 
 from the isolated concrete cases, and yet it lay near enough when it 
 was seen that the fruit could not be understood without a knowledge of 
 its development, that consequently this must apply also to the germen. 
 But a great obstacle met them there : it would have required microscopic 
 research, and that was too inconvenient. By the hasty examination of 
 a few monstrosities, and the spinning of a pretty fiction, the goal was 
 sooner arrived at : thus arose the prejudice that every germen must be 
 composed of foliar organs, and thereby every correct treatment of the 
 theory was cut short. 
 
 More recently Mirbel, Desvaux, and Dumortier have given great Fruit 
 Systems, but fortunately without their most barbarous words finding 
 an entrance into science. Lindley alone has taken the pains to establish 
 some of them, partly with new definitions. But he also, in their practical 
 application, for instance, in his Natural System, is reasonable enough to 
 leave the whole really quite insufferable wilderness of names out of the 
 question. A few expressions have again been brought into use recently 
 by Endlicher. On the whole, however, in most of the best authors,, we find 
 no terms besides those printed in spread italics in the paragraphs. Re- 
 viewing the treasure we have acquired, and the application we make of 
 it, it must be confessed that we are still the slaves of the language of 
 common life, since scarcely one technical term is established except those 
 taken from it. All the rest rock about without principle or consistency. 
 The capsules, so very diverse in the number of their cells and seeds, in the 
 construction of the septa, mode of attachment of the seeds, superior or 
 inferior, with the most varied kind of dehiscence, we call capsules ; but, 
 faithful to common language, we distinguish them only as pod, husk, or 
 shell from the most unimportant characters. For the remarkable struc- 
 ture of Hovenia dulcis and Anacardium we have no special term ; but the 
 Fig has a proper title, because it comes into the domain of the table. 
 Utriculus, achcenium, cari/opsis, are distinguished by the most trifling 
 characteristics ; but the Palms have berries and drupes, and under these 
 are united the Cocoa-nut, the Date, and the fruit of Sagus and Lepido- 
 carya. Every botanist, even only a beginner, must be terrified at the 
 slightest reflection on the unbearable terminology which must arise if 
 men continue to name such distinctions as those between utriculus, ac/ice- 
 nium, and caryopsis, with special names. The above arrangement of 
 technical terms affords sufficient opportunity for such remarks. What 
 totally different things are denominated by the expression strobilus, for 
 instance! Of the superior capsule, often from the most trifling distinc- 
 tions, nine kinds ; of the inferior, only one, and that has not yet received a 
 special name from any one. Folliculus and legumen are only distinguished 
 through the dehiscence of the dorsal suture in the latter ; but the most 
 essential distinction, whether a capsule generally tears regularly or 
 wholly irregularly, as, for instance, in Nicandra, is altogether disre- 
 garded. A completely inferior fruit (in Conipositce] is named achcenium^ 
 as well as a quarter of a fruit, formed of half a carpel, in a superior 
 fruit (in Boraginacece). Drupasm&tryma are distinguished solely through 
 the ignorance of the author of the latter name ; since in Juglans there 
 is never even an indication of a second cell, which is wholly impossible 
 with the single basilar seed-bud. Nuculanimn is a word merely intro- 
 
 G G 2 
 
452 MORPHOLOGY. 
 
 duced through a misconception. L. C. Richard called a drupa a nu- 
 culanium, which contained several stones, each containing one seed, 
 because he thought that in berries with a hard seed there must neces- 
 sarily be an envelope of the pericarp over the seed. But how many 
 study L. C. Richard ? Apparently, not even his son, who applies to the 
 expression nuculanium the meaning of an inferior berry. L. C. Richard, 
 as the examples given by him show, never thought about superior and 
 inferior. Since the name was once there, A. Richard applied it to 
 the superior, Lindley to the inferior berry, while otherwise very few 
 superior and inferior fruits are distinguished. This may suffice, not to 
 complete the criticism of the present theory of the fruit, but to show 
 by some examples how just the objection is which would reject the 
 whole. See also the accordant views of H. von Mohl (Botanische 
 Zeitung, 1843, p. 3.) 
 
 Next to the store of these technical terms we have to consider their 
 application. With the language of common life, which establishes dis- 
 tinctions of the very slightest scientific importance, botanists have 
 gradually introduced certain words, as above named. In the application 
 of Fig and Apple no mistake can of course easily be made, since the 
 words have been in daily use since infancy ; but how stands it with the 
 rest, -which properly belong to science? A selection of examples, very 
 hastily selected, may suffice to show. The Grasses have, according to 
 Endlicher and others, a caryopsis ; Link, a seminium ; Reichenbach, a 
 nucula : the Gyperacece, according to Koch, a nux ; Endlicher, a cary- 
 opsis ; Kunth, an achenium ; Reichenbach, a nucula ; Link, a carpel- 
 letum: the Labiates and Boraginacea, according to Endlicher and others, 
 achenia; Lindley, nuces ; Reichenbach, capsulce ; the Labiatce, ac- 
 cording <to Link, a carpelletum ; the Boraginacea, according to Link, a 
 caryopsis : the JRanunculacecs, according to Link, a carpelletum ; Koch, 
 a carpellum nucamentaceum ; Lindley, a nux or caryopsis ; Endlicher, 
 achenia ; Reichenbach, carpidia : the Umbelliferce, according to Koch 
 and others, 2 mericarpia ; Link, 2 achenia ; Lindley, 2 carpella ; End- 
 licher, 2 carpidia; Reichenbach, 2 drupce. I have thought this fully 
 sufficient to place glaringly enough the wretched condition in which 
 our science is sunk before the eyes of the blindest of its worshippers. 
 That here the vanity of the individual who has an opinion of his own, 
 on any point whatsoever, no matter how subordinate, will so much 
 the less make a sacrifice to the general good the more he is conscious in 
 himself of having neither inclination nor skill to do anything really great 
 in science, that this curse, which is especially the visitation of bo 
 tanists, may have a share in this anarchy I will not wholly deny ; but 
 since most of the men named stand at the head of the science, one may 
 confidently conclude from such facts, that the rotten places are to be 
 sought not in the individual, but in the distorted position which the whole 
 science has assumed through manifold historical conditions, so that of 
 course the individual, proceeding on such a path as supporter of the same 
 bona fide, is not to be blamed. 
 
 I think that for the present, with the correct naming of the naked 
 seeds and the compound fruits, and the correct distinction and charac- 
 terisation of the spurious fruits, the five kinds of fruit I have given 
 (A E) will fully suffice to name the little that remains to be named, if 
 a better and more profound method than we have hitherto had, allow 
 the minute description of the germen and the statement of the pecu- 
 liarities in its mode of development to precede. Most of the conditions 
 
PHANEROGAMIA : FLOWERS. 453 
 
 of the fruit, which have hitherto been named with different technica 
 terms, belong necessarily to the description of the germen, and it is 
 therefore a tedious waste of time to repeat them again in the fruit 
 when no alterations have taken place. What are new and peculiar 
 in the fruit, are the structural conditions, and the diversity of dehiscence 
 depending on those. The former are amply characterised by only four 
 terms ; the latter have hitherto been correctly named, for the greatest and 
 most essential part, with adjective terms ; and therefore the few cases in 
 which authors have inconsistently enough amused themselves in doing 
 otherwise, the substantive in question may be at once expunged. 
 
 In conclusion to this whole morphological investigation, I will "once 
 more express my Ceterum censeo : There can be no Science of Botany 
 without the Study of Development. 
 
 Q s 
 
454 
 
 FOURTH BOOK. 
 ORGANOLOGY. 
 
 183. ORGANOLOGY embraces the doctrine of the life of the whole 
 plant, and of its particular organs. Life is the activity of those 
 powers inherent in the matter constituting the form of the plant, 
 and which present themselves as the special life of the plant. 
 
 Organology is less understood than any other part of botanical 
 science ; a large field of unexplained phenomena remains, which are 
 comprehended as a whole, because we are too ignorant to separate 
 the individual powers from their combinations, or again to recon- 
 struct them. This unknown region we designate by the term life, 
 or organic life, and its complex cause we term vital power or prin- 
 ciple. But this is only a negative term, and can never be assumed 
 as a ground on which to found future explanations in our science. 
 
 The life of plants is designated, to distinguish it from that of 
 (the higher) animals, as vegetable or vegetative life. This dis- 
 tinction is in the highest degree vague ; it rests chiefly upon the 
 growth and development of forms, and upon the chemical processes 
 of the plant. In these last a certain periodicity is frequently pre- 
 sented to us. The chemical processes proceed very quickly (as in 
 the growth of plants during summer, or the rainy seasons of the 
 tropics), or very slowly, apparently almost standing still (as in the 
 spore and embryo in the winter, or in the dry seasons of the tropics). 
 
 I have previously explained what I understand by life : I must here 
 again refer to it. 
 
 In all times a distinction has been made between animal and vegetable 
 life, but, owing to the paucity of our knowledge, it has hitherto been 
 impossible to draw a direct boundary line between the two. The change 
 of inorganic matter into organic matter, united with the formation and 
 development of new forms, and particularly of new elementary parts, is 
 meant by most writers when they speak of vegetation, vegetable life, &c. 
 That the life of plants embraces much more than these two functions is 
 very evident, but the remaining processes are not so strikingly apparent, 
 and certainly not so evidently dependant upon external influences and 
 physical powers as the two first. We are accustomed to consider plants as 
 lower and less self-dependant organisms than animals, and we attach 
 especial importance to those indications which point to their dependance 
 on physical phenomena (Erdleben *). As the formation of new structures 
 
 * Erdleben is earth-life. Amongst the German writers it is not uncommon to call 
 the sum of physical phenomena presented by the earth a lower kind of life. In a 
 posthumous work by S. T. Coleridge, entitled the " Idea of Life," the same view is 
 adopted TRANSLATOR. 
 
ORGANOLOGT. 455 
 
 is closely connected with the presence of the matter of which they consist, 
 so must they be quite dependant upon the chemical processes which furnish 
 this matter. These chemical processes are subject to all the different 
 changes or modifications of acceleration, retardation, &c., which are occa- 
 sioned by variations of temperature, light, pressure of air, and electric 
 tension. In this manner the life of plants is connected through these 
 chemical processes with planetary phenomena, and affected, both mediately 
 and immediately, by planetary changes. Upon these changes depend all 
 the periodical phenomena in the life of plants, the greater part of which 
 are entirely unknown to us, whilst even the more easily comprehended 
 phenomena have been only superficially observed, and this in their 
 relations rather than in their essential forms. 
 
 In the following paragraphs I shall briefly allude to this part of the 
 subject. 
 
 This periodicity displays itself in a double manner : 
 
 1. In certain parts of the plants (as the spore, the pollen-grain, and 
 the embryo), the chemical processes appear almost to stand still, so long 
 as no stimulating external cause excites them. There is, however, by 
 no means an entire cessation of the germinating power of the seed, or it 
 must lie in eternal sleep. This process is constantly carried forward, 
 though sometimes almost imperceptibly. It goes on in different plants at 
 different periods, according as external influences awaken anew the che- 
 mical processes which give to it other directions ; again its activity is 
 extinguished, again to be renewed by external agents, and the result is 
 what we call life. These outward influences only serve to disturb and 
 stimulate the elements of matter, and thus make evident the universal life 
 of nature. 
 
 2. The chemical processes of the entire plant are influenced with great 
 precision by the relations existing between them and the physical changes 
 of the earth and its regions, also the alternation of winter and summer, day 
 and night, and the variation of Aveather produced by them. 
 
 In relation to the first point, we may consider the earth as divided into 
 four regions : 1. The equatorial region, where vegetation never appears to 
 be interrupted, because the heat and moisture are comparatively equalised 
 throughout the year ; 2. The next adjoining region, where the periodical 
 deficiency of moisture retards the chemical process ; 3. The belt lying next, 
 which is of considerable width, and in which the periodical decrease of 
 warmth has the same effect ; and 4. The polar regions, where the small 
 measure, both of warmth and of moisture, almost precludes the possibility 
 of vegetation. 
 
 Of the second, the summer sleep of plants, Martius, in his Flora Bra- 
 siliensis, has given an interesting illustration. We are ourselves, in our 
 latitudes, annual witnesses of the winter sleep of plants, as we observe it 
 at least in the appearances to which it gives rise, though as yet we little 
 understand it. But in this sleep there is only decrease of activity in the 
 chemical processes no actual cessation of them. For though the cold- 
 ness of the temperature may have become such as to cause almost a 
 suspension of these chemical processes, yet they are again stimulated by the 
 action of atmospheric causes ; although, for a short time, the matter of the 
 plant may remain in the same circumstances, the gradual return of the 
 external influences will cause the chemical processes to resume their 
 vigour, and vegetation proceeds in its old course : this may be seen in the 
 careful thawing of frozen parts. 
 
 The alternation of night and day exercises a similar influence, though 
 
 G G 4 
 
456 ORGANOLOGY. 
 
 in a less striking degree. We are at present only acquainted with some 
 of the results of this alternation, of which we shall speak under the phe- 
 nomena of motion. 
 
 The influence exerted by the changes of weather is less understood. 
 Those tribes of plants which are most especially dependant upon atmo- 
 spheric influence, as Mosses and Lichens, exhibit very evidently the 
 action of moisture. It is also well known, that after a tempest an evident 
 revivification occurs in the vegetable kingdom. But these observations 
 must remain superficial and fragmentary, as it is only recently that the 
 facts of meteorology have assumed a scientific form. On this part of our 
 subject only general remarks could be made, as all special scientific 
 observations are deficient. For example, what changes take place in the 
 contents of the vegetable cells, and what chemical processes pass in them 
 with the approach of winter, how far those processes are affected by 
 warmth, light, and electricity, are all problems which must be solved 
 before we shall have gained even a sure foundation on which to work. 
 The field of investigation lies open before us, but at present it has found 
 but few profound or original cultivators. 
 
 184. Organology embraces the phenomena of life in the whole 
 plant (general organology), and in the individual parts as especial 
 organs (special organology). The life of the entire plant is the 
 result of life in its individual cells ; we shall therefore gain no 
 insight into our subject, and no possibility of explaining it, so long 
 as we are unable to trace back the general results of vitality to their 
 origin in the individual cells. Hitherto, in the absence of a right 
 method of investigation, little has been done. The consideration 
 of this part of organology must, therefore, consist principally in 
 stating correctly the problems involved and the mode of solving 
 them. The same, also, with respect to that part of the science 
 which has its foundation in morphology. There it must be dis- 
 covered what morphologically -similar organs the plant possesses ; 
 here it must be considered how far morphologically-similar organs 
 present also similar phases of the universal life of the cell, and how 
 far they may thereby be converted into physiologically-similar 
 organs. 
 
 Both parts of the subject must be pursued in plants arranged in 
 morphological groups; but such investigation cannot at present be 
 carried on, for all we should get would be a loose mass of super- 
 fluous and valueless paragraphs, for with respect to the gene- 
 rality of plants, and parts of plants, observations are wanting. I 
 shall arrange the study of this subject in the following manner: 
 A. General organology. 1. General phenomena in the life of the 
 entire plant : its life, germination, growth, nutrition, reproduction, 
 death. 2. Special phenomena : the development of warmth and 
 of light, movements. B. Special organology. A. Organs of 
 vegetation : , naked spores ; b, covered spores. B. Organs of 
 reproduction: a, Cryptogamia; b, Phanerogamia. 
 
 If we consider the attempts that have hitherto been made to subject the 
 life of plants to scientific observation, we shall find that all those who have 
 
ORGANOLOGY. 457 
 
 conducted them have brought to their works groundless prejudices, and, 
 following the old beaten tract, have not even paused to inquire whether or 
 not it were right, and whether or not their prejudices were just ; and they 
 have even taken these latter as leading maxims to form the basis of all 
 their investigations. I have already discussed the fanciful analogy 
 between the physiology of animals and of plants. In consequence of the 
 use of this absurd analogy, almost all the works which have hitherto 
 appeared on vegetable physiology are perfectly worthless, for in no 
 instance have they adopted the only true fundamental position, namely, 
 the essential peculiarity of vegetable life ; nay, the larger number of 
 writers have not even given a comprehensive view of the facts already 
 known, as such would have destroyed their assumed principles. 
 
 Each branch of natural science, if it would lay claim to such name, 
 must have its own peculiar independent principle of development, which 
 must be drawn from its own data, and only thence. It is not until con- 
 siderable advance has been made towards perfection that it is safe 
 to begin to inquire whether analogies exist between itself and some other 
 branch of natural science, and, if so, what they are. The manner in 
 which science is usually pursued is not following it out gradually through 
 u long course of original investigations, but by grasping hastily at all 
 statements and dogmas that are afloat respecting it, seeking to participate 
 in its treasures as an inheritance from strangers, rather than by examining 
 into its foundations and building up its structure : this is the reason that 
 we find even more dangerous prejudices to combat in science than in 
 practical life. From the very nature of theoretical science, which escapes 
 the continual tests and trials which are applied in practical matters, it 
 happens that mere tradition and well-pursued investigation, old ideas and 
 recent advance, falsity and truth, long remain side by side. Hence pre- 
 judice and misconception exist longer in science than in life. Thus it is 
 that the farther a science is removed from contact with the business of 
 life, and the farther it traces back its origin towards the middle ages, the 
 more likely it is to be treated on the senseless method of developing 
 the science through philological discussions. Thus it has been with 
 Botany: books have been written when plants should have been examined, 
 conjectures have been made when investigations should have been 
 pursued. Hence for about a century we have but revolved in a circle, 
 without making the least advance or discovering new facts ; and new 
 laws are given us which are only the result of the play of chances, 
 whilst correct fundamental maxims and correct methods of advance 
 would have guaranteed the solution of various problems, and secured the 
 progress of the science. 
 
 My aim is to establish the necessity of embracing, as a fundamental 
 principle in the study of the whole, the existence of an essential life in 
 each separate cell. Hence arises the necessity of carrying on investiga- 
 tions in the first instance in the individual cells, or in portions of the 
 vegetable structures, in which we have to do with few cells in combina- 
 tion. On these we must make our first experiments, and from them draw 
 our first conclusions, which we may then proceed to apply to subsequent 
 investigations into the general structure of the plant, pursuing all our 
 inquiries with the aid of the microscope, and placing them under the 
 control of an accurate history of development. Upon such a plan alone 
 can we make a sure advance in the study of vegetable life. 
 
 For want of such a plan little or nothing has hitherto been done. It is 
 hence a consequence that all foregoing physiological experiments, and their 
 
458 ORGANOLOGY. 
 
 results, are and must be almost worthless, because they fail in funda- 
 mental maxims and correct methods of research, and in the smallest as 
 well as in the greatest matter it will be necessary for us to recommence 
 our investigations. 
 
 After this recapitulation and reference to former paragraphs, it now 
 only remains for me to point out the questions to be investigated, and the 
 experiments to be made, in this department of our inquiry. 
 
 CHAPTER I. 
 
 GENERAL ORGANOLOGY. 
 
 SECTION I. 
 
 GENERAL PHENOMENA IN THE LIFE OF THE ENTIRE PLANT. 
 
 A. Of the Life of the entire Plant. 
 
 185. The life of the plant, as of the elementary organs, is seen, 
 in even the process of formation itself, to be nothing else than com- 
 plex physiological and chemical processes, which are connected with 
 a special form. Here, then, well-known physical and chemical 
 powers must be studied. In general we know but little of these 
 in relation to the plant, and of some nothing at all. Heat and 
 light, as necessary conditions of all or of many chemical processes, 
 are also conditions of life in the plant, but in various degrees. 
 Some Alga, and Funyi, as Protococcus nivalis (the so-called red snow), 
 appear at ; others can live in the dark, as Ehizomorpha subter- 
 ranea, Tuber cibarium (truffle) ; others need a high temperature, as 
 many tropical plants, or intense light, as many alpine plants. 
 
 We are unacquainted with the action of electricity and mag- 
 netism. 
 
 The life of plants is, in the highest degree, dependant on the life 
 of the whole earth. Fixed to a particular spot, or if unattached, as 
 is the case with some floating plants, yet without power of sponta- 
 neous movement, they must receive all that they require to support 
 their vital phenomena from without. This dependance is especially 
 seen in the means of reproduction. The dispersion of the spores, 
 the transferring the pollen to the stigma, &c., is frequently entirely 
 dependant upon external circumstances, such as atmospheric 
 moisture, wind, motion of the waves, the life of insects, &c. 
 
 On the process of formation, so far as it is connected with the existence 
 of the entire plant, I shall speak later under the head of reproduction. 
 
LIFE OF THE ENTIRE PLANT. 459 
 
 Our present business is tlie observation of the physico-chemical processes 
 us they are found in the individual elementary organs, or in the groups of 
 the same, called tissue. What has been already said in the First Book will 
 hold good here also ; and we have now to consider how sometimes, through 
 the process of formation in the entire plant, special modifications appear 
 in the sum of the phenomena of the life of individual cells. These are, 
 however, but little known to us. Heat and light, which are essential to 
 many chemical operations, appear to act upon the entire plant in no other 
 way than upon the sum of the cells. The influence of electricity and 
 magnetism upon the cells is as little known to us as is the operation of 
 these agents upon the entire plant ; notwithstanding, electricity appears to 
 play an important part. On this subject there are some vague observa- 
 tions in Froriep's Notizen (vol. xix., No. 9., Aug. 1841.), by Thomas Pine. 
 Instead of indulging in conjectural fancies, I will here propound some 
 queries, which will not appear idle since they require solution. Does a 
 tree in which vegetation is vigorous, or yet better a vegetating Musa, or 
 the same in tropical climates, exercise any influence upon a magnet sus- 
 pended near it ? If a Chara were made to grow so that it should be 
 spirally surrounded by a continuous galvanic stream, which should be 
 either parallel or at right angles with the direction of the ascent of the 
 sap, would it suffer any change in its vegetation, and what ? 
 
 The dependance of the life of the plant upon the life of the earth is in 
 the highest degree interesting. We must here assume, that in the 
 agencies on which the meteorological phenomena, the formative principle 
 in the embryo, &c., depend, is to be found the cause why, at the blooming 
 time of a particular plant, a particular kind of insect is produced, whose 
 life again depends upon the nectar in the flower of the plant, and by the 
 sucking up of which the transference of the pollen to the stigma is 
 effected. For particular plants other agencies are needed; as, for 
 example, it is requisite that wind should occur at the flowering time of 
 the Abietinece, that there should be undulatory motion of the water at the 
 time of the flowering of the Vallisneria, and rain with the development 
 of the capsules of Ambrosinia Bassi. These phenomena may appear 
 accidental, but they are necessary consequences of the primary powers 
 which are seen in the formative processes of the earth. The rain could 
 not fall at the appointed time, and under the existing circumstances, 
 without at the same time causing the internal formative energy of the 
 earth to bring forth an Ambrosinia ; and the meteorological relations 
 would at the same time be so arranged, that on the developed spathe rain 
 should fall. The spathe of the Ambrosinia is boat-shaped, and floats upon 
 the water. By means of the capsule, whose wing-formed appendages, 
 uniting with the spathe, form a little cavity, the spathe is divided into an 
 upper and under chamber. In the upper one is found one single ovary, 
 in the under one exclusively the anthers. The pollen cannot reach the 
 stigma without the assistance of rain, which filling the under chamber 
 and the half of the upper one, lifts the floating pollen to the level of the 
 stigma, and hence the pollen-tubes can pass along. This may be taken 
 as one of the least known examples of the dependance of plants upon the 
 assistance of external natural phenomena. The operations of wind and 
 weather are more generally known, as also is the aid rendered by insects, 
 on which subject we find some interesting observations by Conrad 
 Sprengel, on the Secrets of Nature discovered in the Structure and Im- 
 pregnation of Flowers ; Berlin, 1793. 
 
460 ORGANOLOGY. 
 
 B. Germination. 
 
 186. Germination (germinatio) has a very different significa- 
 tion in Cryptogamic and Phanerogamic plants. With the first, as 
 also with Rhizocarpece, it is the development of a single cell, sepa- 
 rated from the mother plant, to an entire new organisation ; a 
 process which corresponds in the greater part with the formation of 
 the embryo in the Phanerogamic plants. Of these processes we 
 know nothing further than what may be considered analogous to 
 the life of individual cells. That which is most difficult to explain 
 here is the same as in the Plumerogamia, namely, the reason why 
 the spores remain so long without exhibiting signs of vital activity. 
 In Phanerogamia germination is only the development of an already 
 organised embryo into the perfect individual. The continued 
 development has no essential difficulties; but the circumstance of an 
 inactive vegetation previous to germination is the reverse of this. 
 We find here the following circumstances take place. Together 
 with the gradual maturing of the embryo, its cells are gradually 
 filled with assimilated matters, as starch, oil, and mucus, and they 
 lose by degrees almost all their watery particles ; hence arises 
 a condition in which, on account of the failure of moisture, the 
 chemical changes, and with them the vital processes, are slowly 
 effected. This condition remains in different plants various periods 
 of time, and is capable of being with some of them prolonged for 
 even a thousand years, or more, without the seed losing its capability 
 of development. This tendency to development is not aroused by 
 some circumstances which would be sufficient to excite the actual 
 vital processes of the plant. Thus the seeds of the Cerealia will 
 endure exposure to water at 45 C., watery vapour of 60 C., in dry 
 air of 75 C., and in dry cold of 50 C.* That with the com- 
 mencement of germination, the accession of moisture, &c., gives 
 activity to chemical changes, is far less striking than is the fact, that 
 they have not already taken place; but no one has ever dreamt of 
 discovering the cause of this latter. 
 
 The phenomena of germination are as follows. The coverings 
 of the embryo (the testa, and, where present, the albumen and peri- 
 carp) swell up under the influence of water pressing in ; then the 
 cells of the embryo become distended, at first especially those of the 
 radicle and the lower part of the cotyledons (called cauliculus) ; by 
 this means the radicle is forced from the bursting seed, it sinks into 
 the soil, and whilst fastening itself in it, the slight curve of the 
 axis is removed by the distension of the cells lying on the concave 
 side, and the embryo erects itself above. The distension of the 
 cotyledons then forces off the coverings, which at length fall away, 
 and the free young plant grows unimpeded. Usually in Mono- 
 cotyledons, and occasionally in Dicotyledons, as, for example, in 
 Nymph&a, Quercus, jtEsculus, &c., the inferior part of the cotyledons 
 
 * Edward and Colin in Ann. des Sc. Nat., 2d ser. Bot. i. 
 
GERMINATION. 461 
 
 is so exceedingly distended, that the plumule is pushed from its 
 coverings and unfolded, whilst the summit of the cotyledons have 
 not yet left their envelopes. Where albumen is present, the 
 cotyledons often grow so rapidly within the envelopes, that they 
 consume all the albumen," whilst the entire embryo in the mature 
 seed takes up but a very small portion of space within it. Unim- 
 portant varieties in particular seeds are almost countless, and almost 
 every seed in germination exhibits its own peculiarities. 
 
 With regard to the vital processes during germination, two phe- 
 nomena are to be distinguished, one of which has nothing to do 
 with the growth of the plant. 
 
 At the time of the maturing of the seed, the cells of the embryo- 
 sac are usually filled with assimilated matter, whereby its shrinking 
 from the constant loss of water is prevented. The greater proportion 
 of this matter is not needed for the nourishment of the young 
 plant, and is subsequently destroyed, whilst the carbon of the 
 starch, oil, &c., is consumed at the expense of the atmospheric 
 oxygen taken up into the plant with the water, and is liberated in 
 the form of carbonic acid gas, whilst hydrogen and oxygen combine 
 to form water, and during these processes heat is given out. By 
 this means the cells become once more furnished with fluid contents, 
 and an active chemical life in their interior is again rendered 
 possible. The next consequence is the conversion of the remaining 
 substances into gums and sugars, which are then employed for the 
 formation of new cells. Mucus, as a catalytic substance, is doubt- 
 less active in the processes. 
 
 A similar process to that in the embryo goes on in the albumen, 
 and the nutritious matter thus prepared is supplied to the embryo 
 through its surfaces. In many embryos, especially those of Mono- 
 cotyledons, the cells of the cotyledons become quite papillose, and 
 unite closely with similar papillose cells projecting from the inner 
 surface of the albumen. 
 
 The testa, and the fruits enclosed in shells, according to some 
 specific peculiarity of their structure, sometimes exclude the entrance 
 of water, and so retard the process of germination ; and sometimes, 
 on the contrary, they accelerate it. 
 
 We have already spoken of the morphological phenomena of 
 germination ; observations here have been so imperfect that they are 
 of little scientific value. 
 
 We know nothing at all respecting the cause of the direction 
 taken by the germinating plant. Immediately the plant is exposed 
 to the light, it developes in its external parts chlorophyll. 
 
 In order to understand the subject of germination, we must know the 
 structure of the seed. We find that it contains the rudiments of the future 
 plant, namely, a small body, having as essential parts a radicle and a 
 terminal bud. To these are added supplementary organs, which are used 
 at the end of the process of germination. These supplementary organs are 
 either the first leaves (cotyledons) or the albumen. In these we trace 
 three distinct relations, by means of which they subserve the purpose of re- 
 
462 ORGANOLOGY. 
 
 taining the activity of the embryo until the time comes for its development. 
 Their cells contain either less mucus but more starch, as in the leguminous 
 cotyledons, and in the albumen oftheCerealia; or they contain more mucus 
 and, instead of starch, a fat oil, as in the cotyledons of the CrucifercB and 
 in the albumen of some Palms and Euphorbiacece ; or lastly, they contain 
 scarcely any mucus, but their walls are strikingly thickened, and the 
 cellulose is found not to possess its usual physical condition, or is in some 
 way chemically distinct. It is more easily dissolved and decomposed than 
 usual. This is seen in some leguminous cotyledons, as, for example, in 
 the Tamarind, in the albumen of many Palms, as the Date-palm, and in 
 a most striking degree in the Ivory-nut (Phytelephas). From this it 
 results that we have six principal conditions, without mentioning the 
 intermediate states, which demand an accurate investigation. Hitherto no 
 microscopic and chemical history of germination has been given with any 
 accuracy or completeness ; we are still in the infancy of our knowledge 
 respecting it. For the most part, chemists understand nothing of micro- 
 scopic physiology, and botanists little of chemistry. Hence there has been 
 no harmonious pursuit of science between them, the absence of which has 
 retarded both, so that we neither possess, nor are on the eve of possessing, 
 a complete and fundamental knowledge of the history of germination. 
 
 The reason of our ignorance on this subject arises" from the fact, that 
 in investigating it the chief attention has been turned upon that point 
 where the difficulty does not exist. The development of the young plant 
 will be explained when we shall have explained the life of the plant 
 in general. The principal difficulty that requires explanation is how the 
 conditions, which in an embryo result in a definite process, remain for a 
 long time suspended. If we place a ripe acorn in the soil, under all the 
 circumstances requisite to germination, why do not those chemical pro- 
 cesses which excite germination and development immediately take place ? 
 In this case chemical processes slowly go on in the interior of the cells, 
 with which we are as yet altogether unacquainted ; and perhaps, also, the 
 structure of the cells, or the chemical nature of their contents, is such as 
 to make the operation of external agencies only very slowly effective. 
 The Coffee-bean does not germinate at all, unless it is placed in the requi- 
 site circumstances immediately upon its ripening. Wheat has been 
 proved, by the experiments of Sternberg, to germinate after it had lain 
 inactive for three thousand years.* Many facts must be collected, and 
 the most minute chemical investigations must be made respecting the con- 
 tents of the cells and the cell-walls, the structure of the embryo must be 
 accurately examined, before we can obtain correct results : all else is but 
 theoretic dreaming. Only confusion or uncertainty can be expected 
 where so much, if not all, is yet to be investigated. 
 
 Thus much, however, we have ascertained teleologically, namely, that 
 the cells of the embryo and the albumen are completely filled with as- 
 similated matters, in order to prevent, during the drying of the cells, their 
 crushing together, and thus to make their future active life possible. Of 
 these matters, a considerable portion is not only superfluous to the support 
 of the life of the embryo, but is actually in the way, and when germination 
 commences it is disposed of by being converted into carbonic acid and 
 water. To this atmospheric oxygen is essential, and also, as in every 
 other chemical process, a certain amount of heat and moisture, and these 
 
 * He made wheat taken from the coffins of mummies to germinate, and the same has 
 been done in England. [The circumstances under which this has taken place, in Eng- 
 land at least, are not free from suspicion. TRAXS.] 
 
GERMINATION. 463 
 
 are the so-called conditions of germination. The measure of each 
 which is necessary varies with the different kinds of seeds, according 
 to the chemical nature of the contents of the cells, of the cell-walls, and 
 their general structure. 
 
 Water plants germinate best in water, land plants in damp earth. 
 Of the precedents of this process we know nothing at all. We do not 
 even know all the conditions under which starch is produced and de- 
 composed ; and those with which we are acquainted agree so little with 
 those presented in the germinating plant, that they can serve little 
 towards the explanation of the matter. The discovery of diastase by 
 Payen and Persoz made a great noise, and it was generally thought that 
 the key had been found ; but it was forgotten that diastase only dis- 
 solves starch at a temperature of from 65 70 C., and this temperature 
 is not found to exist in germinating plants, and, should it be produced, it 
 must destroy life. It is clear that only the decomposition of the carbo- 
 naceous substances is essential to the process of germination ; all remain- 
 ing phenomena belong solely to the processes of vegetation which appear 
 later. 
 
 A more important point occurs here, namely, the direction which the 
 germinating plant takes. The examples of Viscum and Loranthus 
 prove that it is not a universal law of vegetation that the root should 
 grow downwards towards the centre of the earth, and that the .stem 
 should take a contrary direction. With the generality of plants this is 
 indeed the ordinary manner of growth. However the seed may chance 
 to fall, yet, in germination, the radicle so bends itself as to sink per- 
 pendicularly into the soil, whilst the stem rises perpendicularly from it. 
 The direction which the stem takes is, however, much modified by the 
 influence of light ; it is found to grow in the direction from which the 
 light comes : hence, if the light falls obliquely, the stem rises in a cor- 
 responding direction. Many theories have been invented to explain 
 this, and supported by the very interesting experiments of Knight *, 
 gravitation has been called into aid ; this only proves with what ob- 
 scure notions some persons are satisfied. Whether the experiments of 
 Knight would always give the same result is very doubtful ; but were it 
 so, they would yet be very insufficient to establish that gravitation is 
 the cause of this phenomenon, seeing that Viscum and Loranthus would 
 not fall within the law ; and the causes which determine the direction of 
 the growth of these plants are probably the same as in others. Gravi- 
 tation on the earth is in proportion to the mass and volume. These 
 are sometimes greater in the radicle, sometimes in the upper part of the 
 embryo ; hence, according to the usual law of gravitation, the plant 
 would sometimes grow in one way, sometimes in the other, which does 
 not happen. Moreover, as the radicle lengthens, it draws fluids from 
 the soil, and the contents of its cells are always more dilute and speci- 
 fically lighter than those in the upper parts of the plant ; hence it would 
 turn the root round, which being attracted least to the earth, would 
 ascend into the air. A cone falls to the earth upon its base ; we have 
 embryos of conical form, as well as of other forms, but both germinate 
 so that the radicle sinks into the earth, though it may be projected from 
 the point or base of the cone. No embryo germinates free, all remain 
 for a longer or shorter time enclosed in the testa or pericarp, from 
 which the embryo for some time only projects a small point : gravity 
 
 * Trcviranus, BeStrage zur Pflanzcnphysiologie (in which the works of Knight 
 are translated). Gottingen, 181 1, p. 191. 
 
464 ORGANOLOGr. 
 
 must then act upon the pericarp, and thus determine the position of the 
 embryo. In short, without consideration, an imprudent word has been 
 thrust forward, and supposed to afford an explanation. I have already 
 observed that no botanist is justified in saying absolutely and without 
 reason how much or how little he will adopt of other systems for his own 
 use, or as a point to start from. When he avails himself of other sciences, 
 he must clearly comprehend the notions of these sciences, or he will but 
 make himself ridiculous. But when, in the nineteenth century, a pro- 
 fessor of physics can so err in fundamental principles as to say " action 
 from contact is improbable, because we know no example in which a 
 body at rest can set another body in motion," more at present can 
 scarcely be demanded of botanists. 
 
 It would be too much to assert the impossibility of gravitation being 
 the cause of the phenomena above mentioned ; but we have nothing 
 to do with the power of gravitation, because we have no object on which 
 it could act. 
 
 The various fancies respecting the peculiar vessels which are em- 
 ployed in conveying the nutritive matter from the seed-leaves to the 
 radicle, and all similar theories which are found in old works, I ha\ 7 e 
 left without notice, for they are altogether worthless. I will, however, 
 enumerate some of the matters demanding examination, which will afford 
 a more intimate knowledge of the processes of germination. 
 
 I. An explanation of the cause why, in the embryo and the albumen, 
 the starch is dissolved and the oil of fat is decomposed. 
 
 II. An accurate determination of the degree of heat present during 
 germination, and a comparison of the same with the quantities of carbon 
 and hydrogen which are consumed. 
 
 III. An exact quantitative analysis of germinating plants, and of their 
 separate parts in all stages of germination ; with an exact quantitative 
 determination of the proportion of water taken up, and of gases inter- 
 changed, as well in embryos containing starch as in those containing 
 oil. It is evident that such analyses must be constantly pursued with the 
 help of the microscope. 
 
 IV. A repetition of the experiments made by Knight, with a view to 
 ascertain whether the germination arid continued growth might not be 
 made in a direction the reverse of that which is usual, if earth should be 
 placed upon them from above, whilst they should be subjected to strong 
 light from below. 
 
 The development of the spores of Cryptogamia, which is also termed 
 germination, finds no analogy here but with the development of the 
 pollen-grains in the embryo. In each of these, however, the physical 
 and chemical conditions are different, and a special investigation of the 
 process of development, with respect to the chemical and physical con- 
 ditions of germinating ferns, is much to be desired ; but there are 
 many preliminary difficulties to be overcome. A close investigation of 
 the kind pointed out in the third section above would tend to the ex- 
 planation of many of the laws of vegetation, if it could be followed out 
 with a number of the Algce, for instance, Spirogyra, and in this case the 
 natural position of the plant would greatly facilitate the investigation. 
 
 C. Of Growth. 
 
 187. Growth of plants generally is the increase in their volume 
 and their mass. In the scientific treatment of the subject, we 
 
OF GROWTH. 465 
 
 must distinguish three several processes, namely, growth in the 
 narrow and literal sense, that is, the formation of new cells ; the 
 unfolding or extension and enlargement of cells already present ; 
 and the lignification or thickening of the cell-walls by spiral and 
 porous layers. Each of the three contributes in different ways to 
 the perfecting of the entire plant and its organs. It is especially 
 important to distinguish the first and second of them precisely. 
 The process termed germination is marked by two periods, the 
 first of which consists in the softening and extension of cells al- 
 ready formed, and the second in the formation of new cells. The 
 rapid growth of the seta of Jungermannia belongs to the process 
 of unfolding, also the extension of the internodes in the Phanero- 
 gamic plants. But here we greatly need exact and comprehensive 
 investigations. 
 
 Essential growth goes on, so far as is at present made out, by 
 the formation of new cells in the interior of the old or parent 
 cells, which, by resorption, set the new ones free. No other mode 
 of increase of the cells has been as yet fully established. 
 
 I have already asserted*, and I believe I have made it clear, that 
 there can be no scientific treatment of the vitality of plants without an 
 accurate distinction between the three above-mentioned phenomena, and 
 in every case an apprehension of which of the three is actually present. 
 This is so simple, that when once attention is called to it, it will be 
 understood, for examples of the three kinds of growth must be known to 
 every botanist. 
 
 By attention to the first and second division, we obtain a distinction 
 of two essentially different periods in the development of every part of 
 a plant ; first, the period during which the cells which constitute its 
 substance are formed ; and secondly, when they become expanded. The 
 two periods are often very accurately separated from each other, as, for 
 example, with many petals ; in other cases the one passes into the other, 
 as in the anthers. 
 
 In botanical books a number of examples are given of periodical acce- 
 lerations or retardations of growth.f All these examples are useless for 
 the derivation of laws, because the previous distinctions have not been 
 at all attended to. Treviranus, for example, quotes the rapid repro- 
 duction of the anthers in an ear of rye, when they have been stripped 
 off by passing through the mouth. In this case it is only a question of 
 the distinction of previously existing cells ; the same also with respect 
 to the development of the flower-stalk of the Agave. Thus the 
 investigation of E. Meyer on barley and wheat (Linnaea, vol. iv.), and 
 of Mulder on the leaves of the Urania speciosa (Bydragen tot de 
 naturk. Wetensch. vol. iv.), with respect to the comparative growth by 
 night and by day, and at the varying hours of the day, are useless, be- 
 cause no distinction has been made between the formation, and the mere 
 expansion of the cells. To this branch of the subject properly belongs 
 .ill that has been said upon the distinction in the growth of the stem, 
 the root, the leaves, and all other parts (see Treviranus, Physiologic, 
 vol. ii. pp. 152 179.). All experiments and observations that have 
 
 * M tiller's Archiv, 1838, p. 158. ; Beitrage zur Botanik, vol. i. p. 141. 
 f TVeviranus, Physiologic, vol. ii. p. 442. 
 
 H H 
 
466 OEGANOLOGY. 
 
 hitherto been made, without reference to these essential distinctions, are 
 useless, and must be followed out anew if they are to serve for the ex- 
 tension of our knowledge of vegetable life. 
 
 In germination, the above distinctions are definitely marked ; it yet 
 remains for us to follow this out more accurately by the investigation of 
 the previous chemical changes in the germination of Phanerogamia. I 
 believe that the simple softening and expansion of the cells continues as 
 a first stage until the time comes when the root projects itself into the 
 earth ; then new cells are formed, probably first at the apex of the root, 
 and then in the plumule. In the germination of Cryptogamia, where 
 the development of the reproductive cells continues uninterruptedly, 
 without giving any time for the repose of vegetation, no such period- 
 icity is observed. 
 
 The most important point which here presents itself is the mode of 
 increase of the cells, and the proper growth of the plant. Investigations 
 on this subject are especially wanted. I was the first who (in Miiller's 
 Archiv, 1838) sought to investigate this matter, and thereby to establish 
 a foundation for further inquiries, the necessity for which had scarcely, 
 up to that time, been foreseen. At the same time appeared Schwann's 
 treatise, with the same object, on animals. Immediately there arose a 
 dispute, not upon the correctness of the facts given, but upon the im- 
 portance, or not, of such a foundation for the study of physiology and his- 
 tology : others desired to wear the laurels which Schwann had gathered. 
 Soon, however, a new and strikingly active life, proceeding from the 
 foundation laid by the discoveries of Schwann, appeared in physiology ; 
 and thus first my name was mentioned in friendly union with his. 
 
 This is not the place to enumerate the splendid results which were 
 thus obtained by both physiologists and botanists. Almost five years 
 have gone by since the appearance of my work, and not a single bota- 
 nist has found it worth the trouble to repeat my investigations, conducted 
 with so much care and labour, in order either to confirm or to confute 
 them.* This circumstance seems to me to justify some of the harsh 
 observations that I have made upon the state of botanical science, since 
 it shows beyond dispute that we have failed not so much because of the 
 difficulty of obtaining results as from the want of the scientific spirit 
 which would seek after them. There are honourable exceptions ; but 
 with the generality of botanists, even down to our own times, the ne- 
 cessary possession of a few dried fragments of plants, and a superficial 
 physiology acquired by peeping through a microscope, is called science ; 
 to-day this, to-morrow the contrary, the day after the same as the first ; 
 and all this because they make no fundamental or comprehensive re- 
 searches, and are without the conditions of a scientific induction : and at 
 the present day this is called seeking for the truth ! God save the mark ! 
 In the past year, however, a preparation has been laid for a more fertile 
 future, chiefly by young, vigorous spirits, who, having pursued zoological 
 studies on true principles, have introduced the same scientific method of 
 investigation into their botanical researches. The time is evidently not 
 far distant when no botanist will presume to dictate on the science as 
 long as he has not made fundamental investigations upon cell-deve- 
 lopment. 
 
 * An exception must be made in this country, at least, in favour of my friend and 
 assistant in the translation of this work, Mr. Arthur Henfrey, who has repeated with 
 much care the researches of the gifted author, although he has not been able to confirm 
 all his views and observations. TRANS. 
 
OP GROWTH. 467 
 
 We owe many thanks to Nageli for some communications contain- 
 ing very able observations (Zeitschrift fur wissenschaftliche Botanik, 
 Pt. I.). The writings of K. Miiller, in the Botanische Zeitung, are 
 also valuable ; and in the labours of Hartig, and other such, we recognise 
 pleasing signs of a better time, though with some of the results which 
 Hartig supposes he has obtained I cannot agree. 
 
 The doctrine of the formation of cells is treated of 14. 
 
 188. It has not yet been discovered how far the various parts 
 of plants, or the various groups of plants, present various kinds of 
 growth. Accurate investigations are wanting on this subject. So 
 far as this condition influences the form, or the change of form, in 
 plants, it has been already treated of in Morphology. 
 
 In the animal kingdom the phenomena of reproduction and 
 growth stand in close connection. Under the term reproduction, 
 used in this sense, is to be understood a new formation to supply 
 a part that has been lost, in the same place, and of the same form. 
 There is, probably, no such reproduction in the vegetable kingdom. 
 A part of a plant which is lost is not restored by the repro- 
 duction of a corresponding member; but, on the contrary, the 
 process of the healing of wounds from loss of substance takes 
 place frequently by the filling up of the existing breach with a 
 substance similar to cork. 
 
 Of the varieties of the processes of vegetation in various plants, or 
 parts of plants, we have at the present moment nothing to say. I have 
 already, in speaking of the formation of the pollen, called attention to the 
 opinion of Nageli. The special parent-cell is always formed in the 
 interior of another cell ; but this mode of formation is different from 
 that earlier described. Nageli found it frequent in the Algce. 
 
 Respecting the peculiar chemical processes of individual groups of 
 plants, we know nothing. In the indefinite growth of the entirely inde- 
 pendent individuality of the plant there can be no reproduction in the 
 same sense as the reproduction of the tail of a lizard, &c. ; for the indi- 
 vidual embraces a definite circle of forms, but not a definite number of 
 forms, and never produces all its essential organs at the same time : so 
 that the loss of a member may be replaced in a plant, but it cannot be 
 through the restoration of the same form in the spot from whence it was 
 removed, but by the formation of a similar organ in another place. The 
 loss of certain organs in plants, and the formation of corresponding 
 organs in other places, is quite conformable with the general laws of 
 vegetation, of which we have earlier spoken. The tree, for instance, 
 that loses its leaves in autumn, forms new leaves in spring from its buds ; 
 but each bud is an essentially new individual, which consists of perfectly- 
 formed stem and leaves; but it is developed upon the remains of a 
 former individual, and is vitally united to it. Internodes that have lost 
 their leaves never throw forth new leaves, which grow rather on new 
 internodes, and thus belong to a new individual. But two examples 
 have as yet come to my knowledge wherein there has appeared to be 
 a reproduction in the same place of one and the same part which had 
 been lost. One of these occurred in a plant belonging to the family of 
 
 ii H 2 
 
468 ORGANOLOGY. 
 
 Algce, which we have not yet discovered to possess morphologically 
 definite organs. 
 
 According to the observations of the senator Dr. Binder, it is not 
 infrequent to find in Laminaria digitata and saccharina that a new cell- 
 formation is organised upon the edges between the under stalked part of 
 the plant and the upper flat extended surface, from which the formation of 
 an entirely new upper flat part of the plant is produced, whilst the old parts 
 are at the same time destroyed. In the excellent collection of Dr. Binder, 
 I saw a number of instances of this process in its different stages in the 
 L. digitata. 
 
 The other case appears to exist in the Ceratophyllum, in which single 
 leaves are eoccasionally east off about two lines above their origin, and again 
 produce from the stump a perfect leaf. I have already made known 
 this fact in my contributions to our knowledge of Ceratophyllum (Lin- 
 nsea, 1837) 
 
 The healing process is very general in the vegetable world, and the 
 substance which is produced for the purpose is similar to suberous tissue 
 (cork), which I have fully described in my paper upon Cacti. But this 
 subject belongs rather to the pathology of plants. 
 
 D. The Process of Nutrition. 
 
 189. The collective nutrition of the plant embraces various 
 different processes, by which foreign matters are received into the 
 organism, are entirely or partially appropriated, and through which 
 that portion of such matter which is not fitted for the nourish- 
 ment of the system, or which would impede the vital processes, 
 is thrown off. These processes are physical, so far as regards 
 absorption and excretion ; chemical, so far as the changes pro- 
 duced in the substances ; and morphological, so far as they are 
 concerned in the fixation of the appropriated matters in definite 
 organic forms. With plants which are not furnished with special 
 physiological organs, we cannot pursue the subject of nutrition 
 according to the function of individual co-operating organs. Each 
 cell is nourished according to its own special nature, and in dif- 
 ferent ways. In studying the nutrition of the plant, we must, in 
 the first instance, observe separately the physical, chemical, and 
 morphological processes ; secondly, the varieties of the first, accord- 
 ing to the different nature of the media surrounding the plant 
 or its parts ; thirdly, distinguish the following peculiarities of the 
 physical and chemical processes in the entire plant for instance, 
 an essential vitality may exist in the individual cells of a plant, 
 and certain processes may be carried on within them without 
 producing any effect upon the neighbouring cells, and upon the 
 entire plant, whilst processes carried forward in dead cells of the 
 plant may exercise an important influence upon the surrounding 
 living cells, and thus upon the entire plant ; lastly, the distri- 
 bution of the absorbed matters in the entire plant must be kept 
 in view. 
 
THE PROCESS OF NUTRITION. 469 
 
 From the preceding paragraphs it will be evident that the old analogy 
 between the absorption of food and the processes of assimilation, respira- 
 tion, secretion, and excretion in animals and plants, will not hold good. 
 We are not indeed able at present to supply its place according to the 
 requirements of organology from a more simple and correct point of 
 view, for we have but single facts to deal with, and they are too few in 
 number to enable us to unite them into a system free from objections. 
 It is easy enough to see the fallacy of the analogy hitherto supposed to 
 exist between certain processes in the animal and vegetable organisms ; 
 but it is most difficult, and at present impossible, to substitute a new 
 arrangement of facts, because here, as everywhere else, we are sur- 
 rounded with a vast mass of useless investigations, and are almost 
 totally unprovided with serviceable materials on which to found a basis 
 for our theory. Men have contented themselves by drawing out ro- 
 mances and theories, the mere offspring of fancy, supported only by the 
 slightest and most superficial phenomena ; and even in our own century 
 there is carelessness and crudeness about our physical and chemical 
 investigations which savours very much of the ignorance of the middle 
 ages. The most senseless experiments have been made in perfect igno- 
 rance of physical, chemical, and physiological facts, and on the supposed 
 results obtained from them false theories have been put forth. Expe- 
 riments in which plants have been placed in pulverised marble with 
 water saturated with carbonic acid, and from which has been deduced the 
 supposed fact that carbonic acid is unfit for the nourishment of plants, 
 are as senseless as if a zoologist should feed an animal with strychnia, 
 and should thence make the deduction that food containing nitrogenous 
 matters is not wholesome. 
 
 Experiments upon the phenomena of life in plants can only be of 
 value when performed in one of two different ways: either the plants on 
 which they are made must be allowed to vegetate under all their natural 
 circumstances, means being taken which shall enable us to observe the 
 processes going on in them according to time, measure, and weight ; or 
 else we must compare the phenomena of vegetation according to time, 
 measure, and weight in a plant excluded from one or more natural con- 
 ditions, with the same phenomena in a plant placed under natural cir- 
 cumstances. Both kinds of experiments should have only one end in 
 view, the understanding of the phenomena of life ; and yet we shall not 
 succeed unless we subject the elementary matters and powers which 
 exercise an influence on the plant independent of itself, to an accurate 
 investigation, and understand thoroughly the peculiarity of their action. 
 Since the time of De Saussure innumerable experiments have been 
 performed to ascertain the capacity of plants to select their own nourish- 
 ment ; and the theories and consequent contentions upon the subject 
 would fill a small library. It appears to me, at least since the dis- 
 covery of Dutrochet, that all disputes upon this subject are useless, 
 until we have ascertained whether the organic or the inorganic matter 
 present in the plant may not, independently of the life of the plant, 
 exercise a power of affinity, and how far this harmonises with the 
 phenomena already observed in the plant. 
 
 The question must be thus placed : how do albumen, gums, and sugar 
 behave in the endosmotic apparatus towards a number of soluble salts ; 
 and how would they behave if many of these salts should be mixed with 
 them ? The salts used in this case should be such as are commonly 
 diffused in water and on the earth. If we, therefore, allow plants, in 
 
 H H 3 
 
470 ORGANOLOGY. 
 
 which we have accurately examined the contents of the cells of the roots, 
 to vegetate in the same mixture of salts, we may thus ascertain how far 
 the simple absorption, as to quality and quantity, is affected by the 
 mere mixture of albumen, gum, and sugar in the interior of the cell. 
 We have not such experiments to adduce, or at least very few ; and we 
 must confess that with respect to the nutrition of the plant we know 
 scarcely anything. Part of this subject belongs to morphology ; the 
 materials which remain we may arrange under the following heads: 
 
 I. The nutrition of the plant in general. 
 II. The absorption and excretion of the nutritious matter. 
 
 III. The assimilation of the nutritious matter. 
 
 IV. The external conditions of absorption and assimilation. 
 V. The motion of the sap in plants. 
 
 I. The Food of Plants in general. 
 
 190. The four elements which are essential to the formation 
 of all organised substances, namely, carbon, hydrogen, oxygen, 
 and nitrogen, are found in continual circulation in nature. We 
 find them in union with organic substances in the vegetable world. 
 The animal kingdom is entirely dependant upon vegetation for 
 support, either mediately (as the carnivora) or immediately (as the 
 vegetable feeders). By means of the vital functions of animals 
 (as respiration and perspiration), and by the corrupting and putri- 
 fying of their excrements, as also by the death of animals and 
 plants, and, finally, by the process of burning, organic substances 
 are continually converted into water, carbonic acid, and carbonate 
 of ammonia, which, as purely inorganic combinations, are held by 
 the atmosphere. These are again exclusively appropriated by the 
 vegetable kingdom, and restored to the domain of organised 
 matter. 
 
 In an inductive inquiry into natural objects, before all things we must 
 strive after the discovery of leading maxims, which should be securely 
 founded, and by which we may decide upon the admissibility of hypo- 
 theses, and through which alone science can be made free from fiction.* 
 The paragraph above is a leading maxim of this kind, concerning the 
 changes of matter which go on in the three kingdoms of nature. In 
 
 * In the following remarks a number of authorities will be used, and, in order to 
 avoid further reference, I have once for all given them here : 
 
 1 . Humboldt's Reisen, and Essai sur la nouvelle Espagne. 
 
 2. Codazzi, Resumen de la Geographia de Venezuela. 
 
 3. Darwin's Voyage round the World. 
 
 4. Blasius, Reise im Europaischen Russland. 
 
 5. Ure, Dictionary of Arts. 
 
 6. Macculloch, Dictionary of Commerce. 
 
 7. Liebig, Organic Chemistry, in its Relations to Agriculture and Physiology. 
 
 8. Boussingault, Economie rurale. 
 
 9. Loudon, Encyclopaedia of Agriculture. 
 
 10. Essays on German Agriculture, by Block, Schwerz, Schweizer, Hlubeck, &c. 
 in the Handbuch fiir angehende Landwirthe, by J. v. K. Leipsic. 
 
 11. Lastly, I have used many private communications on methods of culture from 
 travellers and natives of Germany. 
 
FOOD OF PLANTS IN GENERAL. 471 
 
 recent times this has been called Liebig's theory of the nutrition of 
 plants : but this is doubly wrong, for in the first place it is no mere 
 theory of the nutrition of plants ; and in the second place, it did not 
 originate with Liebig, but with Priestley, and has been gradually de- 
 veloped from his time by the most distinguished experimentalists. 
 Liebig has, indeed, in recent times dwelt upon the importance of its 
 universal recognition, and its relation to the development of a true 
 physiology of plants. He has also done great service by working out 
 the whole problem upon a new method, which was first introduced into 
 the natural sciences by Alexander von Humboldt.* This method con- 
 sists in disregarding at first individual and unarranged observations!, 
 and directing attention to the great mass of the phenomena of nature, 
 and where the deficiencies, on account of their great number, attain a 
 minimum of importance, to make calculations, which may be made the 
 basis of points of departure, alike in the estimate of the value of the 
 smallest as of the most isolated part. 
 
 But on account of the great influence which leading maxims exert, com- 
 prehending, as they do, not only facts and groups of facts, but entire 
 circles of hypotheses, it is above all things necessary that they should be 
 placed on a secure footing, and be susceptible of the strongest possible 
 proof. To the most common examples belong the asserted constancy of 
 the composition of the atmosphere, which Liebig has frequently put for- 
 ward in the fore-ground. "Respiration and combustion consume an 
 immense mass of oxygen, yet the quantity of oxygen in the air re- 
 mains the same; consequently the vegetable world appropriates the 
 carbon of the generated carbonic acid, and again sets free the oxygen." J 
 If we need proof of this view, we have the following : A man in the 
 course of a year changes 225 Ibs. of carbon into carbonic acid, so that 
 a thousand millions of men would consume 2250 millions of centners ; 
 for all the animals || on the earth we may take double this quantity : thus, 
 in the whole, 6750 millions of centners of carbon are yearly burned, 
 which, during the process of burning, would consume 1800 millions of 
 centners of oxygen gas, to which may be added about 400 millions of 
 centners for the burning of coal. \. The remaining processes of combus- 
 tion would give 1500 millions of centners of carbon, which consume 4000 
 millions centners of oxygen. Hence we may take the consumption of 
 oxygen in the course of 300 years at 660 billions of pounds, or about 
 -^ths of the present contents of the atmosphere ; and this would fall within 
 the oscillations of our eudiometrical calculations, if we had observed 
 them as accurately 300 years ago as at present, f 
 
 * The talent which forms an epoch in the history of the natural sciences consists not 
 in the discovery of individual facts or laws, but in the introduction of new ways, the 
 discovery of new methods. 
 
 t To what absurdity and charlatanerie a dwelling upon individual facts, without a 
 comprehensive view, may lead, has been recently seen, in the most forcible manner, in 
 the work of C. H. Schultz, on the Discovery of the true Food of Plants. 
 
 J According to Liebig, man consumes daily between 17 and 27 ounces of carbon. 
 
 A centner is about 100 pounds. TRANS. 
 
 || Boussingault calculates the horse consumes 158 oz., and the cow 141 ioz. 
 daily. 
 
 | According to Ure, 67 7| millions of centners of coal contain 71 per cent, of carbon, 
 which is equal to 481 millions of centners of carbon. 
 
 H At my request, my colleague, Professor E. Schmid, had the goodness to calculate 
 
 H H 4 
 
472 ORGANOLOGY. 
 
 All these calculations are much higher than those given by others, 
 but, as will be subsequently shown, are far within the truth. About the 
 pretended constancy of oxygen in the atmosphere, nothing has as yet 
 been established. As the calculation stands, only the contents of the 
 carbonic acid in the air are regarded. According to the above data we 
 receive annually into the atmosphere, through the processes of respira- 
 tion and combustion, about 30,000 millions of centners of carbonic acid, 
 or in 5000 years 15,000 billions of pounds. Unfortunately we car 
 hardly approximately estimate the out-pourings of volcanoes, but the} 
 certainly cannot deliver much less carbonic acid than respiration am 
 combustion ; thus there ought to be from twenty to thirty times as mucl 
 
 afresh the contents of the atmosphere, as the above did not satisfy me. The following 
 are the data on which hfs calculations were based : 
 
 For the determination of the mean height of the barometer, twelve determinations 
 (Berghaus' Physical Atlas) upon the surface of the Atlantic Ocean were taken, the 
 result of which was (the attraction of the earth reduced to 45 latitude) 
 
 = 336"', 973 Par. 
 = 348'", 76 Rheinl. 
 
 The pressure of atmospheric vapour was taken, according to Dove, at a yearly 
 mean 
 
 at Calcutta 8'", 350 Par. 
 
 London 4'", 147 
 
 Jena 3'", 118 
 
 Catharinenburg 1"', 80O 
 
 The mean would be 4'", 353 Par. But as this number of cases is small, in order to 
 obtain round numbers, 4'", 76 Rheinl. was assumed as the mean. The pressure of the 
 dry atmosphere is as follows : 
 
 344'" Rheinl. Mercury. 
 = 4664'", 364 Water. 
 = 32', 39 
 
 1 German mile = 1970,1 Prussian rods. (Berghaus, Grundriss der Geographie, 
 p. 5.) 
 
 1 German D mile = 388 1294,01 D rods. 
 
 The surface of the earth = 928 19 16,28 German D miles. (Berghaus, op. cit. p. 13.) 
 
 iPruss. C.-F. of water = 66lb. at 15 R. = 18, 75 C = - ? r^r. lb. = 66-089 at C. 
 
 u'yyoDt)^ 
 
 (Dove, Rep. vol. i. p. 144.) 
 
 Thus is the collective weight of the dry atmosphere 
 
 = 1371977266662000000,0 Ib. 
 
 The volume of the elements of the dry atmosphere, according to Dumas, Boussin- 
 gault, and Brunner (Gmelin, Chemie, vol. i. p. 818.) are 
 
 79-1 6 N. 
 20-79 O. 
 
 0-05 CO 2 mean. 
 
 According to Berzelius and Dulong, the specific gravity is 
 
 O = 1-1026 
 
 N = 0-9760 
 
 CO 8 = 1-5240 
 
 Thus the weight of the elements of the dry atmosphere is 
 
 77-06 N. 
 22-86 O. 
 0-08 CO 8 . 
 
 Thus the contents of the whole atmosphere may be calculated as 
 1,057245,681 689,000000 Ib. N. 
 313634,003159,000000 - O. 
 
 1097,581813,000000 - CO 2 . 
 1,371977,266661,000000 - atmospheric air. 
 
FOOD OF PLANTft^N GENERAL. 473 
 
 carbonic acid in our atmosphere as^^Wind actually to exist, if some 
 regular withdrawal, a process in nature which consists essentially in the 
 fixing of carbonic acid, does not exist. A similar line of argument 
 might probably be pursued with regard to ammonia. The example, as 
 given by Liebig, fails somewhat in this, that he cannot allow that the 
 organic substances of the soil (humus) can arrive at the plants in 
 sufficient quantity to supply their need of carbon, because he proceeds 
 on the entirely false foundation, that the earth receives its water entirely 
 through the rain (which only supplies the smallest part), and only takes 
 notice of the humate of lime, and neglects the generally necessarily 
 present humate of ammonia, whereby the plant might receive more than 
 enough carbon for its consumption. On the other hand, far more easy is 
 the proof, which Liebig only hints at, that if in individual cases there has 
 been a sufficient quantity of humus to supply the plant with carbon, yet 
 there is not a sufficient amount of humus existing to cover the demand 
 made by the whole vegetable kingdom for carbon, a subject to which 
 we shall presently advert. 
 
 I maintain that the following mode of research is the only correct one 
 to place securely and make evident the truth of the foregoing view. If 
 we disregard entirely any definite geological hypothesis, yet we must 
 admit that the earth has a history of its origin which I will attempt 
 here to sketch. Before their creation there could be no organic sub- 
 stances. Now, for the creation of these there are only two conceivable 
 conditions : either there was at once created a definite quantity of organic 
 matters, or these were formed gradually and continuously out of inor- 
 ganic substances. All the organic substance that the plant derives 
 from the organic matters of the earth, the first hypothesis, proved or un- 
 proved, supposes to occur in the following way : there is a certain quan- 
 tity of organic matter which constantly circulates between the animal and 
 vegetable kingdoms ; the products, excretions, and dead bodies of the one 
 kingdom supplying nourishment for the other. A priori, this view has 
 nothing in it improbable, but according to experience it is impossible, 
 as the processes of life in the animal, decomposition and combustion, in- 
 terfere. Through these a large part of the organic substances are con- 
 verted into inorganic combinations. The organic matters must thus 
 constantly diminish, and at length become perfectly consumed. The 
 process of combustion, it is well known, annihilates entirely organic 
 matters as such, and putrefaction and fermentation know no other 
 bounds than the perfect dissolution of organic in inorganic combinations. 
 Lastly, if we look in the process of nutrition at the collective quantity 
 of organic matters delivered in the manure for the culture of plants, we 
 shall find the following* : 
 
 A working horse receives daily 
 
 Of dry Organic Matters. 
 Ibs. 
 
 Inl51bs. Hay . . .1174 
 5 Ibs. Oats . . . 4-07 
 5 Ibs. Litter . .3-40 
 
 19-21 19-21 Ibs. 
 
 * In this case the statements of Boussingault are used, but they should be coin- 
 pared with the results of German agriculturists in order to obtain the simplest and 
 most useful averages. 
 
474 
 
 ORGANOLOGY. 
 
 Brought forward 
 It produces daily 
 
 In 33-31 Ibs. Urine and Faeces 
 5-00 Ibs. Litter 
 
 f dry Organic Matters. 
 Ibs. 
 
 . 19-21 Ibs. 
 
 6-56 
 3-40 
 
 9-96 
 
 Fresh Manure loses when 1 __ i /-/- 
 put on the land \ 
 
 8-30 
 
 8-30 Ibs. 
 
 Loss 
 
 >ss in organic matter from the pro-1 ,~,M ,-/- 
 
 duct of the field to the manure j 10 ' 91 = 56 P er cent 
 
 A milch cow receives daily 
 
 In 32 Ibs. Potatoes . . . 8-46 
 
 16 Ibs. Aftermath . .12-15 
 
 8 Ibs. Litter . . .5-44 
 
 26-05 
 It yields daily 
 
 78-28 Ibs. Urine and Faeces . 8-77 
 8-00 Ibs. Litter . . . 5-44 
 
 14-21 
 loss thereon . 2-36 
 
 11-85 
 Collective loss in organic matter 
 
 A pig of middle size receives daily 
 
 In 15 Ibs. Potatoes . . .3-96 
 4 Ibs. Litter . . .2-72 
 
 26-05 Ibs. 
 
 11 -85 Ibs. 
 
 14-2 =54 per cent. 
 
 It produces daily 
 
 In 9 Ibs. Urine and Faeces 
 4 Ibs. Litter 
 
 loss thereon 
 
 6-68 
 
 1-28 
 2-72 
 
 4-00 
 0-66 
 
 6-68 Ibs. 
 
 3-33 
 Collective loss of organic matter 
 
 3-33 Ibs. 
 3-35=50 per cent. 
 
 If we make similar calculations with regard to man, for which we 
 have not however so good data, yet, according to the facts communicated 
 by Valentin (Physiol. vol. i.) and Liebig (Organic Chemistry in rela- 
 tion to Physiology and Agriculture), the loss of organic matter in passing 
 through the human body is greater than in any individual animal. How 
 speedily this loss of organic materials is made manifest in the animal is 
 
FOOD OF PLANTS^* GENERAL. 475 
 
 easily shown by a great example. AcoBking to official documents, the 
 stock of cattle in France in the year 1844 comprised of large animals 
 (bulls, oxen, cows, stallions, geldings, mares, and mules) 10,709,391 st. ; 
 of small animals (donkies, calves, foals, pigs, sheep, and goats) 
 = 30,859,454 st. The daily loss of organic matter may be calculated 
 as 1 1 Ibs. in the first, and 3 Ibs. in the second class of animals, so that 
 for their nourishment in one year about 76,789 millions of Ibs. of or- 
 ganic substances are required, a quantity equal to about six times the 
 weight of the whole of the stock of cattle. If we suppose that the ex- 
 isting quantity of organic matter is 600 times as great as that which 
 represents the whole stock of cattle, yet would the loss during the 
 nourishment of the cattle of France result in a perfect desert in the 
 course of a single century. 
 
 It results then from these facts that the organic substances which 
 are burned and serve as food to animals, are at least half destroyed, 
 and that in 100 years they would be reduced to nothing. But we 
 have, both in the history of the earth and in the history of man, in the 
 former from geological period to period, and in the latter from century to 
 century, evidence not of a decrease but of an increase of organic life upon 
 the surface of the earth. There must, therefore, be continually going on 
 a conversion of inorganic matter into organic combinations. From phy- 
 siological researches* it appears perfectly certain that this cannot go on 
 in the bodies of animals. Neither do we know of any facts in the whole 
 of nature that would lead us to conclude that inorganic substances in* 
 dependent of an organism could be changed into organic compounds. 
 Whilst on the contrary all experience proves that the organic substance 
 is unceasingly passing over into inorganic combinations. The only in- 
 ference from all this is, that plants convert inorganic into organic 
 substances ; and this we must hold as a first great law of nature. The 
 only universally diffused inorganic compounds which can be taken up 
 by plants in order to assimilate carbon, oxygen, hydrogen, and nitrogen, 
 are the carbonic acid gas, water, and carbonate of ammonia of the at- 
 mosphere, and from these must the vegetable world be almost exclusively 
 supplied as the materials of their nutrition, f This law concerns not 
 alone the vegetable world in general, but has an important special ap- 
 plication in the culture of plants. This will be seen when we look at 
 the production of manure according to the foregoing calculations ; and 
 further, reflect that on a well-managed estate a considerable part of the 
 produce, as corn, cheese, butter, wool, &c., is annually taken away, re- 
 turning no manure to the soil, and that the organic substance remaining 
 
 * See Valentin, Liebig, Mulder, &c. 
 
 f This thought seems to have floated darkly before the mind of Liebig, when he 
 said " a primitive humus cannot be granted," a proposition to which the sense of the 
 words would give no signification. Under every circumstance, before an organism 
 could be present in the formation of the earth, inorganic must have passed into organic 
 substances, whether as an organic embryo, or as an organic substance from which the 
 embryo would be first developed. As we are ignorant on this point, and are as likely 
 to remain so, as we are with regard to the nature of organic life in the system of Sirius, 
 so is it foolish to assert that either this or that combination could not exist provided it 
 is chemically possible. It may be conceived that, through a special process, dextrin 
 and protein were first formed ; and that, during the decomposition of these substances, 
 humus, or even that, favoured by this process of decomposition, the first plant-cell was 
 formed. Thus we might have a primitive humus. With this explanation, the view 
 that no dextrin and no protein are developed independent of an organism may be re- 
 ceived, as well as the view now universally held by the most distinguished naturalists, 
 that no specifically definite organism can originate but in a maternal cell, although such 
 might once have originated on the earth's surface. 
 
476 OIIGANOLOGY. 
 
 on the estate must be reduced as food by at least one half. Boussingault 
 places the yearly account of dry organic products contained in the ma- 
 nure in contrast with the products obtained from the soil, during a 
 period of twenty-one years, and finds the proportions are as 33 to 124, 
 so that it would be constantly necessary to replace three-fourths of the 
 humus present, and thus every soil within a short time must be per- 
 fectly exhausted of organic matters. According to Sir H. Davy, 
 
 Organic Matters 
 and Salts. 
 
 Good soil for the growth of Hops contains . 8*0 per cent. 
 
 Good soil for Turnips ..... 0*6 
 
 Very good soil for Wheat . . . . . 4'4 
 Extraordinarily fruitful soil . . . . 2-8 
 
 Good soil 1-4 
 
 Excellent Wheat soil 127 
 
 It is thus very clear that the fruitfulness of the soil does not stand in 
 any relation to its contents of organic substances, but that it appears to 
 depend, on the contrary, on the nature of the plants cultivated and the 
 tillage of the soil. 
 
 But we are enabled to take quite a different view of the culture of 
 plants, if we do not confine ourselves to the little spot of earth from 
 which our profound agricultural manuals are supplied with material. 
 Loudon gives a view of the kinds of agriculture according to the follow- 
 ing scheme : 
 
 1. Agriculture with exclusive irrigation, extending to 35 on each 
 side of the equator. 
 
 2. Agriculture with irrigation and manuring, extending from 35 to 
 45 N. and S. lat. 
 
 3. Agriculture with draining and manuring, from 45 to 67 lat. 
 
 As the last zone alone embraces any considerable surface of the earth 
 in the northern hemisphere, and as local circumstances, both in the second 
 and third, according to the nature of the plant, determine the use of 
 manure or irrigation, it may be advanced, without fear of contradiction, 
 that generally three-fourths of the agriculture of the surface of the earth 
 is carried on without the aid of organic manures, and that the produce 
 in such districts is much greater than where it is carried on in unfavour- 
 able regions by the aid of manures. Unfortunately travellers have 
 given us much too little information of the various ways in which agri- 
 culture is carried on in different lands. As plants that are cultivated 
 without manure we may name the Maize, Rice, Sugar-cane, Plantain, 
 Banana, Manioc, Yams, Coffee, &c. ; as regions in which no organic 
 manures are employed, and in which irrigation alone is employed in 
 the culture of plants, we may mention Central Russia, in Spain the 
 district of Malaga, Arabia, Hindostan, Birman, Java, Ceylon, Malacca, 
 Siam, Cochinchina, Tonquin, a part of Japan and China, Van Diemen's 
 Land, a part of New Holland, Polynesia, Abyssinia, Egypt, Morocco, 
 Cape of Good Hope, Madagascar, Madeira, Chili, Mexico, the Brazils, a 
 part of Canada and of North America. In a word, the way in which 
 the experience of agriculture has been employed for a theory of the 
 nutrition of plants, reminds one very much of the contracted horizon of 
 a small town, Philistine. 
 
 In accordance with these views, then, we maintain the right to reject, 
 without inquiry, every theory of vegetable nutrition which does not put 
 
FOOD OF PLANTS JN GENERAL. 477 
 
 forward the same as its basis, and especially all theories which set forth 
 organic materials as a principal source of nourishment for plants. 
 
 Although the leading propositions, through the above development, 
 may appear to be perfectly firmly established, yet we ought not to dis- 
 dain any individual fact that would confirm or extend their basis. To 
 this end the observation of smaller parts of the earth's surface may 
 serve, which we may in some measure regard as a separated whole. 
 
 The Pampas* of Buenos Ayres, at the time of its discovery by the 
 Spaniards, exhibited the same character as it does at the present day. 
 Endless plains, with mostly a poor though, in the low-ground, a cheer- 
 ful growth of grass, interrupted by paths, and here and there hedged in 
 with strips of Algarobias and Acacias, present themselves, and besides the 
 grave Bizcacho, the Turuturu, and similar small animals, are seen Os- 
 triches, herds of Guanacos, and a scarce population of men. All these 
 remain ; but the Spaniards brought with them between 1530 and 1532 
 horses and horned cattle, which, getting wild, have increased in such 
 immense numbers, that during the war of General Rosas with the 
 Indians 20,000 horses were often lost in a few days. They wander 
 about in countless herds, numbering about 15,000 in each, so that horses 
 and cattle have but little value. The European has extended himself 
 over these districts, and has introduced in the neighbourhood of the 
 great cities a more luxurious vegetation, and the artichoke and the 
 thistle occupy large portions of land. The organic substance in these 
 regions, so far from decreasing, has apparently greatly increased. At 
 the same time, the land, without receiving any remarkable contribution 
 of organic matter since that time, has yielded, in constantly increasing 
 proportions, immense quantities of organic substances.f The hides alone 
 would represent an annual loss of 60,000,000 Ibs. of organic substance. 
 But this is only an inconsiderable part. According to their products, these 
 herds cannot be estimated at much less than 20,000,000, and in a single 
 year they would destroy by the process of nutrition 80,000,000,000 Ibs. 
 of organic matter, or in 100 years 8,000,000,000,000 Ibs. All this 
 organic substance must come from plants ; and who could advocate the 
 senseless position, that all these substances were once humus, or some 
 other organic matter stuck in the barren soil of the Pampas? 
 
 A great part of Central Russia is covered with a soil, which, on 
 account of its colour, is called by the Russians Tschornoisem, black earth, 
 and is distinguished for its extraordinary fruitfulness. The rural 
 economy in this district is about the roughest in the world ; manuring 
 is never once thought of; and those crops alone are sown which momen- 
 tarily promise the greatest return for the least amount of labour. 
 Berzelius has given an analysis of this soil by Herrmann, according to 
 whom a more useful soil does not exist : 
 
 Crenic acid ~| 
 
 Apocrenic acid > combined with iron and alumina = 5-66 per cent. 
 
 Humic acid J 
 
 Humus extract ......= 3*10 
 
 Humin and roots ......= 1*66 
 
 10-42 
 
 * Darwin, op. cit., and Tschichatschew's Rcisen dureh die Pampas. 
 
 f According to M'Culloch, in a period of five years, from 1838 to 1842, Monte 
 Video and Buenos Ayres yielded annually about 90,000,000 Ibs. of oxen and horses' 
 hides, 9,500,000 Ibs. of horsehair, a,nd 3,250,000 Ibs. of ox horns. 
 
478 ORGANOLOGY. 
 
 Let us suppose tins would yield 6 per cent, of organic substance, which 
 is the outside of the fact. The old Hessian acre (Morgen) (40,000 n F.) 
 bears, according to Block, at least 1710 Ibs. of straw and 500 Ibs. of grain. 
 I will put it down at only 1076 Ibs. of organic substance for the two. 
 The depth of soil may be taken at 12 inches, the cubic foot 2*0 P. sp. ; 
 thus each Morgen, through cultivation, would yield 57,600 Ibs., which, 
 according to the above calculation, would suffice for a culture of 500 
 years. But mould, according to Saussure, loses, through putrefaction, at 
 least 5 per cent., so that, according to the above calculation of its quantity 
 (6 per cent.), in the first year it would lose 14,400 Ibs., so that the 57,600 
 Ibs. would not supply 10 years' consumption. This analysis of Herrmann 
 must be allowed to be very bad. .With the clay he finds no trace of alkali, 
 although the soil had grown wheat for centuries, and no phosphoric acid, 
 except 0'46 per cent, of phosphate of iron and alumina. A better analysis 
 of this highly interesting soil is wanted. That these calculations, however, 
 may, on the whole, be relied on is proved by other cases. The arable 
 land of the Saalaue at Jena contains nearly one per cent, of humic acid 
 combined with ammonia, and is a very beautiful wheat soil. The specific 
 gravity is 2-59, so that the top soil, 12" deep, of a single old Hessian 
 Morgen of 40,000 n ' weighs 6,800,000 Ibs., and consequently contains 
 about 68,000 Ibs. of humus. According to Boussingault, a soil in an average 
 state of culture delivers 1050 Ibs. per Morgen more organic matters 
 than it receives through manures, so that these fields must be exhausted 
 in 70 years, and, if the putrefaction is reckoned, in 25 years. But this 
 arable land lias been formed within the last century by the breaking up 
 of meadow land, some of which still remains and is remarkable for its 
 growth of grass ; the average of six analyses of this meadow land gives 
 0*49 per cent, of humus, or about half of that of the arable land. 
 
 One of the most striking facts demanding an explanation of the 
 defenders of the organic theory of vegetable nutrition is the agriculture 
 of the Alps. No one thinks of manuring these alpine pastures ; countless 
 herds are nourished in the summer upon its grass and herbs, and return 
 at the utmost in their excrements but half of the organic substance they 
 take up. Large quantities of cheese are annually conveyed away from 
 these pastures, with no return but thanks ; hay is also taken from them 
 and converted into dollars. This system has been carried on in the 
 Alps for centuries, in some places for a thousand years, and yet no one 
 has observed any deficiency in the fruitfulness of these regions. Can 
 any one be so foolish as to maintain that the thin covering of soil which 
 often lies upon the naked rocks is so rich in organic substances as to 
 furnish this constant loss without exhibiting any remarkable change ? 
 
 Lastly, we can make a calculation for the cultivation of land for an 
 indefinite period. According to Boussingault, a Morgen of well-culti- 
 vated soil on an average yields 2480 Ibs. of dry organic substance, and 
 receives in manure only 795 Ibs., or not more than a third part.* Every 
 well-cultivated soil, instead of being the poorer in humus from the loss 
 of organic substance and the attendant putrefaction, is the richer. It is 
 not, however, necessary to refer to the investigations of Boussingault, as 
 any one may be convinced of the absurdity of the humus-theorists by 
 
 * An objection might be urged here, that the ammonia is lost in the drying of the 
 manure ; but I have only taken into consideration the dry organic substance of the 
 manure. 
 
FOOD OF PLANTS IN GENERAL. 479 
 
 Hj 
 
 examining their own data for regarding the organic constituents of plants 
 as a principal source of their nourishment.* 
 
 Boussingault has performed an interesting experiment on a small 
 scale. He sowed 1-072 mgr. of peas in a mixture of burnt clay and 
 sand, and watered it with distilled water; the ripe plants yielded 4-441 
 mgr., thus making 4' 14 times as much as was sown. According to 
 Block, when 138 Ibs. are sown on an acre, in the third year of the 
 manuring 880 Ibs. are harvested. In burnt clay or sand the harvest 
 would have been 571 '32 Ibs., according to the result of the experiment 
 by Boussingault, the difference showing how much organic substance is 
 necessary for the healthy development of the peas. The same experi- 
 ment has been tried on a large scale, with far more splendid results, for 
 many centuries in Cuba, and for 60 years in France. The Tierra colo- 
 rada, in the higher regions of the island of Cuba, produce from year 
 to year the richest harvests of Coffee and Indigo. This soil is never 
 manured, and is a pure clay, which in other places would be called an 
 iron soil. A very accurate analysis of this earth, in the Laboratory of 
 the Agricultural Institute of Jena, by Herr Wapler, gave the following 
 results : 
 
 The earth is very fine, and contains only a small quantity of insoluble 
 quartz, and small bits of chalk or limestone. It is soft to the feel, and of 
 a dark brown colour. 
 
 A. Soluble in Hydrochloric acid .... 24'0 
 Oxide of iron . . . 12-20 
 Alumina .... 6-00 
 
 Carbonate of lime . . 5-80 
 
 Magnesia .... traces 
 
 24-00 
 
 B. Insoluble in Hydrochloric acid . . . . 75-4 
 
 a. Humic acid, soluble in ammonia 
 
 traces 
 
 b. In Sulphuric acid, soluble in 
 
 potassa . . . . 1*41 
 
 Alumina, with traces of oxide of 
 
 iron .... 34-34 
 Magnesia .... 0*71 
 
 c. Silica .... 38-94 
 
 75-4 
 
 C. Loss 0-6 
 
 100-00 
 
 In France the following experiments have been made between the 
 mouths of the Gironde and the Adour. The sand-downs which are 
 washed from the sea are carried by the west wind into the interior, 
 and thus large districts of the land are converted into a kind of 
 
 * Thus, according to the calculations of Block (Mittheilungen landwirthschaftliche 
 Erfahrungen und Grundsatze, vols. i. and iii.), a good wheat soil will yield annually 
 2075 Ibs. per acre of dry matter, and receives 1167 Ibs. of dry manure; but the manure 
 contains, on an average, 30 per cent, of ashes, whilst the cultivated plants contain but 
 5 per cent., so that the proportions of organic substances are as 794 to 1971. 
 
480 ORGANOLOGY. 
 
 Sahara. After many purposeless attempts to arrest the movement 
 of this sand, by planting wood, the sound plan was hit upon in the 
 year 1789, of planting these sand-hills with coniferous trees. This 
 perfectly succeeded, and in the year 1809 there were alread}' 1.5,000 
 Hessian acres converted into a pine forest, which had grown upon the 
 driest possible soil, and which was entirely destitute of organic substance. 
 The same phenomenon is seen in the pine forests of the Mark and in the 
 oases of the Sahara. In most cases where the inorganic elements of the 
 soil are suitable, and water is found in sufficient quantities, vegetation is 
 possible upon the surface of the earth. 
 
 Lastly, I will refer to a point which unfortunately I cannot illustrate 
 with figures, as no accurate data exist. Our economical arrangements 
 generally, and the way in which' rain water is necessarily got rid of 
 from our cultivated soils, and carries with it into brooks and streams 
 their soluble constituents, make it certain that all our rivers carry 
 annually to the sea a large quantity of organic substance from the land. 
 If we were to calculate this loss for the more considerable rivers, accord- 
 ing to the quantity of organic matter their waters presented on chemical 
 analysis, it would probably greatly exceed all our conceptions. As 
 instances, I would refer not merely to the organic substances, but to the 
 entire plants and animals, which are annually brought down to the sea 
 by the two great rivers of America, the Amazons and the Mississippi. 
 
 In short, regard this matter as we will, the theory which would derive 
 the food of plants from the organic substance of the soil is a remarkable 
 example of the perversities to which a hypothetical natural history may 
 lead without fundamental principles. To show how thoughtlessly the 
 humus-theorists have gone to work, a single example will serve. 
 According to Sprengel, plants derive the principal part of their carbon 
 from humic acid. This they take up as humate of lime, and the 
 advantage of lime to the soil is supposed to lie in its forming this salt 
 with humic acid. It contains, according to Sprengel, 1 Ib. of lime and 
 10*9 Ibs. of humic acid. But the produce of wheat on an acre (after four 
 years' manuring, according to Block) in straw and grain would be 
 1071*24 Ibs. of carbon, which would require 1552-52 Ibs. of humic acid, 
 which would require 142-43 Ibs. of lime to convert it into humate of 
 lime. But this wheat contains, at the highest, in the grain 0-527 Ibs., 
 and in the straw 8*873 Ibs. of lime, which is about T Vth of what it ought 
 to contain. And if we take, for example, the clover, which, for this view, 
 is the most advantageous of plants, we shall find the result the same. 
 According to Block, an acre of clover contains 1020*73 Ibs. of carbon, 
 which is equal to 1479*32 Ibs. of humic acid, which would require 135-7 
 Ibs. of lime in the plant, whilst in, reality, the clover contains only 
 40-29 Ibs., or about one-third the quantity.* 
 
 191. The organic substance of vegetables, so far as the 
 
 * Through the absence of the necessary bases alone, the impossibility of the nutrition 
 of plants through humic acid is proved. At the same time, Liebig's attempt to dis- 
 prove the theory, on account of the insolubility of the humates, must be regarded as a 
 failure. The rain which falls upon the earth supplies only the smallest quantity of 
 moisture which is taken up by the plant. Dew, and especially the absorption of vapour 
 through clay, humus, &c., affords a much larger quantity. It does not appear probable 
 that water would fail. An acre of 40,000 Q feet of meadow land vaporises, according to 
 Schiibler, in 120 days, 6,000,000 Ib. of water, which is twelve times as much as falls, 
 on an average, in Germany (Tubingen) as rain-water in an equal period of time. 
 
FOOD OF PLANTS IN GENERAL. 481 
 
 question of their nourishment is involved, may be divided into 
 two classes, one containing no nitrogen, and the other containing 
 this element. The first class may be divided into three groups : 
 one in which, together with carbon, hydrogen and oxygen are 
 found in the proportion requisite to the formation of water (dex- 
 trine, &c.) ; a second, in which oxygen is present in superfluity 
 (vegetable acids) ; and a third, in which it is found in very small 
 proportions, or in which it is altogether absent (the oils). The 
 second class (the protein compounds) contains, together with the 
 four organic elements, sulphur and phosphorus. Hydrogen and 
 oxygen are always present in sufficient quantity in plants in the 
 form of water, without which no vegetation is possible. Carbon 
 is furnished from the carbonic acid derived from the processes of 
 burning and respiration, from putrefaction and from volcanic 
 eruptions ; all of which render it to the atmosphere from which it 
 is received by the vegetable world. Nitrogen is taken up in 
 the form of ammonia, or the salts of ammonia, which are found 
 during the commencement of the processes of combustion, re- 
 spiration, putrefaction, and during the eruptions of volcanoes. 
 Suphur and phosphorus are yielded probably from phosphuretted 
 and sulphuretted hydrogens. The last is formed whenever pro- 
 tein compounds containing sulphur putrify, and whenever organic 
 matter is decomposed in contact with the sulphates, and also during 
 volcanic action. 
 
 In the foregoing paragraphs, I have shown how plants over the whole 
 earth, in order to obtain their food, need the mediation of the inorganic 
 world ; for through it alone organic substances minister to their exist- 
 ence, for plants cannot receive their nourishment in the form of or- 
 ganised, but in the form of unorganised matter. In this place we must 
 afford especial proof that the individual elements are taken up in the 
 inorganic, and not the organic, form, and also point out the essential 
 sources of these combinations. I may, for the time, lay aside any discus- 
 sion respecting the absorption of hydrogen and oxygen, for no plant 
 can vegetate without water ; and usually much more water is received 
 into the substance of a plant than is requisite as the mere vehicle of 
 hydrogen and oxygen. But I must notice sulphur and phosphorus, on 
 account of their union with protein to produce albumen, fibrine, and 
 casein. All the observations which have already been made on organic 
 substances in general will apply to carbon and nitrogen : there is, how- 
 ever, much of a special nature, and in relation to carbon some interest- 
 ing facts to be brought forward ; whilst, with regard to nitrogen, and 
 especially on the sources of ammonia, much has yet to be added. 
 
 1. Carbon. Over the whole face of the earth, with the exception 
 perhaps of some few savage tribes little known to us, man is acquainted 
 with the use of fire in the preparation of his food, and in the colder 
 zones for the purpose of communicating warmth ; whilst in the torrid 
 zones it is used also to keep off wild beasts and deleterious insects. 
 Civilised nations employ it also for a variety of purposes in the arts. 
 Amongst the civilised nations of the temperate zones, combustible 
 materials are used indeed with economy, and especially in cases where 
 numbers live together in one house, since the fire which will warm one 
 
 I I 
 
482 ORGANOLOGY. 
 
 individual will warm, at the same time, several ; and for culinary pur- 
 poses, the fuel requisite to cook food for six men at one time is less than 
 would be required to cook six several meals for one man. Where there 
 is no limitation in the production of fuel, large quantities are needlessly 
 consumed. A great proportion of the inhabitants of the tropics* live 
 upon rice, which must be long under dressing by fire before it is 
 eaten. Extensive conflagrations of forests are even yet frequent; in 
 America, they continually occur when new land is taken into cultivation. 
 Taking together all these facts, I believe that we may arrive at some- 
 thing like an average yearly consumption of fuel to each man, by esti- 
 mating the quantity consumed between 50 and 60 N. lat. According 
 to the calculation made of the consumption of fuel in the barracks at 
 Weimar, in some institutions for boys, in some hospitals, and in sundry 
 families of large size, I reckon that a medium quantity of fuel consumed 
 for each head annually amounts to one klafter of hard wood. A klafter 
 of hard wood weighs on an average 3600 Ibs., and contains about 50 per 
 cent, of carbon. So that a thousand million of men, for domestic com- 
 bustion, would consume 1,800,000,000,000 Ibs. of carbon. 
 
 For use in the arts and manufactures, I calculate on the use of coal. In 
 England, indeed, coal is consumed for household uses ; but then elsewhere 
 wood, turf, and brown-coal are sometimes used in the arts and manufac- 
 tures. According to Karmarsch and Heeren, the coal obtained yearly in 
 England, France, Belgium, Prussia, Austria, Saxony, and some of the 
 smaller German states, amounts to 75,000,000,000 Ibs. The countries not 
 enumerated (and especially North America) in the calculation would pro- 
 bably make it amount to about 80,000,000,000 Ibs. If this contained 72 per 
 cent, of carbon, it would give an average of 60,000,000,000 Ibs. carbon, 
 which would give 200,000,000,000 Ibs. of carbonic acid. In addition to 
 this, the process of respiration yields about 2^ billions Ibs. of carbonic 
 acid. Household fires may be computed to give 6^ billions. The 
 processes of putrefaction and fermentation may be estimated as fol- 
 lows. To every square rood we may allow at the least 100 Ibs. (some- 
 thing more than 0'5 per cent.) of putrifying animal substance, of which 
 yearly 2 Ibs. of carbon is converted into carbonic acid by decomposition. 
 This we assume as an average result drawn from De Saussure's direct 
 experiments. After the subtraction of the desert of Sahara, and other 
 large deserts, and of the polar regions, where vegetation is impossible, 
 the solid land remaining amounts to 3,000,000 square miles ; so for the 
 processes of decomposition 90 billions Ibs. of carbonic acid are obtained. 
 Exclusively of volcanic operations, the carbonic acid generated in one 
 year amounts to 100 billions Ibs., or in 100 years almost ten times as 
 much as is present in our atmosphere ; and 500 years would suffice to 
 make the air irrespirable for men and bejvsts, if there were not a pro- 
 vision in the economy of nature for subtracting the carbonic acid again 
 from the atmosphere, which should be continually carried on. Such 
 provision is found only in the vegetable world. 
 
 The carbon produced in the processes of breathing, putrefaction, and, 
 for the most part, combustion, is annually afforded by the vegetable 
 world, and being freed from its union with organic matter, is converted 
 into inorganic carbonic acid. Can any reasonable man believe that the 
 store of organic substance upon the earth could long withstand such 
 
 * When we reflect on the dense population of China and India, we may perhaps 
 assume that a third part of the inhabitants of the globe live on rice. 
 
FOOD OF PLANTS IN GENERAL. 483 
 
 constant loss ? The carbon consumed by breathing yearly alone cor- 
 responds to the full produce of 500,000,000 acres of the finest wheat- 
 land, or a surface more than twice as large as France.* 
 
 Whatever may have been the manner of the first production of plants, 
 few will be inclined to assume that the mountains, when they first rose 
 from the sea, were thickly covered with humus. It is much more pro- 
 bable that they were at first quite naked, and that they were but very 
 gradually covered with mould by means of vegetation. 
 
 Upon this earth, at first void of humus, the vegetation of the coal for- 
 mation was first developed, the extent of whose remains still fill us with 
 amazement. Should the store suffice to cover the present demand for 
 yet 2000 years to come, as some English geologists f have assured us 
 that it will, then these mineral coals, assuming that in decomposition 
 their loss would only be 20 per cent, of carbon, would have a weight of 
 1290 billion Ibs. of carbon, which manifestly could not be derived from 
 the original earth void of humus. 
 
 If we consider now the cultivation of individual plants, we find such 
 data as follows : The sugar-cane requires a good damp soil, but which 
 is never manured. The acre produces about 4700 Ibs. of cane, which 
 contains at a minimum 700 Ibs. of carbon in sugar, 500 Ibs. of carbon 
 in the pressed cane ; the sugar is taken away and the cane is burned in 
 the sugar-making houses ; 1200 Ibs. of carbon are thus yearly drawn from 
 the earth without any return (Boussingault). The soil in the French 
 colonies, used in the culture of sugar, must in this way yield yearly 
 225 million Ibs. of carbon, which would correspond to a loss of 325 
 million Ibs. of humus. J We may reckon, on the whole, that the tropical 
 regions produce, from coffee and sugar alone, annually about 2300 mil- 
 
 * The produce of the acre amounts, according to Block, to 475 Ibs. of grain, and 
 2970 Ibs. of straw. The quantity of the carbon of the grain amounts to 46 per cent., 
 and of the straw to 48 per cent., according to Boussingault. 
 
 f Mr. Taylor, one of the most extensive proprietors of coal mines in England, 
 reckons that the store of coals in Durham and Northumberland alone would suffice 
 for the consumption of these provinces for 2,500 years yet to come ; or, in case of 
 falling off, at least for 1700 years. Bakewell, in his Geology, reckons that the coal- 
 beds of South Wales alone would suffice for the present necessities of all England 
 for nearly 5000 years. Both these reckonings are accepted by distinguished geolo- 
 gists, and only objected to by some practical men, in so far as they conceive that too 
 little allowance has been made for loss in working, an objection which does not affect 
 our present case. According to the statements of Lindley and Hutton, in the " British 
 Fossil Flora," the coal-beds of the State of Ohio, covering an extent of 12,000 square 
 miles, calculated at an average thickness of five feet, would give a quantity of carbon 
 arnounting to 70,000,000,000,000 Ibs. We cannot estimate with great exactness the 
 contents of the various coal-beds upon the earth ; but when Liebig supposes that the 
 carbonic acid now present in the atmosphere contains by far more carbon than all the 
 coal-beds in existence, he manifestly errs greatly. The carbon contained in the car- 
 bonic acid of the atmosphere certainly cannot amount to a tenth part of that contained 
 in the whole of the coal-beds upon the globe ; and we do not assuredly over-estimate 
 the loss during decomposition and putrefaction, if we rate it at a twentieth part of the 
 carbon which this past vegetation contained during life. 
 
 \ The sugar-cane contains on an average . 
 
 Of dry Vegetable fibre . . . 1 1 '0 
 
 Sugar 15-5 
 
 Water 73-5 
 
 In the pressing, 8 per cent, of sugar is the maximum obtained ; thus 8 Ibs. of prepared 
 sugar, and 26 '5 Ibs. of dry organic substance, corresponds with 40 per cent, of carbon. 
 The French colonies produce yearly 80 mill, kilogr. The islands of Bourbon and 
 Mauritius yield annually about 100 mill. Ibs., and thus lose yearly about 130 mill. 
 Ibs. of carbon. 
 
 i i 2 
 
484 ORGANOLOGY. 
 
 lions of Ibs. of carbon, which, partly by the process of burning, and 
 partly by that of respiration, produce at least half that quantity of car- 
 bonic acid.* 
 
 The Oil-palms (Cocos nucifera and Elais guineensis) grow in sea- 
 sand. The culture of the latter is largely carried on on the West coast 
 of Africa, in moist damp sand, not enriched by manure. Between the 
 years 1821 1830, England alone imported from the coast of Guinea 
 107,118,000 Ibs. of palm oil, and therewith about 76 million Ibs. of car- 
 bon, drawn from a soil which in itself contained no carbon. At present 
 the yearly import is about 33 million Ibs. of oil ; so that the soil upon 
 which the palms grow must, in order to supply the yearly export of oil, 
 deliver about 25 million Ibs. of carbon. 
 
 The banana, however, affords the most striking example of the pro- 
 duction of carbon. It is usual to plant it originally as a slip, upon a 
 moist rich soil, without any manure whatever ; from the time it becomes 
 capable of bearing, it is allowed to produce for twenty years before any 
 new trees are planted, and when at last new shoots are put in, it is not 
 because the old trees cease to bear, but because the plantation is become 
 confused and disorderly, owing to the continual dying away of the old 
 shoots, and the pushing up of new young shoots from the old roots. 
 According to Humboldt, an acre produces about 98,808 Ibs. yearly, 
 which corresponds with about 43,245 Ibs. of dry substance, and at least 
 17,000 Ibs. of carbon ; hence in twenty years such a surface will yield 
 the prodigious quantity of 345,960 Ibs. of carbon. By this, however, the 
 soil is by no means exhausted. The culture has probably been carried 
 on uninterruptedly for a thousand years in the South Sea islands. On 
 the contrary, the soil is constantly rich in humus, and rendered yet 
 more fertile by the continual shedding of the leaves, and the quick pro- 
 cess of putrefaction in those regions. 
 
 It is known how large are the crops of rice produced from the soil on 
 which this vegetable has been long in constant cultivation, and yet that 
 soil is for the most part never enriched with manure, but only watered. 
 According to Darwin, the richest maize harvests are obtained from the 
 interior of Chili and Peru, from the most sterile quicksands, which are 
 never enriched by manure, and where only small streamlets from the 
 Andes supply any water. There are great expanses of sand, which 
 within the last half century have gradually become covered with birches 
 and firs, and which yet discover spots of the original barren quicksand. 
 So far as my information extends, there is no part of the earth where 
 the inhabitants have applied manure to assist the growth of forests. Yet 
 each forest annually yields to us a considerable quantity of carbon in 
 wood, which is converted into carbonic acid by the process of burning. 
 And it is a fact, long known, that the soil of forests becomes annually 
 not impoverished, but, on the contrary, enriched by the decay of its own 
 leaves, and thus has a large amount of the ingredients requisite to the 
 support of vegetation. As an example of this, we may mention the en- 
 
 * The total production of coffee is about 480 mill. Ibs. ; of sugar, 1600 1700 
 mill. Ibs. The carbon is generally reckoned only at 40 per cent. 1650 mill. Ibs. 
 of sugar give 660 mill. Ibs. carbon, half of which is converted into carbonic acid; 3816 
 mill. Ibs. of cane contain 1 1 26 mill. Ibs. of carbon, which is burnt ; the coffee contains 
 192 mill. Ibs. of carbon; so that coffee and sugar together throw into the atmosphere 
 annually about 6043 mill. Ibs. of carbonic acid gas. During nutrition the non-nitro- 
 genous compounds are entirely, and the nitrogenous are partly, converted into car- 
 bonic acid gas. 
 
FOOD OP PLANTS IN GENERAL. 485 
 
 tire district of Brandenburg, whose soil consists entirely of sea and 
 down-sand. It is still in many places composed of a loose and pure quick- 
 sand of 100 feet deep, and so moveable that it does not, as I have had 
 an opportunity of witnessing in the neighbourhood of Berlin, require 
 any very high wind to change entirely the configuration of the surface. 
 Such spots are found likewise between Charlottenburg and Grunewald, 
 and between Berlin and Tegel. Young pines are sometimes found stand- 
 ing with their first branches buried in the soil, and after eight days with 
 a naked stem, three feet in length, and the roots so exposed that one could 
 creep through them. This soil, as is seen in the Spree w aid, so far as it 
 is moistened by the rivers Spree and Havel, produces vigorous pine vege- 
 tation, which most certainly cannot draw all its carbon from sources fur- 
 nished by the soil, for it has never possessed it, nor has it been furnished 
 to it by artificial processes. The older standing forests have obtained 
 by the fall of the leaf and the action of wind upon the trees so much 
 organic substance as to become in a measure suited for arable land, 
 though such land yield very poor crops of corn, because it needs the 
 essential physical and chemical qualities, which only can be supplied by 
 active culture, and the addition of the salts required by the Cerealia. 
 
 In the cases adduced, we find a production of carbon in organic com- 
 pounds which clearly could not arise from the elements of the soil, be- 
 cause it either contained none originally, or would soon become exhausted 
 of that which it contained ; and yet it becomes continually richer in 
 carbon, even though the decay of vegetation continually carries it off, 
 and with astonishing rapidity under the tropics. The substance of the 
 soil, then, is assuredly not the source from whence plants derive their 
 carbon, and no other is left but carbonic acid. Hence it can be easily 
 understood that the carbonic acid of the soil may contribute to the food 
 of plants, as well as carbonic acid derived from any other source. 
 
 It becomes a question whether there is enough carbonic acid existing 
 to supply the necessities of vegetation upon the whole earth. 
 
 Supposing the part of the earth which is covered with vegetation to be 
 one-fifth of the entire surface, that will give a space of two millions of 
 square miles, or of 43,124 millions of acres ; upon each acre we may allow 
 an annual produce of 2000 Ibs. of carbon, which, on an average, is certainly 
 not too little ; we have to provide for a yearly demand of about 300 
 billion Ibs. of carbonic acid, the source of at least a third part of which 
 we have seen above. How near this is to the truth, we may ascertain by 
 considering some secondary facts. North America alone produces (accord- 
 ing to the North American Almanac for 1843) annually 219,163,319 
 Ibs. of tobacco, which being burned, would yield about 340 million Ibs. 
 of carbonic acid, so that the yearly produce of carbonic acid from tobacco 
 smoking alone cannot be estimated at less than 1000 million Ibs. Other 
 very extensive processes involving the formation of carbonic acid are 
 not alluded to in the above computations. Calculations have been made 
 respecting the disengagement of this gas from the lungs ; but from the 
 want of data none have been made upon the production of it from the 
 skin, which is no less important. In the same way, many processes of 
 combustion, which are carried on in various methods of culture or in other 
 cases, are entirely overlooked in our calculations. In the whole of 
 Northern Germany, the burning of moors is a very common practice ; 
 below Ems it is annually done on the largest scale. So in Corsica, the 
 makis, or evergreen shrubs, are cut down once in three years, and burned 
 upon the soil. In North and South America the breaking up of new 
 
 i i 3 
 
486 ORGANOLOGY. 
 
 land always commences with the burning of the aboriginal wood, which 
 is occasionally done also in the Old World, especially in Russia. Amongst 
 the various burnings is also that of the Steppes, so frequent in the 
 Pampas and the prairies of North and South America. Exceeding all 
 these, are those incalculable quantities of carbonic acid which con- 
 tinually issue from volcanoes. When all these sources of supply are put 
 together, we can entertain no doubt that the carbonic acid annually pro- 
 duced upon the surface of the earth is abundantly sufficient to supply 
 all the demands of vegetation. 
 
 The foregoing will serve to make clear the relation of plants to 
 carbon, and the great part which carbonic acid plays, and must play, in 
 the economy of nature. 
 
 2. Nitrogen. The views of botanists upon the taking up of nitrogen 
 by plants are in a twofold manner opposed to those upon the appropri- 
 ation of carbon. It is eighty years since the discovery of oxygen and 
 its qualities by Priestley showed the immense importance of carbonic 
 acid to the vegetable world ; but there is. still at the present day a great 
 number of botanists, and theoretical agriculturists, and even some 
 chemists, who entertain the conviction that the organic matter of the 
 soil is received by plants in order to supply them with carbon. Again, 
 it has been recently ascertained that ammonia, and the salts of ammonia, 
 are the only essential sources of the nitrogenous contents of plants, al- 
 though there may yet be found persons ignorant enough to believe that 
 plants receive their nitrogen from the soil, and who overlook its change 
 in manures into ammonia and the salts of ammonia. The fact is, 
 it is simply impossible to oppose any thing to ammonia and its 
 salts as humus has been to carbonic acid. We are unacquainted with 
 any soluble organic substance containing nitrogen, which is present in 
 the earth in sufficient quantity to supply the necessities of plants, and 
 all experiments have led to the result that neither animals nor plants 
 are capable of assimilating nitrogen in its elementary form. There is 
 nothing left to the theorists on organic nutrition and vital powers but 
 to receive it in the form of ammonia. The simple question to be solved 
 here is, What are the sources of ammonia? and in the discussion of this 
 question it will be requisite to distinguish between cultivated plants and 
 those growing wild. 
 
 It hardly needs to be observed, that plants growing wild are not sup- 
 plied with ammonia through manuring or other organic supplies ; nor 
 can they be, according to De Saussure, who was the first to point out 
 this fact, that the atmosphere is the source from whence plants derive their 
 volatile salts of ammonia, and which have been supplied from the soil. 
 A second source has been recently pointed out by Mulder, namely, the 
 formation of ammonia at the cost of the atmospheric nitrogen by the 
 putrefaction of non-azotised organic substances.* We can make no ac- 
 curate computation of the amount obtained in either way. We know 
 that the last result of the putrefaction and decomposition of substances 
 
 * Mulder, moreover, regards as important, in which I agree with him, the gradual 
 formation of ammonia in the soil. I attach little value to the objection to De Saussure's 
 experiments, that in the decomposition of the non-azotised compounds, which for the 
 most part contain oxygen and hydrogen in the proportions to form water, there is 
 no free oxygen, which ought to be the case if the hydrogen combines with the nitrogen 
 to form ammonia. But it is highly probable that the sources of nourishment are 
 universally the same for all plants, and that this formation of ammonia, according to 
 Mulder, may occur on every primitive soil, and yet leave no organic matters. 
 
FOOD OF PLANTS IN GENERAL. 487 
 
 containing nitrogen consists in the separation of the nitrogen in the 
 form of ammonia ; thus alone, each perishing generation would produce 
 enough nitrogen to furnish the next generation with an equal amount. 
 It is first given to the atmosphere in the form of ammonia, from which 
 it is received by plants in order to be again introduced into the circle of 
 organic existence. We know also from the researches of Daubeny and 
 Jones that ammonia is one among those gases which issue in large 
 quantities from volcanic strata.* By this means large additions are 
 made to the stores of ammonia obtained from its sources. As yet no 
 experiments have been made respecting the amount of ammonia con- 
 tained in the air, but it is known to vary much more with locality and 
 at different times than does carbonic acid. Those who have had any 
 experience in chemical labours, know how very difficult it is to exclude 
 ammonia, which penetrates every where. Every bottle of hydrochloric 
 acid that is not very tightly secured, every bottle of sulphuric acid 
 that has not been perfectly cleaned, affords, in a crust of ammonial salts 
 which forms upon it, the proof of this. All water, especially rain 
 water, and still more snow, contains ammonia. 
 
 The most striking example of the production of nitrogen without 
 the same having been first furnished in the form of manure, is found in 
 irrigated meadows (Rieselwiesen), which annually yield from forty to 
 fifty Ibs, of nitrogen in organic compounds f, whilst on an average the pro- 
 duce of manured land yields only thirty-one Ibs., and after subtracting 
 that which was contained in the manure, "only seventeen Ibs. As we 
 have already seen, plants cannot draw this nourishment from the organic 
 elements of the soil, and this is especially the case with nitrogen. This 
 is seen in mountain districts and meadow lands which are employed only 
 for the breeding and rearing of cattle, and which yet allow more nitrogen 
 to be carried from them than is obtained by any other mode of tillage. 
 It is also confirmed by the amount of nitrogen contained in plants being 
 wholly independent of the amount of the nitrogen supplied by manure. 
 
 In the south, and more especially in the central parts of Russia, the 
 agriculture carried on by the peasantry is of the lowest kind. Manure, 
 where used at all, is exclusively confined to garden and flax tillage ; the 
 fields are never manured. Hence their produce is only from five to six 
 fold. f Yet each acre yields in the harvest 14^ Ibs. of nitrogen ; and in Cen- 
 tral Russia, where we may suppose the land to have been in cultivation for 
 1000 years, each acre must have yielded, without any compensation, 
 14, 500 Ibs. of that substance. The export of corn from Odessa in 
 the year 1827 contained not less than 755 million Ibs. of nitrogen. || 
 
 * The Ammoniacal Grotto near Naples (Gazette Medicale de Paris, No. 49. Froriep's 
 Notizen: 28, 257.). 
 
 f Irrigated meadows ( Rieselwiesen), according to the German farmers, Linke, 
 Scbwerz, &c., yield from 30 to 40 centners of hay. Dried hay, according to Boussin- 
 gault, contains 1'29 per cent, of nitrogen. 
 
 f This poverty of crop is not universal. In some districts of the Ukraine no manure 
 is used. The straw is burned. The corn grows so vigorously that the stalks are as 
 thick as that of the reed, and the leaves resemble those of maize ; whilst crop after crop 
 is drawn from the same soil, with only one ploughing between the harvest and the 
 sowing. (Loudon.) 
 
 The sowing of li Berlin bushels of corn yield six bushels at harvest, or 540 Ibs. 
 The produce of corn to straw is as one to two, making 1080 Ibs. of straw. Wheat 
 dried at 1 10 Cent, yields, according to Boussingault, 85*5 per cent, of dry material, 
 and thus 2-3 per cent, of nitrogen ; the wheat straw 74 per cent, of dry matter, and in 
 that 0-4 per cent, of nitrogen. 
 
 || Odessa exported in the year 1827 1,200,826 Tschetwert of wheat, 39,940 Tschet- 
 
 i I 4 
 
488 ORGANOLOGY. 
 
 From tliis we are naturally led to a closer observation of cultivated 
 plants. I have already shown that irrigated meadows which are not 
 manured yield yearly a much larger amount of nitrogen than lands under 
 tillage. Hence it appears improbable that cultivated plants should re- 
 quire nitrogen from the manure which is supplied to them, since the 
 same sources from which wild plants receive that element are open to 
 them also. I believe that it is more than probable that plants under 
 culture are as entirely independent of manure, so far as it contains ni- 
 trogen, as wild plants themselves. The experiments of Boussingault, 
 against which no objection can be made, seem to prove this. Boussin- 
 gault is an experienced practical agriculturist, a distinguished naturalist, 
 and a superior chemist. The great number of his experiments, and their 
 extreme simplicity, leave no room for objections. Boussingault culti- 
 vated the plants which he observed in the usual method, and made most 
 accurate investigations as to measure and weight ; and these he places 
 before us instead of guesses or fancies. r ihe results which he obtained 
 as to the weight of produce, the quantities of manure, &c., agree in the 
 main with those of experienced German agriculturists, and exhibit a 
 medium between their extremes. An objection which has been put forward 
 by Liebig, that the nitrogenous matters of the manure evaporate during 
 the process of drying (at 110 C.), might have had some weight, had he 
 established the fact by experiment. The ammonia of manure is either 
 disengaged and volatile, or it is not volatile at 110 C. In the last case 
 the objection is at once answered, and I believe this to be the fact with 
 the generality of the ammoniacal salts contained in manure ; but in the 
 first case, that portion of the salts of ammonia which is volatile is not 
 directly taken up by plants, but is dispersed in the air by the ploughing 
 and turning about of the soil. The manure is not immediately or con- 
 tinually supplied to each plant commencing vegetation ; it is put into the 
 ground, often some time before the seed, turned about as the soil is 
 turned, and thus most probably its action extends over the four, five, or 
 six years consumed by a rotation of crops. It must be at once seen that 
 by the second or third year the earth will hardly contain any remnant 
 of the ammonia salts supplied to it with the manure. Now the inde- 
 pendence of the nitrogen in plants of what they receive from manure, is 
 proved by the fact that the amount produced is not larger the first year, 
 and then gradually decreasing, or the contrary ; but it depends rather 
 
 wert of rye, and 6,852 of barley ; in the whole, about 40,000 million Ibs. of dry 
 organic substance, which was more or less directly produced from the soil: and it would 
 be impossible to allow that more than 1,000,000 Ibs. of dry organic substance 
 could have reached the soil in the form of manure. A similar calculation may be made 
 for St. Petersburg. What needs to be done is the laying a basis for a new science, 
 which, by means of most accurate measurements, weights, and analyses, shall supply 
 commercial statistics, and the elements of a national economy, in those forms of matter 
 which constitute the food of plants and animals. We cannot tell how important might 
 be the result, for the benefit of mankind, if we could once be placed in circumstances 
 that should enable us to subject to calculation, and thence also to control, the escape 
 and influx of the elementary substances, their interchange between sea and land, and 
 between both and the atmosphere. Happy would be the country, and sure to carry 
 agriculture to the greatest perfection, which should learn the means of regulating the 
 quantity of the organic elements (carbon, hydrogen, oxygen, nitrogen) in proportion 
 to its area, which should possess the art to draw upon the inorganic stores of the atmo- 
 sphere, and thereby to spare all waste, and multiply the means of fertilising the earth 
 to export its superfluity of some elements, and to import those of which larger supplies 
 would be beneficial. 
 
FOOD OF PLANTS IN GENERAL. 489 
 
 upon the nature of the cultivated plant. In a six years' rotation of crops, 
 was yielded in 
 
 Nitrogen. 
 
 1st year by Potatoes, on the acre 24*75 Ibs. 
 
 2nd Wheat . . .18-92 
 
 3rd Clover . . . 45-21 
 
 4th Wheat and Turnips 29'93 
 
 5th Pease . . . 52-63 
 
 6th Rye . . . 17'33 
 
 In the whole, 1 88*77 Ibs. nitrogen were produced, whilst the manure 
 spread at the beginning contained only 130-31 Ibs. of nitrogen. Again, 
 in three rotations of crops, two of five years, and one of six, an equal 
 quantity of manure was supplied to all ; namely, for the year and for the 
 acre 2 1-90 Ibs. ; but the annual superabundance of the nitrogen obtained 
 over that contained in the manure was, in 
 
 1st course of 5 years 5 -06 Ibs. 
 2nd 5-45 
 
 3rd 6 9-83 
 
 This last fact is sufficient of itself to show the independence of the 
 production of nitrogen of the contents supplied in manure. 
 
 In six rotations, embracing twenty-one years, the average produce of 
 nitrogen from all the harvests, as compared with the manure supplied, 
 was as 1 : 2-8. According to information afforded by Crud in the cul- 
 ture of Lucerne, Boussingault reckons it as 1 : 4*8. It is supposed that 
 a positive proof of this dependance of the production of nitrogen upon 
 the quantity conveyed to the plants in manure, is found in the fact, that 
 with the increase of the one there is an increase of the other. But it is 
 obviously an error to confound what may be a coincidence with cause 
 and effect. If the fact was as represented, why does a plant always sink to 
 the ground when watered with a solution of ammoniacal salts ? Manifestly 
 because the healthy and strong development of the plant, and therewith 
 the assimilation of the nitrogen, demand further conditions than simply the 
 presence of salts of ammonia. I would here also direct attention to the 
 close connection between the salts of phosphoric acid and the nitrogenous 
 substances of plants. Liebig has correctly stated that we must recognise 
 the fact that the latter are never formed without the presence of the 
 former ; but he has not made experiments with various manures con- 
 taining different proportions of nitrogenous substances and phosphates. 
 It is possible that the nitrogen of cultivated plants may come from this 
 source, and thus we may account for its quantity in them being con- 
 stantly the same. Such plants find abundance of nitrogen at their com- 
 mand without need of receiving any through the medium of manure, 
 for we see that with all applications of this kind we cannot produce so 
 much as is yielded by irrigated meadows which are entirely unmanured. 
 
 We want much some exact experiments upon this subject. We can only 
 adduce those of Schattenmann and of Kuhlmann : the first give almost a 
 doubling of the produce of meadows after the application of carbonate 
 of ammonia (Boussingault*); whilst those of Kuhlmanf show the in- 
 
 * The favourable action of the salts of ammonia may perhaps be explained, according 
 to the experiments of Schultze of F.ldena, through some change produced in the 
 mechanical condition of the soil. 
 
 } See Appendix A. 
 
490 ORGANOLOGY. 
 
 dependence of the produce of nitrogenous compounds of the manure. 
 The production increases as fixed alkalies and organic salts are present, 
 and still more as the salts of phosphoric acid are brought into action. 
 
 From the preceding we learn, that wild plants produce these nitroge- 
 nous compounds independently of the organic nitrogenous matters held 
 in the soil, and of all forms of ammonia not proceeding from the atmo- 
 sphere* ; and this makes it at least in the highest degree probable that 
 the same law holds good for cultivated plants. 
 
 3. Phosphorus and Sulphur. The phosphorus and sulphur held in 
 combination with the elements containing nitrogen are very insignificant. 
 If we reckon all nitrogen as albumen, and take the highest produce of 
 nitrogen which occurs, as in peas, we obtain about 2 Ibs. of sulphur and 
 1 Ib. of phosphorus as the produce of each acre of land in the year ; that 
 is, the soil, taken at 12 inches deep, must produce in the course of the 
 year, in 434 Ibs. of earth, one grain of sulphur and half a grain of phos- 
 phorus. Every 434 Ibs. of earth corresponds to a surface of almost three 
 square feet. Now, supposing that this phosphorus and sulphur arises 
 from sulphuretted and phosphuretted hydrogen, whereby the improbable 
 hypothesis of the decomposition of sulphates and phosphates is avoided, 
 then we must assume that the earth, during a period of vegetation of 
 120 days, absorbs within twenty-four hours from an air-pillar of three 
 square feet of surface of the soil, 0*0088 grains of sulphuretted hydrogen, 
 and 0-0046 of phosphuretted hydrogen, f Now, if we take only 3000 
 cubic feet of air as entering into the calculation, then the cubic foot of 
 air would need to contain only -gu^V^nj^ f a g ra i n of sulphuretted hydro- 
 gen, and inroVrroth f a grain of phosphuretted hydrogen, in order to suffice 
 to the total demands of vegetation. No person will attempt to prove 
 the absence of this quantity in the air, and the possibility of its existence 
 arises from the many processes of putrefaction, by which phosphuretted 
 and sulphuretted hydrogen is delivered ; and to these must be added vol- 
 canic processes, such as sulphureous springs, which give out quantities of 
 sulphuretted hydrogen, and probably also of phosphuretted hydrogen, 
 into the air. However, we may well lay aside the consideration of these 
 minimal quantities, since questions of more importance demand our 
 attention. 
 
 192. The vegetable world in general receives its organic 
 elements through carbonic acid, salts of ammonia, and water ; this is 
 probably sufficient for all the tribes of plants excepting the true 
 parasites. Yet we cannot maintain that plants growing in a moor 
 soil may not also need organic nourishment. Nutrition through 
 inorganic compounds serves only for plants with roots, and in 
 these only for the root-cells ; all other cells those which exist in 
 branches, buds, and embryos, in connection with the mother plant, 
 are nourished exclusively upon matters already more or less 
 assimilated. 
 
 * Whether this exists already in the atmosphere, or has been produced by the process 
 of decay in contact with nitrogen. 
 
 f Peas, which of all cultivated plants contain the largest quantity of nitrogenous 
 matters, yield somewhat more than 50 Ibs. of nitrogen on an acre. In albumen, accord- 
 ing to Mulder, there are 15-83 of nitrogen, 0'68 of sulphur, and 0'33 of phosphorus. 
 If we take the most exorbitant case, that of Lucerne, we should have at the utmost in a 
 cubic foot, the Y^gth of a grain of sulphuretted hydrogen, and jgg^th of a grain of 
 phosphuretted hydrogen. 
 
FOOD OF PLANTS IN GENERAL. 491 
 
 We should do very wrong and depart from our fundamental principles 
 if we were from the foregoing considerations to deduce a theory of vege- 
 table nutrition, and were to apply it to explain the mode of nourishment of 
 particular plants. In order to obtain a correct theory of the nutrition of 
 plants, we must first learn to know the plant in its other relations, and 
 in this place the fundamental principle of the independent existence of 
 the life of the cells must be taken into consideration. Every cell lives 
 for itself. What is necessary for one cell is not to those around. One 
 cell may stand in direct relation with inorganic nature ; another, 
 through its extensive union with other cells, may stand in an indirect re- 
 lation between the plant and nature ; it may receive its nourishment not 
 immediately from the common sources of nourishment, but already assi- 
 milated and modified through the agency of other cells. Both conditions 
 may occur to the same cell during different periods of its life : thus live 
 the generality of the cells throughout the body of the plant : branches, 
 leaves, flowers, and even parasites themselves, live only, or almost only, 
 on matter already assimilated. Each bud, each twig, is a new individual, 
 which sucks from the mother plant matter already become organic, and 
 which appears incapable of assimilating inorganic matter. At this 
 point it must first form root-cells, by which means it is placed in circum- 
 stances to receive and assimilate and convert inorganic matters into or- 
 ganic combinations. But even these root-cells possess only for a short 
 time the capability of assimilating inorganic substances for the use of the 
 plant. The older root-cells receive from those of more recent origin 
 matter already assimilated. 
 
 A question which has been referred to in the foregoing paragraphs 
 awaits an experimental solution. It may be thus expressed : 
 
 Are there truly, as Unger and Endlicher have asserted, hysterophytes ; 
 and if so, how many groups of plants belong to them, and in what way 
 is their independence of a preceding vegetation demonstrated ? There 
 can be no doubt that parasites are hysterophytes, that is, that they can 
 by no possibility originate until the subject on which they root them- 
 selves is formed. This may be asserted with respect to a large number 
 of fungi, which are only developed on soil formed from the decay of for- 
 mer organisms. The difficulty of the cultivation of turf-moor plants 
 on other soil than their own, seems to arise from a similar relation. The 
 nutrition of the true parasites, from the assimilated juices of the subjects 
 on which they appear, seems to be established. From these to the Algce 
 and Lemnacece there is a continuous series of transitionary forms : 
 they can vegetate perfectly where water, carbonic acid, and ammonia are 
 present ; and it could only be presumptuous ignorance which should at 
 present decide whether some of the remaining plants may not derive 
 nourishment, in part or entirely, from organic matters. From what has 
 been already said, it is at least clear that, with respect to cultivated plants 
 and those on which available observations have been made, the or- 
 ganic substance of the soil is not to be regarded as the principal source 
 from whence they derive their nourishment, because its amount is not 
 adequate to the necessities of plants. 
 
 With respect, however, to the turf-moor plants, experiment alone can 
 decide whether their nourishment, demanding, as it does, much carbon, is 
 not essentially received from organic substance as such ; for we know 
 that on moors organic substance is present in large quantities in a dis- 
 solved state, and we have as yet no proof that the plants do not receive 
 all which is presented to them in a dissolved form. 
 
492 ORGANOLOGY. 
 
 In all future experiments, it will be most important to bear in mind 
 that each cell carries on its own existence, and that, therefore, what holds 
 good for one cell does not necessarily apply to others. No cells, with 
 the exception of some root-cells, feed upon absolutely raw material, as it 
 is received from the earth ; they live upon matter more or less assimilated, 
 upon fluids that contain albumen (or the like), dextrin, grape sugar, and 
 organic acids, but in which gum is probably never present, and cane 
 sugar only in rare cases. Every individual which, as branch, bud, or 
 embryo, still stands in connection with the mother plant when separated 
 from the original plant, cannot continue to live on organic matter, and 
 perishes unless it can appropriate inorganic matter by the formation of 
 root-cells. All conclusions founded upon leaves, or other parts of the 
 plant which have been separated from its entire body, are inadmissible as 
 applied to the entire plant. 
 
 1 93. For the perfect nutrition of plants, not only is the absorp- 
 tion of the organic elements and the sulphur and phosphorus found 
 in combination with the nitrogenous substances requisite, but also 
 the inorganic salts which they contain. All plants that have 
 hitherto been burned, with the exception of the mother of vinegar, 
 have been found to leave behind them an ash, which must have 
 been taken up by the plant. These substances must be regarded 
 as essential to the nourishment of plants, though as yet we 
 do not understand in what consists their importance. We may, 
 with Liebig, arrange plants or their organs into four classes, ac- 
 cording to the predominating elements left in the ashes (when 
 above 50 per cent.): 
 
 Alkaline plants : succulent, containing meal and sugar. 
 
 Chalk plants ; Dicotyledons, leaves, fruits, and stalks. 
 
 Siliceous plants : Monocotyledons, leaves and stalks. 
 
 Phosphatic plants : Plants abounding in nitrogen, seeds. 
 
 The investigations which have hitherto been made respecting the inor- 
 ganic elements of plants, are much too recent, too inconsiderable, and too 
 inaccurate to permit us to draw conclusions from them with regard to the 
 process of nutrition in plants. It appears, however, to be established, 
 that for every species (and variety) certain. different kinds and qualities 
 of matter are found so constant, that we may regard them as essential 
 elements for those plants without which their vegetation and their nutri- 
 tion would be impossible, and that they must, therefore, be offered these 
 in the form of food. We may even maintain that the specific varieties of 
 plants, so far as their nutritive processes are concerned, depend almost 
 exclusively upon the inorganic elements, whilst the organic elements re- 
 quisite to all plants are alike or nearly alike for all. 
 
 When, however, we find all parts of plants which are rich in com- 
 pounds of the dextrin series abounding also in potassa and soda, and all 
 organs which contain much of the protein compounds containing also 
 almost in equal measure salts of phosphoric acid, we must arrive at 
 the conclusion, that the alkalies have, with the chemical processes of 
 the dextrin series, and the salts of phosphoric acid, with the origin of 
 the protein compounds, a close and essential connection. It further 
 appears that the solidity of the cell walls depends in part upon the in- 
 organic matter received by the plant and deposited in the substance ; 
 
ABSORPTION OF FOOD, AND EXCRETION. 493 
 
 and in the Monocotyledons silica, and in Dicotyledons lime and mag- 
 nesia, appear to be characteristic.* 
 
 II. On the Absorption of Food and Excretion. 
 
 194. We have now to take into consideration, without regard 
 to their intention, all those processes which occur on the external 
 surfaces of plants, by which they take up matter within their 
 structure, or by which they throw it off. 
 
 1 . Of the Form of the Matter. 
 
 All matters which plants either take up or throw off, must pass 
 through a homogeneous membrane moist with fluid, the cellular 
 membrane, and must also be soluble in water, as the only univer- 
 sal solvent. Only as fluids, vapours, or gases can they pass into 
 or out of the plant. Insoluble matters can never become the 
 food of plants by undergoing a chemical decomposition outside the 
 plant. 
 
 Plants have no stomachs, nor the analogue of a stomach, and conse- 
 quently they have no digestion. The animal kingdom has a stomach, 
 in order to enable it to convert the nourishment received from a solid to 
 a fluid, from an insoluble to a soluble form ; then follows the absorption 
 of the nutriment through homogeneous membranes. But plants must 
 find all the substances requisite to their nutrition already in state of 
 solution ; they have no gastric juice by means of which they may chemi- 
 cally decompose and dissolve substances not ready prepared ; nor have 
 they salivary glands, in order to maintain the supply of a solvent juice. 
 The organic elements, carbon and nitrogen, are only present as carbonic 
 acid and carbonate of ammonia dissolved in water. Hence vegetation 
 is absolutely dependant upon water as a common solvent. Countries 
 that are entirely destitute of water are incapable of sustaining vege- 
 tation, as is the case with Sahara, a portion of the Gobiwiiste, c. ; 
 whilst the purest sand, if supplied with water, becomes capable of sup- 
 porting a vegetation, though it may be of a very poor and unproductive 
 order. Upon the supply of rain from the equator to the poles, and more 
 especially upon the supply of vapour in the atmosphere, the luxuriance 
 of vegetation is strictly dependant. 
 
 The inorganic elements, as they are originally found in the firm 
 crust of our planet, are seldom or never soluble. Before they can be 
 used, a chemical process, aided by a mechanical one, must take place ; in 
 a word, they must be acted upon by the weather, in order that plants 
 may digest them. From these facts, two opposite considerations arise. 
 The matters which are taken up by plants must be soluble, but they 
 require to be not easily dissolved'!', or else they must be very gradually 
 set free from the insoluble matter with which they are in combination, 
 and should be yielded in very small quantities, in a soluble form. Plants 
 
 * See Appendix A., 
 
 f Upon this depends the secret of Liebig's patent manure. He maintains that he has 
 succeeded in replacing the easily soluble salts (matters) in the form of difficultly 
 soluble combinations. 
 
494 ORGANOLOGY. 
 
 stand constantly in need of the inorganic elements of the earth, but only 
 in very small quantity. They need, for example, carbonate of potassa ; 
 but a considerable quantity of this salt is either dissolved out of the soil 
 by rain, or by a constant evaporation the water is so concentrated 
 that it exerts a destructive influence on plants. Hence there exists a 
 necessity either that the salt must belong to those difficult of solution, 
 as gypsum, carbonate of lime, &c., in which case all the water taken up 
 would contain the same percentage of salts, because the diminution of 
 the quantity of water is attended with a separation of a certain quantity 
 of the insoluble salt ; or else the salts must be delivered, as are the 
 phosphates and carbonates of the alkalies, very gradually by the action 
 of the atmosphere, and subsequently decomposition. This last is the 
 case with silica, which is so difficult of solution, and so quickly resumes 
 its original solid condition. The plants which need this ingredient can 
 only obtain it when it exists in the form of the silicates, or when, by the 
 decomposition of organic substances in the earth, the requisite quantity 
 is set free. 
 
 Gases enter into the same category as fluid matters, since all gases 
 that come under our consideration here are more or less soluble in water. 
 The relation also of gases separated from each other by a moist homo- 
 geneous membrane is the same, whether they are insoluble in water or 
 not. 
 
 2. Of the Form of the Processes. 
 
 195. We must regard the processes of absorption and excretion 
 from three points of view, according to the form of the matter. 
 
 1. The absorption and excretion of fluid matter, which embraces 
 the question of the interchange of the matters, and of independent 
 excretion. 
 
 2. The absorption and excretion of vapour, which always occurs 
 independently. 
 
 3. The absorption and excretion of gases, which is carried on 
 by interchange, and also independently. 
 
 These three processes may be called nutrition, perspiration, and 
 respiration, provided we do not suppose them analogous to the like- 
 named processes in animals. 
 
 196. The absorption of fluid matters occurs probably mostly, 
 if not always, in connection with a simultaneous excretion of smaller 
 amount, according to the laws of endosmose. 
 
 In reference to endosmose, there are three relations of the plant 
 to the media in which it vegetates to be distinguished. The sim- 
 plest and most natural case is the vegetation of plants in water, or 
 in a soil perfectly saturated with water (as in bogs). In this case, 
 the cell-walls are in immediate contact with the fluid, and receive 
 it by endosmose, so long as no covering prevents it. A trifling 
 difference between the chemical or physical contents of the cells 
 and the surrounding water is sufficient to sustain the endosmotic 
 process. 
 
 The second case is that in Avhich the cells come in contact with 
 solid matter, endowed with the property of absorbing water. In 
 
ABSORPTION OF FOOD, AND EXCRETION. 495 
 
 this case the contents of the cells will vary from the absorbed 
 water much more than in the former ; for" the endosmotic attrac- 
 tion must overpower the resistance with which the water is held 
 in the soil. The most common and important medium in this case 
 is found in the decomposition of vegetable substances rich in car- 
 bon, which are known by the collective names of garden -soil, mould 
 (humus). It is often found also in inorganic substances, endowed 
 with similar physical properties. The greater or less facility with 
 which they are able to absorb and condense water, carbonic acid, 
 and salts of ammonia from the atmosphere, is important. For this 
 purpose mould is the best possible medium. The great aim of 
 culture should be to endow the earth as richly as possible with the 
 physical qualities requisite to serve the plants that are to grow 
 in it. 
 
 The third case is that in which plants vegetate only in the air. 
 It has only recently been discovered with certainty, that this case 
 actually exists in the vegetation of the tropical Orchidacece. In 
 such plants, the root-sheath appears to supply the place of soil, and 
 they draw their nourishment from the surrounding air. 
 
 In all these cases, the absorption of matter by endosrnosis is 
 doubtless connected with a process of excretion, though small. 
 Such excretion is produced by the endosmosis of the cell contents 
 and assimilated matter of the plant. The comparison of these with 
 excrements, as matter which the plant has worn out, is perfectly 
 inapplicable, and cannot be supported by accurate investigation. 
 
 Up to the present time we know of no other power by which fluid can 
 penetrate into the interior of a cell, than that which occurs as the result 
 of mixing two fluids, separated by a permeable organic membrane, and 
 which is at the present time called endosmose. We cannot, therefore, 
 regard the act of absorption from any other point of view ; at the same 
 time, the observations upon endosmosis are only recent, and there are 
 yet many unanswered questions which can only be solved by accurate 
 observation, and all hasty generalisations and hypotheses must be 
 eschewed. The different localities in which plants grow have been well 
 known, but because nothing has been known with regard to the processes 
 of absorption, no distinction of these localities could be made according 
 to the characteristic modes of the absorption of nutriment. No sooner, 
 however, do we see that endosmosis lies at the basis of absorption, than 
 we discover that the above three distinctive modes of it demand atten- 
 tion. The simplest case in which plants are, for the most part, in con- 
 tact with water, occurs least frequently in the Phanerogamia, those 
 plants which have been almost exclusively regarded as the object of 
 physiology; and the results of endosmotic experiments have been applied 
 to these alone. If endosmotic phenomena are regarded, without taking 
 a wide view of the different kinds of vegetation as it occurs in the earth, 
 on stones, in wood, &c., which produce an essential difference in the 
 relation of water to the plant, only the most superficial knowledge can 
 be obtained. It is only by extended observations that we can expect to 
 explain the relations of this subject, and to fill up the hiatus in our 
 knowledge of the subject. Yet all previous vegetable physiologists who 
 have treated of this subject have supposed that a plant is growing in 
 
496 ORGANOLOGY. 
 
 free water, and applied their results to plants growing in the earth. In 
 the next place, it is necessary to ascertain far more accurately than has 
 hitherto been done, in what circumstances the water is retained in the 
 various soils, and most especially in that form of it called humus. That 
 a difference exists is shown very evidently by the differences existing in 
 the root of a plant, when grown in dry earth and in water. In the last 
 case, the entire surface is smooth ; in the first, the cells of the epidermis 
 are more rapidly developed in proportion to the dryness of the earth, and 
 form long papillae which are insinuated around the smallest lumps of 
 earth. The cells of the roots of plants growing in water consist of pro- 
 portionably broad cells, the contents of which are exceedingly thin. On 
 the other hand, in plants growing on the land, those parts which take up 
 the nutrient matter are composed of a very delicate small-celled tissue, 
 the contents of which is mostly mucus, which consequently exerts a very 
 strong endosmotic action. This or a similar difference shows, that if the 
 nutrition of the plant is effected through endosmose, that in this case it 
 has to overcome, not only the power of attraction in the mixture, but also 
 the power with which the constituents of the soil retain the absorbed 
 water. In this case the experiment is required to determine what 
 difference takes place in the endosmometer, between the action of a 
 diluted fluid by itself, and the same mixed with a quantity of mould. 
 
 In recent times we have received important additions to our know- 
 ledge of the physical peculiarities of the substances contained in the 
 soil, and have learned consequently to regard them in quite another 
 light. Generally, the soil consists of various kinds of rocks, decomposed 
 and disintegrated, and also of a quantity of soluble and insoluble, more 
 or less easily decomposable inorganic combinations, mixed with a smaller 
 or larger proportion of organic substances in a state of decomposition. 
 These various organic and inorganic combinations possess, in a very 
 varying degree, the properties of forming looser or more compact masses 
 amongst themselves, of retaining water or allowing it to pass freely 
 through them, of condensing the vapour of the atmosphere, absorbing 
 carbonic acid, oxygen, and ammonia, &c. On these various properties 
 depend, universally and essentially, the fruitfulness of a soil, in so far as 
 it depends on the greater or less facility with which the nourishment of 
 plants is taken up by the process of endosmose. In this relation, the 
 half decomposed organic substance, known by the collective name of 
 humus, is important, as it possesses the properties of absorbing gases and 
 vapour, and retaining moisture for a long time. Wood-charcoal also 
 appears to possess properties of this kind, worthy of investigation ; and 
 according to the experiments of Lucas, it would appear to be especially 
 beneficial to certain kinds of plants. It is on account of this substance, 
 apparently, that certain plants, such as Marchantia polymorpha and 
 Funaria hygrometrica, are almost sure to spring up on the spots where 
 wood fires have been kindled, and their ashes left on the ground. 
 Special researches on this point are demanded by agriculture and 
 horticulture. 
 
 The third case mentioned in the paragraph is, I willingly admit, 
 somewhat hypothetical. When we examine the tropical Orchidacece, as 
 they grow luxuriously in our hothouses, and find that only one or two of 
 their roots adhere by their sides to the bits of cork on which they grow 
 suspended, and consider that the peculiar covering of their roots dis- 
 tinguishes them from all other roots, and that this is composed of a spongy 
 cellular tissue, resembling in its physical properties those bodies which, 
 
ABSORPTION OF FOOD, AND EXCRETION. 497 
 
 like wood-charcoal, absorb gases and moisture from the atmosphere, the 
 expression of the fact in the text seems natural and warranted. This 
 subject suggests a beautiful series of experiments for the purpose of 
 determining the facility possessed by the root-sheaths of absorbing gases 
 and vapour from the atmosphere, and introducing the same to the 
 roots. 
 
 Some observations of the earlier experimentalists, and which are per- 
 fectly correct, but which were employed for the purpose of forming 
 theoretical views, founded upon the false analogy between animals and 
 plants, and have led to the complete doctrine of the excrements of plants, 
 demand the broadest treatment in the history of our science. They have, 
 however, been recently misused, even by Liebig. The historically 
 important points in this subject are as follows : Duhamel* was the 
 first to observe that the earth adhered to the spongioles of plants. 
 Brugmansf described a brown substance in the water in which roots 
 were growing. Brugmans and CoulonJ drew the inference from this, 
 and the well-known fact, that certain plants, as Oats, Cnicus arvensis, 
 Polygonun Fagopyrum, Spergula arvensis, &c., will not grow near each 
 other, that all plants give out from their roots an excretion, which is 
 injurious to certain other plants. This theory was variously opposed 
 and supported, without any new facts being supplied, when DeCandolle 
 suggested to Macaire Prinsep the performance of a new series of 
 experiments to test its value. But these experiments were performed so 
 regardless of securing the essential fact of such a theory, a sound vege- 
 tation, that they are entirely worthless. When plants are removed from 
 their natural soil, as in the experiments of M. Prinsep, the roots become 
 injured, and thus the water in which they are placed penetrates the 
 tissues, and necessarily a part of the juices of the sap must flow into the 
 water ; and when M. Prinsep adds, that no adulteration of the water 
 takes places if a branch cut off a plant be placed in water, this is so 
 evidently an error that we lose all confidence in his experiments. The 
 worthlessness of the experiment of Prinsep has been pointed out by Meyen 
 (Physiologic, vol. ii. p. 528.), Treviranus (Physiologic, vol. ii. p. 117.), 
 and Hugo Mohl. || On the other hand, the experiments of UngerJ. and 
 Welser^l", which were performed with all proper care and accuracy, gave 
 a perfectly negative result ; so that there can be no doubt that an excre- 
 tion from the root, such as that believed in by DeCandolle, Prinsep, and 
 Liebig, has no existence at all. 
 
 It appears almost a necessary conclusion, that if we regard endosmose 
 as the cause of absorption, that excretion from the spongioles, although 
 only to a small amount, must still take place. Such excretion would 
 consist of imperfectly assimilated matters, and some salts, as the special 
 assimilated matters are so bound to the cell that an excretion of them 
 appears almost impossible, as they are never found on the outside of the 
 spongioles, which yet perform especially the function of absorption. 
 But perhaps the assumption of such an exosmose is unnecessary, for 
 
 * Natural History of Trees, vol. i. p. 107. 
 
 f Dissertatip de Lolio ejusdemque varia specie L. B. 1 785 
 
 \ Dissertatio de mutata humorum indole, &c., p. 77. 
 
 Memoires de la Societe de Geneve, vol. v. p. 287. 
 
 || Dr. J. Liebig's Yerhaltniss zur Pflanzenphysiologie. 
 
 j. Ueber den Einfluss des Bodens, p. 147. 
 
 1 Untersuchungen iiber die Wurzelausscheidung. Tubingen, 1838. 
 
 K K 
 
498 ORGANOLOGY. 
 
 recent researches have shown that endosmose may exist without exos- 
 mose, and that the last is entirely dependant on the specific nature of 
 the two fluids. Further observations are needed on this subject.* 
 
 197. The excretion of fluid substances has hitherto been but 
 very imperfectly observed. I mention by way of example the 
 following : 
 
 1. The separation of fluid water, through cells which are filled 
 with water, and which do not impede its passage by the thickness 
 of their walls, or by an external covering which might interrupt 
 its escape in any large quantity ; e. g. the glands in the pitchers 
 of Nepenthes. Whether this water actually escapes in fluid form, 
 we know not ; but it is probable, for we find in other cells with 
 slender walls that water must escape as water, and not as vapour, 
 the proof of which is, that it carries with it and deposits a quantity 
 of matter which could not have accompanied it in the form of vapour ; 
 for instance, the crystallised sugar found in the flowers of the 
 Fritillaria and other nectaries, and the chalk upon the margin of 
 the leaves of so many species of Saxifraga. 
 
 2. All excretions of peculiar matters on the surface of plants are 
 probably to be classed here ; for instance, the numerous clammy 
 juices on account of which we call a plant viscous (yiscosus). 
 
 3. Related to this kind of excretion is the gradual formation 
 of a thicker or thinner layer of wax, the rime (pruina) upon the 
 surface of many plants and parts of plants, which, on account of 
 it, are designated pruinose (pruinosus), glaucous (glaucus), &c. 
 With respect, however, to this last secretion, we might, with some 
 probability, follow out its reaction upon the life of the cells, and 
 thus upon the entire plant, inasmuch as this incrustation on its 
 surface deprives the cells, yet active, of their power of exhala- 
 tion. 
 
 4. Lastly, we may cite the excretion of the volatile oils 
 through evaporation, especially from the leaves, and sometimes the 
 flowers. 
 
 With regard to the excretions, we are yet much in the dark. 
 Wherever a perfectly-formed epidermis exists, they only occur as the 
 result of disease ; as, for instance, the excretion of juices which are rich 
 in sugar through the leaves, called honey-dew, and the excretion of water- 
 drops in the Grasses, Aracece, in Poplars, and in Willows. There are 
 parts of plants in which no epidermis and no superficial layer of secretion 
 are present to prevent exudations ; in such parts the juices formed in the 
 cells penetrate through the membranes, and are found externally. If these 
 juices contain much solid matter, the water may evaporate from them, and 
 the solid matter may accumulate, and, if its physical properties permit, 
 may contribute to the process of exudation by endosmose. 
 
 The separation of clear water in pitcher-formed leaves is one of the 
 most remarkable of these exudations. The fact in Nepenthes is suffi- 
 ciently established, though the observations respecting it are few. In 
 Saracenia I have never observed water in the pitchers, excepting what 
 
 For the most recent information on this subject, see Matteucci " On the Physical 
 Phenomena of Living Beings," translated by Dr. Pereira. TRANS. 
 
ABSORPTION OF FOOD, AND EXCRETION. 499 
 
 had been obtained from without ; but my observations have been few. 
 How far the observations made upon other plants, and mentioned in their 
 morphology, are accurate, I cannot decide. Respecting the anatomical 
 formation of these parts, and the means by which they separate their 
 water, we know much too little. 
 
 I have already remarked, that I can connect no precise and definite idea 
 with the term gland, as referred to a plant. No attentive observer can 
 avoid seeing how different is life in different cells, whether they are 
 found in different plants, or in the same plant, or near each other. It 
 appears to me quite foolish to denominate that cell, or that group of cells, 
 which contains different matter from its neighbours, a gland or organ for 
 secretion ; for there are many plants, and parts of plants, which would 
 then consist only of glands. It is ridiculous to call a cell containing 
 volatile oil a gland, and to refuse the name to one that contains red or 
 yellow colouring matter ; and should we call the last glands, then almost 
 all petals would consist only of glands. The epidermis would be some- 
 times an epidermis but sometimes a glandular surface ; and with many 
 single cells we should have to admit that they are partially glands and 
 partially not so. If we are to retain the term gland at all, we must apply 
 it to those cells and those masses of cellular tissue which, in consequence 
 of some particular structure, not only contain certain fluids, but also secrete 
 them. 
 
 The expression gland, then, must be applied not only to the receptacle 
 of secretions mentioned in the next paragraph, but also to definite groups 
 of cells on the surface of plants, which, not covered by epidermis, and 
 consisting of tender cell- walls, allow their contents to exude externally ; 
 of such are the glands secreting water in the pitchers of Nepenthes, the 
 surfaces secreting chalk in the pits of the leaves of Saxifraga a'izoon, 
 S. longifolia, &c., and almost all the actually secreting nectaries and 
 appendages of the epidermis. 
 
 The last point mentioned in the paragraph has been referred to in other 
 parts of the work, but as yet little is known with regard to it ; we have 
 as yet little pursued the fact of the development of volatile oils (scents) 
 in the blossoms and other parts of plants. Some light is thrown on the 
 subject by Morren, "Rapport sur le Mem. de Mr. Aug. Trinchinetti de 
 odoribus florum, &c.," 1839. (Extrait du torn, vi., No. 5 des Bullet, de 
 TAcademie Royale de Bruxelles). 
 
 198. The second process to be treated of is exhalation. From 
 those parts of plants which are exposed to an atmosphere which is 
 not already perfectly saturated with moisture, a continual evapo- 
 ration of water goes on. The process is purely physical, and, 
 according to accurate investigations, it appears to proceed uninter- 
 ruptedly, according to the dryness and motion of the atmosphere, 
 with the temperature, and the amount of surface exposed to 
 evaporation. It is highly probable that the epidermis permits of 
 no passage to the evaporating water, but that, the evaporation 
 occurring in the neighbouring intercellular spaces, it escapes through 
 the stomates when they are not closed by too strong evaporation 
 and consequent relaxation. From this circumstance the exhaled 
 water is never quite pure, but it contains always a small admixture 
 of vegetable substances which cannot be accurately analysed. 
 
 Besides this evaporation of water, we sometimes find in a very 
 
500 ORGANOLOGY. 
 
 damp atmosphere, and especially in the case of plants that have 
 already exhaled very much, a taking up of moisture, especially 
 through their green parts ; but our observations on this fact have 
 been too little accurate and purposeless to admit of a precise ex- 
 planation of the process. 
 
 The study of vegetable exhalation in general requires a repetition and 
 improvement of the experiments made upon it. We need a set of 
 experiments which should show, with the greatest exactitude, the dif- 
 ference between the quantity of water absorbed and exhaled, from which 
 we might decide the quantity used for the nourishment of the plant. If 
 the amount of oxygen exhaled with the water was also obtained, we 
 should probably be able to arrive at conclusions respecting the nature of 
 the chemical processes carried on within the plant. We have yet to 
 ascertain the relation of the exhalation of the wall to its absorption. The 
 fact of its absorption (by other means than the root) has been established 
 by Hales, but we are still quite in the dark as to the manner. An accurate 
 knowledge of these relations is so much the more to be desired, as the 
 evaporation and absorption of water with the tension of the vapour must 
 exert an influence upon the absorption or exhalation of the several kinds 
 of gases. Yet in the experiments made upon the so-called respiration of 
 plants, this has been lost sight of. 
 
 We know nothing of the organs through which exhalation is effected. 
 To myself it appears improbable that the living epidermis should be per- 
 meable to water and the vapour of water, except through the stomates 
 (see 36.). 
 
 It is an established fact, that all evaporating water carries with it some 
 portion of the matter which it held in solution. This is seen in the 
 vapour of the ocean. It is probable that no water exhaled from plants 
 is absolutely pure. But no accurate analyses have been made on this 
 point. 
 
 The natural consequence of this exhalation of water from the green 
 parts of plants which are exposed to the air, is the continual concentration 
 of the juices in the cells which lie next the evaporating surfaces. By 
 this, the endosmose of the cells which do not exhale undergoes a change, 
 of which we shall have to speak hereafter. 
 
 The information which we possess respecting the exhalation of plants 
 is chiefly found in the experiments of Hales *, Guettard f, Sennebier J, 
 Schiibler, and Neuffer. 
 
 The strange tendency always to attribute to vitality something different 
 from the physical powers, has introduced into the doctrine of the trans- 
 piration of plants a distinction between evaporation and exhalation ; the 
 first being supposed to take place in dead plants and the last in living ones. 
 I can find no distinction in this case in the facts, but merely in the 
 words. 
 
 I will here add some facts upon the quantity of water exhaled by 
 plants. 
 
 According to Hales ||, a sunflower evaporated daily 1*25 Ib. of water: 
 
 * Vegetable Statics. 
 
 f Memoires de 1'Acad. des Sc. de Par. Ann. 1784. p. 419, et seq. 
 \ Physiologic vegetale, vol. iv. p. 56. 
 
 Untersuchung iiber die Temperatur der Vegetabilien und verschiedene dainit in 
 Verbindung stehende Gegenstande. Tubingen, 1829. 
 || Vegetable Statics. 
 
ABSORPTION OF FOOD, AND EXCRETION. 501 
 
 now let us allow to each of these plants 4 Q' space of soil ; then upon the 
 old Hessian acre there would stand 10,000 plants, which in 120 days would 
 exhale 1,500,000 Ibs. of water. 
 
 A cabbage * exhaled in twelve hours of the day 1 Ib. 6 oz. of water : 
 now if, according to Block, each plant occupies 5 D' of soil, and if we 
 reckon an inferior expenditure for the night, yet the plants on an acre 
 would exhale 1,200,000 Ibs. of water in 120 days. 
 
 A dwarf pear-tree, according to Hales, exhaled in 10 hours of the day f 
 15 Ibs. of water. Allowing for each such tree 20 D' of soil, the trees of 
 an acre would exhale 3,600,000 Ibs. of water, and probably another third of 
 the quantity might be added for the grass between the trees, which would 
 make for the acre almost 5,000,000 Ibs. of water. 
 
 An acre of 40,000 square feet, planted with hops, exhaled in 120 days 
 4,250,000 Ibs. of water through the hops alone. $ 
 
 A square foot of soil covered with Ppa annua exhaled, according 
 to Schiibler , daily, on an average, during the summer, 33*12 cubic inches 
 of water : thus an acre of meadow land about 6,000,000 Ibs. 
 
 199. The relation of plants to the gases of the atmosphere has 
 been least of all investigated or understood. Under this head the 
 following processes claim attention. 
 
 1. A fluid that comes into contact with a gas, or that is only 
 separated from it by a membrane saturated with the same fluid, 
 absorbs, according to the specific nature of the gas and the fluids, a 
 definite measure of the gas, corresponding to the density of the 
 volume and the pressure under which the gas stands. Thus 100 vol. 
 water at 28" barom. and 15 C, will absorb 6*5 vol. oxygen, 4*2 vol. 
 nitrogen, 106*0 vol. carbonic acid; 100 vol. of sugar and water of 
 1,104 sp. gr. will absorb 72 vol. carbonic acid; 100 vol. gum water, 
 1,092 sp. gr., 75 vol. carbonic acid. 
 
 2. When a fluid contains more of a gas than, according to the 
 nature of the gas, and the pressure under which it stands, the fluid 
 can hold in solution, the superfluous gas will escape. It will be 
 the same whether the fluid is free or is covered with a membrane 
 saturated with its own moisture. Since water can only hold in 
 solution 6*5 vol. per cent, of oxygen, and a solution of gum or sugar, 
 similar to the contents of the cells, can only hold 4 '6 vol. per cent, 
 of oxygen in solution, it follows that oxygen must escape from the 
 surface of the plant when the juices in the cells contain more than 
 their due proportion of this gas. 
 
 3. When a fluid which is free, or covered merely by a membrane 
 saturated with itself, and is already mixed with as much of some 
 gas as it may be able to take up, comes into contact with another 
 gas, an interchange takes place between the two gases ; a part of 
 that which was first absorbed escapes, and a portion of the free gas 
 is taken up in its place, and this in proportion to the solubility of 
 the two gases. 
 
 * Vegetable Statics, p. 7. \ Ibid. p. 19. 
 
 f Ibid. p. 1 7. Meteorologie, 74. 
 
502 ORGANOLOGY. 
 
 4. Fluids that have chemical affinities with certain gases attract 
 them when they come into contact with them, either free or through 
 a membrane saturated with the same : thus, for example, volatile 
 oils absorb oxygen in order to form resin, &c. 
 
 5. Every solid body condenses vapour and gases upon its sur- 
 face. It does so more largely if it is pulverulent, and still more so 
 if it is porous. Recently-charred wood has this property in the 
 most striking degree. One vol. of box-wood charcoal absorbs 90 
 vol. of ammoniacal gas, 55 vol. of sulphuretted hydrogen gas, 35 
 vol. of carbonic acid gas, 9*25 vol. of oxygen gas, 7*5 vol. of nitro- 
 gen gas. Humus comes nearest to charcoal in this respect. Water 
 expels a part of the absorbed gases. The entire parenchyma of a 
 plant being permeable, by means of the stomates communicating 
 with the intercellular passages and the atmosphere, makes the 
 plant resemble such porous bodies. 
 
 The labours of experimentalists on these physical relations are far 
 from complete. The experiments of Alton *, Theod. de Saussure f , 
 Graham J, and Mitscherlich , only embrace particular points of the 
 enquiry. 
 
 When we pass from the simple experiments with one gas and one 
 fluid, or one gas with another, to a mixture of gases and fluids, which is 
 the case in plants, the question becomes more complicated than even our 
 comprehension or experimental art can embrace. 
 
 The most simple, and perhaps also the most important relation to be 
 observed here, is the escape of gases from a fluid which, while subject 
 to a certain pressure, held them in solution. 
 
 The importance of this fact is seen, as it must regulate the formation 
 of the nutrient fluid, and the absorption of gases through solid porous 
 bodies, and especially through charcoal, humus, and clay. 
 
 The possible influence of these laws upon the life of the plant will 
 be seen in what follows. 
 
 200. We have now to place certain phenomena of vegetable 
 life, which have been more or less well observed, in connection 
 with the following laws : 
 
 1. The germinating seed takes up a certain quantity of oxygen, 
 and gives off a considerable quantity of carbonic acid. 
 
 2. After the period of germination, the plant exhales, during the 
 day and in the sun-light, oxygen from its green surfaces, and takes 
 in carbonic acid through the same parts. By night the process is 
 reversed ; carbonic acid is exhaled, and oxygen gas is absorbed. ' 
 
 3. All parts of the plant, not having a green colour, as the bark 
 and the root, absorb oxygen gas and exhale carbonic acid gas. 
 
 4. The filaments in flowers absorb, in a very short time, an 
 immense quantity of oxygen gas, and give out in exchange carbonic 
 acid gas. 
 
 * Gilbert's Annal. vol. xxviii. p. 390. J Elements of Chemistry. 
 
 t Ibid. vol. xxxvii. p. 163. Lehrbuch der Chemie, vol. i. 
 
ABSORPTION OF FOOD, AND EXCRETION. 503 
 
 5. Succulent fruits also, in the period after ripening, absorb oxy- 
 gen gas, and give out carbonic acid gas. 
 
 6. Almost all the parts of plants absorb, under some circum- 
 stances, nitrogen from the atmosphere, and exhale it again. 
 
 7. Hydrogen also is exhaled by plants, as we know from Hum- 
 boldt's experiments on fungi. 
 
 The experiments which have been made to ascertain the relation of 
 plants to the atmosphere, we owe chiefly to Hales*, Bonnet f, Priestley J, 
 Ingenhousz , Sennebier ||, Woodhouse ^[, Th. de Saussure**, Link if, 
 and Grischow. J f They may be arranged in three groups, except the 
 old experiments on some water plants, which require to be repeated with 
 extreme accuracy. The first group embraces the experiments in which 
 leaves or stalks, cut from the plant, have been observed. These are 
 worthless ; for it has never been ascertained how much air, and what 
 other matters these parts contained within themselves, nor what changes 
 were being carried forward in the interior, nor how long the experi- 
 ments were continued, &c. 
 
 The second group of experiments contains those in which entire 
 plants, vegetating in water or soil, were enclosed in a receiver. These 
 experiments also, the greater part of which were performed by De Saus- 
 sure, are quite useless, since we have no data whence we may learn how 
 much of the changes produced in the atmosphere were wrought by the 
 leaves, and how much through the soil and roots. The third group is 
 that alone which can yield useful results. In these experiments the 
 green parts of plants were enclosed in a receiver, without the plant 
 being withdrawn from its natural place, and the air in the receiver was 
 that of the atmosphere. To this group belong the experiments of Wood- 
 house, Saussure, Link, and Grischow. 
 
 These last experiments gave the rare result, that the plants, after long 
 vegetation in confined air, neither changed the quality nor quantity of 
 the air by their green parts. Hence there must have existed some fault 
 in connection with them, since the result was an impossibility. The 
 principal mass of the matter in the plants contained less oxygen than the 
 mixture afforded by the soil could have enabled them to take up. In 
 whatever way vegetation goes on, the final result must be the disengage- 
 ment of oxygen gas, which, when exceeding in quantity the measure which 
 can be held in solution by the fluids of the plant, must escape. The 
 most recent experiments of Boussingault go to prove, what was before 
 known, that plants absorb carbonic acid through their green parts in 
 
 * Vegetable Statics. 
 
 f Rech. sur 1' Usage des Feuilles dans les PI. (1754), p. 24, et seq. 
 
 j Experiments and Observations relating to various Branches of Natural Philosophy, 
 with a Continuation of the Observations on Air (1779), vol. i. p. 1, et seq. 
 
 Versuche mit Pflanzen, wodurch entdeckt ward u. s. w. A. d. Engl. 1780; und: 
 Ueber die Ernahrung der Pflanzen u. s. w. A. d. Engl. von G. Fischer, 1798, p. 53 ff. 
 Experiments upon Plants, and an Essay upon the Food of Plants and the Renovation of 
 Soils. London, 1796. 
 
 || Physiologic vegetale (1801), vol. iii. pp. 104 148. 
 
 If Gilbert's Annalen, 1803, vol. xiv. p. 351. 
 
 ** Chemische Untersuchungen liber die Vegetation; ubersetzt von Voigt, 1805. 
 
 ft Grundlehren der Anatomic und Physiologic. Gbttingen, 1807. P. 283. 
 
 |i Physikalisch-chemische Untersuchungen iiber die Athmungen der Gewachse 
 und deren Einfluss auf die gemeine Luft (1819). 
 
 K K 4 
 
504 ORGANOLOGY. 
 
 the light of the sun. Boussingault enclosed the branch of a vine in a 
 receiver, through which, by means of an aspirator, air containing a 
 known quantity of carbonic acid was admitted, and after being exposed 
 to the action of the plant, the quantity of carbonic acid was measured 
 by means of an alkali ; whilst at the same time the same air, without 
 having come into contact with the plant, proved its carbonic acid contents. 
 The result was, that half the carbonic acid of the air was absorbed by 
 the plant. The absolute quantity of the air which, in a definite time, 
 came into contact with the plant, and also the absolute quantity of car- 
 bonic acid, were not measured in this experiment. 
 
 I must here also object even to the most accurate experiments of 
 De Saussure. Plants vegetating in the light absorb carbonic acid and 
 exhale oxygen gas ; but the quantities of oxygen and of carbonic acid 
 do not stand in any equal relation to each other in his experiments. The 
 following plants, instead of absorbing an equal volume of 10 cubic cent- 
 ners of carbonic acid gas for each 100 cubic centners of oxygen gas which 
 they exhale, absorbed the following quantities of carbonic acid : 
 
 Vinca minor . . 147'6 cubic centners. 
 
 Mentha aquatica . . 137*2 
 
 Lyihrum Salicaria . . 123*1 
 
 Pinus genevensis . . 123-6 
 
 Of the entire amount of oxygen received, they retain from J to ^. 
 
 The facts which have heretofore been recorded lie as yet unexplained 
 before us. There is no present possibility of bringing them into harmony 
 with our physical knowledge, for both the one and the other are in an in- 
 complete condition. Our next effort must be to pursue those phenomena 
 which we find exhibited in certain definite groups of cells, or which are 
 manifested within certain determinate portions of time, in order to learn 
 to separate them from what belongs unceasingly to the vegetation of each 
 individual cell. 
 
 III. Assimilation of Food. 
 
 201. The principal substances absorbed by plants are water, 
 carbonic acid, carbonate of ammonia, and certain inorganic salts. 
 The plant draws all these from the soil by the spongioles. It re- 
 ceives carbonic acid from the air through the leaves. In what 
 relation these two methods of absorption stand to each other, and 
 to the necessities of the plant, is unknown to us. The exhalation 
 and the interchange of gases is carried on in connection with the 
 air immediately in contact with the surface of the plant, and also 
 between the cellular tissue and the intercellular passages, from 
 whence gas and vapour escape through the stomates. 
 
 As the great mass of substances which form the plant contain 
 less oxygen than the plant absorbs, it follows of necessity that 
 during the process of assimilation oxygen is set free. Probably 
 neither oxygen nor water are decomposed directly, but a series 
 of combinations takes place, from which, at certain points, or 
 else finally, oxygen is set free. For example, a small portion of 
 the oxygen in the green parts of plants appears to originate in a 
 
ASSIMILATION OF FOOD. 505 
 
 decomposition of the starch or similar matters into wax. It 
 would appear that the exhalation of oxygen, and the absorption 
 of carbonic acid gas, never stand in immediate relation with each 
 other. 
 
 The formation of carbonic acid by other than the green parts of 
 a plant, as the bark and the root, is no vital process, but is the 
 commencement of a process of decomposition (decay). The form- 
 ation of carbonic acid during germination and flowering depends, 
 as in fermentation, upon a decomposition of organic substances ; it 
 thus serves the vital processes without being itself a process of 
 organic development.* The absorption of oxygen, or the oxyda- 
 tion of secreted matters, as the volatile oils, tannin, &c., is entirely 
 independent of the essential life of the plant. 
 
 After a long night of physical and chemical ignorance, the dawn of a 
 true theory of the nutrition of plants is breaking upon us, not without 
 having been dreamed of in the previous darkness. " Plants absorb the 
 crude sap from the soil ; it is then conveyed upwards through the spiral 
 and porous vessels to the leaves, where it is assimilated ; from whence it 
 is sent down to the bark, in order to form buds, leaves, and roots." " The 
 leaves absorb carbonic acid gas, decompose it, and give out the oxygen 
 gas which it contained." 
 
 This was the substance of the dream, of which the least possible pro- 
 mises to be realised ; it was only a dream-picture, not founded on obser- 
 vation or inductive enquiry, and therefore of no value. 
 
 In the first place, there is no such thing as crude sap. It cannot, 
 therefore, be carried to the leaves to become assimilated. From whatever 
 part and at whatever time we examine the sap of a plant, we find that it 
 contains organic principles which cannot come from the soil, because they 
 do not exist there ; such are sugar, gum, malic, citric and tartaric acids, 
 albumen, &c. These substances are diluted with a good deal of water, 
 and mixed with a little carbonic acid and carbonate of ammonia, which 
 are contained in the water of the soil. Even in the cells of the roots, 
 which first receive the moisture of the soil, it is chemically changed, 
 assimilated, and the sap is most decidedly not flowing in special vessels, 
 but passing upwards from cell to cell, and thus it is in every new cell 
 which is being developed by the formative chemical processes ; nothing 
 remains for the leaves to assimilate. That the leaves in their natural 
 growth absorb carbonic acid from the air was a pure invention, for, until 
 Boussingault, no one obtained proof of this by experiment. The fact 
 appears to be fixed by Boussingault, but this proves nothing for the 
 assimilating power of the leaves. From whence then comes this car- 
 bonic acid? Not from the cells in which chemico-vital processes alone 
 are carried on, but from the intercellular passages, which in the largest 
 plants communicate one with another, from the extreme points of the 
 roots. The conclusion that the carbonic acid found in the leaves is con- 
 sumed by them is about as rational as the inference would be, from the 
 respiratory movements of the nose and mouth, that the brain performed 
 
 * At the meeting of the British Association at Cambridge in 1845, I read a paper 
 before the Section of Natural History, the principal object of which was to give the 
 explanation alluded to in the text, of the facts which occur in the germination of plants. 
 See Transactions of Brit. Ass. for Adv. of Sc., 1845. TRANS. 
 
506 ORGANOLOGY. 
 
 the functions of the lungs. If, also, we may assume with Mulder, that 
 a part of the oxygen which is thrown off by the leaves results from the 
 change of starch into wax, then this proposition sinks into comparative 
 insignificance. We may calculate roughly how much oxygen is thus set 
 free. An acre of clover yields in a year, according to Boussingault, 
 2,153-5 Ibs. of clover, which contains : 
 
 1020-68 Ibs. carbon. 
 107-70 hydrogen. 
 8 14 -04 oxygen. 
 45-21 nitrogen. 
 
 If we suppose that all the nitrogen was derived from ammonia, and 
 all the carbon from the carbonic acid, we should arrive at the following 
 results : 
 
 1,020-68 C +2,670-74 O= carbonic acid. 
 45-21 N + 9-26 H=ammonia. 
 
 107-70 H + 9-56 H + 786'00 0=water. 
 
 814-44 O - 7,8600 O = 28"040. 
 2,670-74 21-04=2642-7 O, which must be excreted. 
 
 But, according to Mulder, 10 eq. of starch = 20,420-0, exactly 3 eq. of 
 wax ( = 13,070-2) + 3,153-0 water + 4,197'0 oxygen, or the excretion of 
 2,642-70 Ibs., agrees to the formation of 8,229-8 Ibs. of wax, and the de- 
 composition of 12,762*3 of starch. But 21.53-5 Ibs. of dried clover could 
 not possibly contain 8,229*8 Ibs. of wax. It would afford, when extracted 
 by ether, about 86' 14 Ibs. of fatty matters. The excretion, then, of 
 oxygen, in consequence of the change of starch into wax, agrees with 
 about a hundredth part of the collective process. 
 
 But take whatever view we will of the nutrition of plants, it remains 
 certain that a skilfully cultivated soil never becomes poorer in organic 
 compounds containing carbon, but even richer ; thus proving, setting 
 aside the loss of carbon from the soil by decomposition, that the greater 
 quantity of carbon in the harvest is not derived from the manure, but 
 from carbonic acid. An acre of land, in good culture, yields 790-8 Ibs. 
 of carbon more in the harvest than is contained in the manure ; to fix this 
 quantity of carbon not less than 2,000 Ibs. of oxygen would be set free, 
 which, according to Mulder's hypothesis, would represent the formation 
 of 6,300 Ibs. of wax. 
 
 On such necessities hangs the doctrine of the nutrition of plants, in 
 order to account for the excretion of 2,000 Ibs. of oxygen, we are re- 
 ferred to a process which will not yield more than 30 Ibs., and the pre- 
 sence of 2 Ibs. of sulphur is derived from 400 Ibs. of gypsum, employed 
 in the culture of the plants, and which contain 90 Ibs. of sulphur. Of 
 the botanists and agriculturalists who derive the carbon of plants from 
 humus and manure, the former have forgotten their own experiments, the 
 latter never knew them. The tables of Boussingault were not required, 
 as every German manual of agriculture contains calculations of the 
 quantities of manures and harvests which, if the elementary substances 
 had been properly calculated, would have afforded results that would 
 long since have pointed out the true laws of nature. All who have 
 written upon this subject have failed to take a general view, and on this 
 account all earlier works, some few of the oldest excepted, are utterly 
 useless. Whoever writes on these matters ought to give new and exact 
 researches, in order to save himself and others from error. 
 
ASSIMILATION OF FOOD. 507 
 
 The absorption of oxygen by plants at night, which has been con- 
 firmed it appears by experiment, is explained by Liebig as a process of 
 oxidation of the volatile oils. But this process must also go on in the 
 day, and therefore it fails as an explanation. 
 
 The researches upon the absorption of nutriment in plants are of little 
 worth, because they have proceeded from prejudices, often of an oppos- 
 ing nature, without the least regard to the natural circumstances of ve- 
 getation. Land-plants do not grow in water, or in a soil saturated 
 with fluid. The moisture of the soil exists under peculiar circumstances, 
 upon the nature of which there is an absence of all investigation. It is 
 absorbed by solid substances, and can only be retained by some essential 
 modification of the process of absorption. There is no lack of bad ex- 
 periments upon the matters which are absorbed, but not one good che- 
 mical examination of the nature of the moisture ordinarily found in the 
 soil, and which is the true food of plants. The consequence is, that we 
 know nothing certainly of the processes that go on in the interior of the 
 plant, in nutrition and assimilation. The best thing that has been said 
 on this subject appears to me to be a remark of Liebig, who says that 
 the carbonates of the alkalies are apparently gradually converted into 
 salts of vegetable acids, containing little oxygen. The malates are, 
 through a deoxidising process in the potash and dextrin, probably de- 
 stroyed ; but there is no experimental proof of this. 
 
 Upon the origin of particular compounds we know nothing. Liebig, 
 when he speaks of the possibility and probability of the decomposition of 
 carbonic acid, says that this process must take place, in every case, during 
 the formation of fatty matter. We might admit this if we could form 
 fats out of carbonic acid and water ; but we cannot do this, and all ana- 
 logy leads us to the much more probable conclusion that the fats are 
 formed out of the compounds of the dextrin series. To calculate the vari- 
 ous possible combinations of the elements on paper is not very difficult, 
 but for affording a knowledge of what really takes place in nature, such 
 a proceeding is entirely useless. That some few inorganic compounds 
 are converted into organic compounds during the nutrition of plants, 
 we know with absolute certainty ; that during these changes the inor- 
 ganic salts play an important part, is probable. But what organic com- 
 pounds are first formed, through what special chemical processes they 
 originate, is at present entirely unknown, although it must form the 
 foundation of a true theory of nutrition. In recent times we have re- 
 ceived from the researches of Liebig, Mulder, Dumas, and others, numer- 
 ous schemes and explanations of the various metamorphoses of the 
 organic matters in plants. But by far the most extensive part of the 
 question, and for vegetation generally the most important, has been 
 hitherto untouched : here is a wide field for united exertion. The 
 chemist, often with great industry, builds up a theory which one 
 glance through the microscope dissipates. The physiologist exercises 
 great acuteness in bringing his observations into relation, and when he 
 has done, the chemist tells him it is chemically impossible. Thus both 
 time and energy are lost. 
 
 There is another circumstance to be referred to in this place, which 
 renders observations on plants difficult, and which ought to be regarded 
 in the selection of plants for experiment. Although plants, as such, 
 must exist according to the morphological relation of their physiological 
 elementary organs, yet individuals of one and the same species contain, 
 both qualitatively and quantitatively, a great variety of elements, and 
 
508 ORGANOLOGY. 
 
 even they absorb sometimes one kind of matter and sometimes another. 
 This is not exhibited at all in the form of the species of the plant, for this 
 remains the same in all circumstances. The change takes place in indi- 
 vidual cells. Thus, in the same cellular mass, say of 1000 cells, there 
 will be in one case 200 containing starch granules, and 400 containing 
 oil ; in another there will be 500 containing starch, and only 100 oil : 
 but the form of the plant suffers not the slightest change ; or, what is 
 more frequently the case, the relative quantity of particular substances 
 becomes changed : thus, particular cells will at one time contain 7 per 
 cent, of gluten and 70 per cent, of starch, and at another time will con- 
 tain 35 per cent, of gluten and 40 per cent of starch. For every species 
 of plant there are definite quantities of certain matters necessary for its 
 existence, but it frequently takes up matters which are not necessary 
 for its existence, and a superfluity of matters which are necessary for its 
 existence ; and thus both the quantity and quality of its contents are 
 changed. This, then, is a problem for pure empirical research how far 
 plants will bear departures in the quality and quantity of the normal 
 constituents of their food. Many plants appear to require a very pre- 
 cise diet, which will account for their limited distribution and the diffi- 
 culty of their culture, whilst others seem to adapt themselves to all 
 circumstances, and present great variety in their contents. Thus the 
 composition of the milky juice of the Papaver somniferum (Opium), 
 according to Biltz, Mulder, and Schindler, is as follows : 
 
 In Morphia, from 2-842 to 20-00 per cent 
 Narcotin 1-30 33-00 
 
 Caoutchouc 2-00 6-012 
 
 It is also well known that the plants which yield caoutchouc afford 
 very variable quantities, according to the varying circumstances under 
 which they grow. If we also add to this the fact that plants yield 
 poisonous or inert secretions according to their locality, we cannot but 
 conclude that certain substances appear or disappear in the plant when 
 external circumstances are given, without altering their external cha- 
 racter. This great variability in the composition of plants must always 
 be regarded in experimenting upon the vegetable kingdom, . 
 
 IV. External Conditions of the Absorption and Assimilation 
 
 of Food. 
 
 202. As external conditions of the absorption and assimilation, 
 we may here point out : 
 
 I. The soil in which the plants root. This requires, besides its 
 chemical contents of inorganic matter for food, also certain me- 
 chanical and physical properties in order to render the nutrition of 
 plants possible. Hence clay and humus, as substances that absorb 
 gas and vapour, are important. 
 
 Next to the consideration of the materials themselves of the food of 
 plants, in order to form a true theory of the culture of plants, and the 
 understanding the processes of nutrition, there is nothing so important 
 as the investigation of those relations upon which the health of the plant 
 is essentially dependant, and which do not afford the materials of the 
 
EXTERNAL CONDITIONS OF ABSORPTION, ETC. 509 
 
 food. For agriculture these circumstances may be divided into those 
 over which man exercises entire or great control, and those over which 
 he has no influence, and which he must take as they come, or which at 
 most he may press into his service by a knowledge of their perfect regu- 
 larity. These last the child-like man beautifully, and in a certain sense 
 truly, calls "the blessing of Heaven." But for the scientific consi- 
 deration of this subject we need another division, in order to arrange the 
 few facts which are at present known to us. I shall consider, first, the 
 soil; and, secondly, the imponderables, in their relation to the nutri- 
 tionary process in plants. 
 
 1. The Soil. By soil I understand here the earth in the narrowest 
 sense ; all that is necessary has been said above about water and air. We 
 must regard the soil, in relation to the plants growing in it, in a three- 
 fold sense : 
 
 a. According to its chemical constitution, as it contains the inorganic 
 food of plants. 
 
 b. According to its mechanical properties, through which it is fitted for 
 the penetration of the roots, and for holding them firmly. 
 
 c. According to its physical peculiarities. 
 
 The first point has been already dwelt upon ; for the second we have 
 neither facts nor laws. Climate serves the wild vegetation ; this deter- 
 mines the distribution of plants. In agriculture we change the me- 
 chanical constitution of the soil through the plough, the harrow, and 
 manure. It is to the last point, then, we shall address ourselves here. 
 
 Water, as the universal solvent of the nutritive matters, is indis- 
 pensable, and much unnecessary trouble has been taken to calculate the 
 quantity of water, as rain or snow, that falls upon the surface of the 
 earth. The free water in the soil is seldom beneficial to plants, and it is 
 a well-known fact, that when a soil is saturated with water it becomes an 
 injurious locality for the great majority of plants, and that only bog 
 plants, or those which grow in water, will exist in it. In those portions 
 of the earth's surface which produce the most plants, water is only occa- 
 sionally present (as after rain, &c.) as a coherent fluid. The normal 
 condition of water in the soil is as hygroscopic water or absorbed vapour.* 
 The complete independence of vegetation of the atmospheric precipitation 
 of rain in a liquid form, is seen in the vegetation of the Oasis, and of the 
 cloudless coasts of Chili and Peru (see Darwin and Loudon), and in 
 a small way in the experiments of Ward.f The sand of the Sahara pro- 
 duces no vegetation, not because no rain falls upon it, but because it has 
 not the power of condensing aqueous vapour.^ Of the water which falls 
 as rain, very little is used directly by the plant : the greatest part runs 
 
 * How essentially this condition of the water in the soil is connected with chemical 
 processes, and thence with the preparation of the food for plants, is shown by Boussin- 
 gault (Econ. Rur. vol. ii. p. 199.) in a striking manner, in an explanation of the value 
 of gypsum (sulphate of lime) as a manure. Whilst in the presence of fluid water 
 gypsum and carbonate of ammonia are mutually decomposed, in ordinary soil exactly 
 the contrary takes place, and carbonate of lime is decomposed by sulphate of ammonia. 
 
 f On the Growth of Plants in closely glazed Cases: London, 1842. Ward's plan of 
 growing plants in closed cases, where the moisture exhaled by the plant is constantly 
 again absorbed from the soil, is now very generally come into use in Europe, for the 
 purpose of cultivating tropical plants, and with the best possible results. Ward relates 
 cases in which he has kept plants, especially Ferns, in a state of luxurious vegetation for 
 upwards of nine years in a sealed flask. 
 
 \ Perhaps also on account of the absence of aqueous vapours in the air. I know of 
 no hygrometric experiments on the Sahara and other deserts. 
 
510 ORGANOLOGY. 
 
 off, or is evaporated into the atmosphere, whilst another part sinks into 
 the earth and feeds the springs. There are but few observations upon the 
 quantity of water needed by plants, but the facts supplied by Hales and 
 Schiibler show that rain, after making allowances for that which flows 
 away and is evaporated, does not supply more than a tenth part of what 
 is necessary. It is unaccountable and inexcusable, that not a single 
 botanist since the time of Hales should have taken up and carried on his 
 experiments. If we take the previous calculations (page 501.) of the 
 quantity of water required by plants in England, which is deduced from 
 Hales' experiments, and which agree with those of Schiibler on Poa 
 annua, we shall obtain the following approximative results. According 
 to Schiibler *, there falls in England, upon the acre of 40,000 D F., at 
 the utmost 1,600,000 Ibs. of water during 120 days of summer. According 
 to the researches of Dalton, Miiller, Berghaus f , and Dausse J, at least a 
 third part of this water flows away into the rivers, but it is probably 
 more than this, as the great rapidity of the flow of the water in steep, 
 hilly, and mountainous regions is not sufficiently taken into consideration. 
 A considerable, but not accurately to be estimated quantity of water 
 evaporates immediately after the fall of rain, as the vaporous state of the 
 atmosphere indicates. From this it would appear that at the most there 
 is left disposable for plants and future evaporation 800,000 Ibs. of water on 
 the acre. Now this quantity of water, according to the preceding expe- 
 riments, would cover not more than two-thirds of the demand of an acre 
 of Cabbages, half of the demand of an acre of Sunflowers or of the 
 Jerusalem Artichoke (Helianthus tuberosus) ; the fourth of a fruit- 
 garden, the fifth of a hop-garden, and about the seventh or eighth of a 
 meadow. It must be recollected, that here only the water is taken into 
 calculation which is given out from the plants and weeds growing in a 
 meadow, but that which is afforded by the evaporation of the soil itself 
 cannot amount to less than 2,000,000 of Ibs. for an acre. Thus much is 
 very evident from these calculations, that the quantity of rain that falls 
 upon the earth is no more a measure of the quantity needed or consumed 
 by the plant, than is the quantity of humus an index to the fertility of the 
 soil. We may learn from this that the quantity of rain which falls in a 
 given region is not a measure of its fruitfulness, but the quantity of 
 moisture, the absolute and relative quantity of vapour, which yearly, and 
 especially during those months which are most important for vegetation, is 
 contained in the atmosphere. 
 
 Thus much then is certain, that the soil, in order that it may nourish 
 plants, must absorb a large quantity of water from the atmosphere, and 
 must possess the necessary properties for that purpose. This property 
 is only possessed to a great extent amongst the original constituents of 
 the soil by clay, so that a soil free from clay is unfruitful. But the 
 primitive vegetation of the earth enriched the soil, by its death, with a 
 substance (humus), which also possesses this property, and which in 
 proportion to its abundance produces a luxurious vegetation without 
 affording from its own substance any part of the nourishment of the 
 
 * Meteorologie, p. 130. 
 
 f Berghaus Lander und Vblkerkunde, vol. ii. pp. 24, 227. 
 
 | Studer Lehrb. d. physikal. Geog. p. 85. 
 
 The calculations of Berghaus, for the flow of atmospheric water into the Rhine, 
 gives a result of three-fourths ; those of Studer for the same river, four-fifths. But the 
 calculations of Berghaus for the Weser show a larger quantity of water carried away 
 than falls from the atmosphere. 
 
EXTERNAL CONDITIONS OF ABSORPTION, ETC. 
 
 511 
 
 plant. In this way the ability of the soil to support a prolific vegetation 
 is dependant on those climatic influences which rapidly determine the 
 death of plants, or the parts of plants, and converts them into humus. 
 Herein we see the foundation of the variety of the vegetation in different 
 parts of the earth, and the determining cause of the richness of a 
 tropical vegetation. 
 
 The industrious Schiibler * has made a series of experiments, in order 
 to reduce to number the capacity of various kinds of soil to absorb 
 water from the atmosphere. The results are contained in the following 
 Table : 
 
 
 1000 Grains of Earth distributed over a Surface of 50 Square 
 
 
 Inches absorbed in 
 
 Kinds of Earth. 
 
 
 
 
 
 
 12 Hours. 
 
 24 Hours. 
 
 48 Hours. 
 
 72 Hours. 
 
 Quartz Sand 
 
 Grains. 
 
 
 Grains. 
 
 
 Grains. 
 
 
 Grains. 
 
 
 Limestone Sand 
 
 2 
 
 3 
 
 3 
 
 3 
 
 Gypsum . 
 
 1 
 
 1 
 
 1 
 
 1 
 
 Loam Clay ~| 
 (Lettartiger Thon) J 
 
 21 
 
 26 
 
 28 
 
 28 
 
 Muddy Clay 1 
 (Lehmartiger Thon) J 
 
 25 
 
 30 
 
 34 
 
 35 
 
 Resonant Clay 1 
 (Klangartiger Thon) J 
 
 30 
 
 36 
 
 40 
 
 41 
 
 Pure grey Clay . 
 
 37 
 
 42 
 
 48 
 
 49 
 
 Fine calcareous Earth . 
 
 26 
 
 31 
 
 35 
 
 35 
 
 Fine Magnesia . 
 
 69 
 
 76 
 
 80 
 
 82 
 
 Humus . 
 
 80 
 
 97 
 
 110 
 
 120 
 
 Garden Mould . 
 
 35 
 
 45 
 
 50 
 
 52 
 
 Field Mould 
 
 16 
 
 22 
 
 23 
 
 23 
 
 Slaty Marl 
 
 24 
 
 29 
 
 32 
 
 33 
 
 These experiments were performed in an atmosphere saturated with 
 moisture at a temperature of from 12 to 16 R. (59 to 64 Fahr.). 
 In order to apply these results, we want three other series of experi- 
 ments on the absorbing power of these substances. 1. According to 
 varieties of temperature ; 2. The thickness of the layer of earth ; 
 3. The degree of moisture of the air. Should we now attempt to apply 
 Schiibler's results (which are certainly unsatisfactory) to a soil 12" deep, 
 we should find that plants were supplied during a period of 120 days 
 with the enormous quantity of eighteen millions of pounds of water. 
 
 But water is not the only nor the most important portion of the food 
 of plants. They require carbonic acid gas and the volatile salts of 
 ammonia, which must be derived from the atmosphere ; they are ab- 
 sorbed, the carbonic acid partly, and the ammoniacal compounds probably 
 entirely, by means of the roots. The greater proportion of these sub- 
 stances which are brought down by the rain are also evaporated with 
 the water ; hence the necessity of the presence in the soil, in the form of 
 clay and humus, of media to convey them to the plant. In all agricultural 
 estimates of the value of the soil, the entire decision turns upon the 
 contents of clay and humus. Some of the best wheat soils often do not 
 
 Agrikulturchcmie. 2d edition. By Krutzscli. pp. 2, 84. 
 
512 ORGANOLOGY. 
 
 contain a trace of humus, and their only value consists in the quantity 
 of clay they contain. 
 
 There is a prejudice extant among some people, and which unsuspi- 
 ciously lies at the foundation of their view of the nutrition of plants, 
 and that is, that cultivated plants upon prepared soil vegetate under 
 more advantageous circumstances than plants growing wild. The fact 
 seems to be directly the contrary, for in the culture of the land most 
 plants are placed in circumstances so directly opposed to the natural 
 circumstances of their growth, that we have to employ all the art of 
 agriculture for obviating their injurious action. The problem of 
 agriculture consists in covering a given area with plants of the same 
 species. To this end we must first destroy the whole natural vegetation 
 of the soil (uproot the soil), and as much as possible prevent every new 
 growth upon the soil. The mechanical processes necessary for this are 
 attended with injury to the vegetation, which is increased by our yearly 
 carrying away as harvest those products which, with plants growing 
 wild, would remain upon the soil. The working up of the soil, and 
 allowing it to lie fallow, acts injuriously by exposing it to the action of 
 the weather and desiccation from the sun ; at the same time, the decom- 
 position of the substances drawn by the water from the humus is acce- 
 lerated ; and, lastly, the naked and loose earth is exposed to the con- 
 stant washing of the rain. Finally, cultivated plants sustain injury 
 from the fact, that the soil is covered with a species for which it is not 
 naturally adapted, and consequently the produce is never so large as it 
 might be. 
 
 Very different are the results the nearer the culture of the field ap- 
 proaches that of the garden. In this case the cultivated plants have 
 strikingly the advantage of the wild plants of our climate. The garden 
 soil is distinguished by two peculiarities which arise out of the action of 
 excessive manuring. First, it contains all the inorganic elements in the 
 greatest quantity and the most favourable form that is combined with 
 easily decomposable organic substances. Secondly, it has, on account of 
 the quantity of humus it contains, the capacity of supplying the growing 
 plants with the organic elements it contains, and especially with 
 water in the greatest quantity and constancy. The latter property ensures 
 a luxuriant vegetation ; whilst the former, on account of its favouring the 
 chemical processes in the plant, ensures an opulence of form which is 
 quite impossible in a poorer soil. Indeed, we never see in the virgin 
 soils of nature, nor in our fields, the rich variety of forms which are 
 observed in our gardens, and in some instances the action of the cir- 
 cumstances producing these varieties is so permanent that they can be 
 propagated by seeds. It is impossible that these influences should lose 
 their activity even where they are formed without the assistance of man. 
 Thus, we find in the tropics, where the conditions fail for forming a good 
 garden soil, that there, as with us, wildernesses, or a wearisome mono- 
 tonous vegetation, prevail. On the other hand, we find that where in 
 the tropics the conditions of a rich garden soil prevail, that there we 
 have the greatest profusion of forms and the most luxuriant vegetation. 
 In this way many varieties produced in the course of centuries may be- 
 come permanent forms, whilst the forms of a less favoured climate may 
 be only the residue of an earlier period in the history of the earth : so 
 also in higher latitudes, even at the poles, the peculiarities of the atmo- 
 sphere may produce conditions which are now only found under the 
 tropics. 
 
EXTERNAL CONDITIONS OF ABSORPTION, ETC. 
 
 513 
 
 The power possessed by the soil of becoming heated by the sun exerts 
 as much influence on the health of the plant as its power of retaining 
 gases and vapour. The warmth of the soil acts upon plants entirely 
 independently of the temperature of the air, and frequently requires to 
 be much higher, in order that plants may flourish. Unfortunately, on 
 this subject we have but few observations, and these principally relate 
 to our hothouses and tropical districts. 
 
 The following Table gives an approximation to the temperature of the 
 soil borne by plants without injury : 
 
 Place. 
 
 Temperature of 
 Soil : Centigrades. 
 
 Remarks. 
 
 Observer. 
 
 Cape of Good 
 Hope . 
 
 Egypt . . . 
 
 In the Tropics 
 France . 
 Lantao (China) 
 
 70-5 
 56-0062-25 
 52-2556-7 
 47-7550 
 45-00 
 
 In the Soil of a Garden 
 Water in Rice-Fields 
 
 J. Herschell. 
 Edwards and Collin. 
 Humboldt. 
 Arago. 
 Meyen. 
 
 The following interesting Table I have taken from Schiibler. The 
 columns A. relate to observations made by Schiibler in his own garden 
 at Tubingen, 1010 Paris feet above the level of the sea, with a southern 
 aspect, and at mid-day, between the hours of twelve and one o'clock. 
 The columns B. give the average of daily observations made in the 
 Botanic Garden at Gent in 1796, 1252 Paris feet above the level of 
 the sea. 
 
 
 A. 
 
 B. 
 
 Months. 
 
 AVERAGE TEMPERATURE. 
 
 AVERAGE TEMPERATURE. 
 
 
 Surface of 
 
 Air in 
 
 Surface of 
 
 3" under 
 
 4' under 
 
 Air in 
 
 
 the Earth. 
 
 the Shade. 
 
 the Earth. 
 
 the Earth. 
 
 the Earth. 
 
 the Shade. 
 
 January 
 
 + 9-8 
 
 3-3 
 
 + 4-89 
 
 4- 2-88 
 
 4- 3-28 
 
 4- 2-73 
 
 February 
 
 + 24-1 
 
 4- 4-9 
 
 4- 6-10 
 
 4- 3-46 
 
 4- 2-92 
 
 4- 2-17 
 
 March 
 
 4- 30-0 
 
 4 6-5 
 
 4- 9-42 
 
 4- 4-97 
 
 4- 2-72 
 
 4- 2-71 
 
 April . 
 
 + 39-8 
 
 4- 13-2 
 
 + 20-85 
 
 4- 12-75 
 
 4- 7-25 
 
 4- 8-07 
 
 May 
 
 + 44-1 
 
 4- 15-7 
 
 -j- 21-38 
 
 4- 14-40 
 
 4- 10-05 
 
 4- 10-59 
 
 June . 
 
 + 47-9 
 
 4- 19-2 
 
 4- 25-48 
 
 4- 18-49 
 
 4- 13-11 
 
 4- 12-85 
 
 July . 
 
 4- 50-8 
 
 + 21-9 
 
 4- 27-30 
 
 + 18-37 
 
 4- 14-59 
 
 4- 13-86 
 
 August 
 
 4- 43-6 
 
 + 16 4 
 
 4- 28-44 
 
 4- 19-95 
 
 4- 16-27 
 
 4- 15-01 
 
 September . 
 
 4- 39-0 
 
 4- 16-0 
 
 4 22-55 
 
 4- 16-98 
 
 4- 15-16 
 
 4- 13-49 
 
 October 
 
 4- 21-7 
 
 4- 4-8 
 
 + 12-36 
 
 4- 9-93 
 
 4- 11-90 
 
 4- 8-81 
 
 November . 
 
 + 18-1 
 
 4- 3-6 
 
 4- 6-79 
 
 4- 5-18 
 
 4- 7-51 
 
 4 4-23 
 
 December 
 
 4- 12-1 
 
 4- 1-6 
 
 4- 1-44 
 
 4- 0-57 
 
 4- 3-09 
 
 4- 0-03 
 
 Mean 
 
 4- 31-75 
 
 4- 10-04 
 
 + 15-58 
 
 4- 10-58 
 
 4- 9-03 
 
 4- 7-87* 
 
 On the 16th of June, 1828, a thermometer in the soil during a west 
 wind rose to the temperature 54 R., whilst that of the air was 20-5. 
 
 This condition of the earth must influence plants according to their 
 specific nature, and produce many peculiarities in the distribution of 
 plants upon the surface of the earth. The limitation of plants to a larger 
 
 * The temperatures here are apparently marked according to Reaumur's scale. TRANS. 
 
 L L 
 
514 ORGANOLOGY. 
 
 or smaller district may frequently have its origin in the facility with 
 which the soil may be heated. A well-known expression amongst 
 gardeners and farmers for a certain injurious peculiarity of the soil is 
 "cold" ("kaltgrundig"). The colour of the earth has a considerable 
 influence on its power of absorbing heat. In Graziosa, one of the 
 Canary Islands, Humboldt found close together some basaltic sands, 
 which were coloured white and black ; whilst the first had a temperature 
 of 40 C., the last reached 54-2 C. In the experiments of Schiibler, 
 a mixture of various kinds of earth, in an atmosphere of 20 R., when 
 covered with a white surface, afforded a temperature of from 33 
 to 34-8 R., and when with a black one, from 39'1 to 41 R. The 
 same earths in their various natural colours, whilst in a dry state, 
 varied in temperature from 28-1 to 31*8 R., and in a moist state, 
 from 34*1 to 37 '9 R. From these experiments it would appear that 
 the chemical nature of the soil has but an extremely small influence 
 upon its power of absorbing heat. As the dark colour of the soil almost 
 entirely depends upon the mixture of organic matter, so we can see that 
 the humus may thus exert an important influence on vegetation, without 
 affording plants any of their nutriment. When we put together all the 
 foregoing facts, in relation to humus, with this one, we can explain the 
 strikingly favourable results of the action of humus, without in any 
 manner regarding it as a nourishing substance. 
 
 203. II. Heat, light, and electricity must be mentioned in con- 
 nection with the assimilation of the absorbed nutritive matters. 
 Without heat and light none of the important chemical processes 
 in the plant can go on. A similar statement may, perhaps, be 
 made concerning electricity ; we are here, however, without posi- 
 tive proof from experiment. 
 
 Heat has been already spoken of; and in reference to light, only 
 matters of fact should be spoken of, as an explanation of the phenomena 
 is impossible, since we are deficient in a knowledge of light, or rather 
 of the source from whence light proceeds the rays of the sun. The 
 chemical effects of the sunbeams on inorganic matter is seen in the 
 decomposition and combination of various elements, affording evidence 
 of a powerful agency, which can least of all be doubted in the organised 
 world, where isomerism, polymerism, and similar relations, make the 
 transition of one combination into another dependant on the slightest 
 collision. The facts are too evident, and too generally known, for any 
 doubt to be raised. The pale watery appearance which darkness pro- 
 duces in plants, and the quickness with which they become green by the 
 operation of light*; the great difference in the matter which is formed 
 in the plant during the presence or absence of light, as seen in the cauli- 
 flower, endive, and other cultivated plants, are well-known facts. In 
 following the analysis of the general appearances into separate chemical 
 operations we are not always very fortunate, and this is because we have 
 been satisfied with guessing at random instead of observing and investiga- 
 ting. Until recently, it was generally allowed that chlorophyll was a sub- 
 
 * During this summer I allowed some Oats to germinate under a vessel of zinc till 
 the buds were four inches long, when they appeared of a pale yellow colour. They 
 were then cut down, carefully washed, dried in blotting-paper, and then placed upon 
 white paper to be further dried in the sun. In six hours the plants were almost 
 perfectly dried, but they had all become of a green colour. 
 
MOTION OF THE SAP THROUGH PLANTS. 515 
 
 stance rich in carbon, and that the process of becoming green was an active 
 deoxidation, or fixing of the carbon. The first who investigated this sub- 
 ject was Mulder; he at once came to the conclusion that chlorophyll was 
 a substance analogous to indigo, was rich in nitrogen, and that the process 
 of greening depends on an oxidating influence. He also discovered that 
 the changes of sugar, gum, starch, &c. into wax and fatty matters in 
 the herbaceous parts of plants, furnish the oxygen for this oxidation. 
 We find, therefore, chlorophyll combined with fatty and waxy matters. 
 It is equally well-known, since De Saussure's experiments, that the 
 fixing of the carbonic acid and the excretion of the oxygen in the plant 
 are dependant on the influence of light. 
 
 I will call attention here to one point more, even at the hazard of 
 putting weapons into the hands of enthusiasts about vital power, as I am 
 persuaded that chemistry will not long leave the question unexplained. 
 Throughout the vegetable world we find the development of colours 
 depending on the action of light, and still, with few exceptions (perhaps 
 indigo and some resinous colouring matters), the colouring matter of plants, 
 after having been once developed, fades on being continuously exposed 
 to strong light, especially if the colouring matter be separated from the 
 entire plant. Thus chlorophyll and many of the colouring matters most 
 intense in colour, chiefly reds and blues, instantly fade on being exposed 
 to the light, as soon as they are separated from the plant. 
 
 Of the influence of electricity I shall say nothing, because as yet we 
 know nothing. 
 
 V. Motion of the Sap through Plants. 
 
 204. All plants, from mosses upwards, distribute the absorbed 
 fluid, by endosmosis from cell to cell, through the whole plant. 
 Where there is the greatest evaporation, there is the greatest con- 
 centration of sap ; where there is the greatest activity, through 
 perhaps the change of thinner into thicker matter, there is the 
 greatest endosmotic power. Hence the greatest stream of sap is 
 directed to the green parts and the buds. This distribution or 
 absorption is uniform in all tropical plants which vegetate con- 
 tinuously. With plants of other climates it varies periodically, 
 according to the season. A point of time at length occurs when, 
 in consequence of meteorological changes, the chemical activity and 
 evaporation, as also the distribution and absorption of fluids, is 
 almost entirely suspended. On the approach of a genial season 
 they are again active. In what way the chemical activity, exhala- 
 tion, and consequently absorption, is put in motion, in the torrid 
 zone at the approach of rain, in the temperate zone at the approach 
 of spring, is yet unknown to us. Yet in the temperate zone heat, 
 and in the torrid zone moisture, appear to have the greatest share 
 in the process. We must conclude, therefore, that they are the 
 two principal conditions of the chemical processes. Even the 
 phenomena of their renewal of vital activity are only known to us 
 superficially. We only know thus much, that a great quantity 
 of fluid is drawn up with great power, that the starch already 
 
 I. I. 2 
 
516 ORGANOLOGY. 
 
 existing in the plant is changed into sugar and gum, and that with 
 that change the development of the new leaves and buds takes 
 place. In perennial dicotyledonous trees, it is followed by the 
 formation of the new yearly rings. How the single cells assimilate 
 their own sap, is only very generally determined in each species of 
 plants : in the light, they form much mucus, chlorophyll, and bitter 
 extractive (tannic acid) ; excluded from light, more gum, starch, 
 and sugar. Definite compounds, according to the specific variety 
 of the cells, and always as simple matters (volatile oils, fixed oils, 
 gum, and jelly), are discharged into the intercellular passages, 
 and form the very different kinds of milky juice seen in the milk- 
 passages and milk- vessels. The process of this inward excretion is 
 yet unknown. 
 
 Lastly, the following fact must be noticed : All the fluids in 
 particular cells (as in the pith and spiral vessels) are withdrawn, or 
 the cells (as parent cells), or masses of cells (as those of the ovule), 
 are through chemical processes dissolved, and this fluid is absorbed 
 into the general masses of sap. This process, which is yet entirely 
 unexplained, is called Resorption. 
 
 In Vegetable Physiology no part of the science is so much in its 
 infancy as the study of the motion of the sap, because of the aimless 
 and unsuitable experiments and analogies with which unhappy caprice 
 has retarded the progress of the science for a century and a half. The 
 oldest unprejudiced observers, Malpighi, Grew, &c., furnished with the 
 necessary physical knowledge, observed that the spiral and porous vessels 
 only contained air, and named the former trachece. Then came, at the 
 beginning of the last century, Magnol, with the unlucky idea of putting 
 parts of plants which had been cut off into coloured fluids, and there- 
 from drawing conclusions. That parts of plants which have been cut 
 offtake up fluid in their spiral and porous vessels, was made the founda- 
 tion for all the idle theories that have been broached concerning the 
 circulation of the sap in plants, and for the false analogies proposed 
 between them and the higher animals. This resulted in the drawing up 
 of a complete account of the motion of the sap, which had no foundation 
 but in the imagination of its authors. The crude sap was conveyed by 
 the woody bundles up into the leaves, where it was assimilated, and from 
 thence was carried downwards into the bark, in order that the cambium 
 might be separated, and the elongation of the roots effected. It is 
 grievous to pass through the history and literature of the science, and to 
 see with what nonsensical absurdity men spun in their heads fancies, 
 which they endeavoured to prove to be actual facts. The greater part 
 of this error depends on an almost entire neglect of fundamental 
 microscopic investigation. But in recent times, with improved instru- 
 ments and methods of investigation, prejudice is decreasing, and our 
 efforts are encouraged and not overpowered. The most remarkable 
 example of the kind is Treviranus : in his chapter on the vessels he 
 says, most justly, "I have never, on examining the vessels immediately 
 after their separation from the woody bundles, perceived in them any 
 thing but air." He next gives the accurate observations of others, 
 the striking testimony of Bernhardi and Bischoff, to the same facts : 
 he appeals to the evidence of those whose only wish is to investigate 
 cautiously. When speaking of the motion of the sap he, however, 
 
MOTION OF THE SAP THROUGH PLANTS. 517 
 
 almost entirely forgets the result of his own observations, and speaks 
 of it as taking place in the vessels, as if it were unnecessary to bring 
 forward proof of the fact. Link* evidently intends to bring forward 
 some testimony which will be found nearly approaching to the truth, 
 but he twice changes his views with regard to the contents of the 
 vessels ; I think, however, that he puts forth his views without having 
 studied the subject sufficiently. A very clever observer, who bestowed 
 eight days in the summer upon two hundred plants, in order to inquire 
 into this subject completely, convinced himself of the fact, that plants 
 in their perfectly formed spiral and porous vessels contain air only; 
 therefore, when quickly brought under water and examined, they 
 always appear dark. This holds good of our annual and perennial 
 plants, and of the tropical ones, at least in our hothouses. The repe- 
 tition of these experiments will convince every one, that no change 
 of seasons, or time of day, brings about any alteration in this fact, 
 except perhaps in some perennial dicotyledonous trees of our own 
 climate during some weeks of the spring, and under especial and 
 unnatural circumstances. Should this fact be once fully established, 
 there is no further place for what the botanists in general say about 
 the motion of sap, and a new course must be sought out. In what 
 follows I divide the subject into two parts: first, the question con- 
 cerning the absorption of the sap ; and, secondly, the course which the 
 sap takes through the plant. 
 
 On the subject of the absorption of the sap, people have used the 
 unmeaning phrases, vital activity of the plant, vital attraction of the 
 sap through the vessels, &c. Dutrochet first noticed the phenomenon of 
 endosmosis, which gives a satisfactory explanation of the matter: no other 
 explanation has at present been given. The conditions of the existence 
 of endosmosis, namely, a fluid containing in solution gum, sugar, or 
 albuminous (mucous) substances, separated from the water of the soil, 
 impregnated with small particles of foreign substances, by membranes 
 easily penetrated, are found to exist in all plants ; so that, in order to 
 ascertain the force with which the sap rises in the plant, it is necessary 
 to observe carefully the process of the endosmosis. A solution of sugar 
 of IHOsp. gr., according to Dutrochet, caused the quicksilver in an 
 endosmotic apparatus, during two days, to rise 45" 9'", exhibiting a 
 pressure two and a half times greater than that of the atmosphere. In 
 all the experiments of Hales, Meyen, Mirbel, &c. on the vine, the quick- 
 silver never rose in so short a time above 15". If it even be allowed 
 that the sap ascends in the vessels as continuous tubes, there yet remains 
 a superabundance of power for the endosmose. This is, however, not 
 the case, and the endosmotic action is only exerted from cell to cell. 
 In this manner the pressure of the fluid above upon the universally dif- 
 fused endosmotic membranes is reduced to a minimum; and in the second 
 place, it is not probable that its collective effect is thereby increased : 
 but on this subject we have no experiments. There is here, however, 
 a great range of problems to solve, as, besides the various endosmotic 
 experiments in relation to the action of different kinds of endosmosis 
 one upon another, there is the consideration of its effects observed in 
 living plants, especially with regard to the contents of the cells, their 
 specific gravity, their elementary constitution at different heights in the 
 plant, &c. All this occurs in the rising of the spring sap in the trees of 
 
 ' Wiegmann's Archiv, 1841, vol. ii. p. 278. 
 
 L L 3 
 
518 OKGANOLOGY. 
 
 our climate. At all other seasons, and in other plants, endosmosis is 
 assisted by evaporation through the leaves, and it is very probable that the 
 passage of sap at these seasons of evaporation is stronger and quicker 
 than that in the spring. Although much has been said on the subject, yet 
 useful observations fail us. With regard to tropical plants, cultivated 
 artificially in hothouses, they do not offer information of a kind that can 
 be safely relied on. Many twining plants of the tropics, when cut 
 through, allow much sap to exude, and Meyen therefore thinks that they 
 are always to be found in the condition of our forest trees in the spring. 
 I think that such an opinion is without foundation, and I wish that our 
 governments, instead of sending out mere collectors of species, would 
 send out some with the necessary authority and proper instruments 
 into those countries where these phenomena are to be observed. 
 
 The second question is concerning the course of the sap in plants. 
 The facts are as follow: The so-called vessels in most plants never 
 convey sap ; and with others it is probable that they convey it only 
 during a few weeks while the new buds are forming : where the greatest 
 consumption of sap is going on, the vessels of the part are not found to 
 contain it. In many important organs, where the vital processes of 
 vegetation go on, and formative energy is present, as, for example, in 
 the stamens and ovules, there are scarcely any vessels : large masses of 
 parenchyma, in which thousands of cells lie close together, actively 
 vegetating, contain no vessels : five great families of plants, namely, 
 Algae, Lichens, Fungi, Mosses, and Liverworts, have no trace of vessels ; 
 and amongst other plants several species have no vessels. After such 
 premises, unprejudiced observers will hardly assume the motion of the 
 sap through the vessels, or draw conclusions upon such a presumption. 
 Nothing is more certain than that in most cases the nutritive fluid which 
 the single cells need, must be taken up from other cells ; and it is super- 
 fluous to imagine another mode of conduct of the sap for less frequent 
 and less important cases. On the significance of the vessels, and the 
 bundles of vessels, I have before spoken ( 34.); and the conditions 
 which they present, their origin and their form, appear to leave no doubt 
 that they are the effect, and not the cause, of a living movement of the 
 sap in a fixed direction. Where there is a considerable formative pro- 
 cess and great chemical activity exhibited, the circumstances of a 
 stronger endosmosis exist, and a greater stream of sap is afforded. This 
 stream of sap acts upon the cells through which it passes agreeably to 
 the laws of cell-life. The cells become changed into lengthened cells and 
 vessels, and thus far allow the passing of the sap. For this reason vas- 
 cular bundles are seen near every bud, and especially the most active 
 developing terminal bud, and also near each developing leaf, &c. Where 
 chemical activity is feeble there is no such active passage of sap, which 
 shows that it exercises an important transforming influence in the cells. 
 The originating cause at work in this case is the attractive power of the 
 mixing heterogeneous fluids ; but the possibility of the motion lies in the 
 universal property of vegetable membrane of allowing fluids to pass, 
 the capacity of imbibition ( 39.). I have already given, in my treatise on 
 the Cacti, my views of this subject, and remarked that we need not seek 
 any further explanation of how the fluid passes through the membranes, 
 but rather why, in certain cases, it is held back. The reason thereof is 
 partly that one; side of the membrane is in contact with air which cannot 
 escape, and which cannot be absorbed by the fluids contained in it, and 
 partly that there are on each side of the membrane fluids which will not 
 
MOTION OF THE SAP THROUGH PLANTS. 519 
 
 mingle; as oil or resin on the .one side, which will not mingle with watery 
 fluids that may be on the other. Link (Wiegmann's Archiv, 1841) says, 
 in reference to my view of the subject, " That as the inanimate mem- 
 branes of plants resist absorption, as we daily see, so it is plain that this 
 property was originally possessed by the living membrane." This con- 
 clusion was at least rash, for we know from chemistry that there are 
 many substances that were once held dissolved in water, but which, 
 when the moisture evaporates, will not dissolve again ; so may a mem- 
 brane which, when living, was permeable to fluid, lose that power when 
 entirely dried. But it is to be regretted that Link did not pursue his 
 investigations ; as he had daily opportunities of doing so, he might have 
 rendered important service to artificers in wood, who derive from che- 
 mistry their artificial varnishes and paints, by which they prevent the 
 entrance of water into wood. I daily see that wood, linen, paper, &c. 
 are penetrated through and through by fluids, that washed boards are 
 wet to a considerable depth, that wooden vessels standing in water are 
 penetrated by the fluid one quarter of an inch, that the boat-maker 
 reckons on a certain loss in sunken wood, because, when saturated with 
 water, it will lose all the air which, when swimming, it contained ; 
 hence, also, thick wood is longer in being saturated, because the air in 
 the cells is longer escaping : this is daily experience. By scientific 
 investigation we learn that vegetable membranes are as serviceable for 
 endosmotic experiments as animal ; that the starch in the cells of a slice 
 of potato kept for a week is coloured by iodine, as in the fresh potato ; 
 that if old dead wood, pith, cotton, &c. be observed through a microscope, 
 all the cells are filled with air, but as soon as a drop of water is dropped 
 upon them the air will be absorbed and the water fill the cells. In short, 
 the living and dead membranes show no difference : the former, because 
 naturally containing more fluid, will absorb more quickly than the latter, 
 which are entirely dry, and must be wetted before they absorb. All 
 this Link might have known, and should have known, when he wrote 
 upon the subject. 
 
 Yet with all this we have no evident movement of the sap in the 
 plant. The watery sap in the cells is scarcely at all compressible ; the 
 cell-walls are so little elastic, that in the coherence of the entire plant 
 they appear almost as fixed ; expansion and contraction is so slight, that 
 no observation gives us any intimation of it. It is quite different in 
 animals, where, in the elasticity of the walls of the vessels and the mo- 
 tility of the contiguous soft parts, the conditions are afforded of locally 
 or generally emptying or filling them. Fluid cannot, therefore, enter a 
 cell (and consequently a plant) before room has been made for it by the 
 escape of the fluid before contained in it. As, however, all cells are 
 filled with fluid, evaporation alone can empty them. In the most im- 
 portant sense, therefore, is the motion of the sap in plants, as well as its 
 presence, quantity, and direction, entirely dependant on evaporation. 
 The greatest quantity of sap flows in the direction in which there is the 
 greatest evaporation, which is constantly to the leaves and youngest 
 parts. The motion of the sap, therefore, must be strongest where the 
 plant has most evaporating organs : it is strongest in summer, because 
 there is most evaporation ; weakest in winter, because there is least. 
 Together with evaporation is another condition (chemical change), which 
 is, however, but imperfectly explained. By the change of the sap into 
 solid or fluid compounds, the specific gravity will be generally increased ; 
 and by the diminution of volume room is made for the entrance of more 
 
 t x 4 
 
520 ORGANOLOGY. 
 
 fluid. If, however, we observe the processes going forward at any par- 
 ticular instant during the whole time of vegetation, it will be easily seen 
 how inconsiderable is the chemical process in the plant in comparison 
 with the strong evaporation which is constantly carried forward. Eva- 
 poration assists endosmosis by means of suction. Little has been ascer- 
 tained by botanists respecting this important question, because it is much 
 easier to dream about a system at random than to observe, investigate, 
 and experiment. 
 
 To the mind of a correct observer there can be no doubt that the fluid 
 is not distributed regularly and normally through the vessels. A stand- 
 ing fact yet remains, which has puzzled most incorrect observers, namely, 
 the spring sap. Most observations concerning the motion of the sap 
 have been carried on in the spring on the grape-vine, and observers 
 have pursued these experiments without considering plants in general. 
 This is a perverted way of making observations. I am almost per- 
 suaded it will shortly be discovered that the spring sap, in the commonly 
 received sense of the term, does not exist at all. In the mean time 
 I would make the following observations: It is generally known that 
 if the branches of different woody plants, as Vines, Birches, Forest 
 Beeches, &c. are cut, or if their stems are pierced in the spring, a large 
 quantity of fluid escapes from the part with a power which corresponds, 
 as in the vine, to the-pressure of more than two atmospheres. If the sap 
 flows in a continuous stream, such a pressure (at least in vines whose old 
 stems have vessels sometimes 0'3 m. m. (millimetre*) in diameter) must 
 cause it to spirt out in a stream, which it never does ; and this fact is en- 
 tirely opposed to the idea of the motion of the sap in vessels. In the next 
 place, the question is certainly to be answered, Can we draw a general 
 conclusion from the injured plant to the uninjured vegetating normal 
 one ? Plants which are not cut in the spring, as vines, never allow a 
 drop of fluid to escape ; they cover themselves with leaves neither earlier 
 nor later than those which are cut, as I this year observed, and as has 
 been observed by Mr. Baumann, a botanical gardener of great experience. 
 A vine-branch which measured O01 1 m. (metre*) in diameter, and ex- 
 tended in length along the ground 1'446 m., with an almost horizontal ele- 
 vation from the soil of about 0*2 m, delivered between 1 1 A.M. of the 25th 
 of April f , and 5 P M of the 2d of May, 4550 C. Cent, (cubic centimetre*) 
 of sap ; therefore for the hour 30-33 CC. It was united with a glass tube 
 by an India-rubber band, which was fastened into an alembic by a cork ; 
 another tube, drawn out fine at both ends, also went through the cork, and 
 by this means possibly served to lessen the evaporation without making the 
 escape of the air from the alembic impossible. With another branch B. 
 (2'396 m. long and 0*10 m. thick, with a similar direction), I tied up the 
 alembic with only an India-rubber gutter, somewhat open above, so that 
 the air had free entrance to the cut surface. This branch gave out, 
 during the first six hours, less sap than the other, and ceased to bleed 
 much earlier. In the whole, I received from it 3220 CC., therefore for 
 the hour 21 '406 CC. of sap. That so great a stream of sap cannot have 
 place in the uncut and naturally growing plant, is shown by the fact that 
 such a mass of fluid can in no way escape through the dry and air-filled 
 bark. I must say that I have not been able to convince myself of the 
 
 * A millimetre is '03937 Eng. inch ; and a metre is 39-3710 inches, and a centimetre 
 -39371 inch TRANS. 
 
 f On the 10th and J 1th of April, in the same garden, the vine, in a favourable situa- 
 tion, had begun to blossom, and ceased on the 2d and 3cl of May. 
 
MOTION OF THE SAP THROUGH PLANTS. 521 
 
 presence of sap in the vessels of cut and bleeding branches ; but granting 
 they contain sap for a short time, yet, as it appeared to the latest and 
 strictest observer, E. Briike (Poggendorff 's Ann. 1844), the sap passes 
 only passively out of the neighbouring cells into the vessels. But can it 
 be thus in the uninjured plant ? I think not ; for before the sap begins 
 to ascend all the vessels are filled with air. What becomes of the air ? 
 Briike says it escapes or is absorbed. Does it escape through the cica- 
 trices of the leaves ? But the cicatrices do not bleed ; and it seems more 
 than improbable that they should allow of an escape of air, for under a 
 pressure of 2 atmospheres they resist the escape of a fluid of the 
 density of distilled water. That it is absorbed, is not less improbable. 
 The air in vessels is rich in oxygen (Bischoff). In the Vine (not in- 
 cluding the pith, which is filled with air) it is certain that the volume of 
 vessels is equal to the volume of fluid in the cells. Pure water absorbed 
 only 6'5 vol. per cent, of oxygen, and of nitrogen 4*2 vol. per cent. ; fluids 
 which hold in solution sugar, gum, &c., yet smaller quantities (Saussure). 
 It is impossible, therefore, that the air contained in some vessels can 
 be absorbed by the fluids contained in others. By the most careful 
 observation, I have found uncut vines to contain only air in their vessels. 
 I believe that I have now made it out to be at least probable, if not 
 entirely proved, that the effects produced upon plants that have been cut 
 or pierced in the spring are only pathological phenomena, and that con- 
 clusions from them cannot be drawn for uninjured vegetating plants: 
 this, at least, appears to me, at all events after what has gone before, to 
 be very near the truth. It is very probable that there may not exist any 
 other than a rapid stream of spring sap in the uninjured plant, but it is 
 certainly much more inconsiderable than the summer stream. A mid- 
 dling-sized sun-flower receives daily more than a pound of water (Hales). 
 Its leaves have not certainly half the superficies which the leaves of the 
 vine-branch had, on which I made my experiment in the summer. These 
 branches gave out in the spring, at the time of their greatest bleeding, 
 almost 189'48 CC., therefore about 0'508 Ib. p Now^in summer, according 
 to all correct observers, the vessels are filled with air, while at the same 
 time the stream of sap is doubly stronger than when the cut vessels are 
 bleeding in the spring, and consequently every possible condition of a 
 normal motion of the sap in the vessels fails. The phenomenon of the 
 assumed spring sap has misled observers. 
 
 The power with which, according to Hales and others, the fluid is 
 poured from the cut branch exists also in the uninjured plant only as an 
 endosmotic expansion of the extremity of the root, and is very probably 
 greater in the spring than in the summer, because in the summer the sap 
 in the cells is less concentrated, and contains less of the fluids of the soil, 
 and plants at that season vary more in density than in the spring. If the 
 stream of sap is more considerable in the summer than at other times of 
 the year, the cause is that the evaporation is then larger in amount, thus 
 creating space for the stream, and then absorbing it. 
 
 Now, after these preliminary observations, we must keep the following 
 points in view : 
 
 1. That as no vessels with continuous tubes exist in the plant, for 
 absorbing and conveying fluid, so the possibility of the motion of the sap 
 rests on the penetrability of the cellular membranes by fluids. 
 
 2. The moving power which effects the entrance of the sap into the 
 plant, and into each single cell, is endosmosis, assisted by absorption in 
 consequence of evaporation. 
 
522 ORGANOLOGY. 
 
 3. The principle of the activity of the sap-stream in plants is principally 
 found in evaporation, and perhaps, in a slight degree, in the chemical 
 processes, through which a voluminous fluid is reduced to a smaller 
 quantity of solid matter. 
 
 4. Evaporation and the chemical process often determine the direction 
 of the sap-stream. New fluid is drawn up only into those parts where the 
 already existing fluids evaporate, or are subject to chemical changes. 
 
 5. There is no reason for supposing that there is a returning stream of 
 sap, since cells that are already full can receive no more. 
 
 6. A stream of sap passes from the absorbing cells to those where the 
 greatest chemical activity and the greatest evaporation is going on, and 
 both of these are found united together in the youngest and extreme points 
 of most Phanerogamia. 
 
 7. Annual plants wither from below upwards ; perennial plants of 
 our climate, in the chemical inactivity of winter, die also first from below ; 
 the motion of the sap of both, or, at least, of the active stream of the 
 summer period, is terminated in such a manner, that the surplus sap 
 retires into the youngest and extreme points, and from thence escapes. 
 Annual plants carry naturally all their soluble matter into these external 
 evaporating parts ; consequently, a cultivated land will exhaust the soil 
 more when the herbage is cut ripe, or nearly so, than when cut green, 
 because in the latter case more than half the substances remain on the 
 fields with the stubble. Not only have the ripe plants taken up from the 
 soil double as much in their long period of vegetation, but the most im- 
 portant matters, alkalies and soluble phosphates, are not equally distributed 
 in the plant, but are accumulated in those parts carried away at the 
 harvest. 
 
 Each cell now assimilates the sap, which is a longer or shorter time 
 entering, according to the nature of the cells, that is to say, according to 
 the chemical process, which is regulated by their first origin ; and each 
 must give out again as much of its contents as it has taken up by endos- 
 mosis from other cells. The absorbed fluid is distributed through the 
 whole plant as it is required, that is to say, according to the demands of 
 the individual chemical processes. As water is continually exhaled by 
 plants in proportion to the dryness, motion, and warmth of the air, so the 
 sap becomes concentrated, and thus interrupts the endosmotic process 
 towards the other cells ; this action is continued naturally downwards 
 towards the root, by which new watery and unassimilated fluids are 
 absorbed. If this stream of crude sap is artificially interrupted in its 
 course from below upwards, the sap in the upper part becomes more 
 concentrated, and its organising power increased. This is the simple 
 fact which lies at the foundation of all those phenomena which are brought 
 forward to support the groundless hypothesis of a descending bark -sap. 
 The two most important facts upon this subject are, 1. The magic ring 
 (ringing fruit-trees), 2. The action of grafts. If from the circumference 
 of a branch or tree a ring of bark be removed, the upper part will bear 
 richer blossoms and fruit ; the latter will ripen quicker, the leaves will be 
 thrown off sooner, and the trunk will become thicker and stronger than in 
 the part below the cutting. All this is completely explained by the fore- 
 going facts, without making it in the least degree necessary to assume the 
 motion of any descending proper juice or bark-sap, which certainly does 
 not exist.* When an Apricot-graft grows from the trunk of a Plum-tree, 
 
 * The effects of ringing the bark remains the same if the branch be bent down, but 
 not if it be turned back, as the ascending sap immediately enters ; if the upper, instead 
 
MOTION OF THE SAP THBOUGH PLANTS. 523 
 
 the latter is naturally and by degrees clothed with apricot- wood*; for out of 
 the same soil an apricot-tree would merely take up the same crude sap as 
 the plum-tree ; but afterwards, in proportion as the leaves and branches 
 of the plum-tree, or of the apricot, evaporate, assimilate, &c., plum or 
 apricot-wood will remain. For these facts there is less apparent need of 
 the fabulous bark-sap than in the former case. It is, indeed, unnecessary 
 to treat of the various speculations, and on the especial motions of the 
 bark -sap, or the causes of its motion, &c. A close microscopic investi- 
 gation entirely suffices to show that in the parenchyma of the bark there 
 does not exist any general matter capable of organisation, and that in the 
 liber-cells, air, solid resinous matters, or milk-sap, are principally present. 
 Nor is it worth the trouble to investigate the copious statements concerning 
 the movements of the bark-sap, from the outer to the inner parts of the 
 trunk through the medullary rays ; nor to discuss, what is evidently so 
 imaginary, that no one has experimented thereon or can do so. It is very 
 evident, however, that the cells of the medullary rays generally have 
 contents differing from those of the parenchyma of the bark, also from 
 those of the liber. 
 
 I have already spoken of the meaning of the word "gland " with regard 
 to plants. Here we touch on a subject connected with it, namely, the 
 segregation of certain substances in an intercellular sap-passage, which in 
 two ways require further explanation : 1. By what means so large a 
 quantity of cells are destined to form gum, jelly, or oil, and to deposit them 
 in their different canals ; 2. The process of the secretion itself. It is a 
 fact, that in this case the single cells have the same relations as though 
 the walls of the intercellular spaces formed the outer surface of the plant ; 
 but the difficult point is the apparent impossibility of evaporation from 
 sap-passages surrounded by water. 
 
 The complicated relations of the milk-sap to the neighbouring cells, 
 from which it yet must be secreted, is still more doubtful to us, since we 
 do not yet know the cause of the secretion, the manner of its origin, nor 
 its relations to other cells, &c. ( 319.) 
 
 I have now to speak of resorption. The fact is well known to every 
 attentive observer, nothing needs to be added on this subject. Of the 
 cause of the taking up of the fluid, especially in the spiral vessels, we are 
 entirely ignorant. I have often used the word resorption when speaking 
 of this circumstance. Link ridicules this, because there are no resorbing 
 vessels in the plant, and thinks that I intended by this a fluidifying or 
 organic melting (Wiegrnann's Archiv, vol. ii. 1841.) ; this objection 
 brings strongly to one's mind the obscure physiological notions of the last 
 century. Coagulated blood, plastic exudations, cells, and masses of 
 cellular tissue, must, through chemical processes, have first become fluid 
 before they could be absorbed. In this process the absorbents (lymph- 
 vessels) in animal bodies take no part, neither is the idea of resorption 
 connected with them. It consists in a removal of the fluid from the place 
 where it is deposited, and an absorption into the general mass of sap. 
 Absorption cannot take place in invertebrate animals through the 
 absorbing vessels, because they do not exist. It goes on even in verte- 
 brate animals, as in the serous cavities, but not by means of the lymphatic 
 
 of the lower end is made to absorb, sufficient proof is afforded that no descending bark- 
 sap exists. These facts are frequently used to support the theory, that the existence of 
 a downward movement of the bark-sap., neither the movement nor the sap being demon- 
 strable, is not dependant on gravity, but on a living vital power. 
 * Although universally thus stated, it is not the fact ( 204.). 
 
524 ORGANOLOGY. 
 
 vessels, because the fluids are in immediate contact with cells, and can 
 therefore only be taken up immediately by them: in this imbibition 
 consists the very essence of resorption. Where the fluids are distributed 
 by a vascular system, as in vertebrate animals, this happens also to the 
 resorbed fluids ; but if the distribution of fluids takes place from cell to 
 cell in plants and invertebrate animals, so does the same take place with 
 the resorbed juices ; but this distribution of fluid is altogether distinct 
 from resorption. The term, however, I think, is perfectly admissible, and 
 without adopting it, a word would be wanting to designate a recognised 
 important process in Vegetable Physiology. In using it, there is no occa- 
 sion to think of processes going on in the animal system ; and even then 
 it is more correct than such a word as sex (sexus), or male and female, &c., 
 words without any foundation, and only expressing foregone conclusions 
 from Zoology to Botany. 
 
 E. Reproduction of Plants. 
 
 205. There are four conceivable ways in which any given 
 plant may have originated. 
 
 1. From the spontaneous meeting of pure organic matters with a 
 specifically-defined organic form. 
 
 2. From the spontaneous formation of a specifically-definite 
 organic form out of formless organic matter. 
 
 3. From the development of a separate organised (cellular) 
 formation from a definite species of plant. 
 
 4. From the development of a separate organised formation 
 (embryo in the widest sense) from a definite species of plant to a 
 plant of the same species. 
 
 The two first suppositions, the so-called primitive or first gene- 
 ration (jgeneratio originaria, spontanea, equivoca, &c.), and the third, 
 do not appear, so far as observation is concerned, to be admissible. 
 The fourth is alone correct. 
 
 The question about spontaneous generation is very imperfectly under- 
 stood, and the first and second questions are often confounded with each 
 other, which is evidently a great mistake, as a plant may certainly be pro- 
 duced from already formed organic matter, without interfering with those 
 laws of our planet which forbid the supposition of the generation of 
 organic forms from inorganic matter. No evidence can be brought for- 
 ward to show that inorganic matter, independent of an organism, can 
 produce organic matter. What is now wanting in chemistry is the 
 formation of such matters as those which are found to constitute the 
 assimilated substances of plants from the inorganic elements. 
 
 Nothing can be more groundless than the assertion, that chemistry 
 could never succeed in producing actually assimilated substances from 
 inorganic matter. But .the discussion of this possibility has been entirely 
 fruitless. 
 
 The rejection of the other two origins of plants has another foundation, 
 and relates to the understanding of that which we call a species in plants. 
 On this point disputes alone, but no philosophically accurate definitions, 
 
REPRODUCTION OF PLANTS. 525 
 
 are possible, for which we have to await further explanation on many 
 important points. 
 
 I must here return to what I have formerly said respecting the pos- 
 sibility of reproduction. The origin of every definite form is determined 
 by the matter of which it consists, and the conditions under which it is 
 formed. As the mathematical construction of the growth of forms is 
 yet unknown, we ascribe it to the formative power of the earth as the 
 unknown cause of the same, and call the complexity of the conditions, 
 under which the same form arises each time, a specific formative power. 
 
 I must here refer to what I have before developed, with regard to 
 the signification of the cell ( 14, 66.). The individual cell, if it 
 vegetates and passes through all possible stages of cell life, may be defined 
 as a vegetable form generally, yet it cannot be placed along with other 
 simple plants as a definite species, and though not subscribing to the 
 parallel drawn by Schwann between cells and crystals, yet in this ra- 
 tional exposition the possibility is pointed out, that natural science may 
 be able one day to regard the cell as the necessary form of a normal 
 condition of a permeable (assimilated organic) substance, just as the 
 crystal is a necessary form of the inorganic substance. Then would all 
 individual and simple cells originating and existing in organisms be 
 but a definite organic crystallisation, and between them and the definite 
 species of plants, that is, the collecting these organic crystals into a 
 definite form, there remains a wide step, which entitles us to regard 
 them as a class between crystals on the one side, and plants and animals 
 on the other. This would, at all events, give them another and simpler 
 morphological law, as well as plants and animals which are composed 
 of them. If we inquire further concerning the characteristic signs of 
 the conception " species " in organised beings, the following suggestions 
 occur. The law of the specification is of subjective origin ; the man- 
 ner in which our ideas and abstractions are formed, is the reason why 
 we must seek to embrace according to general signs, species, and genera as 
 the objects of our intellectual activity ; and we can never arrive at these 
 conclusions by thinking on individual beings which are intuitively appre- 
 hended by the definite limits of time and space, and known by the " here." 
 These subjective sources of the law of specification would be without sig- 
 nification for our philosophical natural knowledge, if nature did not con- 
 firm our subjective apprehension with an objective reality. This is seen 
 in the simplest form in the specification of elementary bodies, by which 
 bodies closely resembling each other are all distinguished, and through 
 the thousand possible different aspects of individual substances never 
 pass into, however near they may approach, one another. What endless 
 variety of appearances individual elements, such as pure sulphur or pure 
 carbon, exhibit, yet not a single modification of the properties of sulphur 
 or carbon varies, so that the one or the other should ever be regarded as 
 a transition to selenium or iron. In a similar manner, though certainly, 
 on account of their complicated relations in time, not yet accurately com- 
 prehended by us, we find the laws of specification in crystallisation 
 expressed. In this mathematical science lends its acute distinctions ; but 
 in organisation our comprehension fails, and only complicated inductions 
 can make the law available. And yet there, exists the unavoidable 
 necessity of the impossibility of pursuing science without these laws. 
 The individual is perishable, and consequently all which appertains to it 
 is so also. Science depends on the permanence of its objects, and upon 
 this its gradual development and actuality depends, as well as its com- 
 
526 ORGANOLOGY. 
 
 municability ; and it would cease to be science, or capable of develop- 
 ment, if it remained confined to individual men, or perished with them. 
 We must, then, in this case, devise a plan by which we may make use of 
 the previous consciousness to assist in the application of the law of 
 specification. 
 
 The most acute definition of the idea of species is the following : " To 
 one species belong all individuals which exhibit, independent of time 
 and place, and under the same circumstances, precisely the same cha- 
 racters." It is, however, in only a few instances that we are able to 
 apply this principle for the definition of a species, least of all in those or- 
 ganisms in which the conditions of existence are so multiplied and en- 
 tangled, that we can seldom entirely comprehend all, and therefore never 
 establish a perfect identity of circumstances. 
 
 We must here hold fast the importance of the history of development 
 as the principle of Botany ; only in this can we hope to find a notion of 
 the species that can, in the course of time, afford a group of constant 
 and similar characters; but this constancy must be observed in the 
 plant generally, and not in the perishing individual, and must continue 
 through many generations. Nothing can be held to be a species which 
 does not originate in an individual of the same kind ; and, therefore, 
 nothing that originates in spontaneous generation can be held as a species 
 of plant, although it may otherwise, as a natural body, find a specific 
 distinction. 
 
 The determination whether a plant is a species or not. will long 
 remain the most difficult problem in Botany. If we had the entire 
 knowledge of plants, and the laws of their morphological development, 
 at our command, we should then be able to make our distinctions upon 
 fundamental differences which necessarily flow from the idea of the 
 plant beginning from above and passing down, till, out of those known 
 laws which lie at the limits of the comprehension of the individual, we 
 arrive at the idea of the species. The solution of this question will yet 
 long remain an impossibility. Every other definition of the species pre- 
 sents endless difficulties, which proceed from the nature of the plant. 
 The independence of cell life, and the principle which lies at the basis 
 of reproduction, present especial difficulties. As cell life is independent 
 of the morphological combinations under which it appears ; so can a form 
 which is evidently only in the early stage of its development, endure for 
 a long time, because the conditions of its entire development fail, and 
 at last become very much complicated : hence this form may be found 
 in a large number of individual cases as the entirely developed plant. 
 Further, as the foundation of reproduction depends upon the capabilities 
 of such cells to develope themselves according to the same morpho-- 
 logical laws as belong to the whole plant, so may we have, in an earlier 
 stage of development, an individual cell from the mass, which, although 
 it may have the power, yet needs the circumstances to develope a perfect 
 plant, and presents a less complete form ; so that whole families of plants 
 that for a time appear essential, yet consist of unessential forms. Sup- 
 pose that caterpillars and maggots had the power of propagating them- 
 selves, and their power of developing themselves into perfect insects 
 existed under conditiops very rarely arising, would not these be cited, 
 at least for a time, as a peculiar family in Zoology ? Hence we may 
 conclude, that the growth of forms is the governing principle in the 
 vegetable world, and the invariable (essential) characters by which we 
 define classes are necessarily of a morphological nature. But the em- 
 
REPRODUCTION OF PLANTS. 527 
 
 pirical apprehension of vegetable morphology is not yet completed ; a 
 morphological system of laws cannot be yet perfectly laid down ; never- 
 theless, we can alone determine, by morphological laws, what are and 
 what are not essential characters : thus we grope in the dark amidst 
 our researches. The happy grasp of genius is our only guide. Where 
 we have not long-continued observations, embracing thousands of indi- 
 viduals, as in long-cultivated plants, to lay an inductive foundation, it is 
 mere child's play to endeavour to determine what is a species, a sub- 
 species, or variety. But on such questions much time and paper have 
 been wasted. It is, however, important for the progress of science 
 that every form that presents itself, whether it be a species, a sub- 
 species, or a variety, should be described in the most accurate manner 
 possible, in order that it may assist in constituting the definitions of a 
 more advanced science. Every definition of a species must, in indi- 
 vidual cases, be without any possible application, and all disputes pur- 
 poseless, where every one must acknowledge there can be no result, 
 because we possess no laws of distinction. 
 
 It appears probable, that, with regard to single cells, they may not 
 originate by means of an organic germ, but directly out of certain organic 
 or formless matters, as the fermentation-fungus. This, then, can be re- 
 garded neither as a fungus nor as a definite species of plant, but as a 
 kind of organic crystallisation. Whether there are other forms of the same 
 kind, as the species of Protococcus, we must leave to time to develope. 
 
 This discussion was necessary for the right understanding of the 
 facts ; whether any one be pleased to call the origin of the fermentation- 
 fungus generatio equivoca or not, is very immaterial, and discussion 
 thereon would be foolish in the present condition of our knowledge. 
 There remains only the fourth mode of origin as that which can be 
 adopted for the scientific investigation of plants. 
 
 206. The self-subsistence and power of reproduction of the 
 cell is the foundation of the reproduction of plants. From this 
 power can each single living vegetating (parenchymatous) cell 
 (or group of such cells) from amongst the mass of a plant form 
 new cells, which themselves again obey the same morphological 
 laws as the original, and thus form a new plant. The real cir- 
 cumstances whereby a new cell may become self-subsistent, and 
 form itself into a new plant, are very various. There are various 
 kinds of reproduction in plants, and one in particular for the first 
 division of plants, the Angiosporce. 
 
 1. In the Angiosporce, Algae, Lichens, and Fungi, there are no 
 morphologically definite parts of the plant. The entire specific 
 formative power from which they proceed, is present and expressed 
 in each single piece. Hence these plants propagate themselves 
 by means of accidental or normal division. Each piece becomes 
 a new individual. This accidental separation is frequent in 
 Lichens (from the death or destruction of the centre), and in Alga 
 also. The normal division takes place, as far as I know, only in 
 Spirogyra *, a genus of Alyce. 
 
 2. The above general law shows itself in the conjunction of 
 
 * Wk'gmann's Archiv, 1839, vol. i. p. 28G. 
 
528 ORGANOLOGY. 
 
 various unknown favouring circumstances in many of the cells of 
 a living parenchyma (as of a leaf ), in which a self-existent deve- 
 loping process takes place, from which a new plant may arise. 
 This is observed in Malaxis paludosa *, Ornithogalum thyrsoides f, 
 Ranunculus bulbosus J, Scilla maritima , Eucomis regia ||, Hyacin- 
 thus orientalis. 1F 
 
 3. Simple living vegetating cells separate themselves from the 
 mass of the plant, as in the soredia of the Lichens ( 86.), or rising 
 upon the surface of the plant, form themselves into little bmall- 
 celled bodies, and then separate themselves from it, as in Liverworts 
 and Mosses (97, 100.), and from these cells and ceUular bodies a 
 new plant is developed. 
 
 4. In certain spots fallen or broken off leaves, when in or upon 
 damp earth, or in water, there are developed regular buds, which, 
 after the gradual destruction of the leaf, become self-existing 
 plants. Thus it happens in the divided surfaces of the leaves of 
 JEcheveria, Crassula, Citrus, &c., or in the small excrescences of 
 the leaves of Cardamine pratensis* : ' 
 
 5. After wounding the parts of plants, for example, the nerves 
 of the leaves or the stems, after peculiar internal changes, pro- 
 ducing similar conditions, buds will sometimes form on the edges 
 of the wound or on these formations, as on the cracked nerves of 
 Gesneria, on the edges of wounds in the trunks of trees, on the 
 knotty excrescences of the wood (Masern f f), on the separated 
 surfaces of the knob-shaped points of the root in Tropceolum 
 tricolorum, brachyceras, azureum, violceflorum. \\ When naturally 
 or artificially separated from the mother-plant, these buds all form 
 themselves into new plants. 
 
 6. Sometimes buds, and frequently knobs of various forms, are 
 developed on uncertain, seldom definite spots, in leaves still con- 
 nected with the plant, which, after the separation of the leaf from 
 the plant, become independent plants, as in the notches on the 
 edges of leaves in Bryophyttum calycinum ; in the upper or the 
 under side of many Aracea and Ferns, and especially frequently 
 in the angles of the nerves of the leaves. 
 
 7. In the axis of the embryo and stem-leaves, one or more buds 
 are normally formed in definite forms, which, when separated from 
 the plant, become new individuals. 
 
 * Henslow, Annales des Sc. Nat. vol. xxi. p. 103. [Cambr. Phil. Trans, vol. v. part i.] 
 
 f Poiteau, Ann. d. Sc. Nat. vol. xxv. p. 21. 
 
 } Dutrochet, Nouv. Ann. du Musee, 1835. p. 165; also Meyen, Physiologic, 
 vol. iii. p. 47. 
 
 Guettard, Mem. s. diff. p. d. Sc. vol. i. p. 99; also Treviranus, Physiol. vol. ii. p. 624. 
 
 || Hedwig, Kl. Abh. vol. ii. p. 128; also Treviranus, op. cit. 
 
 IT Meyen, loc. cit. 
 
 ** Cassini, Journal de Physique, vol. Ixxxii. p. 408. Miinter, Bot. Zeitung, 1845. 
 
 ff We have no common name for these growths, which Dutrochet calls embryo-buds 
 (Lindley, Introduction to Botany. 3d edit. p. 79.), and which 1 have called abortive 
 branches (Annals of Nat. Hist. vol. v. ). TRANS. 
 
 JJ Munter, Bot. Zeitung, 1845. 
 
REPRODUCTION OF PLANTS. 529 
 
 8. All plants form, in a normal manner, in morphologically dis- 
 tinct organs, cells, which are to become new and independent 
 individuals. They are seen in the three forms of the process of 
 development in the Cryptogamia, JKhizocarpece, and Phanerogamia, 
 in which the reproductive cells are the spores and pollen granules. 
 
 The eight preceding kinds of reproduction resolve themselves 
 into four classes: 1. Reproduction through corporeal division, and 
 only occurring in the Angiospora (1.); 2. That peculiar to the 
 Angiosporce and rootless Gymnosporce, that is, reproduction by 
 single parenchyma cells (3.); 3. That of Gymnosporce, proceed- 
 ing from the formation of buds alone (2. 4. 5. 6. 7. 134.); 
 4. That which occurs in all plants presenting the formation of 
 reproductive cells (8.). 
 
 If we maintain what has been said upon the reproduction of individual 
 cells and the process of growth, it results therefrom that every mass of 
 cellular tissue, under whatever form it presents itself, as also the entire 
 plant, has its origin in an individual cell, through whose reproduction 
 through many generations the cellular tissue is produced, and we have 
 to determine for the various species in what relations the individual cells 
 stand to the whole plant, and what circumstances it requires in order to 
 develope a new individual. The less a plant exhibits morphologically 
 definite forms, the less circumscribed is the formative tendency which 
 holds the cells together in the entire plant ; in consequence, the cell-life 
 will be more independent, and the formative power will be more easily 
 communicated to individual cells, which, as the result of their multipli- 
 cation, are arranged in the loose outlines of the parent -plant. Whilst, on 
 the other hand, the more powerful the formative tendency is towards 
 the independence of the elementary organs, the more manifold and pe- 
 culiar are the forms in which the specific characters of a plant are dis- 
 played, and consequently more intense and permanent must the influence 
 be which the entire plant exerts upon individual cells and their develop- 
 ment into new plants : hence these remain perfectly under the dominion 
 of the same formative tendency, and are a true impression of its type. 
 Therefore, in the simplest plants, as the Protococcus viridis, which only 
 in their elementary organs can be regarded as a species, every formation 
 of a new cell is an act of reproduction, and the new cell requires, in 
 order for the species to remain true, nothing more than the unencum- 
 bered development of the universal cell life. In the constantly inde- 
 finite forms of the Angiosporce (in which, however, the individual life 
 of the cell is brought under an unvarying formative energy), reproduc- 
 tion is divided into two kinds, one from the mass of the cells, the other 
 from a single cell, each originating under a definite form of the processes 
 of formation, and serving exclusively and necessarily for reproduction. 
 We find a continuous series from the almost entire identity of both pro- 
 cesses (in the formation of a special cell) in the simplest Algce, even to 
 one of the customary reproduction of the cell through the peculiar 
 phenomena of essentially varied generation of the definite reproductive 
 cells in the Lichens. In the Mosses and Liverworts, the formative ten- 
 dency exhibits a more strict and limited conformity to law, as is seen in 
 the presence of an axis and leaves, and in the more complicated forms 
 of the remaining organs. Here ceases the first kind of reproduction, in 
 which a single cell, withdrawn from the mass constituting the individu- 
 al M 
 
530 ORGANOLOGY. 
 
 ality of the whole plant, is able to produce a new plant. The isolated 
 cell must first stand in relation with the parent plant, and come under 
 the dominion of its specific formative tendency up to a certain point, 
 before it can be placed in circumstances to introduce the same law of 
 formative tendency into a new independent life. It is formed into a 
 little cellular corpuscle which is separated from the parent plant, as in 
 Mnium androgynum, Marchantia po/ymorpha, &c. From this point 
 and upwards ceases in the vegetable world the process of reproduction 
 through the separation of cells, and in its place commences the forma- 
 tion of buds. And here we arrive at an entirely unoccupied void in our 
 researches, which is filled up with mere hypothesis. Analogy allows 
 us the following conjectures : A parenchymatous cell, through the 
 growth of new cells, without becoming isolated upon the surface of the 
 plant, becomes the occasion of the origin of a mass of cellular tissue, 
 which is in close union with the plant, and scarcely to be distinguished 
 from the surrounding parenchyma, but at the same time it already re- 
 presents a special individuality, but as it originates entirely under the 
 influence of the specific formative tendency of the whole plant, it sub- 
 sequently becomes essentially independent of the parent plant, forms 
 the foundation of a plant with axis and leaf in a word, becomes a bud. 
 To what parts of the plant the first cell belonged is indifferent; and ac- 
 cording to all possible varieties are the circumstances various which 
 determine the development of the cell to the plant. In the axis of the 
 leaves these circumstances are always normally present, at the basis of 
 the leaves frequently, on the surface of the leaves and the ligneous axis 
 seldom, less frequent still on the herbaceous (annual) axis, and least 
 frequent of all on the parts of the flower. At the present we have no 
 accurate researches upon the formative processes which precede the 
 elevation of the bud upon the surface of the plant, and it would be only 
 through an accurate knowledge of the same that we should be in a 
 position to determine whether the facts are as I have above conjecturally 
 stated or otherwise. 
 
 We must now follow another series, the development of the definite 
 reproductive cells (spores and pollen-grains) which are normally formed 
 for the development of the new plant. In the simplest Algce, as before 
 remarked, this process is scarcely to be distinguished. In the simplest 
 way a plant cell forms a filial cell (Brut-zelle), which after the destruc- 
 tion of its parent cell becomes isolated, and is developed into a new 
 plant. In the remaining Angiosporce, the process of growth in the re- 
 productive is connected with a peculiar law, which exerts a special 
 influence upon its nature. In the Lichens are first seen definite indi- 
 cations of a peculiar layer of separation which surrounds the repro- 
 ductive cells, and it is not improbable that it may preserve them from 
 those external agents which, upon the form of the process of develop- 
 ment, could exert any influence. In this also a new circumstance is seen, 
 which is afterwards found in all classes with the exception of plants 
 flowering under water. In the Rhizocarpece, however, the reproduc- 
 tive cell (spore), without further development, proceeds from the mass 
 of the plant and forms a new individual ; but from the Mosses upwards 
 we find that the origin of the same is connected with a definite morpholo- 
 gical law, and constantly originates in a determinate independence of the 
 specific formative tendency, and is exclusively connected with the form- 
 ation of the leaf. But in the Rhizocarpece a new stage sets in, not 
 only the formation of the reproductive cell, but the first development 
 
REPRODUCTION OF PLANTS. 531 
 
 of it under the influence of the parent plant and its specific formative 
 tendency. Of this we have two phases in the Rhizocarpece and Pha- 
 nerogamia : in the first, the influence exerted upon the development of 
 the pollen is mediate, as the seed-bud (ovule) is separated from the 
 parent plant ; in the Phanerogamia, on the other hand, it remains in 
 living union, whereby the developing new plant continues longer and 
 more entirely independent of the specific formative tendency of the 
 parent plant. Thus we see how the specific formative tendency encloses 
 the organism within constantly narrower limits of law, and also how 
 the circumstances of the parent plant under which the reproductive cell 
 must develope become more complicated, and thus communicate to it a 
 similar morphological development, and make it, as a new individual, 
 to represent the same formative tendencies as the parent plant. 
 
 In the paragraph I have arranged the various modes of increase 
 of plants, according to the most general point of view, under four heads. 
 These may be subordinated again as follows : 
 
 A. Immediately that every part of a plant is formed according to one 
 and the same principle of development, every part of the entire plant is 
 capable, through simple division of the plant, of producing a new inde- 
 pendent individual. This is increase of plants by division. 
 
 B. But if in the plant the law of development exhibits an essentially 
 different kind of phenomenon, so that a part of a plant is not developed 
 into the entire plant, but receives the impression of the entire law of 
 development, then is the growth of the whole plant from a part impossible. 
 This occurs in the simple plants among the Gymnosporce, in which the 
 axis and the leaf, as two different processes of development, belong to the 
 idea of the whole plant. In this case the plants increase in the same way 
 as an elementary part ; a single cell would increase through the special 
 properties that were communicated to it. This same process, together 
 with accidental division, is normally present in the Angiosporce ; and this 
 process, in opposition to that of division, is called reproduction, and 
 is found present in all plants. But this reproduction presents itself under 
 two phases, as we have before observed : 
 
 a. In the development of any living cell to a new individual under very 
 various circumstances = irregular reproduction, 
 
 b. In the development of a special reproductive cell, exclusively 
 developed for this purpose = regular reproduction. This divides itself 
 into two, according to the circumstances under which the reproductive 
 cell is developed : 
 
 1. The origin of the reproductive cell, independently of the parent 
 plant = asexual reproduction, as in the Cryptogamia. 
 
 2. The development of the reproductive cell to a new individual under 
 the circumstance of a material influence of the parent plant. This last 
 we call sexual reproduction ; it is present in Rhizocarpece and Phanero- 
 gamia. This, and only this, is the signification of the word sex amongst 
 plants, and all comparisons with the higher animals are lame and unscien- 
 tific. We need an expression for these conditions in the vegetable king- 
 dom, and I would, with Valentin, banish the word sex, if it were not to 
 be feared that those who are not free from ignorant prejudices would, with 
 the abandonment of the word in the one kingdom, seek to do the same in 
 the other. If we divide the word sex into two, male and female, we must, 
 according to analogy with the animals to which the words are applied, call 
 those organs female in which lie the material organised (cellular) foundation 
 which subsequently becomes the new individual. If, then, we apply the 
 
 M M 2 
 
532 ORGANOLOGY. 
 
 terms to the Rhizocarpece and the Phanerogamic we must call the vesicle 
 (sac of the embryo) which receives the pollen-grain the male, and the 
 anther the female organ. 
 
 Of the utmost importance, and a problem yet to be solved, is the perfect 
 history of the development of the bud from the individual cell, or group 
 of cells, in which it has its origin. For this purpose the axillary buds can 
 hardly be employed, as they are developed so early, that the cellular tissue 
 itself, in which they originate, would throw great difficulties in the way. 
 The buds of Bryophyllum cah/cinum and the adventitious buds of stems 
 (which may be artificially produced) seem to offer a means of solving this 
 problem by very careful research. 
 
 207. Every formative effort, especially in the organic world, 
 establishes the possibility that some characters of the individuals 
 which we regard as unessential, and yet falling under the idea of 
 species, may vary within certain limits. The determination of 
 essential and non-essential characters can only be arrived at when 
 we shall know the construction of all the processes of formation. It 
 has been heretofore supposed, that only regular reproduction could 
 bring forth the essential characters of the individual, and irregular 
 reproduction the unessential. This is entirely false ; it depends on 
 the peculiarities of individual plants, how far they are changeable 
 in their characters in general, and how far they have a tendency to 
 produce, through reproduction, unessential characters in the new 
 individual. The general rule might perhaps be thus expressed : 
 the longer and the more intimately the newly-developing plant has 
 been in connection with the parent plant, the more will the forma- 
 tive energy impress upon it both its essential and non-essential 
 characters. Hence, with reference to the several kinds of increase, 
 we come to the conclusion, that, under generally similar circum- 
 stances, plants grown by division or from buds will closely resemble 
 the parent plant in all their characters ; buds, the more closely, the 
 further their development had proceeded in connection with the 
 parent plant ; and in regular reproduction, the farther that the 
 embryo has been developed under the influence of the parent plant, 
 the more like to it will be the characters of the plant which is 
 produced from it. 
 
 Lastly, it is to be remarked, with respect to the Phanerogamia, 
 Rhizocarpece, and some Agamia provided with roots, that the bud, 
 when organically united on one side with the parent plant, never 
 developes a true root, but an adventitious root. 
 
 Physiology, and we may almost add Botany, has paid attention 
 entirely to the Phanerogamia rather than to plants in general ; the 
 remaining plants have been grievously neglected, or treated in an off- 
 hand way, according to false analogies. Hence we find in the old 
 systems that the function of reproduction has been almost exclusively 
 regarded, from the cases most easily observed, as increase by means 
 of either seeds or buds. The foregoing paragraphs will have shown 
 how unjustly circumscribed is this view. Connected with this subject, 
 we must allude to a point which even the superficial observation of the 
 seed and bud suggests. We often find it asserted, " The seed repro- 
 
REPRODUCTION OF PLANTS. 533 
 
 duces the species ; the bud the individual." The instruction of our 
 early days in the Latin and Greek languages has taught us that the 
 German philosophers understand nothing less than their own mother- 
 tongue ; and this is seen in this case. The organic increase of an indi- 
 vidual is termed growth. When by an organic process, conducted under 
 given conditions, a new individual arises from the old one, the plant has 
 been reproduced, or propagated. Species is an idea which, in the 
 abstract, cannot propagate or be propagated, reproduce or be reproduced. 
 If through reproduction one individual existence arises out of another, 
 thus the idea of species is applied explanatorily, because the concrete 
 objects are present that fall within its sphere. Link imagined that he 
 was improving upon the above, when he said, " The seed continues the 
 species, and the bud the individual." * I cannot conceive of the Creator 
 as a journalist, who issues his works leaf by leaf in continuation. Science 
 regards a tree as an aggregate of many individuals, a kind of polyp- 
 stock ; life, proceeding upon another distinctive character, calls it an 
 individual : but neither science nor life as -nyVo^h of an individual. I 
 imagine that any person of sound mind would smile if any one were to 
 regard the 2000 poplars of a German chaussee a mile in length as a 
 continuous individual ; and still less would it be admitted, that a one- 
 year-old span-long shoot of a weeping willow was essentially aeon 
 tinuation of an old individual, who, in his rapid departure from the East, 
 left his youth lying on the border of the Euphrates, where long ago it 
 died and was decomposed, whilst its commencing manhood was cherished 
 by Alexander Popef, and many years since was hewn down and cast 
 into the fire. The above facts, which the want of observation and a 
 knowledge of the mother-tongue have rendered so confused, are, that 
 from buds originate individuals, which frequently resemble the parent 
 plants in more characters than those which originate with the embryo. 
 This fact, but which in no way constitutes an accurate distinction (as 
 seen in the subordinate characters of our common garden vegetables, 
 cabbages, peas, &c., which are produced from seed), bears very naturally 
 on the species produced generally by organic reproduction. Reproduc- 
 tion is nothing else than the passing over of the specific formative 
 tendency of one individual to a new one ; and where the species is not 
 maintained, there no reproduction can take place. But the circumstances 
 under which reproduction takes place determine whether the specific 
 formative energy shall produce a larger or smaller number of characters ; 
 as a form in a condition of development, whether it consists in external 
 shape or internal process, must become more like the earlier form, the 
 longer and more exclusively its origin and development depend upon 
 those circumstances which produced and developed the first form. 
 Regular reproduction, and reproduction through single cells, consist in 
 the fact, that an organic embryo separates itself perfectly from the mass 
 of the plant and its continuity, and developes itself out of itself, so that 
 the influence which the parent plant exerts, even though it be definite 
 and assimilative, is yet always an external one, and is modified by the 
 peculiar vital power of the reproductive cell. In propagation by division 
 and bud-formation, on the other hand, the new individual, up to the 
 
 * Elem. Phil. Bot. ed. 2. vol. i. p. 133. 
 
 f All our weeping willows in Europe have proceeded from a branch, which formed 
 part of a wicker basket, which was sent from Smyrna to the poet Fope, and which he 
 planted, as it showed S'I<<;HS of life. 
 
 M M 3 
 
534 ORGANOLOGY. 
 
 moment of its separation, is in organic connection with the parent plant ; 
 its continuity is the same, and it is developed entirely under the formative 
 tendency of the parent individual, with all the accidental conditions to 
 which it is exposed. But that it can be influenced by many things 
 independent of the parent plant, is proved by many cases. The so- 
 called water-shoots (individuals developed from buds) are frequently 
 distinguished from the parent plant by an enormous development of the 
 leaves. Shoots of the oak, springing from a felled branch, are often 
 found in woods with leaves a foot long. Grafts and eyes frequently 
 become modified in their growth, and in no way possess the characters 
 of their parent plants.* 
 
 208. The various modes of reproduction are subservient in 
 nature to the increase of individuals upon the surface of the earth. 
 In many plants it is constantly present, in others it is only pro- 
 duced by extraordinary external agencies ; and hence it occurs less 
 frequently. There are many plants which produce a quantity of 
 buds in various forms ( 136.), which subsequently, through the 
 death of the parent plant, or of the connecting internodes, become 
 isolated. They are called proliferous plants. 
 
 Many horticultural operations, which have for their object some- 
 times the increase and the preservation and alteration of the plant, 
 are founded upon the formation of buds. 
 
 The formation of buds on leaves, and the natural growth of buds, 
 are both very generally used for the increase of plants. In the 
 last instance, what are called layers are formed, in which a branch, 
 whilst still attached to the parent plant, is placed in the ground, 
 and the buds are allowed to put forth adventitious roots, and is sub- 
 sequently cut away ; or the branch is at once taken away from the 
 parent plant, and allowed to put forth adventitious roots ; such 
 branches are called cuttings. 
 
 For the attainment of certain special objects in the culture of 
 plants, buds are conveyed from one individual to another. This 
 operation consists essentially in the bringing into close contact the 
 exposed, living, vegetating, and similarly constituted cellular tissue 
 of two plants, and then protecting it from external injuries till the two 
 wounded surfaces are grown together. Thus buds are translated 
 (grafted, inoculated), and are removed singly from the parent plant 
 with a piece of the bark (eyes), or young branches (grafts), and 
 are inserted upon stems (stocks) variously cut to receive them : 
 the first are inserted under a loosened portion of the bark ; the last 
 between the bark and the wood, or are placed in contact with the 
 stem, cut in a suitable manner. Another mode is, binding together 
 the cut surfaces of the branches of two plants, and separating the 
 one wished from the parent plant when the two have grown 
 together. This process is called inarching. 
 
 I insert this paragraph, without having much more to say ; for the first 
 point belongs to Special Botany, and the second belongs as little to 
 
 * Lindley, Theory of Horticulture. London, 1840. p, 220. 
 
REPRODUCTION OF PLANTS. 535 
 
 Botany as Surgery does to Zoology. On the union of two individuals, 
 however, through eyes, grafts, or inarching, I have a few words to say. 
 Independent of the care which should be taken in this operation to 
 bring in contact living cell-tissue and, as much as possible, similar tissue, 
 as wood with wood, alburnum with alburnum, cambium with cambium, 
 and to avoid the access of air, yet the success of this operation entirely 
 depends on the species of plants which are thus united. The rule is, 
 that the nearer plants stand to each other, as the varieties of a genus, 
 the more certain will be the result. Plants belonging to different natural 
 families will not unite. The exceptions are only apparent. A twig 
 will blossom and form leaves in water or moist sand, and so it will 
 in the moist tissue of another plant ; but it will not grow together with 
 the other, unless the chemical processes in both plants are similar. Did 
 we know the specific peculiarities of the chemical processes in all plants, 
 then we might a priori determine the results of such transference, and 
 need not to perform the experiment. So soon as the union is effected, 
 the nature of the future-formed cells and organs depends principally on 
 the nature of the new individual, that is to say, when it is the only 
 growing portion on the stock. Yet the stock must always exert a greater 
 or less influence on the eye or graft, as the sap brought to it must pass 
 through the cells of the stock, and become changed there. In this case 
 the relations are too complicated to enable us to offer an explanation. All 
 that is known on the subject is detailed in manuals of horticulture. I will 
 mention one case. If a branch of a quick-growing plant is grafted upon 
 a very slow-growing one, as, for instance, the branch of a plum upon a 
 sloe-stock, the graft will grow rapidly, but not so the stock, which retains 
 its slow-growing character*, a striking example of the permanency of 
 the specific life of the stock, and, as it appears to me, affording a fatal argu- 
 ment against the pretended descent of the sap. If a descending bark- 
 sap existed, the sloe-stock would be naturally covered with annual rings 
 of plum-wood from the graft, and it would grow in proportion to the 
 growth of the graft ; but this is by no means the case, for the new 
 annual rings are formed, not out of a descending bark-sap, but out of a 
 cell development of the cambium already existing in the stock, and 
 Laving essentially the same characters. The formation of new wood 
 of the nature of the graft has always been taken for granted, in 
 order to prove the descent of the bark- sap ; but we find that this wood 
 does not partake of the nature of the graft, and that it must therefore be 
 formed independently of any descending juices. 
 
 209. Peculiar relations are exhibited sometimes in the capacity 
 of plants for regular reproduction. Every simple plant, in the 
 most stringent sense of the word, is only capable of propagation 
 once ; with the unfolding of its terminal bud into reproductive 
 organs, its life is closed. But even the greatest part of the simple 
 plants, in a wide sense, whose axillary buds are exclusively de- 
 veloped into flowers, are only once capable of reproduction ; the 
 plant is so exhausted through the reproductive effort, that it dies. 
 This is the case with annual and biennial plants (plantce monocar- 
 picce). Sometimes they continue to live, and the terminal bud 
 
 * Lindk-y: A theory of Horticulture, p. 237. 
 
 M M 4 
 
536 ORGANOLOGY. 
 
 goes on developing, and is capable of producing new reproductive 
 organs, as in Ananas. In compound plants, the same takes place 
 with the single individuals of which they are composed. In this 
 case a very remarkable condition sometimes occurs ; the seed of 
 many perennial plants, originating themselves from seed, is en- 
 tirely incapable of reproducing the individual, and this power of 
 producing reproductive organs is first possessed by buds produced 
 from individuals in the tenth or more generation. 
 
 In the majority of Algce and Lichens, in which we can hardly speak 
 of a special individuality, and in which the smallest portion of the 
 whole plant represents and lives for itself, the above law finds no appli- 
 cation : on the other hand, it is more applicable to the remaining Lich- 
 ens and to the majority of Fungi, in which the whole plant seems to 
 consist of reproductive organs. In the rest of the vegetable world, it is 
 understood that the individual proceeding from a bud, if its shoot is 
 single and terminal, and is converted into reproductive organs, must die. 
 The same must take place in the simple plant, whose lateral buds are all 
 converted into flowers or flower-stalk, as soon as the terminal buds are 
 converted into flowers. If the last does not take place, it depends upon 
 specific peculiarity, whether the life of the entire individual is exhausted 
 in the formation of flowers (as in Musa, and some palms), or whether it 
 continues to grow with a terminal shoot, which frequently produces re- 
 productive organs (as in most Palms). 
 
 The most remarkable condition is that last . mentioned, which takes 
 place in most dicotyledonous trees. In this case the individuals which 
 are produced very late from the lateral buds form reproductive organs. 
 Perhaps there may be polypes placed in a similar condition, so that an 
 animal developed from an egg is not in a position to form eggs, but that 
 one of its lateral branches subsequently acquires this power. 
 
 F. Death of the entire Plant. 
 
 210. The life of the entire plant through the self-existence of 
 the elementary organs exists as such only in the morphological 
 union of the cells, and, as the plant never possesses all its organs at 
 the same time, in the history of its development. It is thus that 
 plants die immediately that there is no longer any possibility of in- 
 dividual development. If we distinguish plants into simple and 
 compound, we shall find that only in a small part of the simple 
 plant a termination of its process of development, and through this 
 alone its death is determined ; that is in the simple plant, whose 
 terminal buds are developed into reproductive organs. In some 
 other plants, it appears that, without any such development of the 
 terminal buds, the vegetative power of the plant becomes ex- 
 hausted through the development of all the axillary buds into re- 
 productive organs, flowers and flower-stalks ; but in what way we 
 know not. In all compound plants, and in many simple ones, a 
 special condition occurs in which the simple plant, as such, dies ; 
 but in one part, which is quite unable to develope new organs, it 
 
DEATH OF THE ENTIRE PLANT. 537 
 
 continues to live. This living part then maintains in a peculiar 
 manner a union amongst the new individuals (single plants), which 
 are produced by formation of buds from the first individual. This 
 is the condition of all perennial plants with root-stocks and stems. 
 Perfectly simple plants, which entirely die after having completed 
 their regular development, are extremely few. Compound plants 
 have no determinate conclusion to their life which can be called 
 death in the above sense of the word. 
 
 I have frequently pointed out in this book how irrelevant and useless all 
 analogies between the animal and vegetable kingdoms are, so soon as we 
 regard them without prejudice, and compare them, with a profound know- 
 ledge of the nature of each. This is seen in a remarkable manner in the 
 subject of the foregoing paragraph. Not a hundredth part of the vege- 
 table kingdom (the annual and biennial plants) afford the possibility of 
 any comparison between the death of plants and the majority of animals. 
 Not a thousandth part of the animal kingdom (the compound polyps) 
 permits of an analogy with the remaining plants*; and our knowledge 
 of the history of the development of these animals is most defective. 
 The life of the individual animal is dependant, both for its stimulus and 
 maintenance, in a manifold manner, upon the life of the planets [meteor- 
 ological phenomena]. But whilst external nature supports the life of 
 the animal on the one side, yet every act of maintenance is attended with 
 a wearing and resistance which gradually culminates till the maintaining 
 power is overcome, and death takes place. The conditions of death lie 
 in the organism itself of the animal. The organic elements united to an 
 independent individuality have no life for themselves, only so long as 
 they serve for the life of the entire animal, and the specific determinate 
 equilibrium of their chemical nature and physical power are maintained. 
 The destruction of this equilibrium by external nature, however, is 
 always opposed by a specific determinate vis inertice. When the event 
 occurs which produces a perfect destruction of this equilibrium, then the 
 death of the animal takes place ; at the same time, all the organic ele- 
 ments of which it is composed fall under the influence of death and de- 
 composition. 
 
 It is not so with the plant. In it each elementary organ has its own 
 independent life, and dies for itself alone, and the entire plant consists of 
 a morphological and not a physiological union of elements. Individual 
 cells may die, although they give the figure of the entire plant, and yet a 
 portion of the whole remain living ; the entire plant may die, that is, the 
 specific form in which the cells are arranged may be abolished, and yet 
 the life of the elementary organs continue, and even be in a condition to 
 produce again new individuals of the same species. The idea of the 
 whole plant, as I have in so many places pointed out, consists in a speci- 
 fically determinate process of development. Where this produces such 
 indeterminate forms as Algce, Lichens, Fungi, we cannot speak of the 
 death of the entire plant, because every individual part represents the 
 whole plant, and is capable of growth according to the same type. We 
 
 * An interesting relation between the morphology of plants and certain zoophytes 
 was established by Professor Edward Forbes, in a Paper read at the meeting of the 
 British Association for the Advancement of Science in 1 844, entitled, " On the Mor- 
 phology of the Reproductive System of Surtularian Zoophytes, and its analogy with that 
 of Flowering Plants." TRANS. 
 
538 ORGANOLOGY. 
 
 can in this case only speak of death, when all the elementary organs are 
 chemically or mechanically destroyed. On the great Fucus bank of 
 Corvo and Flores we might yet find, floating about, plants of Sargassum 
 which had been cut into strips by the bark of Columbus ; and in the 
 northern drift we might expect to discover Lichens that had been trans- 
 ported, with the soil in which they grew, from Scandinavia. On the 
 primitive rocks we may find frequently examples of Lichens which, from 
 a knowledge of their slow growth, we might regard as at least a thousand 
 years old. The majority of the Fungi, on account of the delicacy of their 
 tissue, are more easily destroyed, especially through decomposition, than 
 other plants, so that we can hardly say that they die a natural death. 
 Amongst high trees we often find the so-called magic circles, formed by 
 Boletus bovinus, B. edulis, &c., having so great a circumference that 
 the plant to which their spore-fruits (sporocarpia) belonged could not 
 be less than from ten to twenty years old, the solid Polyporus igniarius, 
 Dcedalea quercina, &c., must frequently reach an age of above a century 
 before they, Dryas-like, fall to the ground, which they do not because 
 they are dead, but because the dwelling-place with which a hard fate has 
 united them can no longer exist. 
 
 The fact is otherwise in the remaining groups of plants, which, by a 
 definite modification of the process of development, form various organs 
 essential to the idea of their existence. One of these plants can be said 
 to exist only so long as it continues to form organs necessary to the idea 
 of its existence. The occurrence of any thing to render it impossible to 
 develope itself according to its peculiar law is the death of the plant. 
 Hence the importance of the distinction earlier pointed out between 
 simple and compound plants. As the existence of the latter does not 
 depend upon the growth of an individual existence, but upon the continual 
 reproduction and formation of new individuals, we cannot speak of their 
 death, because we know of no necessity in organisms capable of repro- 
 duction that would induce in any one generation the cessation of the 
 reproductive power. There exist no observations to prove that, under 
 perfectly favourable circumstances, any tree ever died from the weakness 
 of old age. On the other hand, we have examples without number of 
 trees of prodigious age. The celebrated Castagna dei cento cavalli 
 (Castanea vescd) on .ZEtna must be a thousand years old at least. 
 The Baobab trees (Adansonia digitata) of the Green Cape demand of 
 us, according to their thickness and the number of zones in some of 
 their branches, an age of 4000 years, or thereabout. The gigantic 
 cypress (Cupressus disticha) at Santa Maria del Tule, six miles east of 
 Oaxaca, in Mexico, has a circumference of 124 Spanish feet, about 40' 
 in diameter. Now, suppose that every annual zone measured 1"', the tree 
 must be nearly 3000 years old. It is historically certain that it is older 
 than the conquest of Mexico by the Spaniards. The age of the great 
 Dragon tree (Draccena Draco) at Orotava, in Teneriffe, is supposed to 
 be 5000 years ; so that, according to the ordinary calculation of the 
 Hebrew chronology, it was a witness of the first creation. These ex- 
 amples* are quite sufficient to prove the possibility of a compound plant 
 living on without end. These plants die ordinarily in consequence of 
 mechanical injuries. A storm breaks off a branch, the broken surface is 
 exposed to the action of rain-water ; putrefaction or decay takes place, 
 the firmness of the cell-tissue of the heart-wood becomes affected ; and a 
 
 * There is a catalogue of old trees in the Appendix. 
 
DEVELOPMENT OF HEAT. 539 
 
 new storm casts the whole tree to the ground, separates the trunk from 
 the roots, and it perishes of hunger. 
 
 In all the perennial plants there is a peculiar condition to be observed 
 which is connected with reproduction, and which has before been men- 
 tioned. In the simple plant a mass of cellular tissue is formed which 
 maintains a connection between the new individuals originating in the 
 formation of buds, and thus renders possible the existence of a compound 
 plant. In this way, individuals originating from seeds remain either 
 living, and continue to grow on, as is the case in most trees, or the plant 
 dies completely down, and leaves behind it only these masses of cellular 
 tissue which, although living, are incapable of individual development, as 
 is the case in undershrubs. In trees this mass of cellular tissue is the 
 cambium of the stem ; in undershrubs it is that of the rootstock. 
 
 In the remaining (simple) plants we see thus much, that a plant whose 
 terminal bud is completely changed into reproductive organs must have 
 reached the end of its life, and cannot continue to grow. How it is that 
 death occurs in simple plants, which only develope their lateral buds into 
 flowers, is not yet understood. There is a negative explanation, which 
 is, that it depends on an exhaustion of the vital powers through the 
 development of the flowers ; but, as we have no definite conception of 
 what these particular vital powers are, we can hardly regard this as an 
 explanation. Much more must be done before we can draw correct con- 
 clusions. 
 
 I know of no book, whether on Vegetable Physiology or on Botany in 
 general, in which the question of the death of" the plant is more than 
 incidentally mentioned. Unger and Endlicher have given a chapter on 
 the subject in their " Grundziige," which was published after my own 
 observations, and contains similar remarks. 
 
 SECTION II. 
 
 SPECIAL PHENOMENA IN THE LIFE OF THE ENTIRE PLANT. 
 
 A. Development of Heat. 
 
 211. The temperature of the living plant scarcely ever cor- 
 responds with that of the surrounding atmosphere. 
 
 The following three relations have hitherto been observed : 
 
 A. Germinating seeds (ofthePhanerogamia) develope a heat which 
 considerably exceeds that of the surrounding atmosphere. This is 
 most probably owing to the process of combustion in the forma- 
 tion of carbonic acid and water during the decomposition of the 
 assimilated matters, starch, oil, &c. 
 
 B. Trees of our climate exhibit in their interior a variable tem- 
 perature, being higher in the winter and lower in the summer than 
 that of the surrounding atmosphere. These changes are always 
 strictly in accordance with the changes of the atmosphere in their 
 
540 ORGANOLOGY. 
 
 rise and fall ; if these conditions are of long duration, the tempera- 
 ture of the tree continually approximates more and more towards 
 them, without, however, entirely reaching their degree of intensity. 
 The reason of this phenomenon may, in all probability, be attri- 
 buted to the temperature of the earth at the depths to which the 
 roots extend ; the temperature is thence imparted to the stem, 
 partly by means of the rising sap, and partly also through the great 
 capacity of conducting heat possessed by the wood in its longi- 
 tudinal direction; and it is protected and preserved in the stem, 
 partly owing to the inferior conducting power possessed by the 
 wood in its transverse direction, and partly also owing to the bark, 
 which is itself a very bad conductor of heat. 
 
 C. The Aracece (in which the effect is more readily traceable, 
 owing to the number of flowers aggregated together) develope, 
 during their period of flowering, a temperature far exceeding that 
 of the surrounding atmosphere. The reason of this is also to be 
 attributed to the formation of carbonic acid (a process of combus- 
 tion), which is especially maintained by the stamens. 
 
 Respecting the subjects touched upon in this and the following para- 
 graphs of the general Organology, I must confine myself to reference to 
 the labours of others, indicating the problems that are still to be solved, 
 as I have not yet been enabled to institute observations of my own. 
 
 Every one who knows any thing of malting for the purposes of 
 brewing must be acquainted with the rise of temperature that takes 
 place during the germinating process of the plants. This fact is beyond 
 dispute ; but I am not aware of any scientific observations on the subject. 
 They ought to be instituted in such a manner as to embrace the entire 
 act of germination up to the cessation of the formation of carbonic acid ; 
 during this period the entire quantity of carbonic acid, as well as the 
 quantity formed during the individual periods, ought also to be ascer- 
 tained ; the quantity of water formed ought also to be calculated accord- 
 ing to the well-known composition of the starch, and the temperature gene- 
 rated from both through the chemical changes should be determined, arid 
 be compared with the temperature observed. 
 
 Observations respecting the temperature of trees were first insti- 
 tuted by John Hunter, subsequently repeated by many with different 
 results ; and animated controversies were carried on upon the subject, of 
 which Meyen* gives an elaborate account. 
 
 All former investigations, however, appear to me to be superfluous 
 after the observations of Schliblerf, the first that were accurate and insti- 
 tuted in a scientific spirit. These researches resulted in the law enun- 
 ciated in the text. The derivation of it from the temperature of the 
 earth is still hypothetical, and accurate observations on certain plants, 
 with simultaneous observations on the temperature of the earth at about 
 the depth of the roots, are much to be desired. It becomes however very 
 probable, after the known facts of the course of the temperature, of the 
 
 * Physiologic, vol. ii. p. 164. 
 
 f Haider, Beobachtungen iiber die Temperatur der Vegctabilien, Tiibingen, 1826; 
 
 and Neuffer, Untersuchungen iiber die Temperaturver nderungen der Vegetabilien, 
 
 &c. Tiibingen. 1829. 
 
DEVELOPMENT OF HEAT. 541 
 
 rise of the sap in the plant, and from the discoveries of De la Rive and 
 Alph. DeCandolle *, from which it appears that wood in its longitudinal 
 direction is a good, but across its fibres a very bad, conductor of heat. 
 It is especially necessary that a greater number of comparative observa- 
 tions should be made ; first, in plants the roots of which attain different 
 depths ; then in herbaceous and woody plants ; and, finally, in tropical 
 plants, which latter we shall probably be only able to obtain when 
 governments begin to send out naturalists instead of collectors for their 
 museums. A physiologist properly supported, and making a good use of 
 his time, would do more for science by a residence of two years in the 
 forests of the Orinoco than all the travels that have been undertaken since 
 the time of A. von Humboldt. 
 
 Observations on the rise of temperature during flowering have hitherto 
 been instituted on the Aracecz f alone. Lamark observed this fact in 
 1777 in Arum Italicum. Sennebier, Bory St. Vincent, and others^: 
 subsequently communicated observations on the subject. The most exact 
 and elaborate investigations are those of Vrolik and De Vriese. Ac- 
 cording to them, the temperature has a regular periodicity within the 
 twenty-four hours, and attains its maximum in the afternoon, between the 
 hours of two and five. The difference between the temperature of the 
 atmosphere and that of the root is sometimes as much as from 20 30 R. 
 In this case, also, the probability is that the temperature is the result of a 
 process of combustion. According to Th. de Saussure, the root of an 
 Arum maculatum changed thirty times its volume of oxygen into carbonic 
 acid in twenty-four hours. We are deficient, however, in comprehensive 
 comparative observations, which should be made on crowded flower- 
 stalks. The chemical processes ought to be measured with the greatest 
 accuracy, and the temperature developed ought to be calculated and com- 
 pared with the temperature observed. In all the cases which we have 
 enumerated, the absolute temperature depends on the intensity of the vital 
 process, and is higher in proportion to the vigour of the vegetation of the 
 plants, or in proportion to the absorption of the sap and the vigour of its 
 chemical processes. 
 
 Of these three phenomena, the first and last seem to have the same 
 origin ; the second is independent. Meyen maintains that the production 
 of temperature in plants is peculiar, which may perhaps be due to the 
 chemical processes that are constantly going on. But no result can be 
 gained in the rude manner in which he pursues the subject. It is 
 merely a guess to say that the temperature in the interior of trees must 
 depend on the same causes as the development of temperature during 
 germination and flowering. Thus much is certain, that, during the pro- 
 cesses of germinating and flowering, carbonaceous matters are consumed 
 and carbon is burned. In the process in the stem it is also certain that 
 a formation of purely carbonaceous substances takes place, and it is as yet 
 quite uncertain whether the chemical processes present absorb or liberate 
 heat, because we are not yet acquainted with those processes. Meyen 
 doubts the rising of the sap in winter, because roots are frequently found 
 thoroughly frozen. But what roots ? The difference of temperature 
 between day and night disappears at a depth of 3', and that between 
 
 * Poggendorff's Annalen, vol. xiv. p. 590. 
 
 f A complete enumeration of all these observations are to be found in the " Flora" 
 (1842, vol. i. Supplement, No. 6, p. 84.). 
 \ Meyen, Physiologie, vol. ii. p. 184. 
 Annales de Chimie et de Physique, vol. xxi. p. 279. 
 
542 ORGANOLOGY. 
 
 winter and summer at a temperature of 60 70'. Roots lying on the 
 surface may be frozen, whilst those deeper may go on absorbing sap. An 
 infinity of observations ought yet to be made in this field, and explana- 
 tory hypotheses are altogether inadmissible, as the facts to be explained 
 are not yet known. Meyen, in this instance, falls into the same error of 
 many other naturalists ; they do not like to give up the flattering idea that 
 science, with the exception of a few trifles, is quite complete, whilst in 
 reality we have scarcely obtained an entrance into the wide field it ope n 
 before us. 
 
 B. Development of Light. 
 
 212. Much has been written respecting the production of light 
 from plants. If we separate, however, all fables and delusions 
 from the real truth, but few facts will remain. 
 
 The whitish points of the black, and as yet problematical (?) 
 fungus, Rhizomorpha subterranea, give out, according to A. von 
 Humboldt, a peculiar phosphoric light. Meyen made similar 
 observations on one of the Algae (?), a species of Oscillatoria. 
 
 Decaying fungi, decaying wood, and other parts of plants, give 
 out, it is well-known, light under certain circumstances. 
 
 The matter affording the light in these cases, consisting of a 
 gelatinous matter, may be stripped off; and the light probably owes 
 its origin to a slow process of combustion, at the expense of the 
 atmospheric oxygen. 
 
 The daughter of Linnaeus first observed a lightning-like phospho- 
 rescence in Trop&olum majus during a sultry, tempestuous night. 
 This observation was subsequently confirmed in that and many 
 other, generally yellow and orange-coloured flowers ; every attempt 
 at explanation respecting it is as yet impossible. 
 
 The following constitute the literature on this subject, which I have 
 principally derived from Meyen's Physiol., vol. ii. p. 192, as I could not 
 myself procure many of the works ; and, indeed, I may add, that I could 
 not see any utility in their study without an opportunity of instituting 
 observations : 
 
 Works on the general subject : 
 
 Placidus Heinrich, iiber die Phosphorescenz der Korper. 
 
 Ehrenberg, vom Leuchten des Meeres. 
 
 On the especial subject of light in plants : 
 
 Conrad Gesner, de lunariis. Zurich, 1555. 
 On Rhizomorpha subterranea : 
 
 A. v. Humboldt, iiber unterirdische Gasarten. Braunschw. 1799. 
 
 Nova Acta A. L. C., vol. xi. pt. ii. p. 605. 
 
 On light in decomposing wood and other decomposing parts of 
 plants : 
 
 N. Act. A. L. C., vol. v. p. 482., and vol. xi. part ii. p. 702. 
 
 De Candolle, Flore frang. Paris, 1815, p. 45. 
 
 Link, Elementa Phil. Bot. ed. 1. p. 394. 
 
 L'Institut de 1836, p. 34. 
 
 Scherer's Journal der Chem., vol. iii. p. 12. 
 
DEVELOPMENT OF LIGHT. 543 
 
 On light from the flowers : 
 Kongl. Svenska Wetenscap-Academiens Handlirignr, J762, p. 284. 
 
 (The observations of Linnaeus's daughter on Tropceolum}. 
 Bertholon de St. Lazare, de 1'Electricite des Vegetaux. Paris, 1783, 
 
 p. 335. ( Tropceoitim majus). 
 Kongl. Wetenscap-Academien Nya Hand!., 1778, p. 82. (Helianthus 
 
 annuus, Lilium bulbiferum, Tagetes spec.}. 
 Treviranus, Zeitschr. f. Physiol., vol. iii. pp. 257 269. 
 Hoppe, Botan. Taschenbuch f. d. Jahr 1809, p. 52. (Tropceolum 
 
 majus). 
 Bauragartner and Ettinghausen, Zeitschrift fiir Phys. und Mathem., 
 
 vol. vi. pp. 459 462. (Calendula qfficinalis, Tropceolum majus, 
 
 minus, Lilium bulbiferum, Tagetes patula, erecta, Helianthus, 
 
 Gorteria rigens). 
 
 DeCandolle, Physiol. Veget., vol. vi. (?) p. 886. 
 
 DeSaussure, Chemische Untersuchungen iiber die Vegetation, trans- 
 lated into German by Voigt. Leipzig, 1805. (CEnothera macro- 
 
 carpa). 
 Trommsdorff's Journal de Pharmacie, vol. viii. part ii. p. 52. (Phytolacca 
 
 decandra). 
 Schweigger's neues Journal d. Chem.u. Phys., vol. i.p. 361. (Polyanthes 
 
 tuberosa). 
 Sennebier, Physiol. Veget., vol. iii. p. 315. (Arum maculatum in pure 
 
 oxygen gas).* 
 
 The giving out of light by the Rhizomorphce and from decayed vege- 
 tables seems to be owing to the presence of a peculiar substance from 
 which the light proceeds. Its nature, however, is by no means yet 
 established, and we know nothing of its chemical properties. The 
 existence of a chemical process, a kind of slow combustion, in this instance, 
 is probable, first, from its analogy with the decomposition of vegetable 
 substances in general, and also from the circumstance that this pheno- 
 menon does not always take place, but only under peculiar circumstances. 
 Meyen says " it is no chemical process, but a phenomenon of expiring 
 life, because it does not always occur." But the very reverse would 
 follow from this. When, however, he asserts in page 205 " that it is the 
 result of the most intense processes of life, or of decaying life, and 
 probably is only an intense respiration," his probable meaning becomes, 
 indeed, obscure and mystical enough. 
 
 In spite of the number of observations enumerated, it is yet possible 
 that the giving out of light from flowers may be dependant upon an illu- 
 sion, the same as occurs in the case of the Schistostega osmundacea, a 
 small species of Moss, the proembryo of which Bridel-Brideri described 
 as Catoptridium smaragdinum, whilst the great algologist Agardh proved 
 that it was decidedly a new species of Protococcus. But it happens to be 
 neither one nor the other, but the proembryo of the Moss mentioned, as 
 Unger has proved beyond doubt. 
 
 The giving out of light from formless fluids, as from the milky juice of 
 
 * To this list I may add, that in the Transactions of the British Association for 
 1843, there is a notice of a " A luminous Appearance on the Common Marigold ( Ca- 
 lendula fM/r/wm*)," by Richard Dowden ; and some remarks of my own on the same 
 subject, in the Gardener's Chronicle for 1843. There are some interesting observa- 
 tions on " Phosphorescence " in Professor Matteucci's Lectures, before alluded to. 
 TRANS. 
 
544 ORGANOLOGY. 
 
 Euphorbia phosphorea (Martius, Reise nach Brasilien, vol. ii. pp. 726 and 
 746), belongs to physical and not botanical science. 
 
 C. Movements of the Parts of Plants. 
 
 213. Two kinds of motions of the parts of plants can be dis- 
 tinguished : 1st, those that are produced in the dead parts of plants 
 by the change from the moist and dry state ( 214.); and, 2dly, 
 those which are caused in a manner as yet unknown to us, by 
 changes in living cellular tissues ( 215.). 
 
 A third kind of so-called movement, which does not belong here, 
 brings a phenomenon of growth which determines the direction of 
 certain parts, as the peculiar form of tendrils and the growth of the 
 climbing plants. 
 
 Finally, those movements must be mentioned which entire plants 
 are said to exhibit, as the OscillatoricR and some other forms of the 
 lower Algce( 215.). 
 
 The third form of phenomena alluded to above does not belong to true 
 movements, although many consider them as such. It depends on the di- 
 rection (the same takes place in the germinating plant when it is growing 
 towards the light) given by an unequal tension of the cells on both sides, 
 whereby that side is curved in which the cells grow least in the longitu- 
 dinal direction. Similar irregularities occur, not unfrequently, in the 
 extension of plants, but without producing any remarkable departure from 
 their normal condition. They only create a tension, the effect of which 
 only becomes visible when the continuity of the parts is interrupted by an 
 accident. We may mention, as belonging to the same phenomena, the 
 sudden curvature which particular parts of plants occasionally exhibit, as, 
 for instance, the hollow flower-stalk of Leontodon Taraxacum, when it is 
 split, or when a longitudinal strip is cut out of it, &c. 
 
 214. The first kind of movements are either perfectly ex- 
 plainable, or, if not, it is owing to our inaccurate knowledge of the 
 structural relations and other elements that demand attention, as 
 the causes, remaining always the same, are known to us. All the 
 phenomena under this head take place in the organs of plants, the 
 elementary parts of which are either already dead or in the act of 
 dying, but all of which are still of importance to the entire life of 
 the plant ; all, finally, are more or less connected with its reproduc- 
 tion by facilitating changes in the locality of the reproductive cells 
 (spores or pollen-grains) or of the seed. We find phenomena 
 of this description in almost all groups of plants. To such belong 
 the valvular bursting of the species of Geastrum and some other 
 Fungi, the opening of the spore-fruits, the movements of the teeth 
 and the seta in Mosses, the bursting of the spore-fruits in the 
 Liverworts, the tearing open of the same in Ferns, Lycopodiacece, 
 and EquisetacecB, the bursting of the anthers of the capsules, and the 
 loosening of some parts of the fruit mEuphorbiacecB, 
 
MOVEMENTS OF THE PARTS OF PLANTS. 545 
 
 GeraniacefR, and the bursting of the hardened endocarp, as in the 
 Almond in the Phanerogamia. 
 
 The causes are owing, Istly, to the universal property of vege- 
 table membrane to contract when in the act of drying up, and that 
 the more so if their chemical nature is the same, the thinner the 
 membrane ; and if it is composed of different substances, the more 
 so, the more they approximate in their quality to jelly; 2dly, 
 the elasticity (however slight) of the vegetable membrane, which, 
 when filled by fluids, is in a state of tension, and which again con- 
 tracts when these fluids withdraw themselves ; 3dly, to the con- 
 traction of a thin- walled cell filled with fluids, which, when the fluid 
 escapes, is either not at all, or only imperfectly filled with air. 
 These causes produce the movements enumerated, the different 
 structure and nature of the cells in the same part of the plant 
 causing an unequal contraction and, with it, a twisting or turning. 
 
 Although the phenomena here enumerated are generally known, I 
 cannot find anywhere a more accurate analysis of the facts that they 
 are based upon. Indeed, this could not be expected when such per- 
 fectly erroneous views of the nature of the vegetable membrane are 
 adopted, as those of Link and Meyen. 
 
 The fact is well known, that vegetable membrane (and, in consequence, 
 also the elongated cells, called vegetable fibres) extends when in a moist 
 state, and contracts when in a dry state. Link has asserted the reverse 
 of this (Elem. Phil. Bot., vol. i. p. 360), and Meyen (Physiologic, vol. i. 
 p. 30.) has invented for it a singular theoretical explanation. I have 
 contradicted this erroneous assertion (Wiegmann's Archiv, 1839, vol. i. 
 p. 274.). Skulls are separated in anatomical researches by filling them 
 with dry pease and putting water into them ; rocks are burst by wooden 
 wedges that are moistened ; if we let fall a drop of water upon paper, it 
 will form a vesicular elevation ; the same takes place on thin boards : and 
 numerous other similar well-known facts might be enumerated. Vege- 
 table substances have frequently been used for hygrometers; for instance, 
 Balance's strips of paper, Hautefeuille's, Tauber's, Ferguson's, Comers', 
 Anderson's, and Franklin's strips of wood, which exhibit, by the amount 
 of their extension, the amount of humidity of the atmosphere. John 
 Leslie constructed a hygrometer of boxwood, similar to Deluc's ivory 
 hygrometer, the former being distended, when wetted, twice as much as 
 ivory (Gehler's Worterbueh, art. Hygrometrie). Others have used 
 other vegetable substances, for instance, strips of fuci, for hygrometers. 
 In answer to my observations, Link says (Wiegmann's Archiv, 1841, 
 vol. ii. p. 407.), " Through disputes that were once carried on between 
 DeLuc and Saussure respecting the hygrometer, it has been proved that 
 dry vegetable fibre contracts by moisture, whilst animal fibre is elongated 
 by it." This statement is altogether untrue, because the question of any 
 material difference between the animal and vegetable fibre was never 
 raised in the discussions of DeLuc and Saussure. But even had this 
 assertion been made by one of them, it could from well-known facts be 
 proved to be a decided error. Link seems to know nothing of the matter 
 but by hearsay, for the result, especially of DeLuc's investigations, was 
 clearly that no difference takes place in this respect between the animal 
 and vegetable parts, excepting a quantitative one. DeLuc, in his Treatise 
 
 N N 
 
546 
 
 ORGANOLOGY. 
 
 on Hygrometry (Philosoph. Transactions, vol. Ixxxi. Parts I. and II.), 
 distinguishes very minutely the double effect which humidity exercises on 
 hygroscopical substances, both of animal^ as of vegetable origin : viz., 
 Istly, the distension of the membrane or fibre itself, which invariably 
 takes place in both by the absorption of moisture ; and, 2dly, the con- 
 traction which takes place in both of entire portions (especially of spiral 
 ones) by water getting between the separate fibres (or between the cell- 
 walls), which are thereby bent, and thus far produce a contraction of the 
 individual part, notwithstanding the simultaneous distension of the mem- 
 brane. The phenomena of hygrometrical substances are connected with 
 both causes, and the sum total of the result must be exhibited according 
 to the predominance of one or the other of these causes, either as a 
 distension or a contraction. How the relations vary in this respect will 
 be shown by the following table from DeLuc, which proves, at the same 
 time, that all vegetable, as well as animal substances, can be distended by 
 moisture. The second effect, however, begins to manifest itself at 100, 
 and a gradual contraction then takes place also in animal substances. 
 
 Table of the relative Rates of Humidity in different Fibres of Vegetable and Animal 
 Substances, taken longitudinally. 
 
 
 Thorny Hair of a 
 Porcupine. 
 
 Whalebone. 
 
 a 
 
 B 
 
 I 
 
 Pita Flax. 
 
 | 
 
 h 
 
 o 
 
 Firwood. 
 
 1 
 
 o 
 
 Longitudinal 
 Strips of Box- 
 wood. 
 
 Transversal 
 Strips of Box- 
 wood. 
 
 Highest 
 
 o-o 
 
 o-o 
 
 o-o 
 
 o-o 
 
 o-o 
 
 o-o 
 
 o-o 
 
 O'O 
 
 72-8 
 
 o-o 
 
 degree 
 of dryness. 
 
 18-0 
 
 12-0 
 
 15-6 
 
 9-7 
 
 20'6 
 
 37-0 
 
 33-2 
 
 26-8 
 
 87-4 
 
 4-5 
 
 
 34-0 
 
 29-9 
 
 29-4 
 
 19-2 
 
 35-1 
 
 66-6 
 
 54-8 
 
 48-4 
 
 93-2 
 
 9-5 
 
 
 48-8 
 
 39-9 
 
 40-9 
 
 26-8 
 
 51-6 
 
 78-7 
 
 74-9 
 
 67-1 
 
 97-8 
 
 14-5 
 
 
 62-3 
 
 50'8 
 
 50-5 
 
 37-0 
 
 57-6 
 
 88-0 
 
 84-6 
 
 76-1 
 
 100-0 
 
 20-0 
 
 
 73-3 
 
 58-8 
 
 59-2 
 
 47-1 
 
 75'6 
 
 93-4 
 
 89-8 
 
 83-9 
 
 95-9 
 
 25-7 
 
 
 81'0 
 
 65-3 
 
 68-8 
 
 57-3 
 
 71-9 
 
 97-2 
 
 93-8 
 
 90-5 
 
 92-7 
 
 31-5 
 
 
 86-8 
 
 70-8 
 
 73-0 
 
 67-4 
 
 76-3 
 
 99-0 
 
 96-0 
 
 95-1 
 
 88-6 
 
 38-0 
 
 
 90-8 
 
 76-1 
 
 78-3 
 
 75-6 
 
 83-0 
 
 94-4 
 
 94-3 
 
 98-6 
 
 79-9 
 
 45-5 
 
 
 93'0 
 
 81-4 
 
 82-1 
 
 82-9 
 
 86-6 
 
 96-2 
 
 97-7 
 
 100-0 
 
 70-3 
 
 51-5 
 
 
 95-0 
 
 85-4 
 
 86-1 
 
 87-8 
 
 93-6 
 
 99'0 
 
 100-0 
 
 98-8 
 
 63-9 
 
 56-5 
 
 
 94-5 
 
 88-4 
 
 88-8 
 
 91-6 
 
 96-5 
 
 95-3 
 
 94-6 
 
 98-0 
 
 .57-3 
 
 61-2 
 
 
 97-0 
 
 90-8 
 
 91-6 
 
 94-7 
 
 94-7 
 
 97-2 
 
 97-0 
 
 97-2 
 
 51-0 
 
 65-7 
 
 
 96-5 
 
 92-8 
 
 93-8 
 
 96-3 
 
 98-2 
 
 98-2 
 
 94-6 
 
 96-2 
 
 45-7 
 
 697 
 
 
 96-5 
 
 95-2 
 
 95-6 
 
 97-8 
 
 lOO'O 
 
 100-0 
 
 93-0 
 
 94-8 
 
 40-9 
 
 73-7 
 
 
 95-0 
 
 97-1 
 
 97-2 
 
 98-7 
 
 99-2 
 
 99-0 
 
 91-4 
 
 92-6 
 
 31-4 
 
 77-7 
 
 
 97-0 
 
 98'1 
 
 98-0 
 
 1000 
 
 98-2 
 
 98-2 
 
 89'0 
 
 89-8 
 
 21-7 
 
 81-5 
 
 
 98-0 
 
 99-1 
 
 lOO'O 
 
 98-7 
 
 96-8 
 
 97-2 
 
 86-9 
 
 86-5 
 
 16-0 
 
 85-9 
 
 
 98-6 
 
 99-6 
 
 100-0 
 
 96-8 
 
 94-1 
 
 95-3 
 
 84-6 
 
 84-0 
 
 10-4 
 
 90-5 
 
 in the 
 
 99-1 
 
 100-0 
 
 99-3 
 
 94-5 
 
 91-5 
 
 94-4 
 
 81-9 
 
 80-9 
 
 5-1 
 
 95-5 
 
 Water. 
 
 100-0 
 
 99-5 
 
 98-3 
 
 91-8 
 
 88-3 
 
 92-5 
 
 77-0 
 
 77-0 
 
 o-o 
 
 100-0 
 
 Next to the boxwood (cut longitudinally) a twisted hemp rope ought 
 to be enumerated, in which, in consequence of the close junction of the 
 fibres, the second effect takes place still earlier. This is the result of 
 scientific research upon this subject ; and Link's assertions to the con- 
 trary are the result of sheer ignorance. 
 
 It is a very common thing to hear general phrases made use of re- 
 specting hygroscopicity as the result of desiccation, &c., without any 
 
. MOVEMENTS OF THE PARTS OF PLANTS. 547 
 
 reason being assigned as to how this effect is brought about. It appears 
 to me that the three following points ought to be distinguished : 
 
 1. Vegetable membrane is certainly only elastic in a slight degree ; it 
 may be distended as almost all other organic substances, but again 
 resumes its former volume on the withdrawal of the tension. The 
 parenchyma of the living plant, in consequence of endomosis, is con- 
 stantly in a state of tension ; each cell occupying a greater space than 
 belongs to it according to the natural circumference of its membrane. 
 On removing, however, a portion of the liquid thus distending it, the cell 
 contracts to its natural size. This effect, trifling as it may be in the 
 single cell, must yet become perceptible when hundreds of cells are taken 
 into consideration. Microscopical observation proves that this is really 
 the case. If we cut off the larger part of a succulent plant when it is 
 distended with fluid, as the joint of an Opuntia, or a large succulent 
 leaf, and allow it to remain for a short time in a dry place, the loss of 
 weight will prove to us that a part of the water has evaporated, and 
 exact measurements will prove that a simultaneous, but very slight, con- 
 traction to a smaller volume has taken place. Nevertheless, however, 
 we find all the cells entirely filled with juice, even on the most accurate 
 microscopical examination : and none exhibits in its membrane the 
 slightest fold, all appearing in a state of absolute tension. Simul- 
 taneously, therefore, with the evaporation of the water, there must have 
 taken place a slight contraction of all the cells. Let us apply this to the 
 external succulent layer of parenchyma in the fruit of the almond. 
 When distended by juice, 'the number of cells suffices perfectly to enclose 
 the hard stone, which is but little changed in volume by the process of 
 drying. But when the cells, becoming ripe, gradually lose their fluid ' 
 contents (which are no longer supplied by the fruit-stalk), a stretching 
 takes place by means of the contraction of the individual walls of cells 
 that are firmly connected with each other, the envelope becomes too narrow 
 for the stone, and if, as really occurs, there happens to be a layer of cell 
 tissue in which the cohesion is not so strong as the expanding power, 
 this layer is torn, and the cleft thus caused becomes wider the further 
 the evaporation of the water proceeds. 
 
 2. To this condition we must add, as its continuation, a second and a 
 much more remarkable phenomenon. The thin membrane of the cell is 
 flexible in the highest degree, and on the liquid evaporating from the 
 cells without their being simultaneously filled with air, the cell dimi- 
 nishes in volume from the pressure of the external air, in the same way 
 that an animal bladder filled with water, gradually losing its water without 
 the vacant space being filled with air, cannot be distended to its former 
 volume without being torn. 
 
 3. Vegetable membrane is very hygroscopical, and becomes distended 
 by moisture and contracted by dryness. But both take place in a very 
 different degree, according to two concurring circumstances. The more 
 the membrane approaches, in its chemical constitution, jelly, the more it 
 contracts when in the act of drying up ; and the more it approximates 
 to the nature of perfectly developed cellulose (membranenstoff), the 
 slighter is the expansion when exposed to the action of moisture. The 
 membrane, when of the same chemical nature throughout, appears to 
 contract the more the thinner it is, and the less the more it is thickened 
 by secondary deposits. This latter view agrees with the circumstance 
 that all spiral fibres (which, as we are in the habit of isolating them, con- 
 sist externally of the spirally-torn primary cell-membrane, and internally 
 
 N N 2 
 
548 
 
 ORGANOLOGY. 
 
 of the deposit-layers) become straight on drying, but again roll up on 
 being wetted, because the primary cell-membrane contracts in a dry and 
 expands in a moist condition. 
 
 I have hitherto been able to make, respecting these facts, only a few 
 experiments, which, although they do not afford anything like correct 
 figures, for I will admit a probable error often per cent., yet, relatively 
 speaking, they have their value. The following are the results : 
 
 Polyides lumbricalis, moderately thick-walled, gelatinous cells, and the 
 rather swollen extremity shortly before the formation of spores =A. 
 Laminaria diffitata, a piece of the ftsitfrons=B. Sphcerococcus crispus, 
 somewhat thicker cells of the frons=C. Sphcerococcus cartilagineus, 
 rather thick cells, a piece of the round peduncle of the frons=D. ; 
 measured in a dry state (all the measures are given in millimetres) =#, 
 after having been lying in the water for 3 hours=&, after 24 hours' 
 soaking in water =c, amount of the prolongation in decimals of the 
 original length =e?. 
 
 
 a. 
 
 b. 
 
 c. 
 
 4 
 
 
 Length. 
 
 Width. 
 
 Length. 
 
 Width. 
 
 Length. 
 
 Width. 
 
 Length. 
 
 A. 
 
 26'5 
 
 1-5 
 
 37-5 
 
 2 
 
 39 
 
 2 
 
 0-471 
 
 B. 
 
 63 
 
 11 
 
 71%5 
 
 16 
 
 72 
 
 15(?) 
 
 0-142 
 
 C. 
 
 16-5 
 
 3 
 
 19 
 
 5 
 
 19 
 
 5-5 
 
 0-181 
 
 D. 
 
 17 
 
 1-5 
 
 18 
 
 2 
 
 18 
 
 2 
 
 0-052 
 
 E. Fibres of hemp (very elongated cells, thick- walled, the light dis- 
 appearing under the microscope, cellulose well developed) were sus- 
 pended in a glass tube, which was wider below, and enclosed in it for 
 24 hours with chloride of calcium, and then measured=a / . The chloride 
 was removed ; the end of the tube, which was open below, was immersed 
 in water, and measured after 24 hours =&'. The tube was then filled 
 with water, and again measured after the fibres had been 24 hours in 
 water=c'. During this process the temperature of the room fluctuated 
 between 10 and 18 R. Finally, the tube was emptied of its water, and 
 dried, with the fibres, over chloride of calcium at about 30 R., and again 
 measured =d'. The amount of the greatest elongation in decimals of 
 the original length gives e. The fibres 1 and 2 had at their end the 
 weight of a small shot, which was scarcely heavy enough to stretch them 
 straight ; the fibre 3 had upon it a rather heavier shot. 
 
 E. \2. 
 1 3. 
 
 a 
 
 469 
 434 
 951 
 
 b' 
 
 470 
 434-5 
 
 c 
 
 470 
 
 434-5 
 
 594-1 
 
 d' 
 
 468-5 
 434 
 
 e' 
 
 0-0021 
 0-0011 
 0-0036. 
 
 F. In the month of February a shoot of Salix alba of the previous 
 year was cut off and placed in water for 24 hours, at a'temperature of 
 10 to 15 R.; the bark was then taken off, and the length measured=a"; 
 it consisted entirely of alburnum, therefore of slightly thickened and 
 elongated cells with imperfectly developed cellulose : the small pith 
 may be here overlooked. The twig was now dried at a temperature of 
 10 to 15 R, and the length again measured=&" ; finally dried for 
 
MOVEMENTS OF THE PARTS OF PLANTS. 549 
 
 24 hours at 30 R., and the determinate length c". The amount of the 
 greatest prolongation in the humid state was then calculated in decimals 
 of the original lengtli=d". 
 
 a" b" c" d" 
 
 F. 260 259 258-5 0-0058. 
 
 G. A strip was cut from the axis of a fresh, straight, thick shoot of a 
 Stapelia, and its length determined=a'", its width and thickness =b"". 
 It consisted entirely of thin-walled parenchyma cells, consisting of per- 
 fectly developed cellulose. It was fastened to a cork, and thus sus- 
 pended in a glass flask, the bottom of which was covered with chloride 
 of calcium. The length it became, after 24 hours' exposure with a tem- 
 perature fluctuating between 10 and 15 R.=e'", width and thickness 
 =^d'", and the amount of the expansion in the humid state, calculated in 
 the decimal fraction of the original length =e' /x . 
 
 a?" b'" c'" d'" e'" 
 
 G. 189 8 174 3-5 0-086. 
 
 The slight contraction that takes place at first in the thin-walled 
 parenchyma cells, which consist of perfectly developed cellulose, is pro- 
 duced by means of elasticity, to which must be added the insignificant 
 hygroscopical contraction of the membrane, whilst the action only 
 becomes so striking through the falling together of the cells in conse- 
 quence of the desiccation. 
 
 As an instance of the application of these phenomena to the expla- 
 nation of the bursting of capsules, I may cite Iris atomaria. The 
 upper half of the wall of the capsule, which separates itself from the 
 other parts, and retracts, consists of the following layers. At the most 
 external part there is an epidermis of flat, very irregular cells, the walls 
 of which are rather gelatinous and slightly porous ; then follow, towards 
 the interior, several layers of parenchyma cells, which are at first flat, 
 and become gradually somewhat rounder, and the walls of which are 
 also rather gelatinous. The walls of the epidermal cells are moderately 
 thick, the layer of parenchyma lying beneath are joined to the latter, the 
 walls become gradually thinner, and, as it appears, are gradually con- 
 verted into cellulose. Very thin-walled cells, which extend almost from 
 the interior to the exterior, form an internal layer containing many 
 intercellular spaces, into which layer the vascular bundles run. Then 
 follows, almost suddenly separating itself from the former, a very thin 
 layer of cells, which being rather thick- walled, and formed of firm cel- 
 lulose, are about ten times as long as broad, and which laterally, for 
 long intervals, frequently only touch each other, like stellate cells, by 
 means of small processes, and which, arranged in different directions, 
 are yet, on the whole, arranged in such a manner that their longi- 
 tudinal diameter is horizontal. Finally, quite towards the interior, comes 
 the epithelium, consisting of tolerably thick-walled, porous, elongated 
 cells, the longitudinal diameter of which almost invariably forms, with 
 the previous cells, an angle of 25 to 30. The entire wall of the 
 capsule, in a fresh state, is li- to 2 millim. thick. The most internal of 
 these layers, together with the epithelium, can contract only a very little, 
 perhaps enough to enable it to tear the margins of the valves from each 
 other. The external layers, on the other hand, must contract very COD- 
 siderably, both in length and width, as it is owing to this that the valves 
 
 N N 3 
 
550 ORGANOLOGY. 
 
 are first of all torn on the external surface, then separate themselves 
 from the point towards the basis as far as about the middle, curving 
 themselves outwards. A complete separation of the valves, and a 
 perfect tearing back, 'would, in consequence of the structure, here no 
 doubt take place, if, firstly, the cells of the suture were not thicker below *, 
 and capable of resisting the tension ; and, secondly, if the very thick 
 and tough partition-wall was not placed upon the centre of the valves, 
 which, like a prop, resists their curvature, and which .last action is still 
 further aided by the two longitudinal ribs, which project upon the 
 external side of each valve. 
 
 The different movements of this kind are almost invariably produced 
 by the co-operation of the three phenomena here explained. It cannot 
 be expected that I should explain all possible cases, for which purpose 
 the necessarily accurate anatomical facts are still wanting. Every one 
 will easily be able to apply the above conditions to individual cases ; as 
 an instance, let us take the tearing of the capsule in Aspidium filix mas. 
 The capsule is flat, almost lenticular. A row of cells, commencing on 
 the one side from the stipes, forms round the greatest part of the cir- 
 cumference an imperfect ring, leaving on the other side a vacant space, 
 about one-sixth of the circumference. The cells are almost parallelo- 
 pipedical, and their walls towards the cavity of the capsule, where they 
 mutually touch each other (not towards the sides and exterior), are very 
 much thickened. The lateral walls, which pass into each other at the 
 before-mentioned one-sixth of the circumference, consist of very flat and 
 extremely thin-walled cells, The thicker and tougher walls of the cells 
 of the ring are but slightly, or not at all, changed by the process of 
 drying, but the thinner walls of the same cells are so. On the evapo- 
 ration of the fluid in the cells, they first contract in a somewhat elastic 
 manner, and thereby shorten the distance between the extreme end of 
 the thick walls, and thus of the whole external circumference of the 
 ring ; but as the moisture continues to evaporate without being supplied 
 with an equal quantity by air, the thin walls are pressed in by the atmo- 
 spheric pressure, and the contraction of the external circumference of 
 the ring is thus still more considerably increased. The internal circum- 
 ference, consisting of cells with thickened walls, remains unchanged, but, 
 through the contracted side walls that act as a rectangular lever, it 
 receives a tendency to straighten itself. This tension only continues as 
 long as the thin-walled cells at the last one-sixth of the circumference 
 are capable of resisting the expanding power ; as soon as the tension 
 becomes more powerful, they burst into a transverse slit, and the capsule 
 is opened. The progress of this process is quite similar in the teeth of 
 the capsules of the Mosses. 
 
 215. The second kind of movements are seen in living parts 
 of plants during vigorous vegetation, and depend probably on the 
 distribution of the sap, and upon the elastic expansion of the in- 
 dividual cell-membranes. The facts, however, connected with this 
 subject are as yet too little known to admit of a clear explanation. 
 The following varieties of movements may be distinguished : 
 
 * According to this, we can beforehand, by means of anatomical examination of the 
 cells, determine, in valves that are not completely separated, how far separation of the 
 valves will take place. 
 
MOVEMENTS OF THE PARTS OF PLANTS. 551 
 
 A. Movements which evidently depend on external influences, 
 as 
 
 a. Periodical. 
 
 In many plants it is observed that the foliar organs, the leaves 
 of the stalk as well as of the flower, assume a different direction 
 during night from what they do in the day, and these phenomena 
 are frequently produced by the brightness or the cloudiness of 
 the sky. This, since the time of Linnaeus, has been called the 
 sleep of plants. In general, it may perhaps be assumed as a rule 
 that the parts of plants during the absence of light resume as 
 nearly as possible the position which they occupied in the bud, 
 and this the more accurately the younger and more tender the leaf. 
 The deviations arising in this respect from day and night are 
 slighter in older and tougher leaves ; they disappear entirely in per- 
 ennial and leathery leaves. The very compounded leaves of the 
 Leguminosce and Oxalidacea exhibit these phenomena in the most 
 striking manner. 
 
 Similar movements may be observed in some flower stalks, which 
 are curved during night in such a manner that the flower is turned 
 towards the ground ; for instance, Euphorbia sp., Ranunculus poly- 
 anthemos, Draba verna, Verbascum blattaria. 
 
 In opposition to this, there are some few flower leaves which 
 deviate from their normal position in the bud during night, and 
 again return to it in the day; for instance, Mesembryanthemum 
 noctiflorum. 
 
 The movements here mentioned, especially of the first kind, are so 
 remarkable in some plants that even Pliny observed them (N. H. viii. 
 35.) But Linnaeus first of all traced them more accurately, and pub- 
 lished an elaborate account of them. (Somnus plantarum. Upsaliae, 1755, 
 Amosnit. Acad. vol. iv. p. 133.) The number of observations has subse- 
 quently increased, and every one may by individual researches confirm 
 the matter. I am of opinion that it is based upon the same cause as the 
 phenomena which will be spoken of under b. The anatomy of the parts 
 in which the movement takes place should be examined in a larger series 
 of plants, and the state of the cellular tissue, especially in the day, should 
 be accurately compared with the state which it exhibits at night ; exact 
 measurements should also be made of it. The movements are observed 
 most frequently and most strikingly in that region where the petiole of 
 the leaf passes into the stalk, and where the petiolules pass into the com- 
 mon petiole of the leaf, particularly when that swelling of the cellular 
 tissue called the pulvinus is very considerable. But experiments in 
 which the pulvinus has been carefully stripped off seem to prove that 
 the cause of this motion is not seated in this part, as Dutrochet supposed. 
 
 With regard to the facts of the present paragraph, I have no observa- 
 tions of my own to offer, and therefore merely communicate the most 
 essential of these facts. I must refer to Meyen's Physiologic (vol. iii. 
 pp. 473 562.) and to Dassen's works (the principal work quoted by 
 Meyen*) for details, and more especially respecting the results of ex- 
 
 * Natuurkundige Verhandelingcn van de Hollandschc Maatschappij der 
 schappen te Harlem II. Deel. Te Harlem 1835, pp. 309-346. and: Tijdschrift voor 
 natuurlijke Gcschiedenis en Phys. 1837, vol. iv. pp. 106131. 
 
552 ORGANOLOGY. 
 
 periments which were instituted, and which, according to my view, were 
 very imperfect. The conclusions which Meyen comes to from experi- 
 ments of his own and of others, are for the most part unfounded, and are 
 most intimately connected with his prejudice of an analogy between 
 plants and animals. He evidently very frequently obtains the results 
 which he previously wished to arrive at. 
 
 b. Not periodical. 
 
 Perfectly similar movements to those which occur gradually on 
 the change of day and night are exhibited by the leaves of some 
 plants suddenly, or at least with great rapidity, as soon as they are 
 brought under the influence of any external chemical or mechanical 
 agency. The following are pretty nearly all the plants in which 
 these phenomena have been observed : 
 
 Mimosa pudica L., M. sensitiva L., M. casta L., M. viva L., M. 
 asperata L., M. quadrivalvis L., M. pernambucana L., M. pigra 
 L., M. humilis Humb., M. pellita Humb., M. dormiens Humb. 
 
 ^EscJiynomene sensitiva L., A. indica L., A. pumila L. 
 
 Smithia sensitiva Ait. 
 
 Desmanthus stolonifcr DeC., D. triqueter DeC., JD. lacustris 
 DeC. 
 
 Oxalis sensitiva L. 
 
 Averrhoa Carambola L., A. Bilimbi L. 
 
 The movement of the leaf of Dionaa muscipula Ell., supported 
 by a winged petiole, appears peculiar. The leaf is furnished with 
 cilia, and on the upper surface covered with stiff hairs. On this 
 surface being touched, for instance, by an insect, the leaf closes 
 together along the central nerves, and the cilia fold within one 
 another, so that the object brought in contact with it is enclosed, 
 and held fast with some force as long as the movement continues. 
 On the latter ceasing, the leaf slowly expands again. In this 
 manner irritable insects are kept captive till they are dead. 
 
 The reproductive organs in some of the Phanerogamia exhibit 
 a sudden movement in consequence of external influences which 
 produces a transference of the pollen from the anther to the stigma. 
 By way of example, we may mention the stamens of Berberis 
 vulgaris, Parietaria judaica, the style of Stylidium adnatum, S. gra- 
 minifolium, Goldfussia anisophylla, &c. The movement takes place 
 also in this case without an external cause, although not so rapidly. 
 
 It cannot be denied that the so-called Sensitive plant (Mimosa pudica\ 
 which folds up its leaves from the shaking of the ground caused by 
 the tramp of a horse, and at every rude touch, presents a most welcome 
 object for poetic treatment ; and the circumstance of this plant not having 
 been known to the old Greeks has certainly made us poorer by one 
 beautiful myth at least. The task of the naturalist, however, is 
 different ; he has other problems to solve, and to him this plant, and 
 its relations in time, must for the present be a land-mark indicating to 
 him the boundary of his knowledge, and a significant warning not to 
 people with the mere creations of his fancy that domain which demands 
 of him earnest and true work. A glance at all that has been done with 
 
MOVEMENTS OF THE TARTS OF PLANTS. 553 
 
 respect to this plant proves to us very clearly that, with regard to the 
 palpable parts of the phenomena, we have only obtained a mere sensa- 
 tionary knowledge of the rudest external aspect of the mechanism of 
 these motions, and that elaborate, careful researches must precede our 
 arriving at the point when the question of the cause of this phenomenon 
 can be put, and an explanatory theory of the movement can be proposed. 
 Until that time arrives, the reflective naturalist had better not enter into 
 any examination of hypotheses, or criticisms upon the explanations of 
 others. The uselessness of such a proceeding is evident. It would be 
 time wasted, time which might be much better devoted to the investi- 
 gation itself. 
 
 Meyen, as has already been observed, has taken immense pains to arrive 
 at a conclusion, and in which, by means of some break-neck leaps by 
 way of inferences, he actually seems to have succeeded. Some experi- 
 ments, however (the only ones which I once had an opportunity of in- 
 stituting with a Mimosa pudica\ proved to me how little has as yet 
 been truly ascertained on this point, since they furnished me with re- 
 sults almost directly contrary to the statements of Meyen. The matter 
 stands thus : Meyen experimentalised on some very susceptible plants, 
 kept at a high temperature, being of opinion that this is the only way of 
 arriving at correct results. But this is opposed to correct practice, as the 
 least susceptible and strongest organisms are always selected for experi- 
 ments, by way of preference, in order to avoid unintentional secondary 
 interferences with the result of the experiment. A Mimosa, which is so 
 susceptible that it closes all its leaves upon the least shaking of the 
 ground, is certainly not well calculated for the purpose of showing that 
 it only closes some particular leaves on the division of its vascular bun- 
 dles. I purposely caused my plant, therefore, to vegetate for some time 
 at a low temperature, so that it did not close its leaves on slight shakings; 
 and the result was, that I found almost every thing different from what 
 Meyen had stated. It appeared to me that the loss of sap beneath a leaf 
 was invariably followed by a depression of the leaf, which continued 
 until the wound was closed by the coagulation of the sap. It is not, 
 however, worth while to communicate the details of these isolated obser- 
 vations,Jsince, so long as we are ignorant of the mechanism of the motion 
 itself, they could only give rise to useless guessing respecting the cause. 
 I can only assert again, that, hitherto, we are not only unacquainted with 
 the cause, but perfectly unacquainted even with the specialities of the 
 fact itself; and the same may be said of the movements of the other 
 plants mentioned. 
 
 B. Movements independent of external influences. 
 a. Periodical. 
 
 These are seen in some tropical species of Hedysarum, especially 
 H. gyrans L. and H. gyroid.es Roxb. The movements of the first 
 plant are known best of all, and are double. The compound leaf in 
 these plants consists of a couple of small lateral leaflets, and of a 
 large terminal leaf. The latter and the common petiole move up 
 and down according to the varying intensity of the light ; and the 
 terminal leaf is, especially in its changes of position, a most de- 
 licate photometer. These movements evidently correspond with 
 those enumerated under A., a. The two lateral leaflets, ho\vever, 
 exhibit a constant vibrating movement, every leaflet describing a 
 
554 ORGANOLOGY. 
 
 little circle with its point, but in such a, manner that the axes of 
 both leaflets always remain in a straight line. This motion is 
 entirely independent of light, of day and night, and is increased by 
 heat and by a more luxuriant vegetation of the whole plant. No 
 explanation can be given of this phenomenon. 
 
 b. Not periodical. 
 
 Such movements take place in most of the Phanerogamia, 
 with the object of transferring the pollen upon the stigma ; the 
 stamens and stigma approaching either one or the other, or both 
 changing their position. In many plants, the stamens assume again 
 a different position after they have distributed the pollen. These 
 movements can no more be explained than the others. 
 
 216. The phenomena exhibited by the Oscillatorics, a small 
 genus of AlgcBy are very remarkable ; the species appear to consist 
 of short fibres composed of cylindrical cells united to each other, 
 which are broader than they are long, and filled with a green 
 matter and other contents, which are partly liquid and partly gra- 
 nular. The point of every fibre is somewhat contracted and 
 rounded, frequently as clear and colourless as water. As long as 
 they vegetate vigorously, these fibres exhibit a three-fold move- 
 ment an alternating slight curvature of the anterior extremity, a 
 half pendulum-like, half-elastic bending to and fro of the anterior 
 half, and a gradual advancing movement. These movements are 
 frequently observed to occur simultaneously, and often, also, sepa- 
 rately. The causes are perfectly unknown. 
 
 The movements of the Oscillatoria have something strange, I feel 
 almost inclined to say something mysterious, about them. I will not 
 conceal my opinion, which is entirely based upon a subjective feeling, 
 that their position in the vegetable kingdom appears still doubtful to me. 
 At all events, it appears to me to indicate a very hasty judgment for any 
 one, as Meyen has done, to ridicule those who hold such an opinion. 
 Our knowledge of these organisms is very defective, and although Ehren- 
 berg refers them to plants, this is by no means a proof of their vegetable 
 nature, but rather of Ehrenberg's modest caution, a quality of which it 
 would be very desirable that Meyen should possess a little more, and 
 which would prevent him going further than exact and certain observa- 
 tions would warrant. Meyen further associates this movement with 
 those of Spirogyra, which contracts spirally, and remains so. I have 
 never observed it : I do not deny it. But when he states that the plant 
 creeps upwards on the walls of vessels in which it is kept, and that this 
 is not the case with any other Algce, he states that which is false, and 
 which can be easily disproved, for the Algce grow naturally up the sides 
 of a glass vessel, and the water they need follows them through the action 
 of capillarity. 
 
 All other so-called Algce of the families of Bacillarice, Desmidiece, &c. 
 are, according to Ehrenberg's observations, of yet too doubtful a nature to 
 afford them a space in this work. 
 
 * Recent investigations on these families in Great Britain have induced some 
 botanists to adopt them unreservedly into the vegetable kingdom. See Lindley, Vege- 
 table Kingdom, p. 12. 1846. Rulfs, The British Desmidica?. 1848 TRANS. 
 
ORGANS OF VEGETATION. 555 
 
 CHAPTEK II. 
 
 SPECIAL ORGANOLOGY. 
 
 217. THE object of Special Organology is to develope the func- 
 tions of the individual organs of plants, and we have now principally 
 to give here a synopsis of what has already been presented in other 
 parts of the work. The result of the whole will be that, excepting 
 the organs of reproduction, the plant possesses no definite physiolo- 
 gical organs at all, namely, such as perform one certain, determinate 
 function. Our knowledge respecting these functions is as yet very 
 defective, and with regard to the Angiosporce we are almost entirely 
 without observations. 
 
 The best method of distributing the matter will be to regard the 
 organs of reproduction independent of the other organs (those of 
 vegetation), and to divide the former into Cryptogamia and Phane- 
 rogamia, including the Rhizocarpea ; and the latter into Angiosporcs 
 and Gymnosporcs. 
 
 A. Organs of Vegetation. 
 a. Angiosporce. 
 
 4 
 
 218. As organs are almost out of the question in the whole 
 group of the Angiosporce, we have only to consider here the tissues 
 and elementary parts. The organs for attaching or fixing the 
 plant to the ground can only be mentioned as having a certain 
 locality, but most of them also grow with the plant when detached 
 from the ground. The whole external surface is only intended to 
 receive nutritive fluids ; and this is all we know of these plants. 
 With regard to the Lichens, the green, round cells may occasionally 
 project from beneath the bark, and become new plants when dis- 
 persed about ; this is probably the case in the other orders, but has 
 not yet been observed. 
 
 b. Gymnosporce. 
 
 2 1 9. The leaf and axis, as fundamental organs, have no deter- 
 minate physiological functions, except such as belong to them in 
 their metamorphosis into reproductive organs. As, however, the 
 axis originally forms the connecting link of all parts, and alone is 
 of a permanent nature, whilst the leaf, on the other hand, is sub- 
 sequently formed and dependant, is isolated and transient, so we 
 may say that the function of the distribution of the sap belongs 
 
556 OIIGANOLOGY. 
 
 principally to the former, for through it all the currents must pass ; 
 whilst, on the other hand, the processes of secretion principally 
 take place through the leaf. 
 
 220. No essentially different functions can be attributed to 
 the different forms which the axis exhibits. With regard to the 
 distinction of the two poles, the root and the axis, in a limited sense, 
 the former is frequently an organ of attachment, which fixes the 
 plant in a certain spot, and, from its being in contact with fluid 
 matters, serves especially for the absorption of nutriment ; it is 
 likewise a secreting organ, and, through the formation of buds, 
 serves the reproduction of the plant. 
 
 That none of these functions are essentially and exclusively con- 
 nected with the roots, is proved by their never being found in 
 Mosses and Liverworts ; and also by their undeveloped state in so 
 many other plants, for instance, many Grasses, Nelumbium, c. ; 
 and finally, their decay in other plant?, for instance, in Ferns, 
 Palms, Cuscuta, &c. Their absence in all these plants is not 
 supplied by secondary roots, which might wholly or in part perform 
 these functions ; for instance, Ceratophyllum remains perfectly 
 rootless in every sense of the word. 
 
 The functions of the axis, in a limited sense, can only be divided 
 according to anatomical systems, and not according to its various 
 morphological organs. The vascular bundles, where they exist, 
 serve in their youngest parts (the cambium) for the distribution of 
 the sap ; in their older parts they serve as a stiff and firm hold 
 (skeleton) for the plant. The parenchyma assimilates, and forms all 
 the peculiar substances which occur in the plant. Its external 
 parts (back and epidermis) serve for the absorption of nutritive 
 fluid, and also for secretion in plants under water, and for respira- 
 tion and transpiration in plants exposed to the air. In their sub- 
 sequent state, after the cellular layers of the bark have been 
 formed, the bark serves, on account of its being a bad conductor of 
 heat, as a means of maintaining the temperature of the interior of 
 the plant. Finally, the axis is an important organ of reproduction, 
 on account of its frequent regular and irregular development of 
 buds. In peculiar forms, as in cirrhi or in climbing plants, the axis 
 becomes an organ of attachment. 
 
 221. The leaves are mostly very independent of each other, and 
 exhibit great variety in their chemical processes, according as they 
 are stem-leaves or flower-leaves. The stem-leaves, being those parts 
 of the plant which expose the largest surface to the air, form prin- 
 cipally the organs of respiration and transpiration, as also of various 
 secretions. In plants growing under water, they serve for the 
 absorption of fluid nutritive matter. By the formation of buds they 
 become organs of reproduction. The leaves in the region of the 
 organs of fructification frequently exhibit a very weak vegetation, 
 and easily die altogether (for instance, the pappus, the bracts, and 
 
ORGANS OF REPRODUCTION. 557 
 
 bracteoles of the Paronychiacea}, or if not, at least partially (as in 
 many white flowers), or are so far dead that their cells are entirely 
 filled by special matters or substances not calculated to sustain 
 chemical processes (as most of the coloured bracts and petals). It 
 is only the calycine and carpellary leaves that exhibit an active 
 vegetation not different from that of the stem-leaves. 
 
 The function of protecting the tender, newly-developed parts by 
 a firm enclosure around the buds against the influences of the 
 atmosphere, and against excessive moisture which readily produces 
 decomposition, belongs to all leaves, without any exception. They 
 continue to protect these tender parts until the development of the 
 epidermal system enables them to resist these injuries. This last- 
 named function seems to be that which is more especially performed 
 by calyx and corolla. As soon as the flower has opened itself, the 
 sepals and petals may be removed without injuring the development 
 of the seed and fruit in the slightest degree, provided they do not 
 still serve the purpose of protecting the tender organs of repro- 
 duction against rain, &c. ; or if, after their removal, the transfer of 
 the pollen to the stigma is rendered impossible, an artificial transfer 
 is substituted. 
 
 The leaves also become organs of attachment in the form of 
 cirrhi. 
 
 B, Organs of Reproduction. 
 a. Cryptogamia. 
 
 222. Among the Angiospora, the sporangia are the only parts 
 to which we can attribute a definite function, namely, that of 
 forming the spores, of which they are the parent-cells. We know 
 nothing of the object of the other parts of the sporocarp, and, indeed, 
 it is very improbable that they should possess any other than a 
 morphological significance. The nature of the so-called anthers has 
 been already explained ( 84.). 
 
 There are likewise parent-cells of the spores in the Cryptogamia 
 and Gymnosporce, which, as such, exercise an important function. 
 The sporocarps only serve as envelopes of the spores, and facilitate 
 and regulate the distribution of the spores by their hygroscopic 
 properties. With regard to the Antheridia, we can state for certain, 
 that not a single fact exists from which we could infer, in the 
 remotest degree, that they have the slightest connexion with the 
 function of reproduction. Every thing that has been hitherto 
 written on this subject are only fine-spun fancies, founded upon 
 decidedly false analogies. 
 
 It may be further stated, that we are still ignorant with regard 
 to the peculiar function possessed by the external spore-case in 
 relation to the development of the spore. It is possible that it may 
 be principally intended, through its indestructibility, for the pro- 
 tection of the delicate cell of the spore against injurious agencies 
 
558 ORGANOLOGY. 
 
 and the action of humidity, until the cell itself is in a state fit to 
 assimilate foreign matters. 
 
 b. Phanerogamia. 
 
 223. With regard to the anthers, the parent-cells form the 
 pollen, and the external, and frequently so richly and curiously- 
 formed membrane seems to perform no other function than that of 
 the spore-case alluded to at the conclusion of our last paragraph. 
 The formations, secreting surfaces, or organs that secrete sweet 
 juice, the true nectar, have no imaginable organic connexion with 
 the function of reproduction; but they appear to attract the insects, 
 which latter so frequently assist in the transfer of the pollen to the 
 stigma. 
 
 The seed-bud (ovule) is intended for the reception of the pollen- 
 tube. It is protected by the germen in the same manner as the 
 terminal shoot is by the external leaves of the bud, and at the same 
 time it conveys to it the pollen-tube. 
 
 The most important part of the seed-bud is the embryo-sac, 
 because the embryo (with the exception of the Rhizocarpece) is 
 developed in it. We are as yet entirely ignorant of the influence 
 which this sac exercises on the embryo. 
 
 It is certain that granules of pollen produce genuine tubes in other spots 
 besides the stigma ; it is also certain that many pollen-tubes descend 
 through the stigma and style into the cavity of the germen, without 
 being converted into embryos, because they have not penetrated the seed- 
 bud. But it is likewise as certain, that the tubes in the Rhizocarpece do 
 not come into immediate contact with the embryo- sacs, being constantly 
 separated from them by a thin layer of cells. An observation of my own, 
 referred to on a former occasion *, is also highly remarkable, viz., that 
 two pollen-tubes entered into the seed-bud of an Orchid, one of which, 
 penetrating through its internal opening, reached the embryo-sac, and 
 pressing upon this was converted in the usual way into an embryo, 
 whilst the other penetrated between the external and internal covering 
 of the seed-bud, and was developed into the rudiment of an embryo (a 
 kind of graviditas extrauterina) (see Plate VI., fig. 1.). It appears, 
 therefore, that the influence of the embryo-sac may extend to some dis- 
 tance, but it is entirely unknown to us what kind of influence; and it is 
 the more difficult to be discovered, as the most important elements in the 
 enquiry, viz., an accurate chemical investigation of the contents of the 
 pollen-tube and of the embryo-sac, are not yet forthcoming, and are not 
 likely to be so for a long time to come. I may here remind my readers 
 of Caspar Fr. Wolff's expression, " Nutrimentum magnum in minima 
 mole." As to analogies between the production of plants and the pro- 
 creation of the higher animals, it can merely afford employment for the 
 wit of those who have nothing better to do, since the act itself, and the 
 part which the different materials play in it, are as yet entirely unknown 
 to us, even with regard to the higher animals. 
 
 * Acta. Acad. C. L. C. N. E. vol. xix. pt. i. p. 46, in Orchis latifolia. 
 
ORGANS OF REPRODUCTION. 559 
 
 224. At subsequent periods the plant, which is gradually deve- 
 loped from the embryo, is decidedly nourished by the embryo- sac, and 
 even afterwards, in the later stages of germination, the assimilated 
 substances deposited in the endosperm serve for the sustenance of the 
 plant. The nucleus of the bud performs a similar function with the 
 perisperm, and acts as a substitute for the latter. The envelopes of the 
 bud are converted into the testa of the seed, and protect the delicate 
 germinating plant; the envelopes of the fruit perform the same 
 function, and subsequently assist in the distribution of the seed by 
 means of their hygroscopicity. The succulent parts of the fruit 
 may also serve, through their decay, to form a nutritive soil for the 
 first development of the young plant. 
 
 Conclusion. 
 
 The insufficiency and deficiency of our generalisations in Botany 
 are acknowledged by all competent investigators. It was believed 
 that more favourable results might be expected as Physiology and 
 Anatomy advanced, and systematic Botany looked for aid from the 
 same sources. The meagreness of our Physiology, freed from 
 all that does not properly belong to it, as I have endeavoured to 
 give it, affords but little hope at present from that quarter. It 
 cannot have escaped the notice of the attentive reader of the Mor- 
 phology, that little also can be expected from Anatomy. Whence, 
 therefore, are we to look for help ? By the study of external forms ; 
 not in the manner that it has hitherto been done, superficially 
 and without fundamental principles, but from the study of Mor- 
 phology as a science, whose leading principle must be the history of 
 development. It has been my object in the present work to indicate 
 the proper path, and to open an entrance into it according to the 
 best of my ability. May better men continue the work ! 
 
560 
 
 ORGANOLOGY. 
 
 APPENDIX, 
 
 A. 
 
 ANALYTICAL PAPERS BELONGING TO THE DIVISION RESPECT- 
 ING THE NOURISHMENT OF PLANTS. 
 
 I. BOUSSINGAULT'S EXPERIMENTS, COMMUNICATED IN HIS 
 RURALE," VOL. II. 
 
 ECONOMIE 
 
 a. Tables showing the Contents of Water in the Vegetable Matters analysed in 
 Boussingaidt's Experiments. 
 
 
 Dry Matter, 
 (dried at 110 C.) 
 
 Water. 
 
 Wheat 
 
 0-855 
 
 0-144 
 
 Rye 
 
 0-834 
 
 0-16<> 
 
 Oats 
 
 0-792 
 
 0-208 
 
 Wheat Straw 
 
 0740 
 
 0-260 
 
 Rye Straw 
 
 0-8 1 3 
 
 0-187 
 
 Oat Straw ..... 
 
 0-713 
 
 0-287 
 
 Potatoes 
 
 0-241 
 
 0-759 
 
 Beetroot ...... 
 
 0-122 
 
 0-878 
 
 Swedish Turnips 
 
 0-075 
 
 0-925 
 
 Topinambour ..... 
 Pease 
 
 0-208 
 0-914 
 
 0-792 
 0-086 
 
 Pease Straw ..... 
 
 0-88? 
 
 0-118 
 
 Clover Hay 
 
 0-790 
 
 0-210 
 
 Stalks of Topinambour 
 
 0-871 
 
 0-129 
 
 b. Composition of the Manure (dried in a vacuum at 110 C.). 
 
 
 Carbon. 
 
 Hydrogen. 
 
 Oxygen. 
 
 Nitrogen. 
 
 Salts and Earths. 
 
 I. 
 
 32-4 
 
 3-8 
 
 25-8 
 
 J-7 
 
 36-3 
 
 11. 
 
 32-5 
 
 4-1 
 
 26-0 
 
 1-7 
 
 35-7 
 
 III. 
 
 38-7 
 
 4-5 
 
 28-7 
 
 17 
 
 26'4 
 
 IV. 
 
 36-4 
 
 4-0 
 
 19-1 
 
 2-4 
 
 38-1 
 
 V. 
 
 40-0 
 
 4-3 
 
 27-6 
 
 2-4 
 
 25-7 
 
 VI. 
 
 34-5 
 
 4-3 
 
 27-7 
 
 2-0 
 
 31-5 
 
 Average 
 
 35'8 
 
 4-2 
 
 25-8 
 
 2-0 
 
 32'2 
 
APPENDIX. 
 
 561 
 
 The Analysis shows that the quantity of manure, which is said to manure the 
 soil ( 1 Hectar = 40,000 D feet) during a successional harvest of five years, 
 contains : 
 
 Kilogr. 
 
 Carbon 3637'6 
 
 Hydrogen 426'8 
 
 Oxygen 
 
 Nitrogen 
 
 Salts and Earths 
 
 2521-5 
 
 203-2 
 
 3271-9 
 
 Dry Manure 10161-0 
 
 (1 Kilogramme is equal to 2' 138 Ibs. Pr., or 2'2 Ibs. English.) 
 
 c. Composition of the Produce (dried in a vacuum at 110 C.). 
 
 
 With the Ashes. 
 
 After Deduction of the Ashes. 
 
 
 | 
 
 I 
 
 i 
 
 c 
 
 1 
 
 cc 
 
 1 i 1 
 
 1 
 
 i 
 
 
 i 
 
 SB 
 
 >> 
 
 X 
 
 
 
 E 
 
 
 
 1 
 < 
 
 1 I 
 
 o 
 
 
 
 Wheat 
 
 46-1 
 
 5-8 
 
 43-4 
 
 2-3 
 
 2-4 
 
 47-2 6-0 
 
 44-4 
 
 2-4 
 
 Rye .... 
 
 46-2 
 
 5-6 
 
 44-2 
 
 1-7 
 
 2-3 
 
 47-3 5-7 
 
 45-3 
 
 1-7 
 
 Oats .... 
 
 50-7 
 
 6-4 
 
 36-7 
 
 2-2 
 
 4-0 
 
 52-9 i 6-6 
 
 38-2 
 
 2-3 
 
 Wheat Straw 
 
 48-4 
 
 5-3 
 
 38-9 
 
 0-4 
 
 7-0 
 
 52-1 
 
 5-7 
 
 41-8 
 
 0'4 
 
 Rye Straw . 
 
 49-9 
 
 5-6 
 
 40-6 
 
 0-3 
 
 3'6 
 
 51-8 
 
 5-8 
 
 42-1 
 
 0-3 
 
 Oat Straw . 
 
 50-1 
 
 5-4 
 
 39-0 
 
 0-4 
 
 5-1 
 
 52'8 
 
 5-7 
 
 41-1 
 
 0-4 
 
 Potatoes 
 
 44-0 
 
 5-8 
 
 44-7 
 
 1-5 
 
 4-0 
 
 45-9 
 
 61 
 
 46-4 
 
 1-6 
 
 Beetroot 
 
 42-8 
 
 5'8 
 
 43-4 
 
 1-7 
 
 6-3 
 
 45-7 
 
 6-2 
 
 46-3 
 
 1-8 
 
 Swedish Turnips . 
 
 42-9 
 
 5'5 
 
 42-3 
 
 1-7 
 
 7-6 
 
 46-3 
 
 60 
 
 45-9 
 
 1-8 
 
 Topinambour 
 
 43-9 
 
 5-8 
 
 43-3 
 
 1-6 
 
 6-0 
 
 46-0 
 
 6-2 
 
 46-1 
 
 1-7 
 
 Yellow Pease 
 
 46-5 
 
 6-2 
 
 40-0 
 
 4-2 
 
 3-1 
 
 48-0 
 
 6-4 
 
 41-3 
 
 4-3 
 
 Pea Straw . 
 
 45-8 
 
 5'0 
 
 35-6 
 
 2-3 
 
 11-3 
 
 51-5 
 
 5'6 
 
 40-3 
 
 2'6 
 
 Red Clover Hay . 
 
 47-4 
 
 5-0 
 
 37'8 
 
 2-1 
 
 7-7 
 
 51-3 
 
 5-4 
 
 41-1 
 
 2-2 
 
 Topinambour Stalk 
 
 45-7 
 
 5-4 
 
 45-7 
 
 0-4 
 
 2-8 470 
 
 5-6 
 
 47-0 
 
 0-4 
 
 d. The Experiments themselves. 
 First Series. 
 
 Succes- 
 sive 
 Years. 
 
 Substances. 
 
 Crop per 
 Hectar. 
 
 Dry 
 Harvest. 
 
 Carbon. 
 
 Hydrogen 
 
 Oxygen. 
 
 Nitro- 
 gen. 
 
 Salts and 
 Earths. 
 
 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 1. 
 
 Potatoes . 
 
 12800 
 
 3085 
 
 1357-4 
 
 178-9 
 
 1379-0 
 
 46-3 
 
 123-4 
 
 2. 
 
 Wheat . 
 
 1343 
 
 1148 
 
 529-3 
 
 66-6 
 
 498-2 
 
 26-4 
 
 27-5 
 
 
 Wheat Straw . 
 
 3052 
 
 2258 
 
 1093-0 
 
 119-7 
 
 878-2 
 
 9-0 
 
 158-1 
 
 3. 
 
 Clover (Hay) . 
 
 5100 
 
 4029 
 
 1909-7 
 
 2O1-5 
 
 1523-0 
 
 84-6 
 
 310-2 
 
 4. 
 
 Wheat . 
 
 1659 
 
 1418 
 
 653-8 
 
 82-2 
 
 615-4 
 
 32-6 
 
 34-0 
 
 
 Wheat Straw . 
 
 3770 
 
 2790 
 
 1350-4 
 
 147-8 
 
 1085-3 
 
 11-2 
 
 195-3 
 
 
 Swedish Turnips 
 
 9550 
 
 716 
 
 307 -2 
 
 39-3 
 
 302-9 
 
 12-2 
 
 54-4 
 
 5. 
 
 Oats 
 
 1344 
 
 1064 
 
 539-5 
 
 68-0 
 
 330-5 
 
 23-3 
 
 42-6 
 
 
 Oat Straw 
 
 1800 
 
 1283 
 
 642-8 
 
 69-3 
 
 500-4 
 
 5-1 
 
 65-4 
 
 
 Total 
 
 40418 
 
 17791 
 
 8383-1 
 
 973-3 
 
 7172-9 
 
 250-7 
 
 1010-9 
 
 Manure applied 
 
 49O86 
 
 10161 
 
 8637-6 
 
 426-8 
 
 2621-5 
 
 203-2 
 
 3271-9 
 
 Difference . . + 7363 + 4747'5 + 546'5 + 5551-4 + 47 -5 -2261-0 
 
 O O 
 
562 
 
 ORGANOLOGY. 
 Second Series. 
 
 Succes. 
 give 
 Years. 
 
 Substances. 
 
 Crop per 
 Hectar. 
 
 Dry 
 
 Harvest. 
 
 Carbon. 
 
 Hydrogen 
 
 Oxygen. 
 
 Nitro- 
 gen. 
 
 Salts and 
 Earths. 
 
 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 1. 
 
 Beetroot 
 
 26000 
 
 3172 
 
 1357-7 
 
 184-0 
 
 1376-7 
 
 53-9 
 
 199-8 
 
 2. 
 
 Wheat . 
 
 1185 
 
 1013 
 
 467-0 
 
 58-8 
 
 439-6 
 
 23-3 
 
 24-3 
 
 
 Wheat Straw . 
 
 2693 
 
 1993 
 
 964-0 
 
 105-6 
 
 775-3 
 
 8-0 
 
 139-5 
 
 3. 
 
 Clover (Hay) 
 
 5100 
 
 4029 
 
 1909-7 
 
 201-5 
 
 1523-0 
 
 84-6 
 
 310-2 
 
 4. 
 
 Wheat . 
 
 1659 
 
 1418 
 
 653-8 
 
 82-2 
 
 615-4 
 
 32-6 
 
 34-0 
 
 
 Wheat Straw . 
 
 3770 
 
 2790 
 
 1350-4 
 
 147-8 
 
 1085-3 
 
 11-2 
 
 195-3 
 
 
 Carrots . 
 
 9550 
 
 716 
 
 307-2 
 
 39-3 
 
 302-9 
 
 12-2 
 
 54-4 
 
 5. 
 
 Oats 
 
 1344 
 
 1064 
 
 539-5 
 
 68-0 
 
 390-5 
 
 23-3 
 
 42-6 
 
 
 Oat Straw 
 
 1800 
 
 1283 
 
 642-8 
 
 69-3 
 
 500-4 
 
 5-1 
 
 65-4 
 
 
 Total 
 
 53101 
 
 17478 
 
 8192-7 
 
 956-5 
 
 7009-0 
 
 254-2 
 
 1065-5 
 
 Manure applied 
 
 49080 
 
 10161 
 
 3637 -6 
 
 426-8 
 
 2621-5 
 
 203-2 
 
 3271-9 
 
 Difference . . + 7317 + 4555'! + 529'7 + 4387'5 + 51-0-2206'4 
 
 Third Series. 
 
 Succes. 
 sive 
 Years. 
 
 Substances. 
 
 Crop per 
 Hectar. 
 
 Dry 
 Crop. 
 
 Carbon. 
 
 Hydrogen 
 
 Oxygen. 
 
 Nitro- 
 gen. 
 
 Salts and 
 Earths. 
 
 1. 
 
 Potatoes 
 
 Kilogr. 
 12809 
 
 Kilogr. 
 3085 
 
 Kilogr. 
 1357-4 
 
 Kilogr. 
 178-9 
 
 Kilogr. 
 1379-0 
 
 Kilogr. 
 46-3 
 
 Kilogr. 
 123-4 
 
 2. 
 
 Wheat . 
 
 1343 
 
 1148 
 
 529-3 
 
 66-6 
 
 498-2 
 
 26-4 
 
 27-5 
 
 
 Wheat Straw . 
 
 3052 
 
 2258 
 
 1093-0 
 
 119-7 
 
 878-2 
 
 9-0 
 
 158-1 
 
 3. 
 4. 
 
 Clover (Hay) 
 Wheat . 
 
 5100 
 1659 
 
 4029 
 1418 
 
 1909-7 
 653-8 
 
 201-5 
 82-2 
 
 15230 
 615-4 
 
 84-6 
 32-6 
 
 310-2 
 34-0 
 
 
 Wheat Straw . 
 
 3770 
 
 2790 
 
 1350-4 
 
 147'8 
 
 1085-3 
 
 11-2 
 
 195-3 
 
 5. 
 
 Swedish Turnips 
 Pease 
 
 9550 
 1092 
 
 716 
 998 
 
 307-2 
 464-1 
 
 39-3 
 61-9 
 
 302-9 
 399-2 
 
 12-2 
 41-9 
 
 54-4 
 30-9 
 
 
 Pease Straw . 
 
 2790 
 
 2461 
 
 1127-3 
 
 123-0 
 
 876-1 
 
 56-6 
 
 278-1 
 
 6. 
 
 Rye 
 Rye Straw 
 
 Total 
 
 1679 
 3731 
 
 1394 
 3033 
 
 644-0 
 1513-5 
 
 78-1 
 169-8 
 
 616-1 
 1231-4 
 
 23-7 
 9-1 
 
 23-1 
 109-2 
 
 46566 
 
 23330 
 
 10949-7 
 
 1268-8 
 
 9404-8 
 
 353-6 
 
 1353-2 
 
 Manure applied 
 
 58900 
 
 12192 
 
 4364-2 
 
 512-2 
 
 3145-5 
 
 243-8 
 
 3925-8 
 
 Difference . . + 11138 + 6585-5 + 756-6+ 6259-3 + 109-8-2572-6 
 
 Fourth Series. 
 
 Succes- 
 sive 
 Years. 
 
 Substances. 
 
 Crop per 
 Hectar. 
 
 Dry 
 
 Crop. 
 
 Carbon. 
 
 Hydrogen 
 
 Oxygen. 
 
 Nitro- 
 gen. 
 
 Salts and 
 Earths. 
 
 1. 
 
 Manured Fal- 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 
 low 
 
 
 
 
 
 
 
 
 
 
 
 
 
 , 
 
 2. 3. 
 
 Wheat . 
 
 3318 
 
 2836 
 
 1037-4 
 
 164-5 
 
 1230-8 
 
 65-2 
 
 68 -1 
 
 
 Wheat Straw . 
 Total 
 
 7500 
 
 5550 
 
 2686-2 
 
 294-2 
 
 2159-0 
 
 22-2 
 
 388-5 
 
 10818 
 
 8368 
 
 3993-6 
 
 458-7 
 
 3389-8 
 
 87-4 
 
 456-6 
 
 Manure applied 
 
 20000 
 
 4140 
 
 1284-5 
 
 173-9 
 
 1068-1 
 
 82-8 
 
 1333-1 
 
 Difference . . + 4246 + 2511-5+ 284-8 + 2321-7 + 4-6-876'5 
 
APPENDIX. 
 
 563 
 
 Fifth Series. 
 CULTIVATION OF TOPINAMBOUR. 
 
 Succes- 
 sive 
 Years. 
 
 Substances. 
 
 Crop 
 rer 
 Hectar. 
 
 Dry 
 Crop. 
 
 Carbon. 
 
 Hydro- 
 gen. 
 
 Oxygen. 
 
 Nitrogen. 
 
 Salts 
 and 
 Earths. 
 
 1. 
 2. 
 
 Man i 
 Di 
 
 Topinambour 
 Woody Stalk 
 
 Total . 
 ire applied . 
 
 fference 
 
 Kilogr. 
 52880 
 28200 
 
 Kilogr. 
 11020 
 24542 
 
 Kilogr. 
 4763-0 
 11224-7 
 
 Kilogr. 
 638-0 
 1326-3 
 
 Kilogr. 
 4763-0 
 11224-7 
 
 Kilogr. 
 176-0 
 98-2 
 
 Kilogr. 
 660-0 
 
 687-2 
 
 81080 
 45450 
 
 35562 
 9408 
 
 15987-7 
 3368-1 
 
 1964-3 
 395-1 
 
 15987-7 
 2427-3 
 
 274-2 
 188-2 
 
 1347-2 
 3029-3 
 
 . +26154 + 12619*6+ 1569-2 + 13560-4+ 86'0 1682-1 
 
 e. Synopsis of all the Experiments. 
 
 Series. 
 
 Dry Manure 
 per OneHectar 
 per Year. 
 
 Nitrogenous 
 Contents of 
 Manure. 
 
 Dry Crop in 
 One Twelve- 
 month. 
 
 Nitrogen of 
 the Crop. 
 
 Gain in Organic 
 Material. 
 
 Gain in 
 Nitrogen. 
 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 Kilogr. 
 
 1. 
 
 2032 
 
 40-6 
 
 3558 
 
 50-1 
 
 1526 
 
 9'5 
 
 2. 
 
 2032 
 
 40-6 
 
 3495 
 
 50-8 
 
 1463 
 
 10'2 
 
 3. 
 
 2032 
 
 40-6 
 
 3888 
 
 58-9 
 
 1856 
 
 18-5 
 
 4. 
 
 1360 
 
 25-8 
 
 2795 
 
 29'1 
 
 1435 
 
 3'3 
 
 5. 
 
 4704 
 
 94-1 
 
 17781 
 
 137-1 
 
 13087 
 
 43-0 
 
 II. CULTIVATION OF LUCERNE, COMMUNICATED BY MR. CRUD, AND CALCU- 
 LATED BY BOUSSINGAULT. 
 
 (Lucern-hay contains, upon an average, in 100 parts, 2 -35 nitrogen.) 
 
 Cultivated Plant. 
 
 Crop per Hectar 
 in Kilogrammes. 
 
 Nitrogen 
 in Kilogrammes. 
 
 1st year Lucern-hay .... 
 2nd . 
 
 3360 
 10080 
 
 79 
 
 237 
 
 3rd } , 
 
 12500 
 
 294 
 
 4th .... 
 
 10080 
 
 237 
 
 5th 
 
 8000 
 
 188 
 
 
 1580 
 
 31 
 
 6th Wheat [ t r r a n w ; 
 
 3976 
 
 12 
 
 
 
 1078 
 
 Manure applied . 
 
 44000 
 
 224 
 
 Excess of Nitrogen .... 
 Do. do. for the year 
 
 
 854 
 142 
 
 o o 2 
 
564 
 
 ORGANOLOGY. 
 
 III. CONTENTS IN ASHES OF SOME CULTURED PLANTS. 
 
 
 Names of the Plants, 
 and of the Examiners. 
 
 Salts of 
 Potash and 
 Soda. 
 
 Salts of 
 L^me 
 and 
 Mag- 
 nesia. 
 
 3 hosphatic 
 
 Salts. 
 
 Silica. 
 
 
 Oats : Straw and Seed, 
 
 
 
 
 
 
 ( Wiegmann & Polsdorff) 
 
 34-00 
 
 4-00 
 
 . . 
 
 62-00 
 
 
 Barley : Straw and Seed, 
 
 
 
 
 
 
 ( Wiegmann & Polsdorff) 
 
 19-00 
 
 25-70 
 
 . . 
 
 55-03 
 
 Siliceous Plants 
 
 Hay (Haidlen) . 
 Rye Straw (Fresenius) 
 
 5-50 
 18-65 
 
 28-60 
 16-52 
 
 21-10 
 6-98 
 
 60-10 
 63-89 
 
 
 Wheat Straw (DeSaus- 
 
 
 
 
 
 
 sure) 
 
 22-00 
 
 7-20 
 
 11-20 
 
 61-05 
 
 
 Barley Straw (De Saus- 
 
 
 
 
 
 
 sure) 
 
 20-00(?) 
 
 20-25 
 
 7-75 
 
 57-00 
 
 
 Meadow Clover ( Wieg- 
 
 
 
 
 
 
 mann and Polsdorff ) . 
 
 39-20 
 
 56-00 
 
 . 
 
 4-90 
 
 
 Lucerne (Hertwig) 
 
 36-13 
 
 60-73 
 
 13-52 
 
 2-26 
 
 
 Tobacco, German, 
 
 
 
 
 
 
 (Hertwig) 
 
 23-07 
 
 62-23 
 
 17-95 
 
 15-25 
 
 Lime- ? 
 
 Tobacco, Havanna, 
 
 
 
 
 
 Magnesia- \ ^ ants 
 
 (Hertung) . 
 
 24-34 
 
 67-44 
 
 9-04 
 
 8-30 
 
 
 
 Potato Stalks ( Berthier 
 
 
 
 
 
 
 and Braconnot) 
 
 4-20 
 
 59-40 
 
 
 36-40 
 
 
 Potato Stalks (Hert- 
 
 
 
 
 
 
 wig) . 
 
 6-97 
 
 53-17 
 
 9-78 
 
 29-81 
 
 
 Pea Straw (Hertwig) . 
 
 f 27-81 
 \_20-05 
 
 61-38 
 60-08 
 
 11-62 
 12-61 
 
 7-81 
 15-54 
 
 
 Maize Straw (De Sous- 
 
 
 
 
 
 
 sure) 
 
 71-00 
 
 6-50 
 
 14-70 
 
 18-00 
 
 P t h 7 
 
 White Turnips ( Liebig) 
 
 81-60 
 
 18-40 
 
 
 
 o as i- / pi ants , 
 
 Beet-root (Hruschauer) 
 
 88-00 
 
 12-00 
 
 
 
 J 
 
 Potatoes (Hruschauer) 
 
 85-81 
 
 14-19 
 
 
 
 
 Topinambour (Bra- 
 
 
 
 
 
 
 connot) 
 
 84-30 
 
 15-70 
 
 
 
 
 Wheat, red, (Fresenius) 
 
 86-64 
 
 22-96 
 
 104 -64(?) 
 
 0-15 
 
 
 Wheat, white, ( mil) . 
 
 52-98 
 
 38-02 
 
 91-67 
 
 0-30 
 
 Phosphatic Plants, 
 
 Rye (Fresenius) . 
 Peas ( Will) . 
 
 65-16 
 71-50 
 
 32-12 
 24-55 
 
 96-18 
 85-46 
 
 0-50 
 
 
 Large Beans (Buchtier) 
 
 71-54 
 
 28-46 
 
 97-05 
 
 
 
 Maize (De Saussure) . 
 
 . 
 
 . 
 
 83-50 
 
 1-00 
 
 
 Barley (De Saussure) . 
 
 
 
 
 
 76-70(?) 
 
 0'5(?) 
 
APPENDIX. 
 
 565 
 
 IV. PROPORTION OF NITROGEN AND OF PHOSPHORIC ACID IN NUTRITIVE 
 PLANTS, ACCORDING TO BOUSSINGAULT. 
 
 Nutritive Plants. 
 
 Constituents 
 of Ashes. 
 
 Nitrogen. 
 
 Phosphoric 
 Acid. 
 
 Hay .... 
 
 62'33 
 
 11-50 
 
 3-57 
 
 Potatoes .... 
 
 9-64 
 
 3-70 
 
 109 
 
 Beetroot .... 
 
 7-70 
 
 2-10 
 
 0-46 
 
 Swedish Turnips . 
 
 5-70 
 
 1-30 
 
 0-35 
 
 Potatoes .... 
 
 12-47 
 
 3-75 
 
 1-35 
 
 Wheat .... 
 
 20-51 
 
 20-50 
 
 9-64 
 
 Maize .... 
 
 11-00 
 
 16-40 
 
 5-51 
 
 Oats .... 
 
 31-74 
 
 17-87 
 
 4-73 
 
 Wheat Straw 
 
 51-90 
 
 3-00 
 
 1-61 
 
 Oat Straw 
 
 35-70 
 
 3-00 
 
 1-07 
 
 Clover Hay 
 
 7350 
 
 21-00 
 
 4-63 
 
 Peas .... 
 
 30-00 
 
 38-40 
 
 9-03 
 
 White Beans 
 
 35-00 
 
 45-80 
 
 9-38 
 
 Large Beans 
 
 3000 
 
 51-10 
 
 10-26 
 
 The proportion of phosphoric acid to nitrogen is here, upon an average, 
 1 : 3'5. The greatest deviations in maxima are I : 4'9, in minima I : 1-9. If we 
 omit the four greatest deviations, the average would be 1 : 3'6, and the greatest 
 deviations are 1 : 2*8 and 1 : 4*5. We ought, however, to take into considera- 
 tion that the determination of the nitrogen, but still more of the phosphoric acid, 
 is attended with the greatest difficulty, and therefore may be still open to con- 
 siderable corrections. 
 
 V. EXPERIMENTS OF KUHLMANN ON THE EFFECT OF AMMONIAICAL MA- 
 NURES UPON THE PRODUCE OF MEADOWS. (Comptes rendus, Nov. 13, 
 1843.) 
 
 The experiments were instituted in the rather rainy year of 1843 ; the salts of 
 the manure were applied on the 28th of March, and the harvest took place on 
 the 30th of June. The following Table gives the results : 
 
 
 
 
 
 
 The 
 
 
 
 
 
 
 manured 
 
 
 
 
 
 
 Meadow 
 
 No. 
 
 Nature of the Manure. 
 
 Quantity 
 per 
 Hectar. 
 
 Crop 
 per 
 Hectar. 
 
 Nitroge- 
 nous Con- 
 tents of the 
 
 therefore 
 delivered 
 more than 
 
 
 
 
 
 Manure. 
 
 the imma- 
 
 
 
 
 
 
 nured one, 
 
 
 
 
 
 
 as follows : 
 
 
 
 Kilogr. 
 
 Kilogr. 
 
 
 
 1. 
 
 No manure .... 
 
 
 4000 
 
 
 
 2. 
 
 Sulphate of Ammonia . 
 
 266 
 
 5233 
 
 50-08 
 
 12-33 
 
 3. 
 
 Hydrochiorate of Ammonia . 
 
 266 
 
 5716 
 
 70-33 
 
 17-16 
 
 4. 
 
 Nitrate of Soda 
 
 266 
 
 5723 
 
 44-10 
 
 17-63 
 
 
 
 Litr. 
 
 
 
 
 5. 
 
 Urine of Horses 
 
 21666 
 
 6240 
 
 349-27 
 
 22-40 
 
 6. 
 
 Ammoniacal Water from the Gas-\ 
 works at Lisle J 
 
 5400 
 
 6300 
 
 9 
 
 23-00 
 
 7. 
 
 Water from Animal Bone Mills 
 
 21666 
 
 6493 
 
 938-14 
 
 24-93 
 
 8. 
 
 Flemish Manure 
 
 21666 
 
 7433 
 
 43-22 
 
 34-33 
 
 OBSERVATIONS ON THE ARTICLES OF MANURE. 
 
 No. 6. This water was neutralised by the hydrochloric acid water of the 
 glue manufactories, and thus a precipitate of phosphate of lime was applied to 
 the meadow. 
 
 o o 3 
 
566 ORGANOLOGY. 
 
 No. 7. The bones having been boiled in order to remove the fat, contained 
 about 2 per cent, of impure gelatine, with 16'98 per cent, of nitrogen. (The 
 specific gravity I have put at 1*021. The water of course likewise contained all 
 the insoluble salts of the bones, the vessels, skin, and sinews attached to it.) 
 
 No. 8. The Flemish manure, in this instance, consisted almost exclusively of 
 the urine and excrement of human beings (etat normal ?) : the specific gravity I 
 assume at 1'05 ; the nitrogenous contents, according to Boussingaiilt, at 0'19 
 per cent. 
 
 The most rapid and remarkable effects were exhibited by No. 6, 7, and 8. 
 
 B. 
 
 LIST OF OLD TREES, ACCORDING TO MOQUIN-TANDON. 
 ( Teratologie Vegetale.) 
 
 THERE are known 
 
 Palms of ...... 200, 300 years. 
 
 Cercis . . . . . . 300 
 
 Chirodendron ...... 327 
 
 Ulmus (Elm) ..... . 355 
 
 Cupressus (Cypress) ..... 388 
 
 Hedera (Ivy) ...... 448 
 
 Acer (Maple) . . . . . . 516 
 
 Lark (Larch) ...... 263, 576 
 
 Castanea (Chestnut) ..... 360, 626 
 
 Citrus (Oranges, Lemons, &c.) . . . 400, 509, 640 
 
 Platanus (Plane) . . . ... 720 
 
 Cedrus (Cedar) ... . 200, 800 
 
 Juglans (Walnut) . . . ... 900 
 
 Tilia (Lime) .... 364, 530, 800, 825, 1076 
 
 Abies (Spruce) ...... 1200 
 
 Quercus (Oak) . . 600, 800, 860, 1000, 1600 
 
 Olea (Olive) 700, 1000, 2000 
 
 Taxus (Yew) .... 1314, 1466, 2588, 2880 
 
 bchubertia . . . ... 3000, 4000 
 
 Legummosas ..... 2052,4104 
 
 Adansoma (Baobab) . 6000 
 
 Dracaena (Dragon Tree) ... 6000 
 
ADDENDA TO BOOKS I. AND II. 567 
 
 c. 
 
 CONTAINING THE NEW PASSAGES IN THE THIRD GERMAN 
 EDITION OF THE FIRST AND SECOND BOOKS: Leipsic, 1849. 
 
 Page 18., fourth line from the bottom. 
 
 Development of the Starch Granule. In very young potatoes we 
 find exceedingly minute granules ; in general, a greater number of small 
 than of large ones : even in the cells of .old potatoes minute granules 
 occur, mingled with the larger. If we regard the very minute granules 
 as the rudiments of the structure, and take the different size as standard 
 for estimating the age, the result is as follows : the smaller (therefore 
 the younger) the granules are, the more truly spherical they appear, and 
 the ovate or irregular outline is subsequently acquired. It is easy to 
 see that this deviation from the original globular form is not caused by 
 internal layers, but by the outer, the unequal thickness of which pro- 
 duces the gradual alteration of the outline ; while the innermost layers 
 continue to exhibit the form (spherical) which the youngest, that is, the 
 most minute, granules present. The conclusion from this is, that the 
 outermost layers are the youngest, and the innermost the oldest ; that is 
 to say, the starch grows by the successive deposition of new layers upon 
 the older. The probability deduced from the investigation of the potato 
 becomes almost certainty when we compare the starch granules in the 
 tuberous stem of Bletia TankerviUuB, in the rhizome of Lathrcea squa- 
 maria, and in the stem of Dieffenbachia seguine. In Bletia, by far 
 the greater part of the granules have a most characteristic outline, easy 
 to be detected ; and the structure of the layers is equally peculiar. 
 Others are enclosed by additional layers of a totally different shape, 
 laterally excentric from the former ; arid it is almost impossible to refuse 
 the conviction that the outer layers are the last formed. The same 
 holds good of Dieffenbachia^ only the granules are here more difficult to 
 observe. Fritsche arrived at the same conclusion from the consideration 
 of the "twin-granules," enclosed by simple outer layers ; and most 
 observers have since maintained it. The only other views are the base- 
 less and daring speculations of, in some cases, most superficial observers : 
 these require no refutation, since they are not supported even by an 
 appearance of probability. 
 
 Page 23. 10. 
 
 The author adopts the term protoplasma, proposed by Mohl, in the 
 place of mucus (schleim), the name formerly given to the quaternary 
 and proteine compounds, and which has been adopted in this transla- 
 tion. 
 
 o o 4 
 
568 APPENDIX. 
 
 Page 31., substitute for 14. 
 
 14. By the plant-cell (cellula) I understand exclusively the 
 elementary organ, which, when fully developed, possesses a wall 
 formed of cellulose and a semi-fluid nitrogenous lining, constitut- 
 ing the sole essential element of form of all plants, and without 
 possessing which nothing can be called a plant (ohne ivelche eine 
 Pflanze nicht bestehf). 
 
 Cells can only be formed in a fluid which contains sugar, dex- 
 trine, and proteine compounds (formative matter, cytoblastema). 
 The proteine compounds appear to be the primary producers of 
 the process here, as in the chemical metamorphoses ( 11.). Two 
 points must be distinguished : 
 
 I. The formation of cells without the influence of another cell 
 previously existing. This occurs in fluids capable of fermentation. 
 A globule of nitrogenous substance originates ; in this a cavity is 
 formed, it grows, and the complete cell has a delicate coat of cellu- 
 lose, without our being able to determine the epoch of its pro- 
 duction. 
 
 II. Formation of cells under the influence of a complete cell 
 already existing, or multiplication of the plant-cell. The mode of 
 multiplication of vegetable cells does not appear to follow the same 
 type in all cases. Apparently we may at present distinguish at 
 least two kinds of multiplication. 
 
 1. The nitrogenous substance, the protoplasma, collects into a 
 more or less perfectly spherical body, at length sharply defined, 
 the nucleus of the cell (cytoblastus) ; upon this is deposited a layer 
 of protoplasm, which expands as a vesicle, and forms the subse- 
 quent lining of the cell : at a very early period the whole becomes 
 enclosed by a wall of cellulose, and the cell is completed. This 
 appears to occur especially in the embryo-sac and the embryonal 
 vesicle. 
 
 2. The whole contents of a cell, including the nitrogenous 
 lining, divide into two portions, which appear to be separated by 
 a lighter zone ; and around each portion is formed a wall of cellu- 
 lose. The nucleus of the cell appears to behave differently here, 
 since : 
 
 a. It divides, and is thus doubled, so that each of the newly- 
 formed nuclei becomes the central point for one of the cell-forming 
 portions of the contents ; or, 
 
 b. It disappears, so that a new nucleus is developed in each of 
 the new cells after their production. 
 
 This mode (2.) of multiplication appears to occur in all the 
 other parts of the plant. 
 
 This subject requires a very great deal more investigation. 
 
 I exclude from the term "cell" all hollow elementary particles of 
 plants which do not bear the characters given in the paragraphs ; and 
 
ADDENDA TO BOOKS I. AND II. 569 
 
 this appears to be the only way to avoid great confusion, such as has 
 bep;un to prevail in some parts of Animal Histology. 
 
 [Other work has hitherto prevented the author from resuming his 
 researches on cell-formation in a systematic manner. He therefore gives 
 only a few additional observations in this edition, with a short report of 
 the labours of others.] 
 
 Page 33. line 33., add : 
 
 Mohl asserts that the primordial utricle is the forerunner of the forma- 
 tion of the cellulose cell-wall. I have not been able to satisfy myself of 
 this. I not unfrequently find the cell- contents of young cells wholly ho- 
 mogeneous, and of yellowish colour ; then one or more colourless, spherical 
 or ovate spaces originate, which expand and meet together like the 
 bubbles in froth. On their junction, the more viscid yellowish sub- 
 stance is then seen to move like little currents ; the bubbles gradually 
 coalesce into a cell-cavity ; the viscid fluid becomes the lining, and often 
 circulates for some time longer. I believe, also, that I am justified in 
 considering Mohl's primordial utricle and the circulating fluid to be per- 
 fectly identical. According to this view, the primordial utricle would 
 be so much the more fluid the younger it was, and therefore could not 
 be the often rather tough wall of the cell only just formed. Of course, 
 however, an extremely delicate and not easily isolated layer of the fluid 
 may, in a more solidified condition, form the primordial utricle, and thus 
 the foundation of the cell. 
 
 Page 37., before the History and Criticism. 
 
 Karsten (Botanische Zeitung, 184?8, p. 457, et seq.) is compelled to 
 oppose my observations on the ferment- cells. His chief objection is : 
 " The ferment-cells (which I must have overlooked) exist already in the 
 uninjured fruits, and pass through the filter;" and he then concludes 
 with a very peremptory protest against all future similar assertions. 
 Nevertheless, after a careful repetition of my researches, I still hold 
 provisionally to my opinion. I am quite convinced by my investigations 
 that the utricles well known to me in certain (not in all, e. g. not in the 
 Apple) fruits, the juice of which is capable of fermentation, have nothing 
 at all in common with the ferment-cells I have so often examined ; that 
 the ferment-cells also certainly originate in some fruits, such as the grape, 
 with the others, and quite independently of them, and then multiply so 
 rapidly in the must, that I could not decide that they were not already 
 nascent in the filtered drops ; but that there is certainly an epoch for 
 the grape, in which neither ferment- cells nor those utricles exist, notwith- 
 standing that the juice is capable of fermentation, and developes per- 
 fectly good ferment ; that especially apple-juice, which ferments so well, 
 contains neither those utricles nor ferment-cells ; that, altogether, the 
 juices of all fruits prepared and filtered before the commencement of 
 the formation of ferment-cells are altogether destitute of anything solid, 
 anything organic ; in fact, of any thing visible besides drops of oil. I 
 believe that Karsten would have kept back all his objections, at least for 
 the present, if he had combined the internal development of succulent 
 fruits with his fermentation experiments. These peculiar utricles have 
 to be spoken of at length in another place ( 39. Appendix, 574, c.). 
 
570 APPENDIX. 
 
 Page 38., add to History and Criticism. 
 
 In conclusion, I give an as complete as possible review of the whole 
 history of the study of vegetable cell-formation since 1838, in which 
 year, through my work, the origin of the vegetable cell was first declared 
 to be the fundamental problem in Botany. 
 
 A dissertation on the multiplication of the vegetable cell by division, 
 by Hugo von Mohl, had indeed appeared earlier, in 1835, but this only 
 bore reference to one isolated case, and a more recent revision of it will 
 be mentioned below. In other cases, I place the researches in chrono- 
 logical order. I restrict myself to a brief statement of the peculiar 
 observations and opinions of the authors, without entering upon a criti- 
 cism of them, or the refutations which they have received one from 
 another. Only I must mention that I do not go minutely into Hartig's 
 views (Das Leben der Pflanzenzelle, Berlin, 1844), because, as Mohl has 
 already remarked, he has such a very different way of looking at the 
 things from us, that it is impossible to give an account of the matter 
 without using his own words, and at equal length with himself. 
 
 1838. Schleiden, Beitrage zur Phytogenesis, in Miiller's Archiv 
 (Beitriige zur Botanik, p. 129.), The contents have been given at 
 length above. 
 
 Unger, Aphorismen zur Anatomic u. Physiologic der Pflanzen. 
 Vienna, 1838. Here we find a resurrection of Grew's opinion, that 
 the cells originate as cavities in homogeneous mucilage, without inde- 
 pendent walls. This appears to me rather speculation than observa- 
 tion. 
 
 Hugo von Mohl, On the Development of the Stomates, in the Linna3a, 
 1838 (Vermischte Schriften, p. 252.). An instance of multiplication of 
 cells by the so-called division. 
 
 1839. H. v. Mohl, Development of the Spores of Anchoceros Icevis, in 
 the Linnaea, 1839 (Vermischte Schriften, p. 84.), relates the origin of 
 transparent utricles in the mucilaginous contents of the cells, whereby the 
 nitrogenous lining (primordial utricle) is gradually detached from the cell- 
 contents, and at the same time, by the meeting of the utricles, becomes 
 defined at the points of junction of the course of the little mucilage 
 currents in cells. The nucleus of the parent-cell is persistent, and 
 another is formed, which, by repeated division, multiplies to four, which 
 arrange themselves tetrahedrally. Septa then divide the parent-cell 
 into four parts, in such a manner that the nuclei lie in the middle of 
 each subdivision. At the same time the nucleus of the parent-cell dis- 
 appears. The four newly-formed cells subsequently separate, with 
 special walls, from the parent-cell, lie free in it, and finally are emitted 
 by the destruction of the parent-cell. 
 
 1840. Schleiden, Zur Anatomie der Cacteen (Mem. de 1'Acad. de St. 
 Petersbourg, 6th series.) The contents have been incorporated above. 
 
 1841. Unger, in the Linnaea. The nuclei are formed subsequently 
 in the completed cell. 
 
 1842. Ndgeli, Ueber Entwicklung des Pollens; Zurich. Describes the 
 development of the cell around a central nucleus in the pollen granules 
 of the Phanerogamia. 
 
 Ncigeli, in the Linnaea. Development of the cells of the stomates. A 
 small triangular mark between the two secondary cells, which have 
 
ADDENDA TO BOOKS I. AND II. 571 
 
 originated in the parent-cell, is said to represent the intercellular passage 
 between them. Endosmose of water completely isolates the two secon- 
 dary cells from each other. 
 
 1843. Quekett, in the Microscopical Journal and Structural Record 
 for 1841, ed. by D. Cooper (in the extract in the Botanisehe Zeitung, 
 p. 80.). The primary utricles of the vessels are derived from cytoblasts, 
 which subsequently become absorbed. 
 
 Mirbel and Payen, in the Comptes rendus, January. A globule- 
 cellular substance, the cambium, precedes the formation of cells ; consists 
 of hydrates of carbon, dextrine, gum, sugar, &c., and nitrogenous sub- 
 stances. 
 
 Endlicher and Unger, Grundziige der Botanik. Distinguish primary 
 and secondary cell-formation. The first consists in the development of 
 cavities in an uniform mucilaginous substance. Originally the cavities 
 have no proper walls ; these are subsequently formed particularly in 
 Algae, Lichens ; general in the lower plants, rare in the higher. The 
 second is either intra-utricular or merismatic cell-formation. In the 
 former, the cells are formed, singly or in numbers, from the contents of 
 cells already existing, so that the parent-cells expand and become dis- 
 solved ; especially in the formation of spores and pollen. The latter, or 
 merismatic cell-formation, consists in the division of existing cells by the 
 formation of septa. This kind of cell-formation is the most general. In 
 both the latter kinds of cell-formation it is not the nucleus from which 
 the new cells are immediately produced, but the mucilaginous granular 
 contents of the cell. 
 
 Hermann Karsten, De Cella vitali Dissertatio. The cells originate 
 by the expansion of amorphous granules of organic matter in the 
 cells. 
 
 1844. Hugo von Mohl, Some Observations on the Structure of Vege- 
 table Cells (in the Botanisehe Zeitung, p. 273.). In all vitally active cells 
 a living membrane occurs, consisting of a nitrogenous layer : this mem- 
 brane exists earlier than the cell-wall formed of cellulose, and therefore 
 Mohl calls it the " primordial utricle." The new cells probably originate 
 by the solution of the old primordial utricle, and the formation of several 
 new ones effected through a nucleus, which always precedes the cell- 
 formation. 
 
 Unger, The Growth of Internodes considered anatomically (in the 
 Botanisehe Zeitung, p. 506.). The multiplication of the cells is the 
 result of the formation of septa. The nucleus is a secondary matter 
 here. 
 
 Nageli, Nuclei, Formation and Growth of Cells in Plants (in the 
 Zeitschrift f. wiss. Botanik, B. I. Heft 1.). The opinions are essen- 
 tially those given at pages 33, and 34 II. 
 
 1844. Grisebach (in Wiegmann's Archiv, 134, et seq.). The cells 
 are multiplied by division, without cytoblasts. Appendix to this. There 
 occur 1 . free rudiments of cells, swimming in the parent-cell ; 2. fre- 
 quently free secondary cells,~swimming with these ; 3, cells with parietal 
 cytoblasts, i. e. perfect secondary cells. From this it is concluded that 
 my theory of cell-formation is correct. 
 
 1845. Anonymous, Researches on the Cellular Structures which fill up 
 Vessels (in the Botanisehe Zeitung, p. 225, et seq.). The cellular organs 
 originate in the cavities of old vessels as vesicular protrusions of the 
 neighbouring cells, which penetrate through the canals of the pores, while 
 a nucleus is subsequently developed in them. 
 
572 APPENDIX. 
 
 Karl Mutter, Development of the Charce (in the Botanische Zeitung, 
 p. 410, et seq.). A fluid composed of amylum becomes agglomerated as a 
 ball into a cytoblast ; this is therefore nitrogenous, since the abundance 
 of nitrogen in starch is well known in gluten (!!!); around the cytoblast 
 is formed a cell. 
 
 Karl MuJler, On the Scales of Trichomanes membranaceum (in the 
 Botanische Zeitung, p. 580, et seq.). The cell-formation occurs in the 
 known manner, through cytoblasts : this is founded on dried speci- 
 mens (!). 
 
 Hugo von Mohl, On the Development of Stomates (in his Vermischte 
 Schriften). Appendix. The nucleus becomes doubled by division. 
 Then a simple septum is somewhat suddenly formed between the two, 
 dividing the whole cell into two portions. The septum subsequently 
 splits into two lamellae, as a furrow penetrates it at the upper and under 
 sides of the cells. 
 
 Schaffner, Some Researches on the Multiplication of Cells (in the 
 Flora, p. 481, et seq.). Cells are formed around one or more cytoblasts, 
 also around cytoblasts and cells already completed. The cytoblasts may 
 also be developed independently into cells, by becoming hollow. Cells 
 are also formed without a nucleus, the nucleus growing afterwards. 
 Multiplication of cells by division does not occur. The very youngest 
 cells exhibit no primordial utricle ; this is subsequently formed. 
 
 Karl Mutter, Some Observations on the Formation of Starch (in the 
 Botanische Zeitung, p. 833, et seq.). The cytoblasts are converted into 
 starch, and this only occurs in the completed cells. The cytoblast 
 expands vesicularly, is metamorphosed into amylum (passes into a dif- 
 ferent condition of aggregation ! ! !) ; new layers are deposited upon the 
 interior of its walls from the cytoblastema. The whole is observed in 
 the fruits of rotten Chares. 
 
 Hugo von Mohl, On the Multiplication of Vegetable Cells by Division 
 (in his Vermischte Schriften, p. 362, et seq.). In the Conferva, particu- 
 larly in Conferva glomerata, the primordial utricle forms a circular 
 fold inward, and thus divides the cell-contents into two portions ; this 
 fold of the primordial utricle is followed somewhat later by a fold of the 
 cell-membrane itself, which, finally arriving at the axis of the cell, blends, 
 and from the nature of its origin forms a complete double septum : thus 
 one cell has become two by division. 
 
 1846. Ndgeli, Nuclei, Formation and Growth of Cells in Plants 
 (in the Zeitschrift fiir wiss. Botanik, Heft 3 and 4. p. 22, et seq.). 
 
 1. There is a free cell-formation without a nucleus, through expansion 
 and excavation of a minute globule, in certain of the lower Algce, and in 
 the formation of the spores of the Lichens and Fungi. Sometimes a 
 nucleus is subsequently produced in the completed cell. This process of 
 abnormal cell-formation also occurs in the older cells of the Confervas, 
 as also in the formation of the spores in the species of Zygnema. 
 
 2. Perfectly homogeneous globules of mucilage are formed, the nucleoli; 
 around these a perfectly homogeneous nucleus, on which a proper 
 membrane is soon to be distinguished. A homogeneous layer of muci- 
 lage is deposited around the nucleus; this gradually becomes thick, 
 especially at one side ; then granular in the interior ; next it is enveloped 
 by a membrane, and the cell with a parietal nucleus is complete. 
 This process characterises the cell- formation in the embryo-sac of the 
 Phanerogamia. 
 
 Karl Muller, Development of the Lycopodiacece (in the Botanische 
 
ADDENDA TO BOOKS I. AND II. 573 
 
 Zeitung, p. 521, et seq.). The young cells consist of a nucleus, surrounded 
 by several concentric layers ; both these and the nucleus are coloured 
 blue by iodine. A coagulated gelatinous layer encloses the whole in the 
 form of a cell. These cells soon disappear as amylum-cells, since they 
 are gradually converted into a substance which becomes brown with 
 iodine (! ! !), and so forth. 
 
 1847. Karl Muller, Contributions to the History of Development of 
 the Vegetable Embryo (in the Botanische Zeitung, p. 760.). The first 
 cell of the embryo undoubtedly proceeds from the cytoblastema ; the 
 most indubitable confirmation of Schleiden's theory of cells (?).* 
 
 ffofmeister, Researches into the Process of Fertilisation in the (Eno~ 
 thereat (in the Botanische Zeitung, p. 788.). The first cell in the embry- 
 onal vesicle is formed by a sudden production of a septum ; consequently 
 the most indubitable refutation of Schleiden's theory of cells (?). 
 
 Page 48., add to History and Criticism. 
 
 The whole of Hartig's view has, moreover, been refuted by Hugo von 
 Mohlf , in his usual profound manner, and it can scarcely be a matter for 
 scientific discussion again. Harting \ makes far more solid objections to 
 Mohl's view of the gradual development of the cell-wall, and with him, 
 in part, Mulder , both in an anatomical and chemical point of view. 
 Hugo von Mohl | refutes the opinions of both, and also answers the sub- 
 sequent defence of Harting \. in a special treatise.^ Harting stated that 
 the original, yet unthickened, cell-membrane is perforated, and exhibits 
 in its earlier conditions, when treated with iodine and sulphuric acid, a 
 great number of white transparent pores, which subsequently become 
 closed by the layer of deposit upon the outer surface of the cell-walls. 
 On the other hand, Mohl repeats that these pores, previously seen and 
 described by me**, are not perforations, but closed by a delicate mem- 
 brane, the original membrane of the cell, which membrane also assumes 
 a blue colour, though very light. Mohl does not mention what I have 
 met with frequently in delicate transverse sections ; for instance, in the 
 parenchyma of the cabbage stalk, in the albuminous body of the Tagua 
 nut (vegetable ivory), &c., that a fine streak extends between the cells, 
 of a substance which remains almost colourless, while the cell-mem- 
 brane becomes deep blue with iodine and sulphuric acid. When the 
 section was successful, I always saw this substance separated into two 
 portions (the original membranes of the two contiguous cells) by a 
 delicate line. Harting further deduces, from micrometric measure- 
 ments, that the cavity of the cell does not become smaller through 
 
 * This author, as his researches in Monotropa show, cannot even distinguish the 
 embryo from the endosperm. 
 
 f H. v. Mohl, Observations on the Structure of the Vegetable Cell. Botanische 
 Zeitung, 1844, p. 273. 
 
 \ Harting, Microscopic Researches into the Walls of vegetable Cells (in Scheikondige 
 Onderzoekingen ; extract by H. v. Mohl in the Botanische Zeitung, 1846, p. 64.). 
 
 Mulder, Physiological Chemistry, translated by Moleschott ; in English, by 
 From berg. 
 
 || H. v. Mohl, On the Growth of Cell-membrane. Bot. Zeit. 1846, p. 337. 
 
 | Harting, Letter to H. v. Mohl, &c. Bot. Zeit. 1847, p. 337. 
 
 ^ H. v. Mohl, Investigation of the Question, Is Cellulose the Element of all Vege- 
 table Membranes? Bot. Zeit. 1847, p. 497. 
 
 * Wiegmann's Archiv, 1838, vol. i. p. 49. ; Beitr. z. Botanik, vol. i. p. 16. 
 
5*74 APPENDIX. 
 
 the thickening; therefore the layers of thickening must be deposited 
 on the outside. This objection again is refuted by H. v. Mohl, by the 
 help of most accurate measurements and acute reasoning. The third 
 point refers to chemical relations. They are as follows: The entire 
 wall of the young cell re-acts purely as cellulose, for, treated with 
 iodine and sulphuric acid, it becomes blue throughout its entire thick- 
 ness. The older cells exhibit various layers. The most external 
 consist of a matter quite insoluble in sulphuric acid. This membrane 
 is therefore deposited externally upon the original cellulose layer, 
 and closes up the original pores at the outside. The remainder of 
 the layers acquire a colour less blue and more green and yellow in 
 proportion as they lie more externally ; wherefrom Mulder deduces 
 either a disappearance of the cellulose and replacement by new sub- 
 stance, or a deposition of new layers always on the outside of the pre- 
 ceding. Harting, on the contrary, finds in this a proof that the ori- 
 ginally pure cellulose becomes subsequently saturated with an incrusting 
 (proteinous) substance, which accumulates especially in the outer parts. 
 In opposition to these, Hugo von Mohl demonstrates that, in the first 
 place, the results deduced from chemical relations are not conclusive ; 
 and, secondly, that all membranes in the entire plant, all so-called 
 intercellular substance, and the secreted layer of the epidermis, have 
 cellulose for their element, and are only brought to re-act differently 
 to iodine and sulphuric acid by a gradual and varying degree of satura- 
 tion by a foreign matter which penetrates them ; that this inter-pene- 
 trating substance may be removed from all the parts forming the external 
 coverings of plants, e. g. the secreted layers of the epidermis, cork and 
 bark, by action of caustic potash, or from all the internal greatly 
 thickened elements of the plant, e. g. pith, wood, and liber-cells, by 
 boiling in nitric acid ; a single exception occurring in a very delicate 
 lamella on the secreted layer of the epidermis, which remains of a yellow 
 colour under all circumstances, and therefore Mohl wishes the term 
 cuticula to apply exclusively to this lamella. 
 
 In conclusion, I will only observe, that from my own researches I 
 must accede to these results of Mohl's in every respect. 
 
 Page 92., add before 40. 
 
 c. At the period of complete maturation occur in the cells of succulent 
 fruits, the grape, gooseberry, many kinds of Solanum, &c., numerous 
 more or less minute spherical vesicles of extreme delicacy, the walls of 
 which consist of a slightly granular protoplasma, the contents of a 
 watery, and often coloured, juice. So far as I could see, they originate 
 at once of full size, as vesicles or bubbles of the primordial utricle, upon 
 which they are at first flatly applied. Subsequently they separate by 
 constriction. Hartig*, who mixes them up with many other things, calls 
 them metacardial cells. Karsten f confounds them with the ferment-cells. 
 Nao-eli \ enumerates them in part under his abnormal cell-formation. 
 I regard them as altogether dependant forms, incapable of further 
 development. 
 
 * Das Leben der Pflanzenzelle : Berlin, 1844. 
 i Creation (Die Urzeuguny), Botanische Zeitung, 1848, p. 457. 
 Zeitschrift fur wiss. Bot., vols. iii. and iv. (1846), p. 23, et seq. 
 
ON THE USE OF THE MICROSCOPE. 575 
 
 Page 97., add at line 3. 
 
 We have recently received an excellent treatise on the origin of these 
 motions, from H. v. Mohl (On the Motion of the Sap in the Interior of 
 the Cell. Botanische Zeitung, 184-6, p. 73.). He demonstrates how 
 several cavities filled with watery fluid are gradually formed in the young 
 cell, originally filled with homogeneous protoplasma ; how these cavities 
 expand, by degrees meet, and thus at last displace the protoplasma to such 
 an extent that it only forms a thin layer on the internal surface of the 
 cell, with thickened places in it, filaments as it were, some of which run 
 across the cell ; while the motion simultaneously commences in all these 
 filaments, or perhaps now first becomes visible through granules begin- 
 ning to appear in the originally homogeneous protoplasma. I can wholly 
 confirm this account. 
 
 Page 104., add to line 17. 
 
 Hugo Mohl, in a revision of his first treatise*, has placed the matter 
 beyond all doubt. See Appendix, page 572, line 30. 
 
 D. 
 
 ON THE USE OF THE MICROSCOPE IN BOTANICAL 
 INVESTIGATIONS. 
 
 CONSIDERING the experience of the last thirty years, there is no need to observe 
 that a profound study of any of the natural sciences, and especially of organisa- 
 tion, is impossible without the aid of the microscope. He who expects to become 
 a botanist or a zoologist without using the microscope, is, to say the least of him, 
 as great a fool as he who wishes to study the heavens without a telescope. I 
 will therefore say no more respecting the value of this instrument. But as 
 yet there has been no satisfactory work on its use, owing to the deficiency of a 
 proper theory of vision itself. I will therefore attempt to give some indications 
 in this respect. 
 
 The conception of distance is the result of a mathematical judgment. We 
 must consider accurately the conditions connected with the simplest cases. We 
 take up images on the retina at first as luminous points, and afterwards as 
 planes, situated beyond us. The lines on the different points of this surface 
 form angles among themselves, and these angles, in various directions, are next 
 apprehended. But it is evident that these angles differ according to the different 
 distances of these various points from the eye. All relative determinations of size 
 must, therefore, first be mathematically constructed, the starting-point of which is 
 evidently the size of the angle of vision. The second element would be the dis- 
 tance, of which also we become gradually conscious through comparison of many 
 impressions, the angle of vision being again the simple foundation for this ; since 
 we generally place things at a greater distance when they appear to us under 
 
 * On the Multiplication of Vegetable Cells by Division. Verm. Schrift., 1845, p. 362. 
 
576 APPENDIX. 
 
 a smaller angle of vision, and thus add distinctness to them ; for we naturally feel 
 that our eye can see nearer objects more distinctly than distant ones, owing 
 to its having its sensibility diminished through the strata of air that intervene 
 between distant objects. We shall find, however, on considering the physical 
 conditions of vision, that a minimum must exist with regard to nearness, within 
 the boundary of which distinct vision becomes impossible, because the image of 
 the luminous point falls behind the retina. 
 
 On examining all the other means by which we judge of the bulk of objects, 
 we shall find that we determine their relative size according to the angle of vision 
 if they are presented to us with an equal degree of distinctness, or according to the 
 distinctness where the visual angle is the same. In order to let an object appear 
 larger, we therefore only need to approximate it to the eye : by this the angle of 
 vision becomes enlarged, and the individual points of the body are removed further 
 from each other, so that we distinguish more points in the same object than was 
 previously possible ; since two points which form an angle of vision below 40 
 cannot be distinguished as separate. There is, however, a limit to this in the 
 refracting media of the eye, which amounts, on an average, to 8. Near ob- 
 jects are not seen perfectly distinct, because the rays issuing from each point 
 diverge too much to allow of their uniting in one on the retina. But it is 
 a well-known fact that the divergent rays which issue from the focus of a lens 
 become parallel after their passage through the same ; it is further known that 
 rays falling parallel upon a lens furnish an accurate image of a luminous point 
 within the focal distance of the lens. If, therefore, we place a lens between 
 our eye and the object, which we have approximated too near to the eye, in 
 such a manner that the object is placed exactly in the focus of the lens, the 
 rays proceeding from it will become parallel by passing through the lens, and, 
 as such, falling upon the eye, will be concentrated on our retina with perfect 
 distinctness. Since, then, the determination of size by the angle of vision depends, 
 where equal distinctness exists, on the nearness of the object to the eye, the body 
 in question will appear magnified to us, as we are enabled to distinguish a greater 
 number of distinct points than before. This is the theory of the Simple Microscope, 
 of the pocket lens, &c. The amount of magnifying power will depend on the 
 nearness of the object : the nearer the object, the shorter must be the focal 
 distance of the lens, by which the rays issuing from it are made parallel; or, as it 
 has been said, the shorter the focal distance of the lens, the greater its magnifying 
 power. Since the central angle on the same chord bears nearly an inverse pro- 
 portion to the radius of the circle to which it belongs, the angle of vision at a 
 distance of 4 from the eye will be twice as large as at a distance of 8, &c. ; and 
 we may obtain the apparent enlargement by dividing the focal distance of the lens at 
 the point of distinct vision by 8. The degree of magnifying power, therefore, in 
 the simple microscope, depends on the proximity of the object to the eye, as the 
 lens only serves the purpose of rendering vision possible so near to the object. 
 The impossibility of placing a lens between the object and our eye, when we have 
 arrived at a certain proximity, very soon shows us the limits of our magnifying 
 power. But we may obtain aid in another manner. It is a well-known fact in 
 physics, that a magnified image is created, under certain conditions, by objects 
 placed behind the lens. The image will correspond very exactly with the object 
 if the lens is well made, and many points will be represented in the latter which, 
 at the distance of distinct vision, would appear under a smaller angle of vision 
 than 40". This image may again be treated as an object, and be observed and 
 magnified through a simple microscope as long as there appear simple points and 
 lines capable of being resolved into two or more. This is the theory of the 
 Compound Microscope, in which we observe the object or image formed by one 
 lens (the object-glass), with another lens, (the eye-piece). These two instruments, 
 the simple and compound microscope, are the only two of scientific value. The 
 so-called solar microscope, or others constructed upon the same principles, but 
 illumined by a different light, the oxy-hydrogen microscope, are nothing more 
 than playthings a somewhat enlarged magic-lantern. The object can never 
 be so strongly magnified, nor with so much strictness and distinctness, by 
 such an instrument as by a simple microscope: the physical conditions them- 
 
ON THE USE OF THE MICROSCOPE. 577 
 
 selves involve this. The million-fold powers blazoned forth by quackery are 
 nothing more than the most absurd statements of cubical enlargement, and are 
 calculated by the distance of the lens from the surface which receives the image, 
 in the same way as in the magic-lantern, and by which all accuracy of defini- 
 tion the very thing requisite in scientific researches is lost. 
 
 As a matter of course, we may mention that concave mirrors may be employed 
 instead of transparent lenses, in the same way as in the telescope : this was first 
 done by Amici, of Modena, and at a time when the aplanatic lens was not dis- 
 covered it certainly was a very desirable improvement. This arrangement, how- 
 ever, has almost entirely lost its value at the present time, for, independently 
 of the difficulty of always keeping the glass or mirror perfectly clean, it can 
 only be made use of to afford a very low magnifying power, as otherwise the 
 object could not be placed, and thus the greater portion of the magnifying power 
 has always to be performed by the eye-piece, and which is liable to errors of 
 spherical aberration in a much higher degree than is the case with the dioptrical 
 instrument. 
 
 It is evident, from the representation we have just given, that the excellence of 
 the microscope depends principally on the good quality of the lenses, and, in the 
 compound microscope especially, on the correctness and definition of the object- 
 glass, since every error belonging to the image is still more magnified through the 
 eye-piece. There were two errors particularly which have been only recently 
 remedied, but that with great success, namely, the chromatic and the spherical 
 aberration, which are now removed, the former by achromatic lenses, and the 
 latter, in simple microscopes, by Wollaston's or Chevaliers doublets ; in the com- 
 pound microscopes by aplanatic object-glasses. The instrument also, in which 
 the eye-piece removes the spherical aberration by means of aplanatism, is very 
 excellent. I do not think that much more can be seen by any microscope now 
 manufactured in Europe, than by the combination of the three strongest object- 
 glasses with the aplanatic eye-piece of Pldssl's microscope, although it only gives 
 a two-hundred linear magnifying power. The dimensions in the stronger powers 
 of the same artist, in which the aplanatic eye-piece is not used, are certainly 
 more considerable, but we do not distinguish more points or lines in the image, 
 and therefore we do not see more, but only rather more conveniently. It 
 follows, from the preceding explanations, that we should only use instruments 
 furnished with achromatic doublets in the simple microscopes, and in compound 
 microscopes furnished with achromatic, or at least with aplanatic, object-glasses, 
 in order to obtain results as much as possible free from optical errors. Schiek 
 in Berlin, and Plossl in Vienna, undoubtedly furnish the best instruments at the 
 present time. Plossl's instruments are pretty nearly on an equality with Schiek's 
 in all combinations in which the strongest object-glass does not occur. On the 
 other hand, all combinations with the three strongest object-glasses are certainly 
 to be preferred, and form the best instrument that has as yet come under my 
 observation. The brass work is undoubtedly better in Schiek's instruments. 
 Next to the instruments of those distinguished artists, we may probably name 
 the more recent instruments of Pistor and Hirschmann in Berlin, of Oberhauser 
 and Chevalier in Paris ; of the latter I have certainly not seen any, but infer as 
 much from the results obtained through them by the French. The more recent 
 English instruments seem to be so much inferior to those we have mentioned, 
 that they bear no comparison. I likewise have not seen any of these, but there 
 certainly is no lack of clever observers in England ; and since, therefore, no 
 microscopical botanical researches of any importance have been very recently 
 furnished by England, excepting those of Robert Brown, and since what obser- 
 vations the English have made can frequently be easily refuted by a cursory 
 glance through our glasses, this deficiency can only be attributed to the de- 
 fectiveness of their instruments.* 
 
 * I should not, I think, be doing justice to my countrymen were I to allow the 
 above remarks to pass without comment. Since the time the above was written, many 
 improvements have taken place in the construction of the microscope, and in no coun- 
 try in Europe have so many of these been made as in England. Even at the time the 
 
 P P 
 
578 APPENDIX. 
 
 We have still to answer the question, Whether the simple or the compound 
 microscope is preferable for scientific investigations ? I must decidedly declare 
 myself in favour of the latter, and that from the following reasons. Ceteris 
 paribus, the simple microscope injures the eye much more than the compound, 
 because the strength of the light (which is quite independent of the strength and 
 clearness of the image, and ought to be clearly distinguished) is more intense, and 
 strikes a smaller portion of the retina, and therefore causes a greater inequality 
 in the excitement of the optic nerve ; secondly, on account of the great incon- 
 venience of the very short focal distance in higher powers ; thirdly, because we 
 can obtain higher powers, with the same mathematical accuracy, through the 
 compound ; and, lastly, because all the objections which were formerly urged 
 against the compound microscope have been removed. Habit will also do much ; 
 but on comparing the observations of the last twenty years, it must undoubtedly 
 be admitted that the discoveries and observations which have advanced science 
 have been made by the compound microscope, with the exception of those of 
 Robert Brown of a man who, because he is perfectly sui generis, and has not 
 his equal, should not be compared with ordinary observers. Thus much with 
 regard to the value of the instrument. Previously, however, to proceeding to the 
 method of observation, I must touch upon two points demanding careful con- 
 sideration, because they frequently exercise great influence on scientific results, 
 namely, the measurement and the illumination of objects. 
 
 a. The determination of the magnifying power of a microscope was of much 
 greater importance in former times, before we possessed a suitable apparatus for 
 determining directly the size of microscopical objects, than now. Formerly they 
 divided the apparent diameter of the object by the number of the magnifying 
 power, and thus discovered the size of the object itself. This mode of pro- 
 ceeding is, of course, too primitive to have any scientific value, and has conse- 
 quently been abolished long ago. Nevertheless, it is of great interest to know, in 
 many cases, of what degree the magnifying power is of which we avail ourselves. 
 Good opticians generally attach an index to their instruments* for the magnifying 
 power of the different combinations. But as considerable errors will occasion- 
 ally be made by them, it is necessary that the observer himself should be able to 
 ascertain the magnifying power of his instrument. This is attended with no great 
 difficulty with regard to the simple microscope ; it is also easy, after some 
 practice, with the compound microscope. All that is required for it is a measure 
 inscribed in black on ivory, or on very white paper, which gives lines, and a glass 
 micrometer, which contains the same lines divided into optional parts (if intended 
 for a very strong magnifying power, into at least sixty). The glass micrometer is 
 then laid under the microscope, and on arranging it so that the divided lines may 
 be seen distinctly, the measure is laid on the stage of the microscope. On 
 looking now with one eye through the microscope, with the other on the measure 
 beside it, which in most of the newer instruments will be within the distinct 
 range of sight, owing to the length of the tube, both measures may bs compared 
 the one with the other, which, after some practice, is very easy : thus, if we have 
 
 author wrote (1845), instruments had been made by the great English makers, Ross, 
 Powell, and Smith, which have certainly never been surpassed, if they have been 
 equalled, by continental makers. Dr. Schleiden's observation on English observers is, 
 I fear, the reverse of the truth : we have plenty of microscopes, and those the best in 
 the world ; but we have had but few observers. Our microscopes have been used rather 
 as playthings than as the instruments of profound philosophical research. Let us hope, 
 however, that this reproach will soon be wiped away. Already, through the efforts of 
 the Microscopical Society of London, which was founded in 1839 to cultivate a branch 
 of scientific inquiry which the older societies neglected to encourage, improvements in 
 the microscope have been made, and a knowledge of its powers and mechanical arrange- 
 ment diffused, which are bearing fruits not only in its own transactions, but in the 
 transactions of some of our other scientific societies. Those who would wish to study 
 the history of the microscope, and all that relates to it, I must refer to the admirable 
 treatise on the microscope, by Mr. John Quekett, secretary to the Microscopical 
 Society. TRANSLATOR. 
 
 * Schiek's statements are generally very accurate; Plossl's, however, are almost all 
 erroneous, and, it may be said to his honour, almost all too low. 
 
ON THE USE OF THE MICROSCOPE. 579 
 
 ^ decimal line to a quarter of an inch, we have a magnifying power of seventy- 
 five times, &c. The methods suggested by Jacquin* and by Chevalier-}- are more 
 tedious, without affording more accurate results to the practised observer. On 
 the application of a very high magnifying power, it does not indeed matter about 
 an error of ten per cent. It is not of much consequence whether an instrument 
 magnifies 400 or 440 times, since an essential difference in the result is only 
 obtained when the power is increased at least by one half. 
 
 It is a matter of course, that all magnifying powers should be stated only 
 in ; terms of linear enlargement (enlargement of the diameter). It is quite an 
 unnecessary proceeding to state the superficial enlargement, because it must be 
 again reduced to the square root before a clear idea of the matter can be 
 obtained. It is only quackery, desirous of deceiving the ignorant, that employs 
 measurements of the magnifying power according to the cubical contents, and by 
 which are obtained full-sounding millions. The thing is altogether a monstrous 
 absurdity, as we cannot embrace the third dimension of space, either by the 
 naked eye or by the microscope, for, in fact, we do not see bodies, but only 
 luminous surfaces. 
 
 The highest magnifying powers which have hitherto been obtained by the most 
 distinguished opticians, by Amici, Chevalier, Pistor, Schiek, and Plossl, do not 
 exceed 2400 3000 diameters. But they are only scientifically available to 
 about one third of that, say 1000 1200 diameters. If any one should assert 
 that he had seen anything magnified 3000 diameters that could not be seen at a 
 much lower magnifying power, it may safely be pronounced to be mere imagina- 
 tion. 1 have had an opportunity of comparing the most remarkable modern mi- 
 croscopes, and possess the best instruments that were ever made by Schiek, 
 Plossl, Amici and Nobert, and am tolerably conversant with their use ; but I 
 maintain that although everything one wishes to see can be seen with a magnifying 
 power of 3000 diameters, yet too great a loss of light occurs, and no single 
 line can be seen with due accuracy and precision. The reason of this is obvious. 
 The magnifying power in all the microscopes is only gained as far as 280 300 
 diameters, through the object-glass. Hence we obtain the remaining enlargement 
 through the eye-piece, but which only magnifies the image subject, as it always 
 is, even if the object-glasses be ever so well finished, to a certain amount of 
 spherical and chromatic aberration, and thus increases these errors in a rapidly 
 increasing proportion. To this must be added, that the condenser of the eye-piece 
 (collectivglas des oculars) must be omitted on account of the diminution of light 
 which takes place in very high powers, and this not only increases, to a tenfold de- 
 gree at least, the errors of the imege of the object-glass, but also the very con- 
 siderable errors (in consequence of the smallness of the lenses) of the eye- 
 piece. It is a very general notion that expensive instruments are requisite for 
 microscopical researches, and therefore only attainable by a few. But this is 
 a most erroneous prejudice. Owing to the progress of the optical art, very 
 useful instruments may be obtained at comparatively reasonable prices, from 
 almost any respectable optician ; and none, even among the youngest of 
 our contemporaries, will live to see the moment when nothing further can 
 be secured for science by the aid of such an instrument. He, however, 
 who wishes to make original researches on the more difficult questions con- 
 nected with the elementary structure of plants, must certainly provide himself 
 with the best and most accurate instruments. It is not every one who is des- 
 tined to advance the science considerably, but every one has a right to make himself 
 master of the sdence as it at present exists ; nor does the investigation of the ele- 
 mentary structure constitute by any means the whole of the science, for 
 although very essential, yet it is but a very small part of it. The value of 
 high magnifying powers is overrated by most, and frequently we only need a low 
 magnifying power, particularly if we wish only to convince ourselves of the correct- 
 ness of things discovered, described and delineated, by others. It is the same here 
 as in perspective. A spire, for instance, which first of all could not be discovered 
 
 * Baumgartner, Natur-Lehre, Supplement. Vienna, 1831, p. 636. 
 f Ch. Chevalier, Des Microscopes et de leur Usage, &c., p. 146. 
 
 p p 2 
 
580 APPENDIX. 
 
 by the naked eye, is readily and distinctly recognised as soon as it has been made out 
 by the telescope. On the same principle, it only requires a very low magnifying 
 power (perhaps 100 times) in order to be perfectly convinced of most facts in 
 the anatomy of plants. The very high magnifying powers are, to a great extent, 
 useless for morphological researches, and, with respect to these, there is still so 
 productive and so little cultivated a field of investigation before us, that we may 
 safely promise scientific immortality to any one who undertakes such researches 
 with sincere industry and honest zeal, even with the most simple instruments. 
 There is so much to be done in this department, that it would be difficult to 
 avoid discovering something new. Skill in the preparation of objects, practice, 
 and natural talent, are here of much greater importance than expensive instru- 
 ments. I would here particularly draw attention to the pocket microscopes, 
 which are now manufactured by Dr. Korner, in Jena. They are packed in a 
 little case, the cover of which serves as a stand. The moveable stage is fur- 
 nished with a screw for the purpose of affixing it during the preparation of an 
 object, and with a round plate of glass, in order to moderate the light from below, 
 or to arrest it altogether. In a moveable arm, four double lenses may be placed, 
 which afford a clear and beautiful magnifying power of 15 120 diameters. 
 This instrument is quite sufficient for all entomological, pharmacognostical, and 
 botanical researches, and even for perfecting satisfactory anatomical observations. 
 This instrument, with case and apparatus, only costs three Friedricsd'or, or se- 
 venteen dollars Prussian currency [about 21. IQs. sterling], which would unques- 
 tionably be better laid out than if we were to purchase hay with it, or, in other 
 words, 300 or 400 specimens of dry plants.* 
 
 The determination of the absolute size of very small objects is far more im- 
 portant than the determination of the magnifying power of the microscope. Ac- 
 curate observers, long ago, sought for means to accomplish this ; Leeuwenhoek, 
 for instance, used clean grains of sand : having first ascertained how many of 
 them went to a line, he strewed them among the microscopic objects, and thus 
 determined the size of the latter by comparison. Other small substances, for 
 instance, pollen, were subsequently used for this purpose. After the discovery of 
 the transverse striae upon the muscles, they were recommended for the same pur- 
 pose, likewise the blood-globules of different animals. But all these experiments 
 are of little value in a scientific point of view. The production of real microsco- 
 pical measuring instruments was, therefore, early thought of. The oldest of them 
 was the so called glass micrometer, namely a smooth little plate of glass, in which 
 very fine divisions were cut by a diamond. Dollond especially distinguished 
 himself by the manufacture of excellent and accurately finished micrometers. 
 Within a more recent period they have been made by all good opticians. Che- 
 valier manufactures micrometers in which the millimeter is divided into 500 parts, 
 or the line into about 1000 parts. But these micrometers have nevertheless, 
 some important drawbacks. Even with the best diamond, the splintering of the 
 edges of the drawn lines can scarcely be avoided. In many cases, also, a glass- 
 micrometer is not available at all. It is impossible, with very small objects, or 
 with very high magnifying power, to keep the object and the divisional lines of 
 the micrometer simultaneously within the same focus, which renders an accurate 
 measurement almost impracticable. Objects also, which must necessarily lie in 
 the water, in order that they may be brought under the microscope, cannot well 
 be measured by the glass micrometer, as the small divided lines are filled up with 
 water, and are thus rendered almost invisible. 
 
 The screw micrometer, which was first applied by Frauenhofer, is now made 
 use of for all real scientific researches, and is generally provided with all the larger 
 
 * I am not aware that a good working microscope could be obtained in England at 
 the above price ; but a very serviceable instrument may be obtained of any of our great 
 makers at a moderate sum compared with the price given for the highest powers, ac- 
 companied by the complicated accessories of a complete apparatus. It should be 
 recollected that Ehrenberg, with a thirty-shilling microscope, produced his great work 
 on the Infusoria, a work with which British microscopy has nothing to compare, 
 although it has spent thousands of pounds annually on its instruments. TRANSLATOR. 
 
ON THE USE OF THE MICROSCOPE. 581 
 
 instruments of the German opticians. The whole instrument is based upon a 
 contrivance which enables one to carry the object to be measured through the 
 field of the microscope by a continuous movement in a right line, and to measure 
 the distance performed. A moveable stage is constructed for this purpose, which 
 consists of a plate moveable within grooves. A screw is attached to this plate, 
 by the turning of which it is moved backwards and forwards. This screw is very 
 accurately made of steel, and usually has 100 turns to an inch : such a screw is 
 called a micrometer screw. Each entire turning of the screw, therefore, moves 
 the stage forward at O'Ol". Provided the turning of the screw is perfectly 
 uniform, the stage is moved forwards O'OOOl at each I -100th part of a turn. In 
 order to determine these parts, a disc divided into 100 parts is attached to one 
 end of the screw, and likewise a fixed index, in which the number of the divi- 
 sional parts may be read ; finally, there is also a nonius besides the index, which 
 enables us to determine the 10th part of the 100th part of a turn ; therefore alto- 
 gether 0*00000 1". The measurement by this instrument is effected in the fol- 
 lowing manner. A fine cobweb-thread is fixed across the diaphragm of the 
 eye-piece, and the screw-micrometer being placed upon the stage of the micro- 
 scope, the eye-piece is turned in such a manner that the cobweb crosses the 
 axis of the screw rectangularly. The object to be measured is then laid upon 
 the plate of the micrometer in such a manner that one of its edges exactly touches 
 the thread in the diaphragm ; and the object, by the movement of the screw, is 
 then cautiously carried through the field of vision until the thread touches the 
 other edge of the object. On having accurately observed the position of the di- 
 vided disc at the commencement and end of this operation, the difference of both 
 will exactly give the diameter of the object to the 100,000th part of an inch. It 
 is somewhat difficult during this operation to bring the object exactly into the 
 right position. Some further contrivances are connected with the micrometer, in 
 order to facilitate this. First of all, another plate is laid upon the plate, move- 
 able in the direction of the axis of the screw, which additional plate is also move- 
 able by a screw in a rectangular direction upon the former. A disc is likewise 
 attached to the additional plate, which can be turned exactly round its axis. The 
 placing of the object is thus facilitated. Much controversy has arisen with regard 
 to the advantages of the screw micrometer. Its fault is principally this, that a screw 
 can hardly ever be so accurate as to render its turnings equal among one another, 
 and each single turning uniform in itself. On that account, many have given the 
 preference to the glass micrometer; but this is only owing to a want of knowledge 
 of the manner in which the glass micrometer is manufactured. I have already enu- 
 merated the defects peculiar to this instrument. To these must be added all the 
 faults of the screw micrometer, for the production of a glass micrometer is only pos- 
 vsible by means of a micrometer screw, which forms the lines. In addition to this, 
 there is this disadvantage in the glass micrometer, that it only represents a very 
 small part of the micrometer screw, and, as it may happen, perhaps the most 
 inaccurate one, whilst the screw micrometer, enables us to repeat the measure- 
 ment with different parts of the screw, and therefore it puts us in a position to 
 rectify errors by taking an average of measurements ; and indeed, at the best, 
 there is a limit to the value of these measurements. It only needs intercourse 
 with a practical optician to know the limits of accuracy in these instruments. A 
 single measurement has, therefore, no value at all ; for if we determine with it the 
 breadth of an object at one 10,000th part of an inch, it may in reality be quite as 
 likely to be one 7,000th or one 14,000th. The average, however, from three or four 
 measurements, at different parts of the screw, gives us something like an accu- 
 rate result. But comparative measurements are always the safest for scientific 
 purposes, namely, measuring at the same time, with the same instrument, a well- 
 known, readily attainable object, which is every where of an equal size, for 
 instance, the blood-globules of a certain animal, so that the statement of the size 
 becomes, as it were, the rule to which every one may reduce the results arrived at 
 with his instrument.* 
 
 b. Much depends on the illumination of objects. The more intense the light is 
 
 * For more detailed observations on micrometry, see Quckett's valuable work on the 
 microscope. TRANS. 
 
 p p 3 
 
582 APPENDIX. 
 
 which issues from an object, the less is the loss which the light experiences in its 
 passage through so many media, partly by reflection at the surfaces, partly by 
 absorption in the interior. Two methods of using the microscope must here be 
 distinguished the examination of opaque and transparent objects. 
 
 The first is the oldest, most simple, and natural method. It corresponds with 
 the manner in which we view objects with the naked eye by means of the light 
 diffused about them. Mere daylight usually suffices for this, if the magnifying 
 power is not very great ; but if the magnifying power is high, the light (which 
 in that case had best be artificial) is passed through a lens, or what is called 
 Selligue's prism*, and concentrated upon the object. The examination with 
 transparent light is very different. It is remarkable that no natural philosopher 
 has as yet presented us with a theory of this manner of seeing ; indeed, the 
 essential difference in the two modes of observation has not even been indicated 
 in any of the works on physics which I have read. It seldom occurs to us in 
 ordinary life except when observing air-bubbles or other irregularities, or slightly 
 cut designs in glass. The whole act of seeing here is founded on the different 
 reflection or absorption of the rays of light through unequally refracting and 
 unequally dense media in close proximity. The more powerfully refracting 
 or denser parts permit fewer rays of light to pass through them and arrive at 
 the eye, and appear, therefore, darker than the others. Indeed, it is very 
 possible that two substances lying near to each other, having equal densities and 
 equal refractive power, and therefore not to be recognised as different under the 
 microscope, may exhibit an evident difference through the circumstance of their 
 having a different polarising or depolarising effect upon light. The result, 
 therefore, would always depend on the greater or less quantity of light which 
 passes through the object from below. We must, however, take into consi- 
 deration that a different quantity of light is reflected according to the angle of 
 incidence and the direction of the rays of light coming from below. 
 
 The usual contrivance in all microscopes is a mirror, moveable in all directions, 
 under the stage of the microscope. It is made either plane or concave, and the 
 latter is used in order that the pencil of light proceeding from it may exactly fill 
 up the opening in the 'stage ; and a greater quantity of light is also obtained in 
 this case. The best and most usual plan is to have both a plane and concave 
 mirror, turned with their backs to each other, in the same frame, so that they 
 may be alternated or changed at pleasure. If anything, the illumination by the 
 plane mirror is preferable ; the quantity of light is certainly not so great, but the 
 parallelism is decidedly of greater advantage for accuracy of observation. It 
 does not seem improbable that a distortion may take place in the image, through 
 the convergence of the rays in the concave mirror. My attention has often 
 been drawn to these phenomena ; but I confess that I know little about it, 
 as the opticians leave us perfectly in the dark on this point. According to 
 Wollaston, a converging lens may be appropriately used in the simple microscope 
 if a greater quantity of light is required. 
 
 During the examination of delicate objects, it is, however, not unfrequently the 
 case that we are obliged to moderate the amount of light. The eye is too much 
 irritated by a strong light, when observing very transparent objects, to be able to 
 perceive slight or delicate differences, which are more readily perceived with less 
 light. For this purpose the plain mirror may be covered with a small piece of 
 white wood, ivory, or ebony, or it may be placed in such a manner that it sends 
 no rays upon the object. There is a peculiar contrivance in the stage of all well- 
 constructed microscopes, which serves as well to moderate the light as to allow it 
 to fall obliquely on the object. This contrivance consists of a disc, perforated 
 with holes of different sizes, which is attached under the stage in such a manner 
 that the light may be made to pass at will through one of the holes, or it may 
 even be excluded altogether. On placing this disc, which ought to be very easily 
 moveable, in such a manner that only a part of a hole meets at one side the 
 section of the stage, it will give us an oblique light. This contrivance (called 
 a diaphragm) is almost indispensable. We can only get rid of a great number of 
 illusions by a continual change of the light. An attentive observer will soon 
 
 * A prism with two convex surfaces. 
 
ON THE USE OF THE MICROSCOPE. 583 
 
 see, by the shadow consequent on changing the illumination, whether a body is 
 concave or elevated, or whether a small body is solid or hollow. But there 
 are numerous other cases, which prove the great advantage to be derived from a 
 proper use of various forms of illumination. Great weight has justly been always 
 placed upon the regulation of the illumination in the microscope ; and although 
 many precautionary measures formerly employed, and the frequently very com- 
 plicated apparatus, have been rendered partly superfluous in modern times through 
 the great improvements of the optical part of the microscope; for instance, in the 
 use of achromatic and aplanatic lenses ; yet there still remains one point which 
 deserves great attention, and the importance of which has been very much 
 neglected by many microscopical observers. The principle laid down by Wol- 
 laston, that all light which does not immediately subserve the purpose of illu- 
 minating the object is injurious to the distinctness of vision, is a sound principle 
 for guiding our observations at the present day. It is particularly to be recom- 
 mended that all lateral light should be excluded from the eyes by a suitable 
 screen, and with transparent objects ; that all side-light should be excluded from 
 the object by means of a hollow pasteboard tube, blackened inside, reaching from 
 the body of the microscope to the table. 
 
 In the next place, I will make a few remarks on the method of microscopical 
 investigation. The object of all microscopical investigations is to obtain as perfect 
 a knowledge of forms and processes, which, from the dimension of the object, are 
 invisible to the naked eye, as would be possible were the objects possessed of 
 dimensions equal to those of substances which we can with perfect distinctness 
 recognise by means of the naked eye. Our eye is in itself an optical contrivance ; 
 the microscope repeats nearly the same means ; and we should therefore re- 
 member that the microscope can in no way give us new qualities any more than 
 the eye itself. The function of the eye is to transmit directly to our perception 
 variously coloured and illuminated points, which are arranged in a mathematical 
 picture upon a plane surface, and we become conscious of the corporeal quality, 
 the third dimension of space, by a subsequent process of the mind. We must 
 therefore keep in view the fact, that the mode of action of the eye we mean, of 
 course, of the healthy eye is founded, like that of the microscope, upon im- 
 mutable mathematical laws ; that errors consequently are only committed by the 
 erring judgment in all observations, whether instituted with the naked eye or the 
 microscope. The healthy sense and the optical in strument are always right. 
 " Nature does all things well : confusion is only found in the heads of men." 
 We mention this in order to allude to two very common prejudices, the influence 
 of which upon science has been injurious in many respects, because they prevent 
 people from tracing error to its proper source. 
 
 One of these consists in the vague phrase, that microscopical researches can 
 never be depended upon, inasmuch as the microscope is frequently very deceptive. 
 Such an expression, alas ! has been employed within a very recent period by 
 men who are looked up to as authorities in the natural sciences. It is easy to 
 refute this notion. The microscope is perfectly innocent of every thing of which 
 it is accused. The evil spirits which, as long as the world has existed, have 
 always impeded the advances of the human mind, and which, even at the present 
 day, and especially in the natural sciences, and still more in microscopical re- 
 searches, have caused so much mischief, are precipitation, superficial^, and we 
 may add to these scientific dishonesty, of which frivolousness is always guilty. 
 These give us occasion, with much justice, to be upon our guard when micro- 
 scopical researches are put forth ; but this is not due to the falseness of the 
 instrument, but to the untruth of men. How many persons, for instance, have 
 given erroneous impressions by attributing the colours due to chromatic aberration 
 to bodies, by describing air-bubbles as objects, &c. ; but this is not the fault of the 
 microscope, but of the stupidity, and the want of judgment arising therefrom, of 
 people who make researches with an instrument of whose laws and mode of 
 action they are ignorant, and gave their opinions about subjects of which a little 
 reflection would have taught them that they were not in the slightest degree 
 qualified to judge. 
 
 The other prejudice is the direct opposite of the preceding, and yet it is 
 
 p r 4 
 
584 APPENDIX. 
 
 frequently expressed by the same individuals, but in a concealed form. It i 
 supposed that nothing more is requisite for microscopical investigation than a 
 good instrument and an object, and that it is only necessary to keep the eye over 
 the eye-piece, in order to be aufalt. Link expresses this opinion in the preface 
 to his phytotomical plates : " I have generally left altogether the observation to 
 my artist, Herr Schmidt, and the unprejudiced mind of this observer, who is 
 totally unacquainted with any of the theories of botany, guarantees the correct- 
 ness of the drawings." The result of such absurdity is, that Link's phytotomi- 
 cal plates are perfectly useless; and, in spite of his celebrated name, we are 
 compelled to warn every beginner from using them, in order that he may not be 
 confused by false views. Link might just as well have asked a child about the 
 apparent distance of the moon, expecting a correct opinion on account of the 
 child's unprejudiced views. Just as we only gradually learn to see with the 
 naked eye in our infancy, and often experience unavoidable illusions, such as that 
 connected with the size of the rising moon, so we must first gradually learn to 
 see through the medium of the microscope, and the more so as the latter is a 
 much more difficult instrument than our eye, owing to the isolation of the objects, 
 and of the absence of the possibility of comparison, as also on account of the 
 necessity that compels us to exclude the use of one eye. We can only 
 succeed gradually in bringing a clear conception before our mind of that which 
 we have physiologically seen ; and just as it is easier for us to put ourselves right 
 in a foggy day, or in a moon-illumined region, if we have already frequented the 
 spots where they occur under other kinds of illumination, and are accurately 
 acquainted with their separate parts, so it will be only possible for a man to make 
 useful microscopical observations, who has not only made himself perfectly fa- 
 miliar with science in general, but has also paid especial attention to the particular 
 objects which he subjects to his examination. It is in consequence of these pre- 
 judices that microscopical discoveries progress so slowly, and that they are generally 
 only admitted in science long after their announcement. For most observers desire 
 to see at a glance what has been done by others, and do not consider that it fre- 
 quently requires years of most active research before an accurate result can be 
 obtained, and that, even after it has been found, that it may require weeks of study 
 before we are able to follow the course traced out by the hand of a master. 
 Hence have arisen the many silly objections made to that greatest of microsco- 
 pical observers, Ehrenberg. 
 
 The above observations will not only enable us to trace the two injurious pre- 
 judices which impede the proper use of the microscope to their source, but we 
 may also deduce from them the leading principles which should guide us in 
 microscopical researches. 
 
 First of all, we must once more compare the impression of light derived from 
 the microscope, with the act of seeing by our eye. The eye, as already observed, 
 only gives us the perception of a luminous or coloured surface. This impression, 
 however, could scarcely be called by us a sight of the corporeal world, if we (as 
 is the case with simple elementary observations) only saw with one eye. But, 
 firstly, our eye is moveable, and we may wander about with it among the objects. 
 Whilst our rolling eye passes over a number of objects, they produce different 
 impressions on our retina at each successive moment, and each successive im- 
 pression falls upon different parts of the retina. Secondly, we do not see with 
 one eye alone, but with two. There belongs, as it were, a particular mode of 
 viewing things to each eye, but habit combines both the images so received (but 
 which mathematically can never entirely cover one another) into a central one. 
 It is only when both impressions impinge on unaccustomed parts of the retina 
 that they produce different perceptions, in the same manner as we feel a small ball 
 double, if we touch it simultaneously with the external sides of the points of two 
 fingers. We further see with two moving eyes, by which the number of intuitive 
 elements connected with an object are increased. Finally, we are able to move 
 ourselves or the objects, and thus to gain quite different views of one and the 
 same object. Thus we obtain a tolerably broad basis upon which a construction 
 of the figure of objects may be confidently undertaken. Practice in this case 
 makes the master, and we see a great difference between a learned man, who has 
 spent the greatest part of his life in his study, and the sportsman, or still more, 
 
ON THE USE OF THE MICROSCOPE. 585 
 
 the savage, over whom, from his infancy, the instinctive conceptions of nature 
 have prevailed. 
 
 But all these various relations are foreign to the microscope. We invariably, 
 when using it, see with but one eye, generally in a state of rest, and always in a 
 certain given position in relation to the object. We also see the object always in 
 an isolated condition, and cannot therefore form a notion of it by a comparison 
 with impressions from other objects. Further, our eyes possess a certain power 
 of accommodation to different distances, not confined within very narrow limits; 
 we can see objects equally distinct, although they may be at unequal distances 
 from our eye, and we receive our visual impressions in such rapid succession, 
 that it is an easy matter for us to combine all these impressions. This also, for 
 the most part, is wanting in using the microscope, especially with a high 
 magnifying power (and also the more accurately the instrument has been finished), 
 as we only see a mathematical surface. This is particularly the case in the com- 
 pound microscope, where we do not look at a real object, but merely an image, 
 and there is therefore, for the moment, no other object of sight existing excepting 
 this mathematical surface, and the power of accommodation of our eye is of no 
 use in seeing what may be placed above or below this surface (which is in a 
 manner the profile of the object under examination), but we are compelled to 
 annihilate the one object of sight, and to substitute another in its place. It will 
 easily be conceived how infinitely this must increase the difficulty of combining 
 the separate impressions into one corporeal whole. 
 
 Taking the whole of these remarks into consideration, the results will be 
 firstly, that there is a difference between vision with the naked eye and with the 
 microscope ; and, secondly, the fundamental principles from which rules for the 
 conduct of microscopical examination must be sought. In the first place, the 
 instinctive knowledge of the material world is made manifest to us in the percep- 
 tion of form previous to the mathematical conception, for which latter the eye, as 
 the organ of sight, only furnishes us with some few elements, whilst we receive 
 the rest from other senses ; the conception derived by the other senses is entirely 
 lost in microscopical objects, and the elements furnished to us by the eye are, 
 moreover, divided during microscopical observation ; the separate parts are 
 isolated, and presented to us under circumstances which infinitely increase the 
 difficulty of their combination. Secondly, in order to avoid these disadvan- 
 tages, and to secure the results of microscopical researches against the errors of 
 judgment arising from the exercise of the faculty of mathematical conception, 
 we must endeavour to increase the number of elements in such a manner as to 
 gain thereby, as much as possible, a perfect and safe foundation for the perception 
 of form. 
 
 This task involves the necessity of examining thoroughly every aspect of 
 the same object, and of removing from it everything which does not belong 
 to it. This last part of the task is partially accomplished by improvements in 
 the instrument, in as far as they obviate errors of form and colour (which are 
 based upon the spherical and chromatic aberration). Respecting these two 
 points, which concern the optician more than the observer, we have already 
 before mentioned every thing necessary, and the only concern of the observer 
 ought to be to procure himself the best possible instrument. Besides these, 
 however, there are many other optical phenomena, of which the observer should 
 be conscious, which, although belonging to the image, yet do not belong to the 
 object observed, and with which every one ought to be acquainted, in order to 
 be able to eradicate their share in forming our conception of the nature of the 
 object. To such belong many of the phenomena of colour which are not pro- 
 duced by chromatic aberration. The bending of the rays of light not unfre- 
 quently occurs in using the microscope. On observing, for instance, verj' small 
 holes, perhaps pores of the cellular walls, if the object does not happen to lie 
 exactly at the right distance from the object-glass, the internal surface will appear 
 coloured, and, according to the size of the pore, or the distance from the focus, 
 yellowish, reddish, or greenish. During the observation of very small globules, or 
 other solid substances, a delicate coloured border will be seen under similar cir- 
 cumstances. But both phenomena disappear if the object is brought exactly 
 within the right focal distance. We should therefore always endeavour to get rid 
 
586 APPENDIX. 
 
 of such colours by placing the object exhibiting them, even when it does so, in the 
 centre of the field, where naturally perfect achromatism takes place in ail posi- 
 tions, and should attribute such colours to the object itself, after it has been 
 found impossible to get rid of them by every precaution. The assertion of some 
 observers, that the inner circle of the pores in the cells of the Coniferce (the real 
 pores) occasionally appears to be of a green colour, furnishes an illustration of 
 this kind of error. 
 
 Under this head, also, belong certain aberrations of form, which are caused by a 
 defective method of placing the object within the correct focal distance : thus, lines 
 will appear double, or of a certain breadth, which, on being accurately placed, 
 present simple lines, or as sharp lines without any apparent breadth. This is 
 probably a phenomenon of diffraction. In this instance, neither the apparent 
 breadth nor the reduplication of the lines belong to the object itself, as these phe- 
 nomena disappear when perfect distinctness of the image is obtained by means of 
 a correct way of placing the object. An instance of optical illusion may be found 
 in Mirbel's treatise, " Nouvelles Notes surle Cambium" (Archives du Museum 
 d'Hist. Nat., 1839. p. 303. etseq.). He there makes mention of cells (pp. 306, 
 238, Table xxi. fig. 3. and fig. 6.), the walls of which appeared to be marked on 
 a transverse section by transverse striae, which, however, disappeared on the 
 examination of a longitudinal section, then presenting longitudinal striae. I have 
 frequently observed this phenomenon, and have no doubt of its being an optical 
 illusion. Mirbel has been rather too free with his stria? in the plates mentioned, 
 as we never see more (less) than four, viz. the upper and lower cut surface of the 
 cell and two lines. The proof of its being an optical illusion is made evident by 
 the fact, that we can never obtain a sight of two of these lines alone by any change 
 of the focus. They either all four appear, or only the upper, or only the lower 
 surface. I do not find that any one has as yet directed attention to this pheno- 
 menon, and much less has any explanation been given of it. It is unquestionably 
 certain that the object only lies in the correct focal distance when its image 
 appears to be most distinctly and accurately represented. But the differences in 
 distinctness and accuracy are so fine, that they frequently hardly become per- 
 ceptible to the most practised eye. The rule may, therefore, be better given by 
 saying that the correct focal distance has been found when the image appears 
 smallest, and when the dimensions of all the parts, and of all the lines and points 
 of which it is composed, exhibit the smallest size. It will always be found that 
 the greatest accuracy and distinctness exist in that case, where each line and each 
 point appear the darker, the smaller and the narrower they are. There are 
 probably many other conditions which embarrass our judgment with regard to 
 microscopical objects, but at present none else have come within my own cognisance. 
 We find, alas ! no information at all respecting these things in the writings of 
 natural philosophers, because no one has as yet occupied himself with the theory 
 of microscopical observation. 
 
 Another preparation, besides the knowledge of the optical facts, is necessary for 
 the task of enabling us to distinguish the phenomena that do not in reality belong to 
 the object under observation. These optical facts belong to the image which the 
 object-glass produces, and only occur in the compound microscope. But there are 
 a great number of phenomena which are connected with the real object on the 
 stage, but yet do not belong to the real object of our observation. These likewise 
 interfere during the use of the simple microscope. We must be thoroughly ac- 
 quainted with these phenomena before we can proceed with any microscopical 
 examination with any hope of success. The requirement, indeed, in this case would 
 be to make ourselves masters from personal observations of all objects already 
 examined, before we proceed to the examination of a new object. But a cursory 
 glance at the results already attained by the microscope shows the impossibility 
 of satisfying such a demand. We must therefore limit ourselves, and instead of 
 so comprehensive a demand, we will state two more practicable, but quite in- 
 dispensable requirements. The first consists in the necessity of making ourselves 
 acquainted with the general phenomena that may possibly occur on every examina- 
 tion, before we avail ourselves at all of the microscope for our researches ; and 
 the second consists in the necessity of studying accurately, previously, every- 
 thing that is already known respecting the special object of our examination. We 
 
ON THE USE OF THE MICROSCOPE. 
 
 587 
 
 can only direct attention to this in the shape of examples. The objects of micro- 
 scopical examination are either forms or processes. 
 
 A. With regard to the former, we have to consider two kinds of things : 
 
 a. Actual forms, which are so universally distributed that they may interfere with 
 every examination and obscure its results. 
 
 To these belong every thing which in ordinary life we call dust ; hence small 
 fibres of vegetable or animal tissue, or small granules of inorganic substances. 
 
 As most objects, at least all transparent ones, are moistened with water, there 
 belongs to this category the infusoria usually occurring in water, which, without 
 very tedious preparation, by means of boiling and hermetically sealing the water, 
 can never be wholly excluded. These objects should be well known and frequently 
 observed under various magnifying powers and circumstances, so that, being per- 
 fectly conversant with them, we may at once exclude them from our consideration 
 as not belonging to the object of our observation, should they be present with it. 
 
 b. Apparent substantial forms, consisting of substances which are formless. To 
 
 such belong all kinds of gas which may be mechanically separated in fluids ; also 
 mechanical mixtures of two fluids that do not mix with each other ; for instance, 
 bubbles of atmospheric air in water and oil, or drops of oil in water or gum. Air- 
 bubbles especially have caused many microscopical errors, even up to the present day. 
 They always appear under the microscope, when in a fluid, as spherical bodies, with 
 a very black margin and a very small, clear, round centre. On a more accurate 
 examination of them, we may recognise reflected images of objects which happen 
 to be in the vicinity, on the black margin of the side which is turned towards the 
 light, as, for instance, the cross bars of a window-casement, &c. The explanation 
 of this phenomenon is easy. Rays falling parallel from below experience (with the 
 
 72 a b Is the object-glass of the microscope ; c, d, e, f, a layer of water, in which is 
 enclosed g, h, p, an air-bubble. The ray of light (a-) consequently passes directly 
 through the perpendicular axis of the air-bubble ; near to it, also, the next rays, as, 
 for instance, y. The more remote ones (z), on the other hand, impinge obliquely on 
 the tangential plane of g, are thus refracted, and that from the perpendicular, from v g, 
 as they pass from a denser into a thinner medium, from water into air ; they therefore 
 travel the road g h. They are again refracted at h, but of course upwards from v A; 
 they then travel the road h i, and here they once more take a diverging direction, so 
 that none of the rays, which do not pass through the axis of the air-bubble, or close to 
 it, can ever reach the object-glass, and consequently the eye. An air-bubble must 
 therefore appear to be furnished with a broad black lightless margin, and with a bright 
 nucleus. This explanation may be readily applied to other cases of enclosed air. 
 
588 APPENDIX. 
 
 exception of the central rays) a refraction during their transit from the denser 
 medium into the air, and this diverts them considerably from the rays of the axis; 
 they strike, therefore, the periphery of the atmospheric globule, and on emerging 
 from it again experience a refraction, by which they diverge so far from the rays of 
 the axis, that they cannot arrive at the object-glass, and, consequently, not at the 
 eye. A similar process takes place with all gases enclosed in a fluid. This, even 
 at the present day, is a stumbling-block. We meet with elaborate explanations of 
 a dark material said to be deposited in the membranous glands, and also with 
 theories based upon the observation of them ; but, on strict examination, we find 
 that it is only the air enclosed in the stomates which has deluded the observer. 
 Now we have plenty of means of convincing ourselves whether we have air before 
 us or not ; for instance, water, which soon imbibes the air, caustic potash, alcohol, 
 oil of turpentine, &c. ; but we ought to expect from a practised observer that he 
 should be able to distinguish air from a solid substance by merely looking at it. 
 Air contained in the intercellular passages has also been described as a dark juice. 
 On the other hand, air has been sought for where it can never be found. In man) 
 works it is still stated that " the epidermal cells contain air." It only requires 
 a glance through the microscope, and some elementary knowledge of optical 
 science, to convince us that nothing more than fluid, which has nearly equally 
 refractive power with water, is contained in the epidermal cells of any healthy 
 living plant. But such matters are committed to paper, and copied again, without 
 any one inquiring about their correctness or asking for reasons. 
 
 Drops of oil present the same appearance under the microscope, only with this 
 difference, that the black margin in the oil- drops is much narrower, owing to the 
 difference of refractive power between air and water being greater than between 
 oil and water, and a greater number of rays are therefore lost in the air-bubble. 
 The explanation is the same in this case as was given when speaking of the air, 
 only the rays take exactly the opposite directions, owing to the greater refractive 
 power of the oil. 
 
 Other thick fluid substances, for instance mucus (protoplasma), assume 
 different forms in fluids with which they are mixed, and in which they are not 
 dissolved, and which forms are generally caused by their adhesion to other 
 objects, as, for instance, to the surface on which they are examined, and in that 
 case they are fibrous or membranous ; if, on the other hand, they are more iso- 
 lated, and left to their own cohesive power, they assume a spherical form. 
 
 B. There are also processes very generally met with which a microscopic 
 observer ought to be acquainted with, in order not to be deceived by them when 
 they occur. Certain motions, first of all, belong to such. 
 
 a. Robert Brown, the gifted English botanist, first made the important dis- 
 covery, that all substances, organic as well as inorganic, on being suspended in a 
 fluid in sufficiently small particles, are in a state of constant trembling or vibratory 
 motion, similar to a mass of monades, when seen with a low magnifying power. 
 The motion is difficult to be characterised, and it can only be accurately compre- 
 hended, and distinguished from other similar motions, by frequent observation. 
 It has been frequently observed in parts of plants, for instance, in the fine 
 granular contents of the pollen-cells, and has been described as a special living 
 action, which it certainly is not. We know nothing yet of the origin of these 
 movements ; but they are probably owing to slight electrical tensions and com- 
 pensations. 
 
 b. Another movement, which is frequently seen, is produced when two different 
 fluids, which have a considerable affinity for each other, for instance, water and 
 alcohol, or water and solution of iodine, are mixed with one another. A 
 powerful current usually takes place in them, frequently in quite opposite 
 directions. 
 
 c. A third case is, when fluids rapidly evaporate. During this process there 
 usually takes place a double current, namely, an upper one, from the margin to 
 the centre of the drop, and a lower one, from the centre towards the margin. 
 
 d. There are two further occurrences to be observed, which give rise to fre- 
 quent illusions ; one of them is the process of solution. Since most objects are 
 in a fluid, when under observation it frequently happens that a solution of many 
 objects takes place. The movements and changes of form occasioned thereby 
 
ON THE USE OF THE MICROSCOPE. 589 
 
 ought to be recognised. The other is the process of coagulation, which is also 
 produced by the influence of the surrounding fluid upon the substances under 
 observation. In this respect great caution ought to be used in the examination 
 of organic bodies, since apparent fonnations are frequently produced by such 
 coagulation, with which the nature of the thing has nothing to do. The best 
 rule in this case is always to examine organic objects in as fresh a state as pos- 
 sible, and to prefer unconditionally the image which exhibits itself at first sight, 
 to all others, and to regard it as normal, when a frequent repetition of the obser- 
 vation has convinced us that we have taken a correct view of it at the first sight. 
 Meyen has frequently described and represented coagulations of mucus and other 
 substances as forms (cells), for instance, in his Physiologic, III., Plate X., fig. 6. 
 Mirbel has done the same in his work, Sur le Cambium, &c., Plate XX., fig. 2. 
 Finally, we must direct particular attention to the second point above mentioned, 
 and which must be substituted for the exorbitant general requirement, viz., that 
 the microscopical observer should, before he proceeds to any research, make 
 himself most intimately acquainted with every thing that has already been 
 observed and made known with regard to the respective objects of his research. 
 
 We now proceed (to make use of a medical expression) to the second indica- 
 tion, namely, to the many-sided comprehension of one and the same object. To 
 do this in the preparation of an object for microscopical examination, we must 
 consider how we may obtain from such object, properly prepared, as many views 
 as can possibly be obtained from it, in order to construct a clear image from the 
 combination of the individual conceptions. In this respect there is least diffi- 
 culty in the observation of opaque objects, since the object is here brought in any 
 manner we please into the focus of the object-glass, or of the simple lens. It is 
 simply laid in a suitable position on a small glass plate, and the latter on the 
 stage of the microscope ; or it is taken up between the small forceps, which are 
 usually given with every microscope, by which we obtain the advantage of turning 
 it round under the microscope, thus enabling us to view it on all sides. 
 
 The observation of transparent objects is attended with much greater difficulty, 
 and,in fact, they form generally the objects of more accurate scientific examinations. 
 The object, in itself, is seldom so transparent as to enable us to bring it under the 
 microscope in an unprepared state. The wetting with water or with other liquids, 
 as fixed or volatile oils, Canadian balsam, &c., is of great assistance. Generally 
 we are compelled to make fine sections of the object, which, when sufficiently 
 thin, are always transparent, as, amongst organic substances, which form the most 
 important objects, we have no perfectly opaque objects. A double knife has been 
 invented for making such sections, which, however, is only calculated for a very 
 few botanical objects, its performance being anything but perfect. (Valentin, Re- 
 pert, vol. iv.). There is in fact no alternative but that of obtaining the neces- 
 sary skill by practice, so as to enable us to cut very fine slices by hand. The 
 anatomical scalpel was in former times commonly made use of for this purpose. 
 Subsequently very thin two-edged knives, in the shape of the grafting-knife, were 
 recommended, instead of the scalpel. I have found that a good razor with a 
 sufficiently heavy blade is the best instrument ; it may either be used merely with 
 one's hand, or by putting the object between one's thumb and fore-finger, and then 
 cutting through it. In this manner an accurate section may easily be obtained of 
 small objects, which may again be taken in the same way between the fingers, and 
 a thin slice cut off as 'before. If the object happens to be very delicate and 
 thin, as, for instance, hairs, the leaves of moss, &c., it must be attached to the 
 nail of the thumb, by means of a little oil or saliva ; the edge of the razor is then 
 placed upon it diagonally, and a to and fro motion is made with it, gently 
 advancing towards the root of the thumb. In this manner we may readily 
 obtain a number of thin segments, of which some are always perfectly available. 
 One great difficulty which we have to get over in this process consists in the 
 great softness of the object, which opposes so little resistance to a knife, that 
 even the sharpest blade tears and crushes rather than cuts it. I have invented 
 a method, which I have often applied with great success, in order to remove this 
 evil, and several of my friends have also availed themselves of it in the observ- 
 ation of animal substances. We first prepare, namely, a very concentrated solu- 
 tion of pure colourless gum arabic, and soften the object to be investigated 
 
590 APPENDIX. 
 
 thoroughly in this mucilage. It can then be readily fixed to a small board, on 
 which it must be perfectly dried, whilst a small quantity of the mucilage is occa- 
 sionally poured upon it. Before, however, it has become so dry as to cause the 
 gum to resume its brittleness, delicate sections of the object are made, which are 
 then wetted with a little water on a small glass plate ; the gum imbibes the water, 
 and the object assumes again almost its pristine form. 
 
 Such a preparation with the hand, however, does not suffice for very accurate 
 investigations. Indeed, the view of a section is by no means of importance in 
 many objects; and the thing to be desired is a division of the object into the 
 separate parts of which it is composed : and here we must have recourse to the 
 microscope in order to prepare the object properly. The simple microscope is 
 the most suitable for this purpose, which, especially when Chevalier's or Wol- 
 laston's double lenses are employed, still affords sufficient space between the 
 object and the lens, at a magnifying power of 100 times, to enable us to work with 
 very delicate instruments. The compound microscope has the great disad- 
 vantage, that the object is reversed, requiring, therefore, a very difficult practice 
 of opposing the motion ; and in the next place, our hands are so far removed from 
 the eye as to render their movements uncertain, so that a tearing or crushing of 
 the object at random is scarcely avoidable.* But the greatest hindrances to 
 preparing under the microscope are the instruments. They are, of course, mag- 
 nified as much as the object ; and we soon find that no point is sufficiently fine 
 to enable us to divide the parts of the object with accuracy : very fine needles, 
 which we may sharpen ourselves upon a very fine grindstone, afterwards observ- 
 ing the edge and point under the microscope, are the best for this purpose. 
 English needles, intended for very fine operations, and sharpened in the same way, 
 will answer the purpose. The other difficulty is less easily overcome, viz. the 
 circumstance that our hand is not used to such delicate movements as are neces- 
 sary at a magnifying power of 50 or 60 : practice, however, will serve to remove 
 this impediment. 
 
 After these preliminary considerations, I shall now proceed to the methods by 
 which the object under investigation may be placed in as many different circum- 
 stances as possible, in order thereby to increase the number of points of view. 
 Optical, mechanical, chemical, and physical auxiliaries are here to be distin- 
 guished. They may be called, generally, microscopical reagents. 
 
 a. The Optical. 
 
 First of all, we may remark, that the observer should never limit himself to the 
 observation of an object by one magnifying power alone. It is always advisable 
 to commence with the lower powers^ and gradually to use the higher ones. This 
 mode of proceeding is necessary on account of the fact that the field of vision 
 must diminish in proportion to the degree of magnifying power ; and as it is 
 always requisite, in order to obtain a correct conception, to have a distinct view 
 of the individual parts in all their relations. 
 
 2dly. The changing the direction of the light is also a matter of importance, 
 as we have already explained. 
 
 3dly. It is frequently of advantage to observe an object in a coloured, or, still 
 better, in a monochromatic light : this may be done by using coloured glass for the 
 stage, or employing a spirit-lamp for the illumination, the wick of which has been 
 previously dipped in a solution of common salt, or in which the spirit has been 
 previously diluted with water as much as possible. Both methods, according to 
 Brewster, give a homogeneous yellow light. 
 
 Finally. It is advisable in many cases to observe the object by polarised light, 
 for which purpose a crystalline body, suitably polished for it, is fastened under 
 the table of the microscope. But any working-optician will supply informa- 
 tion on this subject : I need not, therefore, make any further remarks upon it. f 
 
 * An erecting eye-piece in the body of the compound microscope obviates nearly all 
 objections to it as an instrument for dissection. TRANS. 
 
 f Compare Chevalier, Des Microsc. et de leur Usage, pp. 125 128. [For further 
 information on this subject, the English reader is referred to a little work, by Mr. C. 
 
ON THE USE OF THE MICROSCOPE. 591 
 
 b. Mechanical Means. 
 
 It is advantageous in many respects to observe how an object alters on 
 the application of pressure. A double disc was formerly made use of for this 
 purpose : this, however, was attended with the disadvantage that we could only 
 observe the result, not the gradual effect, of the pressure. More recently, an 
 instrument invented by Purkinje, and which bears the discoverer's name, has 
 been made use of for this purpose, and also an improved form by Shiek. The 
 gradual effect of the pressure can very readily be observed under the microscope 
 with this auxiliary. The value of this instrument has been overrated by Purkinje, 
 but has been very unjustly rejected altogether by Meyen. It is, perhaps, the only 
 means of distinguishing a small globule from a vesicle, which latter, without 
 having any real existence, occupied so prominent a position for a long time in 
 botanical works. 
 
 c. Chemical. 
 
 The different phenomena which a substance presents upon the application of 
 chemical reagents are of the highest importance for the formation of our opinion. 
 Indeed, it very frequently occurs that we are obliged to determine substances 
 according to their chemical nature, which, enclosed in organised bodies in a 
 small quantity, cannot mechanically be separated from them, at least not in such 
 a manner as to enable us to institute a chemical analysis of them. There is no 
 other means left to us, therefore, but to use such agents under the microscope 
 itself.* The principal of such reagents are : 
 
 1. Tincture of Iodine. Particularly useful for rendering visible very trans- 
 parent objects, and for the determination of various vegetable substances. 
 
 2. Sulphuric Acid. For the destruction of certain parts. 
 
 3. Fixed Oils. The best of all is the oil of almonds. Volatile oils, oil of 
 lavender, alcohol and ether, and Canadian balsam, in order to render objects 
 transparent, and to dissolve species of fat and resin, and bring substances into a 
 state of coagulation ; as, for instance, albumen. 
 
 4. Solutions of Sugar, Gum, and Albumen. In order to prevent endosmosis, 
 and the changes of form consequent thereon. 
 
 5. Solution of Caustic Potash. For the destruction of certain parts. 
 
 6. Acetic Acid, Nitric Acid, Muriatic Acid. In order to dissolve many sub- 
 stances. 
 
 The reagents enumerated last (under No. 6.) ought to be avoided as much as 
 possible, when the achromatic microscope is made use of; and at all events the 
 object ought to be covered by a glass plate, since the evap6rating acids very 
 readily produce an effect upon the very susceptible flint-glass. 
 
 d. Physical. 
 
 It may occasionally happen to be of interest to observe the effect of heat and 
 electricity upon certain objects under the microscope. Peculiar contrivances are 
 necessary for this. The application of heat requires glass plates that have pre- 
 viously been thoroughly annealed, which may be heated by means of a small 
 spirit-lamp at one end, or by means of very thin glass plates loosely put into a 
 brass frame, and heating the latter. For the observation of electrical effects we 
 have a small peculiar stage, on both sides of which two small forceps hold move- 
 able little pieces of a glass tube, through which wires are drawn. These wires 
 reach the stage at one end, and have a small hook at the other, in order to attach 
 the conducting wires. 
 
 Many errors, which but too frequently occur in botanical works, will be avoided 
 if the auxiliary means enumerated above are applied, and if attention is paid to 
 the cautions and hints communicated. Once for all, however, I must repeat the 
 fundamental rule, that he who wishes to observe with success, must observe 
 frequently and with the most profound attention : by observing this rule, he may 
 gradually learn to see, for seeing is a very difficult art. 
 
 Woodward, on polarised light ; and also the Transactions of the Microscopical Society. 
 THA NSI.ATOR. ] 
 
 * J. Vogel, Anleitung zum Gcbrauch des Mikroskops, &c. 
 
592 APPENDIX. 
 
 EXPLANATIONS OF THE PLATES. 
 
 PLATE I. 
 Figs. 116 : see 14. 
 
 Fig. 1. Contents of the embryo-sac of Vicia faba soon after fecundation. In 
 the clear fluid, which consists of gum and sugar, swim granules of protein com- 
 pounds (a), amongst which are some of a larger size. Around these last the first 
 are rolled together so as to form a little disc, and sometimes two such discs are 
 seen blending one with the other (6). Around other discs can be discerned a clear, 
 sharply-defined edge (c), which gradually extends further from the disc (thec}to- 
 blast), and at last may be clearly distinguished as a young cell. 
 
 Fig. 2. Young and very irregular cells from the albumen of Vicia faba, with 
 beautiful parietal cytoblasts and nuclei. 
 
 Fig. 3. Free cytoblasts in the sac of the embryo of Sanguinaria canadensis ; three 
 of them are hollow (?), with a firm nucleus. 
 
 Fig. 4. Cytoblasts with nuclei from the embryo-sac of Pimclea drupacea : 
 a, Free cytoblast with nucleus; b y a cytoblast with two nuclei ; c, cytoblast with 
 three nuclei, and the cell forming around it. 
 
 Fig. 5. Cytoblasts from the sac of the embryo of Fritillaria imperialis, in various 
 stages of development. 
 
 Fig. 6. Some cells from the albumen of the same plant, having a correct rela- 
 tive size to the foregoing figure. The cytoblasts are partly round (a) and partly 
 lenticular (6) ; they are always, through a peculiar substance, firmly adherent to 
 the wall. 
 
 Fig. 7. Cells from the albumen of Pedicularis palustns. rr, The single wall of the 
 cell; b y section of the surface of the cell in focus. Around the cytoblast is seen 
 a great quantity of a muco-granular substance, which moves in little reticular 
 streams on the inner surface of the wall. 
 
 Fig. 8. Mature pollen-grain of Frilillaria imperialis, with parietal cytoblasts ; the 
 great central cavity is the result of endosmosis. 
 
 Fig. 9. Formation of the fermentation-fungus in currant-juice (page 37.). 
 a. The first appearance of solid matter (protein ?) in the clear juice. These 
 globules pass gradually into the forms at b. These are found suspended in the 
 juice when it begins to become opalescent, and before the slightest trace of the 
 development of gas or of fermentation can be detected ; b and c are transitionary 
 stages ; rf, e,f, ferment-cells in various stages of increase. 
 
 Fig. 10. Decomposition of pure protein in a solution of sugar (during fermenta- 
 tion), page 37. a. A small portion of protein breaking up into granules (b} at the 
 under part; d, a portion of protein, with the edges well defined on one side, and 
 at the other breaking up into little granules, from which proceeds, indistinctly at 
 its commencement, a little cellular fibre ; c, various forms of cellular fibres pro- 
 duced in the fermentation of a solution of sugar with pure protein and protein 
 compounds. 
 
 Figs. 11 13. Gradual development of the hairs on the stem and leaves of 
 Glaucium luteum. In the original elongated epidermal cells, transverse cells are 
 formed, which are clearly seen to be free. At a, one of these cells displays two 
 

 
 
" 
 
 
 
EXPLANATIONS OF THE PLATES. 593 
 
 others in its interior ; under this is a second of the same kind, and below this is a 
 third containing two free cytoblasts. 
 
 Fig. 12. A condition somewhat later than fig. 1 1. a. The encasing of the cells 
 in one another is very evident. 
 
 Fig. 13. A part of the living hair. Reticulated streamlets proceed from the 
 cytoblast in all the cells, but they are drawn in only two of the cells. 
 
 Fig. 14. The first commencement of the formation of an embryo in Pedicidaris 
 palustris : a, b. and c, d. display the outline of the ernbryo-sac in the region of the 
 penetrating pollen-tube, which at the end, in the embryo-sac, is swollen globularly, 
 and contains two very young cells and a free cytoblast ; below in the pedicel there 
 are three oval, free cells. 
 
 Fig. 15. Very early condition of the embryo of Sagittaria sagittcefolia. It may 
 be here seen how the pollen-tube, loose at the beginning, is gradually formed into 
 a little cellular body by the continued formation of cells in cells. 
 
 Fig.16. First commencement of an oil-duct in the tubers of Georgina variabilis. 
 In a single cell of the parenchyma, two free cells have been formed, which have 
 already separated between them a large drop of oil, and are characterised by their 
 cytoblasts. 
 
 Figs. 1724 : see 1819. 
 
 Fig. 17. Porous cell-walls in Abies excelsa: a. transverse section. The two 
 primary cell- walls are clearly separated (Hartig's Eustathe), and the deposit- 
 layers are penetrated by the pore-canals (Hartig's Astathe and Ptychode). b. The 
 longitudinal section : it displays at c. the simple wall of the cell, at d. the double 
 wall of this and the neighbouring cell. 
 
 Fig. 18. A delicate section from the wall of the spiral-fibrous cells in the leaf 
 of Oncidium (cdtissimum ?). The spiral fibres appear separated from the original 
 cell-wall by a sharp line. The bark (external layer) of the fibre is not to be dis- 
 tinguished in the thinner and younger fibres, b. 
 
 Fig. 19. A similar section, as in fig. 18, from the leaf of Vanda teretifolia, but 
 upon the double wall there are two spiral fibres lying one on the other. The 
 external layer of the individual fibre is at least as thick as the doubled wall of the 
 two cells. 
 
 Fig. 20. A similar section of an annular vessel in the stem of Arundo Donax. 
 The external layer of the annular fibre is at least three times as thick as the 
 original cell-membrane. The internal portion of the spiral fibre was treated with 
 warm caustic alkali, it swelled up, and became gelatinous without changing the 
 original cell-wall, or the external membrane of the spiral fibre. 
 
 Fig. 21. In the gynophore of Magnolia grandiflora, after flowering, the cells 
 are very thick, and consist of several layers which are traversed by branched 
 pore-canals. The figure displays two of these projecting one against the other. 
 The pore-canals pass through the layers of the cell often at right angles. 
 
 Fig. 22. The pore-canals as above are seen to represent a very thickened cell 
 from the bark of Fraxinus excelsior var. jaspidea. 
 
 Fig. 23. Two cells from the tuber of Georgina variabilis with delicate spiral 
 fibres. 
 
 Fig. 24. A cell from the root membrane of Oncidium altissimum, with delicate 
 spiral fibres, which in some places separate from each other. These spaces ap- 
 pear at a later period to produce an actual perforation of the primary cell-wall. 
 
 PLATE II. 
 Figs. 1 6: Siliceous Shield of Navicula viridis ( 82.). 
 
 Fig. 1. Anterior view. In the middle line are two clefts, each about half the 
 whole length, and terminating at the centre, as well as at the other ends, with a 
 little circular enlargement. This is seen more clearly in figs. 3. and 4. Above, 
 below, and in the middle, upon the anterior and posterior surface of the shield, 
 
 Q Q 
 
594 APPENDIX. 
 
 are seen thickened spots of siliceous matter (like drops of glass on the surface of 
 a bottle) ; but by no means a round hole, as it is represented by Ehrenberg and 
 many others. That such a hole is decidedly sometimes not present in the centre, 
 is seen unanswerably in such fragments as fig. 3., and especially fig. 4., which may 
 be easily obtained by crushing the shield. On each side the central clefts are 
 seen a great number of oblique clefts, which, according to the direction of the 
 light through the focus, appear smaller or larger. In these spots the shield con- 
 sists of two leaves lying one over the other. These leaves are penetrated with 
 the small clefts which, where both the lamellae touch each other, are somewhat 
 broader, which explains the varying breadth of the clefts according to the altera- 
 tion of the foci. Fragments in which this structure is clearly represented may 
 be frequently obtained by crushing the shield (fig. 6.). 
 
 Fig. 2. Lateral view of the shield. The three enlargements are seen here on 
 both sides, from which it is very evident, and what we might have supposed at 
 first sight, that the central enlargement is a little depression upon the external 
 surface. The two sides of the shield exhibit only a few of the oblique stripes : in 
 the centre is seen a broad smooth surface, which is traversed in its whole length by 
 two parallel clefts. In this figure is seen more strikingly than'^in fig. 1. the double 
 contour which denotes the thickness of the wall of the shield, and which sud- 
 denly ceases both above and below. This clearly shows that a passage exists 
 from the top to the bottom of the shield, which may be easily confirmed, if the 
 shield, or, what is better, the same obliquely fractured, is looked at from above. 
 This may be done by taking some of the siliceous earth of Erbsdorff and mixing it 
 with mucilage, and before it is perfectly hardened cutting off delicate plates with 
 a razor. Fig. 5. exhibits a section of the upper part of a shield prepared in this 
 way. 
 
 Such an artificial and complicated structure amongst plants has no explanation, 
 and is entirely without signification. In all actual plants we find the silica pre- 
 sent in quite a different form, as little separate scales or drops, and distributed 
 through the substance of the cell-wall. 
 
 Fig. 7. Spirogym quinina ( 82.) The end of a filament of the plant. A three- 
 fold wall of the cell may be distinguished. Externally, a gelatinous covering (a), 
 which extends over all the cells of the fibre ; under it lies the special cell-mem- 
 brane (b). Both are transparent, and separated by a delicate black line, and are 
 easily distinguished from one another, especially at the commissures where 
 two cells unite. The cell-membrane is clothed on its inner surface with a deli- 
 cate but clearly distinguishable pale yellow layer, of a semi-fluid proteinaceous sub- 
 stance (d). Upon this layer lie the bands, dentated at their edges, of chlorophyll (*), 
 the basis of which is probably wax. These bands are externally furrowed, and 
 take up in the furrows a clear firm substance (c), which may be easily distinguished 
 from a mere interspace if the whole fibre be moistened with tincture of iodine. 
 In the continuity of this transparent substance (vegetable jelly) there exist in- 
 dividual larger or smaller granules (/), which, at least at certain times, consist 
 of starch. Accidentally in the midst of the cell there exists a somewhat elongated 
 cytoblast (g), which contains a nucleolus surrounded by an areola of mucous 
 matter, from which proceed on all sides little streams towards the wall of the 
 cell. There is always in the nitrogenous layer a circulation consisting of innu- 
 merable very varying streams which unite together in a reticular manner. The 
 direction of some of these is shown in the plate by the direction of an arrow. 
 These little streams are so changeable, that if a drawing from nature be made 
 of the system of streams, in the course of a quarter of an hour, on comparing it 
 with the original it will be found that every one of the streams has taken a dif- 
 ferent direction. If a representation of the new streams is made, and thus on 
 from one quarter of an hour to another, it will be found that they keep on chang- 
 ing, and that the whole layer of nitrogenous matter takes part in the movement 
 of the little streams. The remainder of the contents of the cell contains a trans- 
 parent fluid. 
 
 Fig. 8. Mould found growing on the stems of Passiflora alata ; the upper part 
 of the little plant with a lateral branch. In this case also the nitrogenous layer 
 circulates in little streams. This little plant exhibits a tolerably complete history 
 

 
 10 
 
 //d 
 
 
 
EXPLANATIONS OF THE PLATES. 595 
 
 of the development of the spore of the fungi, if the steps a, b y c, d y e y f are com- 
 pared, whilst g,g represent the cicatrices of pollen-spores : see the text, $ 84>. 
 
 Fig. 9. Borrera ciliaris. Development of the spore, 88. a. A full-grown 
 spore-case filled with a thickish cytoblastema, in which can be discerned individual 
 cell-nuclei. The wall of the spore-case is gelatinous and very thick ; b is a much 
 younger spore-case ; c y the fibres of which the disc of the sporocarp is formed 
 ( 88, fig. 127.); d, a spore-case with almost perfectly-formed spores. If the 
 spore-cases at the various stages of their growth are separated from the sporo- 
 carps, and their contents accurately examined, they will be found to constitute a 
 series such as are represented from e (a free cytoblast) to s (a perfectly ripe 
 spore). In fis seen the formation of the primary simple spore, in g, k, i the 
 gradual destruction of the nucleus, in k, /, m the appearance of two cytoblasts, 
 around which, from n q y two cells organise, till at last, in r and s, the primary 
 spore is dissolved, and the double spore appears perfectly completed. 
 
 Fig. 10. Sphagnum cymba:folium (A. E.) and Polytrichum commune (-F-). 
 Formation of the Antheridia ($ 102. Z).) A. Youngest condition of Antheridia 
 ever observed by me. B. Perfectly-developed organ, consisting of a cellular 
 peduncle and an oval sac, which are formed out of a layer of cells and a large 
 central cell, as is shown in the section, fig. D., which was accidentally made. 
 C. The central cell isolated and burst by gentle pressure, with its contents, con- 
 sisting of gum, sugar (?), albumen, and half-solid, nitrogenous (?) granules. E. 
 The contents of the central cell at a later period, consisting of free cytoblasts 
 and very delicate flat cells, in which the nucleus is yet recognised, and which 
 gradually elongates and appears to be converted into the moving spiral fibres. 
 F. Various forms of moveable spiral fibres (so-called spermatozoa). The so-called 
 head is evidently unessential, as its form is constantly changing. 
 
 PLATE III. 
 
 Figs. 1 11. Pisum sativum. History of Development of Leaf. 
 
 Fig. 1. Germinating plant, a, Root ; b y cotyledons ; c,d y e,f, first to fourth 
 leaf. 
 
 Fig. 2. A cotyledon seen from the inner side. Where the sheathing petiole 
 passes into the disc of the leaf, are seen two little processes, which are the first 
 indications of stipules, and formed by the upward pressure of the bud during its 
 development. 
 
 Fig. 3. Second leaf seen from the back, small lanceolate, with two lanceolate 
 (so-called adherent) stipules. 
 
 Fig. 4. Second leaf seen from the back, small lanceolate with two large 
 stipules. 
 
 Fig. 5. Third leaf, front view, with two leaflets and two stipules. 
 
 Fig. 6. Terminal bud. a, Leaf spread out ; b, point of the same ; c, termin- 
 ation of the axis ; d y plane on which the leaf originates. 
 
 Fig. 7. Third leaf separated from the foregoing terminal bud. a. Stipules ; 
 b, point of the leaf; c, leaflets. 
 
 Fig. 8. Fourth leaf of the same bud. a y b, c. The same as in the last figure. 
 
 Figs. 9 1 1. Three terminal buds in various ages of the leaves, seen from above. 
 The leaves of figs. 11 of, 10 c y 9d, 10 c y 1 1 c, 9 c, exhibit a perfect series of stages 
 of development, which may include also those opposite figs, at We. and 1 1 d. at the 
 youngest period of growth. It results from this, with direct evidence, that the 
 stipules are the last parts of the leaf to appear, as they originate in a part of the 
 stem where no other parts of the leaf are ever found. It is also impossible that 
 the stipules should alternate at any time with the first pair of leaflets. 
 
 Figs. 12 20. Canna exigua. Development of the Flower. 
 
 Fig. 12. Youngest condition. The calyx (a, a', a"} and the external circle of 
 the corolla (b y b f , b") are as yet alone present, but long before this the cavity of 
 
 Q Q 2 
 
596 APPENDIX. 
 
 the gerrnen is formed through the cup-shaped, spreading flower-stalk, which 
 is easily understood through a longitudinal section of the flower, as seen in fig. 13, 
 where e represents the cavity of the germen. 
 
 Fig. 14. A somewhat later condition. The inner circle of the corolla has 
 appeared. Alternating with these and the most external circle we have three little 
 elevations, forming a fourth leaf-circle of the flower. 
 
 Figg. 15, 16. Perpendicular sections of the last, in which the four circles of leaves 
 are figured a, b, c, d from without inwards. This section does not exhibit accurately 
 the centre of the corolla. 
 
 Fig. 17. The same in much later circumstances (the whole flower was three- 
 quarters of an inch long), seen from above. The parts of the flower have been 
 cut away about half a line above the germen : d' is the leaf of the innermost 
 circle, which becomes the stamen ; d" is the leaf of the same circle, which is 
 folded together to form the style, and is already grown together by the edges ; d is 
 the third leaf of this circle, which is aborted. 
 
 Fig. 18 represents a longitudinal section of the leaf (17 d.) seen from 
 within. 
 
 Fig. 19. A somewhat earlier condition of the style, before the edges of the 
 leaf are grown together, as is more clearly seen in the transverse section, fig. 20. 
 
 Figs. 21 23. Agrostisalba Schrad. Development of the Flower. 
 
 Fig. 21. A very young ear: a, b, the two bracts (calyx Linn., glumce Auct.) ; 
 c. the flower-envelope (corolla Linn., pakcs Auct.) ; d, anthers ; e, germen. 
 
 Figs. 22, 23. Flowers from the same ear, seen from two sides. The letters 
 signify the same in both figures : c c' c", three perfectly separate leaves of the 
 flower-envelope standing upon the same level ; c" is already somewhat larger than 
 the other two (palea inferior), c and c' grow together at a later period (pa/ea 
 binervis 1. superior) : d' d" d" the stamens. Between d'" and d" (fig. 22). is seen 
 a little wart, and at d' (fig. 23.) are seen two : the three stand upon the same 
 plane, and, like the large warts (leaves), form a nectary (tquamuUe Auct.), which 
 are not seen in the further development of the flower. The three stamens (fig. 
 22.) enclose the germen from which the nucleus of the seed-bud projects. 
 
 Figs. 24 26. Carex lagopodioides. Development of the female Flower. 
 
 Fig. 24. Very young condition of the female flower, seen from above : a, 
 bract cut through ; b b' b" the three at present perfectly free leaves of the 
 flower-envelopes, of which b and V grow together with one another, and form the 
 flask-shaped tube, which latter surrounds the germen, whilst the third leaf is not 
 developed. This flower-envelope encloses a carpellary leaf not yet closed, and 
 the nucleus of the seed-bud. 
 
 Fig. 25. The same flower seen from the side : c, carpellary leaf; d, nucleus of 
 the seed-bud ; b b' b", as in fig. 24. 
 
 Fig. 26. A flower in a somewhat later condition. The two leaves of the flower- 
 envelope b and b' are now grown together, and surround the third, b", which 
 retires in its growth, and at last entirely vanishes, c. The developing germen. 
 
 PLATE IV. 
 
 Development of the Parts of the Flower of Passiflora. Figs 1 4. are P. princepg. 
 The remainder P. cceruleoracemosa. 
 
 Figs. 1 11. Development of the Parts of the Flower generally. 
 
 Fig. 1. A very early condition of the flower (about one-fourth of a millimeter 
 in length). Around the elevation of the pith in the centre (the termination of 
 the stem) are five foliar organs (calycine leaves, sepals), already become slightly 
 irregular in their development, and in the early condition of the foliatio valvata 
 ( 134.). 
 

 >' 
 
 fm \ 
 
EXPLANATIONS OF THE PLATES. 597 
 
 j. 2. Longitudinal section of the same. The letters indicate the same 
 sepals. An epithelium distinct from the parenchyma can be clearly seen. 
 
 Fig. 3. A later condition. The sepals have already the commencement of the 
 wing-shaped keel upon their backs. The foundations of the bud are perfectly 
 developed. 
 
 Fig. 4. Longitudinal section of the same. The same letters designate the same 
 sepals. Between the two there is a leaf of the corolla, and in front of b another 
 cut through. Right and left of the corolla-leaf, in the middle, are two little ele- 
 vations, which are the commencement of stamens cut through. 
 
 Fig. 5. A somewhat late condition (the bud with the bracteola, about l mil- 
 limeter long) : the three calyx-leaves (sepals) alternate with the two corolla- 
 leaves (petals), and between these there is a little elevation, which is the first 
 appearance of a stamen-leaf (stamen). The two last figures are somewhat 
 smaller than half, so that the wart-like termination of the axis in the centre is 
 not seen. 
 
 Fig. 6. A later condition. The five sepals are distinct. The petals are seen 
 alternating with them, and the stamen with these. In the centre the axis is 
 conspicuous as the germen (cauligenum) with a cavity, but as yet no trace of a 
 style (carpellary leaf). 
 
 Fig. 7. Longitudinal section, later still. The whole flower is perfectly deve- 
 loped, a, Longitudinal section of sepal ; a', a second, seen from the edge ; 
 6, petal ; a and b are attached to a cyathiform extension of the axis f, (a disc) j 
 c, section of stamens ; d, another from the side ; e, pistil. 
 
 Fig. 8. The pistil at the same stage of development, seen from above. Three 
 carpellary leaves are seen at the edges of the germen. 
 
 Fig. 9. Outline of a transverse section of a corolla, directly above the pistil. 
 The petals still exhibit the valvate condition of the bud. In the three last tissues, 
 where all the leaf-organs are formed, from the calyx to the carpellary leaves, there 
 is not the slightest trace upon the disc of the presence of the corona. It cannot, 
 therefore, be formed from the foliar organs. 
 
 Fig. 10. A longitudinal section in a yet later condition, a, Sepal ; b', petal 
 seen from the edge ; c, stamen cut through ; c', lower part of the germen and 
 disc f, upon which, at g, the various forms of the corona begin to be developed 
 as mere cellular (hair-like) growths. 
 
 Fig. 11. An almost complete longitudinal section of the entire flower, at a 
 yet later period, a, Sepal (lower half) cut through near the wing-shaped keel ; 
 of sepal seen from the edge ; b, petal ; b', another seen from the edge ; c, lateral 
 view of a stamen ; c' ', lower part of a stamen cut through ; d, germen (germen cau- 
 ligenum) cut through : on both sides the commencement of the seed-bulbs project 
 into the cavity ; e, style (carpellary leaf), with a lateral view of the stigma ; e' ano- 
 ther, with the canal exposed ; /, enlargement of the axis between the calyx and 
 petals (disc) ; g, continuation of the axis above the petals (filaments) ; h, continu- 
 ation of the stamens (gynophore) ; i, corona. 
 
 Figs. 12 18. Development of the Anthers. 
 
 Fig. 12. Transverse section of anthers of fig. 7.: a, groups of strongly thick- 
 ened cells ; b y foundation of vascular bundles ; c, foundation of four anther- 
 valves. 
 
 Fig. 13. Transverse section of part of an anther-cell, at a period between 
 figs. 7. and 10. a. Epithelium, b. Developing cellular tissue with great cytoblasts, 
 out of which at a later period the various layers of anther-valves are developed. 
 c. Primitive parent-cells, with great parietal cytoblast for the formation of pollen. 
 After these cells are perfectly formed and arranged by the formation of cell 
 within cell, there originates in every cell an individual cell which is perfectly and 
 easily separable, and these remain isolated when the first are dissolved up. In 
 the isolated cells (parent-cells of Niigeli ; they might be called special parent-cells) 
 are formed four free cytoblasts, and around these are formed four free cells. 
 
 Fig. 14 exhibits the last condition. A. A parent-cell in which are two 
 active (pollen) cells and a cytoblast : the fourth lies on the other side, and is not 
 seen. J3. An individual pollen-cell separated from another parent-cell of the 
 
 Q Q 3 
 
598 APPENDIX. 
 
 same kind : it exhibits a large cytoblast and a very evident circulation in stream- 
 lets. The pollen-cells are empty, but the parent-cells are full of a thickened 
 muco-granular (especially nitrogenised) contents. Gradually the contents of the 
 parent-cell become clear and gelatinous, whilst the four pollen-cells get filled 
 with a similar substance to that contained earlier in the parent-cells. This is 
 seen in 
 
 Fig. 15. Parent-cells at a period the same as fig. 11. The parent-cells soon 
 become dissolved, the pollen grains begin to assume a round form, and to sepa- 
 rate the external pollen membrane. During this time the cellular tissue of the 
 anther-wall (fig. 13. b.) becomes developed and arranged. 
 
 Fig 16. A somewhat later condition than fig. 11. The pollen grains are quite 
 completed (as fig. 17.) a, The perfectly developed epidermis ; Z>, the cell-layer, 
 in which is evident a circulation in reticulated streamlets (later spiral layers) ; c, 
 somewhat elongated cells, containing chlorophyll grains; d, cells still more elon- 
 gated, very flat, and containing opaque (nitrogenous) contents ; <?, radical, elon- 
 gated, sac-formed cells, in which a process of cell-formation is going on, and 
 which contain two free cells with large cytoblasts ; these cells are subsequently 
 entirely resorbed. 
 
 Fig. 17. A perfectly-formed pollen grain, consisting of the essential pollen-cell 
 and a layer of secretion (the external pollen membrane). It has four circular 
 clefts, in which the pollen lies free (uncovered). 
 
 Fig. 18. Section of the pollen-membrane, c, Essential membrane of the pollen- 
 cell ; 6, layer of secretion ; d, projections formed of the same substance, and in 
 union with the layer of secretion. It forms the reticulated united elevations on 
 the whole surface of the granule. The little pits or cavities thus formed are filled 
 with a clear, firm, gelatinous substance, a, perhaps tne residuum of the dissolved 
 parent-cells. 
 
 What I have observed on the development of the pollen, I have here, and in the 
 text on other plants, communicated. Whether myself or Na'geli is right, or both 
 wrong, the future alone can decide. 
 
 PLATE V. 
 
 Development of the Seed-bud (Ovule), Stigma, and Embryo. 
 Figs. 1 3. Development of the Seed-bud in Passiflora 2'iKceps. 
 
 Fig. 1. Three seed-buds at a period somewhat earlier than fig. 11. a, Very 
 young seed-bud, forming a simple, rather curved wart (the nucleus of the bud and 
 the stalk of the bud undistinguishable) ; b, a seed-bud further developed, in which 
 the first integument is already formed, and which embraces the base of the 
 nucleus so as to distinguish it from the peduncle of the bud (funiculus) ; 6", longi- 
 tudinal section of one in a medium condition; 1, point of the nucleus (nuclear 
 wart) ; 2, appearance of the first integument. At the point of the nucleus 
 is seen a strikingly-enlarged cell containing cytoblasts : this is the future embryo- 
 sac. 
 
 Fig. 2. Seed-bud at a somewhat later period than fig. 11. (PI. IV.) , The 
 nucleus already covered with the first integument, 2, and this again with a second, 
 3, so that the peduncle (4) of the bud is perfectly separated j a', a similar bud 
 seen in front ; b, longitudinal section of the upper part of a somewhat further 
 developed bud, which is explained fig. 1 b f and fig. 2 a ; c, a seed-bud unfolding in 
 an abnormal way. The figures are the same as in a. The contrast is striking in 
 this case between the cells of the peduncle (4) of the bud, arranged in long rows, 
 and, on account of the air in the intercellular passages, of a black colour, and the 
 round, succulent, cellular tissue of the seed-bud. 
 
 Fig. 3. Longitudinal section of a perfectly-developed (inverted) seed-bud before 
 impregnation, a, Peduncle of the bud ; b, external integument ; c, internal 
 integument ; d y nucleus, e, embryo-sac ; /, opening of the bud (micropyle) ; 
 g, base of the bud j 7z, raphe. 
 


 
EXPLANATIONS OF THE PLATES. 599 
 
 Figs. 4 6. Formation of the Stigma. 
 
 Fig. 4. , Style ; b, stigma, slightly magnified. 
 
 Fig. 5. Longitudinal section of part of the style and stigma, a, Epidermis ; 
 b, parenchyma ; c, canal of the style, in which is continued the delicate gelatinous 
 parenchyma of the stigma as a conducting cellular tissue ; d, papilla of the 
 stigma. 
 
 Fig. 6. An individual stigmatic papilla, strongly magnified, terminating in two 
 papillary cells (a), between which eventually the pollen-tube penetrates. 
 
 Development of the Embryo. 
 
 Figs. 7 9. Epilobium hirsutum. 
 
 Fig. 7. A small portion of the stigma. , Pollen-grain with detached fibres (b) 
 and two pollen tubes (c), of which the left has already penetrated through the 
 papillae (d) to the parenchyma (e) of the stigma. 
 
 Fig. 8. a, The seed-bud and a portion of the conducting cellular tissue (e) of 
 the germen. The pollen-tubes (d d) are passing down the conducting cellular 
 tissue, and one of them enters the foramen (b) of the seed-bud (ovule) ; c, hairs 
 of the seed-bud at its base. 
 
 Fig. 9. Longitudinal section through the foregoing seed-bud, a, Papillary 
 epidermis; b, parenchyma of the external envelopes of the bud; c, internal enve- 
 lope ; d, nucleus ; e, raphe ; /, tuft of hair at the base of the seed-bud ; g, pollen- 
 tube entering the foramen ; h, sac of the embryo. 
 
 Figs. 10. and 11. Orchis Mono. 
 
 Fig. 10. Soon after the entrance of the pollen-tube. a y Inner integument: 
 b, sac of the embryo, which has perfectly supplanted the nucleus ; c, pollen-tube. 
 
 Fig. 11. Prepared free from the seed-bud, a, The pollen-tube, which clearly 
 as a continuous membrane surrounds the cells which are contained in it, and of 
 which (6) forms the embryo ; c, the peduncle of the embryo (embryotrager), which 
 at a later period projects from the seed-bud. 
 
 PLATE VI. 
 
 Development of the Embryo continued. 
 Figs. 1. and 2. Orchis latifolia. 
 
 Fig. 1. Longitudinal section of a seed-bud, a, External integument ; b, inter- 
 nal integument ; c, d, two pollen-tubes, whose penetrating extremities have formed 
 the foundation of two embryos. 
 
 Fig. 2. Longitudinal section of the lower part of a seed-bud, a d, As in fig. 1. 
 The pollen-tube, c, has penetrated the right spot and has developed a perfect 
 embryo ; but the other, d, has missed the inner foramen and passed between the 
 internal and external integument, and in this case has formed a rudimentary embryo. 
 
 Figs. 3. and 4. Salvia bicolor. 
 
 Fig. 3. Longitudinal section through the seed-bud, a, Epidermis of the simple 
 integument (&) ; c, the epidermis of the supplanted nucleus (inembrana nuclei, 
 Rob. Brown) ; d, raphe ; e, the sac of the embryo, which has extended itself above 
 the nucleus into the canal of the foramen of the seed-bud ; f, pollen-tube pene- 
 trating into the embryo-sac, where it lays the foundations of the embryo. 
 
 Fig. 4. Pollen-tube prepared from the foregoing, a, The under, looser part 
 dilated (with the extension of the embryo-sac) ; c, upper portion attenuated and 
 filled with some cells which subsequently form the peduncle of the embryo ; b, 
 large globular cell developed at the extremity of the pollen-tube, and which is 
 the basis of the embryo. 
 
 Q Q 4 
 
600 APPENDIX. 
 
 Figs. 5. and 6. Martynia diandra. 
 
 Fig. 5. Longitudinal section through the seed-bud, a, Simple integument ; 
 b, the remaining epidermis of the nucleus ; c, the sac of the embryo already filled 
 with a delicate endosperm ; d, the pollen-tube which runs almost through the 
 whole length of the embryo-sac to the base of the seed-bud ; e, raphe. 
 
 Fig. 6. Pollen-tube prepared from the foregoing : b, a large globular cell which 
 forms the foundation of the future embryo; lying under this cell are some others, 
 which form the peduncle of the embryo. 
 
 Figs. 7. and 8. CEnothera r/rizocarpa. 
 
 Fig. 7. Longitudinal section through the seed-bud, a, External ; b, internal 
 integument ; c, nucleus ; d, sac of the embryo ; e, pollen-tube. 
 
 Fig. 8. Pollen-tube separated from the foregoing, , Internal integument ; 
 b, nucleus ; c, sac of the embryo; d, pollen-tube, which in passing through the 
 internal and external integument exhibits irregular bulgings and contractions, in 
 order to pass through the inner foramen of the seed-bud. It then again be- 
 comes broader (e) as it passes through the nucleus, and at/ presents a considerable 
 enlargement (which subsequently becomes the peduncle (g) of the embryo); it 
 then again contracts, and at last terminates in a little vesicle which eventually 
 becomes the embryo. As the pollen-tube contains in its sap a good deal of 
 albumen, it becomes coloured of a dark yellow colour, and almost opaque, when 
 treated with tincture of iodine. 
 
 Figs. 9 1 1. Momordica Elaterium. 
 
 Fig. 9. Transverse section of the germen. <z, The seed-buds, which are repre- 
 sented in the following figure : 
 
 Fig. 10. Longitudinal section through a seed-bud and a part of the spermophore ; 
 a, conducting cellular tissue ; b, peculiar group of spiral vessels in the spermo- 
 phore ; c, external ; d, internal integument ; e, nucleus ; /, sac of the embryo ; 
 g, pollen-tube. 
 
 Fig. 11. Point of the nucleus prepared from the foregoing : e g, as in the pre- 
 vious figure. In the embryo-sac are visible cell-nuclei and young cells, the 
 commencement of an endosperm. The pollen-tube, before its entrance into the 
 seed-bud, forms a considerable irregular enlargement ; it then passes through the 
 elongated nipple of the nucleus, and forms a very considerable vesicular enlarge- 
 ment in the embryo-sac, which is the foundation of the future embryo. 
 
INDEX. 
 
 601 
 
 INDEX. 
 
 ABIES, 71, 109, 277, 385. 
 alba, 298. 
 balsamea, 417. 
 excelsa, 45, 244, 263, 268, 397, 401, 
 
 288. 
 
 pectinata, 268. 
 Abortion in a flower, 326. 
 Abrus precatorius, 426. 
 Absorption, 494, 497. 
 
 of sap, 517. 
 
 Abutilori graveolens, 112. 
 Acacias, 355. 
 Acer, 288. 
 Acetic acid, 88. 
 Achaenia, 442. 
 Achsenium, 448. 
 Achlya prolifera, 95, 100. 
 Aciculatus, 70, 135. 
 Acinaciforme, 129. 
 Acne rosacea, 1 56. 
 Aconitum, 285, 331, 364. 
 Napellus, 339. 365. 
 Acropera Loddigesii, 44. 
 Acrostichum alcicorne, 51. 
 Actinomeris alter nifolia, 342, 353. 
 Aculei, 69. 
 Acuminatus, 131. 
 Acutus, 131. 
 Adansonia digitata, 538. 
 Adiantum pubescens, 1 95. 
 Adoxa Moschatellina, 393. 
 Adventitious roots, 216, 218. 
 JEcidium, 156. 
 Aerides odoratum, 51, 75, 79. 
 JEschynomene indica, 552. 
 pumila, 552. 
 sensitiva, 552. 
 jEsculus, 68, 250, 286. 
 Age of trees, 538. 
 Agaricus, 152, 376. 
 campestris, 155. 
 Oreades, 155. 
 Agama?, 167. 
 Agave americana, 6, 120. 
 
 lurida, 74. 
 Agriculture, 476. 
 Agrostis alba, 314. 
 Air canals, 54. 
 vessels, 114. 
 
 Albumen, 23, 37, 83, 424, 444, 461. 
 corneum, 10. 
 of seeds, 18. 
 animal, 81. 
 
 Alburnum, bundles of, 110. 
 Alcohol, 21, 83. 
 Aletris, 234. 
 
 fragrans, 239. 
 Algae, 33, 34, 91, 145. 
 
 cells of, 41. 
 Alisma natans, 276. 
 Plantago, 116. 
 Alkalies, salts of, 5. 
 Alkaloids, 27, 30. 
 Allium, 72. 
 
 Cepa, 291. 
 fistulosum, 153. 
 Moly, 292. 
 ursinum, 291. 
 Almond, 23, 435. 
 Alnus, 261, 332, 288. 
 Aloe, 73, 105, 276. 
 
 nigricans, 74, 118. 
 Aloineae, 225. 
 
 Alps, agriculture of the, 478. 
 Alsine media, 412. 
 Alsophila, 192. 
 Alternanthera axillaris, 76. 
 Althea, roots of, 111. 
 Aluminium, 4. 
 Alyssum, 347. 
 
 rostratum, 76. 
 Amanita, 155. 
 Amaranthaceae, 112, 337. 
 Amaranthus caudatus, 310. 
 
 viridis, 112. 
 Amentaceac, 302. 
 Amidbn, 10. 
 Ammonia, 5, 82, 478, 486. 
 
 salts of, 489. 
 Amphisarca, 448. 
 Amplexicaul leaf, 262. 
 Amyloid, 9. 
 Amylum, 1O. 
 
 Anacardium, 305, 436, 451. 
 Ananassa, 448. 
 Anatherum Ivarancusa, 17. 
 Anceps, 128. 
 Anchusa, 40. 
 
602 
 
 INDEX. 
 
 Anchusa crassifolia, 41. 
 
 italica, 40. 
 Andreaea, 184. 
 Anemoneae, 329. 
 Anethum, 483. 
 Angiosporae, 139, 143. 
 Annuals, 288. 
 Annular ducts, 48. 
 
 rings, 56, 238. 
 Annulus, 180. 
 Ansa, 238. 
 Anthela, 310. 
 Anthemis, 226. 
 Anther, 296, 347, 558. 
 
 structure of the, 352. 
 Anthera, 201. 
 Anthoceros, 171. 
 
 laevis, 168, 172. 
 Anthocyan, 27. 
 Anthoxanthin, 27. 
 Anthurus, 310. 
 Antiaris toxicaria, 117. 
 Apex, 131. 
 
 Apocynacea;, 42, 50, 64, 66, 379. 
 Aponogeton, 16, 54. 
 
 distachyon, 293, 419. 
 Apothecium, 145. 
 Aquilegia vulgaris, 306. 
 Arabin, 20. 
 
 Aracea?, 65, 69, 271, 540. 
 Arachis hypogaea, 215, 229. 
 Archegonia, 184. 
 Archegonium, 178. 
 Arcyria, 152. 
 Areca oleracea, 221. 
 Aril, 430. 
 
 Arisarum australe, 320. 
 Aristolochia biloba, 253. 
 
 Sipho, 280. 
 
 Aroideae, 65, 69, 217, 540. 
 Arrow root, 16. 
 Articulation, 266. 
 Arum maculatum, 17. 
 Arundo, 42. 
 
 Donax, 45, 51. 
 
 Asclepiadaceae, 50, 64, 66, 379. 
 Asexual plants, 140, 166. 
 Asparagus, 207, 235. 
 
 officinalis, 71. 
 
 rhizome of, 215. 
 Aspidium Filix mas, 192. 
 Assimilation, 80. 
 Astomi, 184. 
 Astrantia, 302. 
 Atmospheric air, cells in contact with, 
 
 107. 
 Atmosphere, composition of, 471. 
 
 in relation to plants, 503. 
 Atropa, 440. 
 Auricula, 168. 
 A vena sativa, 223, 272. 
 Averrhoa Bilimbi, 552. 
 
 Carambola, 552. 
 Avicennia, 63. 
 Axes, 221. 
 
 Axes, structure of the, 235. 
 Axial organs, 216, 221. 
 structures, 258. 
 
 authors on, 256. 
 Axillary buds, 216. 
 Axis, floral, 386. 
 
 functions of, 556. 
 primarius, 221. 
 Azolla, 204. 
 
 Bacca, 447, 448. 
 Balanophoreae, 22. 
 Balausta, 449. 
 Balsamina hortensis, 52. 
 Balsaminea?, 47, 54. 
 Banana, 476, 484. 
 Banksia, 72, 340. 
 Baobab trees, 538. 
 Bark, 236. 
 Base, 131. 
 
 Batrachospermum, 145. 
 Bauhinia, 254. 
 Beech, 55, 241 . 
 Begonia, 26, 113, 275, 384. 
 Bell-shaped leaves, 130. 
 Bell is perennis, 361. 
 Berberis, 343, 351. 
 
 vulgaris, 552. 
 Bernhardia complanata, 1 89. 
 
 dichotoma, 17. 
 Berry, 448. 
 Berries, stone, 442. 
 
 true, 442. 
 Bertholletia, 423. 
 Betula, 286, 332. 
 Bignonia capreolata, 252. 
 Bignoniaceae, 251. 
 Birch, 237. 
 Birdlime, 28. 
 Bisehoff, 179. 
 Blasi*, 167. 
 Blastidia, 102. 
 Blechnum gracile, 34, 196. 
 Bletia, 294, 361. 
 
 Tankervillia, 248, 567. 
 Bloom, 118. 
 
 Blooming of a flower, 310. 
 Blossom, 170, 177. 
 Boletus bovinus, 538. 
 
 edulis, 538. 
 Bolbophyllum, 294. 
 Bombaceae, 60. 
 Bombax pentandra, 60, 62. 
 Boragineas, 40. 
 Borago officinalis, 122. 
 Borrera, 158. 
 
 ciliaris, 34, 159. 
 Botrytis Bassiana, 152. 
 Boxwood, 546. 
 Bracts, 280. 
 Bracteoles, 280. 
 Brassavola cordata, 79. 
 Brassica, 22. 
 Braun, Dr. A,, 266. 
 Bravais, 264. 
 
INDEX. 
 
 603 
 
 Brewing, 540. 
 
 Briza maxima, 224. 
 
 Bromine, 3. 
 
 Brosimum Alicastrum, 363. 
 
 Brown, Robert, 38, 97, 183, 392, 588. 
 
 Bud, 177, 280. 
 
 organs, 280. 
 
 scales, 280. 
 
 structure of a, 286. 
 
 terminal, 282. 
 Buds, 126. 
 
 accessory, 282. 
 
 adventitious, 282. 
 ' axillary, 282. 
 
 of ferns, 193. 
 
 particular forms of, 287. 
 
 flower, 282. 
 
 mixed, 282. 
 
 nature of, 177. 
 
 propagative, 29O. 
 
 of shoots, 287. 
 Bulbels, 189, 292. 
 Bulbs, 18, 290. 
 
 leafy, 290. 
 
 scaly, 290. 
 
 solid, 290. 
 
 tunicated, 290. 
 Bunch, 310. 
 
 Bupleurum perfoliatum, 274. 
 Buxbaumia, 182. 
 Bryonia, 16. 
 
 Bryophyllum calycinum, 528, 532. 
 Bryum, 183. 
 Byssi meteorici, 146. 
 
 Cacoma, 151. 
 
 Cactaceae, 6, 10, 43, 49, 65, 87, 259, 261. 
 
 Cacti, 468. 
 
 Cactus, 287. 
 
 Caesalpineas, 10. 
 
 Caladium, 6. 
 
 Calamus, 228. 
 
 Rotang, 4, 230. 
 Calanthe, 361. 
 Calathea, 354. 
 Calathium, 308. 
 Calceolaria, 324, 367. 
 Calcium, 4. 
 Calyptra, 178. 
 Calymperes, 177. 
 Calystegia sepium, 395. 
 Calyx, 303, 314, 333, 341, 436, 446. 
 Cambium, 55, 257. 
 Campanula, 78, 95, 347, 410. 
 
 Medium, 307. 
 Campanulaceae, 78. 
 Campanulatus, 130. 
 Cane sugar, 21. 
 Canna, 54, 55, 329, 424. 
 
 exigua, 314, 323, 341. 
 
 occidentals, 47, 52. 
 CannaceaB, 16. 
 Cannabis, 122, 223, 332. 
 Caoutchouc, 28, 81. 
 Capsula, 194, 448, 452. 
 
 Capsula, circumscissa, 447. 
 Capitate, 133. 
 Capitulum, 3OO, 307. 
 Carbon, 3, 8, 481. 
 Carbonic acid, 5, 82, 85, 485. 
 
 formation of, 5O4. 
 Carbonate of ammonia, 85. 
 Carcerulus, 448. 
 Cardamomum minus, 14. 
 Carduus, 274. 
 Carex, 274, 340. 
 
 arenaria, 235. 
 Carices, 82. 
 Carolinea minor, 60. 
 Carpels, 314, 368, 372. 
 Carpelletum, 452. 
 Carpidia, 452. 
 Carpinus, 286. 
 Caruncula, 443. 
 Caryopsis, 448, 452. 
 Casein, 23, 83. 
 Cassava, 18. 
 Castanea vesca, 538. 
 Casuarina, 212. 
 Catalysis, 86. 
 
 Catha'rinea undulata, 176, 187. 
 Catkin, 308. 
 Catoptridium, 175. 
 
 smaragdinum, 543. 
 Cattleya Forbesii, 79. 
 Caudex, 221, 228. 
 Caulerpa prolifera, 39. 
 Caulina, 64, 346. 
 
 fragilis, 94, 212. 
 Caulis adscendens, 232. 
 
 frondosus, 168. 
 
 geniculatus, 233. 
 
 nutans, 232. 
 Cauloma of Palms, 230. 
 Cell, 211. 
 
 formation, 217. 
 
 kernel, 31. 
 
 life, termination of, 1O4. 
 
 membrane, 80, 90. 
 
 multiplication of, 572. 
 
 production, 31. 
 
 reproduction, 102. 
 
 walls, 39. 
 
 contact of, 110. 
 
 contents of, 568. 
 
 formation of, 568. 
 
 ferment, 569. 
 
 in connection with others, 1O6. 
 Ciliatus, 132. 
 Cellulse annuliferae, 43. 
 
 retiferas, 44. 
 
 spiriferae, 44. 
 Cellulose, 8, 80, 85, 105. 
 Celosia, 351, 376. 
 Celsia cretica, 351. 
 Cerasus avium, 306. 
 Ceratium, 448. 
 
 Ceratophyllum, 64, 95, 96, 236, 468. 
 Cerbera Thevetia, 354. 
 Cerealia, 18, 23. 
 
601 
 
 INDEX. 
 
 Cereus, 67, 252. 
 
 grandiflorus, 407. 
 
 phyllanthoides, 4O. 
 
 senilis, 6. 
 
 Ceropegia dichotoma, 66. 
 Ceroxylon, 22. 
 Cetraria, 161. 
 
 islandica, 11, 68. 
 Chaetophora, 7, 101, 109. 
 Chatnaedorea Schiedeana, 224, 420. 
 Chara, 7, 43, 65, 92, 162. 
 
 vulgaris, reproductive organs of, 164. 
 Characea?, 90, 92, 1 62. 
 Chelidonium, 428, 433. 
 
 majus, 1 16. 
 
 Chemistry in relation to Botany, 2. 
 Chenopodiaceae, 1 1 2. 
 China regia, 49, 65. 
 Chlorine, 3. 
 
 Chlorophyll, 25, 86, 147. 
 Chondrus crispus, 10. 
 Chymocarpus pentaphyllus, 398. 
 Cilia, 98, 132, 180. 
 Cinchona scrobiculata, 49, 65. 
 Circulation, 80, 93, 94. 
 
 spiral, 43. 
 Citric acid, 27. 
 Citrus, 332, 528. 1 
 Clematis integrifolia, 306. 
 
 stem of, 251. 
 
 Vitalba, 79. 
 Climate, 509. 
 Climbing plants, 544. 
 Club-mosses, 189. 
 Cnicus arvensis, 497. 
 Coal, 482. 
 
 Cocoa-nut, milk of, 424. 
 Cochlidiospermae, 426. 
 Cocos nucifera, 484. 
 Coffee, 426, 476, 484. 
 
 bean, 462. 
 
 Colchicum autumnale, 17, 34, 407. 
 Collema, 144, 157. 
 Collum, 180. 
 Colouring matters, 27. 
 Columella, 434. 
 Colutea arborescens, 394. 
 Coma, 444. 
 Commelineae, 48. 
 Compound granules, 1 6. 
 
 leaves, 267. 
 
 plants, 127. 
 
 Concentric vascular rings, 250. 
 Conceptacula, 447. 
 Cone, 308. 
 Conferva;, 34, 41, 49, 82, 101, 128. 
 
 cells of, 100. 
 Conferva castanea, 175. 
 
 glomerata, 41, 148. 
 
 rivularis, 41, 107. 
 Confervaceae, 145. 
 Conia, 86. 
 Coniferse, 53, 56, 60, 244, 417. 
 
 seed-buds of, 385. 
 
 woody tissue of, 45. 
 
 Coniothalami, 158. 
 Coniomycetes, 151. 
 Convolvulus, 367. 
 Coprinus, 157. 
 Copper, 4. 
 Costus, 6, 354. 
 Cotyledon, 213, 280. 
 Cordatus, 132. 
 Cork, 69, 78, 118. 
 
 oak, 53. 
 
 tissue, 24 J. 
 Cornus alba, 239. 
 
 mascula, 40, 282. 
 Corolla, 314, 341, 353. 
 Corona, 333. 
 Corsica, 485. 
 Cortex, 150, 186. 
 Corti, 94. 
 
 Cortical layer, 240. 
 Corydalis, 398. 
 Corylus, 286, 448. 
 
 avellana, 274. 
 Corymb, 308. 
 Corymbi, 134. 
 Crassula, 250, 528. 
 Cremocarpium, 448. 
 Crenaturae, 132. 
 Crenatus, 132. 
 Cribraria, 152. 
 Crocus, 296. 
 Croton sebiferum, 22. 
 Cruciferae, 22, 391. 
 Cryptogamia, 32, 35, 57, 64, 297. 
 Cryptocoryne spiralis, 406. 
 Crystals, 91. 
 Cubicus, 129. 
 Cucifera thebaica, 225. 
 Cucurbita Pepo, 35, 47, 393. 
 Culmus, 229. 
 Cupressus disticha, 538. 
 Cupula, 436. 
 
 Cupuliferae, 224, 302, 316, 325, 332. 
 Cupuliformis, 131. 
 Cup-shaped leaves, 131. 
 Cuscuta, 215, 220, 261, 423. 
 Cuticula, 118, 120, 378. 
 Cuttings, 534. 
 Cyathea, 192. 
 
 arborea, 193. 
 
 Cycadaceae, 6, 15, 18, 20, 56, 60, 270, 
 346. 
 
 seed-buds of, 385. 
 Cycas, 74, 71, 108, 350. 
 
 revoluta, 45, 47, 50, 53, 61, 71, 120, 
 
 244. 
 
 Cyme, 308. 
 Cynarhodon, 449. 
 Cypripedium Calceolus, 35. 
 Cytoblasts, origin of, 32. 
 Cytoblastema, 31, 424. 
 
 Dacrydium, 385. 
 Daedalea, 152. 
 
 quercina, 538. 
 Dahlia, 21, 47, 293. 
 
INDEX. 
 
 605 
 
 Dahlia, variabilis, 22. 
 
 Dalton, 87. 
 
 Daphne Lagetta, 249. 
 
 Date Palm, 462. 
 
 Datura, 331, 390, 429, 436. 
 
 Stramonium, 394. 
 Daoun, 78. 
 Death of vegetable cells, causes of, 106. 
 
 of the entire plant, 536. 
 Dehiscence, 441. 
 Delcsseria, 146. 
 Delphinium, 331. 
 
 tricorne, 396. 
 
 Dentaria bulbifera, 235. 290. 
 Dentatus, 132. 
 Dentes, 132, 180. 
 Desfontaines, 257. 
 Desmanthus lacustris, 552. 
 
 stolon ifera, 552. 
 
 triquetra, 552. 
 De Saussure, 89. 
 Dextrine, 9, 20, 86. 
 Developed internodes, 245. 
 Devil's leaf, 78. 
 Dicotyledons, 213, 239, 257. 
 
 embryo of, 422. 
 
 list of, 404. 
 
 vascular bundles of the, 60. 
 Dicksonia, 192. 
 Diclesium, 449. 
 Dicranum, 186. 
 Dionaea muscipula, 552. 
 Diphyscium, 182. 
 Diplotegia, 448. 
 Dipsacus, 307. 
 
 Fullonum, 77, 119, 121. 
 Dischidia Rafflesiana, 268. 
 Discomycetes, 145. 
 Disc, 446. 
 
 Dissolution of dead cells, 106. 
 Dolabriforme, 129. 
 Donax, 42. 
 
 Dorstenia, 226, 303, 448. 
 Double spores, 159. 
 Draba verna, 412. 
 Dracama, 225, 287. 
 Drebbel, Cornelius, 37. 
 Drosera, 77. 
 Drupa, 448. 
 Drupe, 439. 
 Dryandra, 72, 341. 
 Dryas octopetala, 321. 
 Dumas, 84. 
 
 Du Petit Thouars, 257. 
 Duration of species, 258. 
 
 Earth, black, 477. 
 Echeveria, 528. 
 Echium vulgare, 27. 
 Echinocactus, 387. 
 Echinops ruthenica, 320. 
 Ehrenberg, 101, 580. 
 Elais guineensis, 484. 
 Electricity, 514. 
 Elm, 55. 
 
 Elymus arenarius, 26, 118, 151. 
 Emarginatus, 131. 
 Embryo, 444. 
 
 formation of, 413. 
 Embryo-sac, 558. 
 
 sacs, 401. 
 Embryonal globule in the embryo, 416. 
 
 vesicle in continuity with the pollen- 
 tube, 411. 
 
 Embryonary vesicle, 135. 
 Encephalartos, 22. 
 Endlicher, 370. 
 Endocarp, 440. 
 Endogens, 257. 
 Endosmose, 497. 
 Endosmosis, 80, 88, 107, 495. 
 Endosperm, 423. 
 Endostome, 427. 
 Endorhizae, 219. 
 Ephedra, 212, 385. 
 Ephemerum Matthioli, 320. 
 Epiblema, 68, 218. 
 Epicalyx, 337, 345. 
 Epidendrum cochleaturn, 248, 294. 
 
 elongatum, 71, 79, 120. 
 Epidermal cells, 118. 
 Epidermis, 68, 179. 
 
 cells of the, 279. 
 
 of fruit, 433. 
 
 of leaves, 279. 
 
 Epilobium angustifolium, 415. 
 Epipactis latifolia, 322, 371. 
 Epiphytce, 151., 
 Episperm, 444. 
 Epithelium, 68, 70, 118. 
 
 of leaves, 279. 
 Equiseta, 103. 
 
 stem of, 200. 
 Equisetaceje, 57, 70, 198, 211. 
 
 fructification of, 1 98. 
 Equisetum, 350. 
 
 arvense, 4, 43, 95, 198. 
 
 fluviatile, 200. 
 
 hyemale, 4. 
 
 limosum, 4, 198. 
 Ergot, 152. 
 Ericaceae, 28, 360. 
 Erosus, 133. 
 
 Erythrina corallodendron, 426. 
 Etaerio, 448. 
 Euphorbia, 313, 318, 324, 353. 
 
 ccerulescens, 67. 
 
 meloformis, 169. 
 
 pallida, 397. 
 
 trigona, 67. 
 
 Euphorbiacea;, 16, 20, 64, 66, 116, 238. 
 Euryale, 278. 
 Evaporation of water, 499. 
 Evernia, 158. 
 Excisus, 131. 
 Excretion, 80, 494. 
 
 of fluids, 498. 
 
 of plants, 493. 
 
 of volatile oils, 498. 
 Excoecaria, 117. 
 
606 
 
 INDEX. 
 
 Exhalation, 80, 499. 
 Exorhiza;, 219. 
 Exogens, 257. 
 Exosmose, 88. 
 
 Fagus, 286. 
 
 sylvatica, 288. 
 Faux, 131. 
 
 Fegatella conica, 172. 
 P'ermentation, 88. 
 
 cells, 36, 83. 
 
 fungus, 147. 
 
 Ferns, 27, 32, 57, 90, 192, 346. 
 Ferns, stem-formation, 243. 
 
 germination of, 192. 
 
 leaves of, 192. 
 
 stem of, 193, 196. 
 
 tropical, 193. 
 Fibrine, 23, 83. 
 Fibrous tissue, 68. 
 Fibrous cells, 42. 
 Ficus, 122, 226, 227, 308, 448. 
 
 Carica, 12?, 321. 
 
 elastica, 28. 
 Filament, 314, 347. 
 Filamentous tissue, 118. 
 Filices, 192. 
 Fir, 244. 
 Fissidens, 175. 
 Fixed oils, 22, 111. 
 Flask-shaped leaves, 131. 
 Flax, cells of, 44. 
 Flocci, 151. 
 Floral axis, 386. 
 Floral envelopes, 330. 
 Flower, axial organs of, 318 
 
 abortion in a, 326. 
 
 definition of a, 298. 
 
 during formation of fruit and seed, 
 436. 
 
 parts of a, 324. 
 
 foliar organs of the, 330. 
 
 leaves, 280. 
 
 terminal, 300. 
 Flowers, 296. 
 
 hermaphrodite, 316. 
 
 change of, into fruit, 402. 
 Folia caulina, 280. 
 
 floralia, 280. 
 
 Foliar organs, 216, 261, 280. 
 accessory, 364. 
 structure of, 276. 
 Folium perfoliatum, 27. 
 Folliculus, 447. 
 Food, absorption of, 493. 
 
 assimilation of, 504. 
 
 of plants, 470. 
 Form of plants, 259. 
 Forskcehlea tenacissima, 122. 
 Fraxinus, 239. 
 
 excelsior, 50. 
 Fritillaria, 340, 356, 49S. 
 
 imperialis, 21, 26, 410. 
 Fritsche, 14, 358. 
 Fronds, 194. 
 
 Fructifications, 448. 
 Fructus, 437. 
 
 multiplex, 437. 
 
 simplex, 437. 
 Fruit, 434, 437. 
 
 accessory organs of, 446. 
 
 forms of, 447. 
 
 individual parts, 440. 
 
 produced from flowers, 402. 
 
 rudiments of, 367. 
 
 capsular, 441. 
 
 closed, 446. 
 
 multiple, 448. 
 Fruits, simple, 447. 
 
 splitting, 448. 
 
 spurious, 449. 
 
 stone, 448. 
 Fucoideae, 10. 
 Fucus nodosus, 146. 
 Fumaria, 331, 342. 
 Fumariaceae, 326. 
 Fungi, 3, 68, 89, 145, 151, 542. 
 Funnel-shaped leaves, 130. 
 Funaria hygrometrica, 176, 177, 185, 
 
 496. 
 
 Funiculus, 390, 429. 
 Funkia, 339. 
 
 Gagea lutea, 291. 
 Galbulus, 447. 
 Galium Aparine, 394. 
 Galphimia mollis, 394. 
 G arnica?, 201. 
 Gas, 89. 
 
 of the atmosphere, 501. 
 Gases, 494. 
 Gasteria nitida, 35. 
 Gasterothalami, 157. 
 Gasteromycetes, 152. 
 Geastrum, 152, 544. 
 Gelatin, 23. 
 
 Gelatina inorganica, 146. 
 Gemmae, 126, 280. 
 Gemmula, 389. 
 
 anatropa, 390. 
 
 basilaris, 387. 
 
 campy lotropa, 391. 
 
 erecta, 389. 
 
 hemitropa, 391. 
 Gentiana lutea, 325, 354. 
 Germen, 314, 432. 
 
 origin of the, 370. 
 
 development of, 423. 
 
 false, 369. 
 
 inferior, 369. 
 Germinal organs, 217. 
 Germination, 88, 216, 460. 
 
 processes during, 461. 
 Gesneria, 365, 528. 
 
 latifolia, 44, 278. 
 Gesneriacea;, 384. 
 Geum rivale, 320. 
 Glands, 236, 499. 
 Glans, 448. 
 Glaucus, 498. 
 
INDEX. 
 
 607 
 
 Globularis, 129. 
 
 Glomerule, 310. 
 
 Gluten, 88. 
 
 Gnidia virescens, 327. 
 
 Godetia Lehmanniana, 322,371. 
 
 Goethe, 312. 
 
 Goldfussia anisophylla, 71, 552. 
 
 Goodyera discolor, 326'. 
 
 Goppert, 256. 
 
 Graham, 87. 
 
 Gramineae, 419. 
 
 Granulosus, 135. 
 
 Grasses, 73. 
 
 embryo of, 421. 
 
 stems of, 2 "2 9. 
 Gratiola officinalis, 235. 
 Gravitation, 464. 
 Green vegetable wax, 25. 
 Grimaldia hemisphaerica, 172. 
 Grimmia apocarpa, 182. 
 Growth of plants, 464. 
 Gymnospermaa, 139, 164, 212, 244, 403. 
 Gymnosperms, 417. 
 Gum, 20, 81, 90. 
 
 solutions of, 83. 
 Gutta percha, 29. 
 
 Hakea, 278. 
 
 amplexifolia, 74. 
 Hairs, 69, 236. 
 
 stinging, 78. 
 
 Hand-shaped leaves, 133. 
 Haplomitrium Hookeri, 169. 
 Hartig, 256. 
 Hazel-nut, 426. 
 Heat, 514. 
 
 development of, 539. 
 Heart-shaped leaves, 132. 
 Hedera, 220. 
 
 Hedychium, 18, 48, 55, 400. 
 Hedysarum, 553. 
 Helianthus, 22f>, 283. 
 
 annuus, 263, 320. 
 Helianthemun denticulatum, 403. 
 Helleborus, 364. 
 
 fcetidus, 50, 76. 
 Hellenia ccerulea, 391, 395. 
 Helvellacea?, 158. 
 Hemerocallis, 339. 
 Hemlock, 30. 
 Hemp, fibres of, 548. 
 Hepaticas, 41. 
 Heuchera villosa, 321. 
 Hermaphrodite flowers, 316. 
 Hesperidium, 448. 
 Hibbertia volubilis, 49. 
 Hibiscus, 378. 
 Hilus, 389. 
 Hippomane, 117. 
 Hippuris, 390. 
 
 vulgaris, 393. 
 Hofmeister, 573. 
 Holcus saccharatus, 21. 
 Honey dew, 498. 
 Hooke, Robert, 37. 
 
 Hordeum, 16. 
 
 vulgare, 223. 
 Horsetails, 198. 
 Hovenia, 436. 
 
 dulcis, 451. 
 
 Hoya carnosa, 45, 50, 66, 1 11, 408. 
 Humic acid, 29. 
 
 Humidity in vegetable and animal sub- 
 stances, 546. 
 Humulus, 122, 332. 
 
 Lupulus, 123. 
 
 Humus, 6, 29, 495, 496, 502. 
 Hyacinth, 121. 
 
 Hyacinthus orien tails, 119, 291. 
 Hydrocharaceae, 272. 
 Hydrocharidaceae, 92. 
 Hydrocharis, 71, 428. 
 
 Morsus Ranae, 92. 
 Hydrogen, 3, 8, 481. 
 
 compounds with, 5. 
 Hydropeltis, 280. 
 Hydrurus, 7. 
 Hymenaea, 9. 
 Hymenophyllum, 194. 
 Hyphomycetes, 95, 152. 
 Hypnum, 183. 
 
 abietinum, 181, 183. 
 
 molluscum, 176. 
 
 undulatum, 175. 
 Hypochaeris radicata, 215. 
 Hypocrateriformis, 130. 
 Hysteria?, 145. 
 
 Iberis, 303. 
 Idiothalami, 157. 
 Inarching, 534. 
 Inorganic elements, 3. 
 Incomplete parenchyma, 51. 
 Indigo, 26. 
 Indigofera, 26. 
 Inflorescence, 296, 308. 
 
 centripetal, 306. 
 
 simple, 307. 
 Infundibuliformis, 1 30. 
 Infusoria, 100. 
 Inner bark, 236. 
 Intercellular spaces, 113. 
 
 substances, 112. 
 
 system, 53. 
 Internodes, 245, 246. 
 
 of the same axis, 259. 
 Inula Helenium, 22. 
 Inulin, 21, 90, 358. 
 Involucre, 300. 
 Involucrum, 338. 
 Iodine, 3, 13, 
 Iodide of starch, 1 1 . 
 Iris, 1 75, 224, 333, 357, 375. 
 
 atomaria, 549. 
 
 chinensis, 247. 
 
 Florentine 16, 378. 
 
 pallida, 15. 
 
 variegata, 70, 76. 
 Iron, 4. 
 Isatis tinctoria, 26, 34 1 . 
 
608 
 
 INDEX. 
 
 Isocarpae, 101. 
 Isoetes, 189. 
 
 stem of, 243. 
 Isolepis supina, 419. 
 Ivory nut, 462. 
 
 Jelly, 90. 
 Juglandaceae, 387. 
 Juglans, 448. 
 
 regia, 242. 
 Juncacea3, 339. 
 Juncus, 128. 
 Jungermanniaceae, 94. 
 Jungermannia bidentata, 170. 
 
 exsecta, 170. 
 
 multitida, J69. 
 
 pinguis, 172. 
 Jungermanniae, 43. 
 Juniperus, 299, 346. 
 
 Sabina, 108. 
 Jussieu, A. de, 256. 
 Justicia carnea, 113. 
 
 Kidney-shaped leaves, 132. 
 
 Knight's experiments on germination, 
 
 463. 
 Kiitzing, 91, 101. 
 
 Labellum, 326. 
 Labiata?, 238. 
 Lacis, 128. 
 Lagenaeformis, 131. 
 Lagenaria, 442. 
 Lamina, 266. 
 Laminaria, 146. 
 
 digitata, 468, 548. 
 Lamium, 285. 
 Lanceolatus. 130. 
 Lankester, 187. 
 Larix, 359. 
 Latex cells, contents of, 117. 
 
 motion of, 116. 
 Lath yr us Aphaca, 271. 
 
 odoratus, 344. 
 
 sphaerirus, 257. 
 Lathraea, 7. 
 
 Squamaria, 15, 395, 567. 
 Laticiferous tissue, 40. 
 Laurus carolinensis, 361. 
 Lavatera, 345, 327, 373. 
 Layers, 534. 
 Leaflet, 267. 
 
 amplexicaul, 262. 
 
 nascent, 276. 
 
 nature of a, 262 
 
 primary form of a. 266. 
 Leaves, 280. 
 
 whorl of, 263. 
 
 bearing leaf-buds, 270. 
 
 curviserial, 264. 
 
 compound, 267. 
 
 development of, 275. 
 
 functions of, 556. 
 
 formed under ground, 269. 
 
 Leaves of the inflorescence, 280. 
 
 perianthial, 340. 
 
 position of, 263. 
 
 rectiserial, 264. 
 
 scattered, 263. 
 
 seed, 280. 
 
 stem, 280. 
 
 with round folds, 284. 
 
 with sharp folds, 284. 
 Lecidea, 158. 
 
 sanguinea, 161. 
 Lecythis, 423. 
 Legumen, 438, 447. 
 
 Leguminosse, 9, 15, 18, 23, 70, 257, 272. 
 Lemna, 212, 324, 419. 
 
 gibba, 420. 
 
 minor, 421. 
 
 toots of, 218. 
 
 trisulca, 393. 
 Lemnacea?, 282, 379. 
 Lemon, 426. 
 
 Lenses of the microscope, 377. 
 Leontodon Taraxacum, 544. 
 Leontice, 328. 
 Lepidum ruderale, 343. 
 Leptomiteae, 151. 
 Leucophaneae, 51. 
 Leucojum vernum, 321. 
 Lianes, 251. 
 Liber, 64. 
 
 cells, 14, 64. 
 
 layer, 239. 
 
 Lichen, Carragheen, 10. 
 Lichens, 68, 90, 145, 157. 
 
 colour of, 161. 
 
 fruit of, 1 59. 
 
 starch, 10. 
 Liebig, 84. 
 Life, 24. 
 
 of a plant, 458. 
 Light, 514. 
 
 development of, 542. 
 
 from flowers, 543. 
 
 sun, 86. 
 Lignine, 8. 
 Ligula, 257. 
 Liliaceaj, 15, 423. 
 
 starch of, 11. 
 Lilium, 290, 395. 
 
 bulbiferum, 15. 
 
 camtchaticum, 18. 
 
 candidum, 224, 400. 
 
 Martagon, 263. 
 Limbus, 131. 
 Lime, 46, 50, 274. 
 
 cells of, 44. 
 
 oxalate of, 6, 424. 
 
 sulphate of, 6. 
 
 tree, 241. 
 
 Limes, bracts of, 303. 
 Limnocharis Humboldti, 66, 114. 
 Link, 230. 
 Linum, 379. 
 Lip of a flower, 326. 
 Liriodendron, 288. 
 
INDEX. 
 
 609 
 
 Liverworts, 166, 169, 184. 
 
 blossom of, 170. 
 
 stem of, 173. 
 Llanos, 251. 
 Loasaceae, 78, 364. 
 Lobes, 1 32. 
 Locomotion, 8O. 
 Lombardy poplar, 234. 
 Lobelia, 40. 
 Lobuli, 132. 
 Lomentum, 432, 438. 
 Lonicera Caprifolium, 274. 
 Loranthaceae, 244, 385, 389. 
 Loranthus deppeanus, 396. 
 Lucerne, cultivation of, 563. 
 Lupinus, 354. 
 
 rivularis, 71. 
 
 tomentosus, 34, 
 Lyellia, 189. 
 Lychnis, 257, 271, 331. 
 Lycopodiaceae, 57, 70, 189. 
 Lycopodia, stem of, 191. 
 Lycopodium annotinum, 190. 
 
 canaliculatum, 190. 
 
 inundatum, 190. 
 
 stolonniferum, 192. 
 Lycopsis, 302. 
 
 Madia sativa, 22. 
 Magnesium, 4. 
 Magnolia, 50, 329. 
 
 funiculus, 431. 
 Mahernia, 351. 
 Mahonia nepalensis, 63. 
 Maize, 21, 476. 
 
 stem of, 229. 
 Makis, 485. 
 Malic acid, 27. 
 Mallow, 10. 
 Malopeas, 327. 
 Malpighi, 37, 77, 391. 
 Malting, 540. 
 Malus, 226. 
 Malva miniata, 344. 
 Malvaceae, 40, 327, 376. 
 Mammillaria, 49, 53, 61, 67, 255, 288. 
 
 quadrispina, 61. 
 Mammillaris, 129. 
 Mandiocca farinha, 13. 
 Manganese, 4. 
 Manilla, 38. 
 Manioc, 476. 
 Mannite, 21. 
 Manure, composition of, 560. 
 
 observations on, 566. 
 
 produce of, 561. 
 Maple, 46. 
 Maranta, 427. 
 
 arundinacea, 18, 23. 
 Marantaceae, 16. 
 Marathrum, 128. 
 Marcgravia, 268. 
 
 Marehantia polymorpha, 170, 496, 530. 
 Marchantiacea;, 40, 69, 73, 74, 144, 168. 
 
 Marginal nerves in mosses, 188. 
 Margo, 132. 
 Marsilea, 203. 
 
 fruit of, 207. 
 
 leaf of, 210. 
 
 pubescens, 207. 
 
 quadrifolia, 207. 
 Martius, 257. 
 
 Martynia diandra, 384, 415. 
 Massa sporacea, 147. 
 Materia secreta, 86. 
 Matrix, 102. 
 Matter, forms of, 493. 
 Matthiola, 448. 
 Maxillaria, 44, 79, 111. 
 
 atropurpurea, 65. 
 Mayaca fluviatilis, 64. 
 Meadows, irrigated, 487. 
 Melocactea;, 12, 47, 49, 71. 
 Melocactus, 49, 71, 128, 136, 169, 212. 
 Membrana externa, 180. 
 
 interna, 180. 
 Meconic acid, 27. 
 Meconostigma pennatifidum, 393. 
 Medulla, 150, 186. 
 Medullary rays, 56, 238. 
 Mericarpia, 448. 
 Merisma, 152, 
 
 Mesembryanthemum, 69, 267. 
 Metamorphosis of plants, 311. 
 Meyen, 88, 104, 408. 
 Microscopical Society, 577. 
 Microscope, use of, 575. 
 
 used, 37. 
 
 Milk of cocoa-nut, 424. 
 Milk-sap, 115. 
 
 vessels, 40, 64, 66, 110. 
 Mimosa asperata, 552. 
 
 dormiens, 552. 
 
 pernambucana, 552. 
 
 pellita, 552. 
 
 pigra, 552. 
 
 pudica, 552, 553. 
 
 quadrivalvis, 552. 
 
 sensitiva, 552. 
 
 viva, 552. 
 Mimoseae, 20. 
 Miquel, 256. 
 Mirabilis, 331. 
 Mitscherlich, 86. 
 Mnium androgynum, 1 70, 1 77. 
 Mohl, 104, 113, 196, 233,256, 570. 
 Molecular motion, 98. 
 Moldenhauer, 256. 
 Momordica Elaterium, 416. 
 Monoclea, 172. 
 
 Monocotyledons, 58, 213, 237, 239, 245, 
 418. 
 
 vascular bundles of the, 60. 
 Monocotyledons and Dicotyledons, dis- 
 tinction between, 257. 
 Moor plants, 82. 
 Monstera, 65. 
 Morus, 436, 448. 
 Morphology, 2, 124. 
 
 R R 
 
610 
 
 INDEX. 
 
 Moss capsule, 172. 
 
 Mosses, 41, 90, 138, 168, 174, 
 
 archegonium of, 178. 
 
 blossoms of, 177. 
 
 leaves of, 32. 
 
 structure of, 186. 
 Mother-cell, 103. 
 Mother of vinegar, 83, 492. 
 Motion of cell-contents, 93. 
 Mougeotia genuflexa, 147. 
 Mould, 495. 
 Movements, periodic, of plants, 551. 
 
 of parts of a plant, 544. 
 Mucor, 152, 154. 
 Mucronatus, 131. 
 Mucus, 23, 81, 460, 
 Mucuna gigantea, 9. 
 
 urens, 9. 
 Mulder, 84. 
 Miiller, Karl, 572. 
 Musa, 7. 
 
 Paradisiaca, 22, 48. 
 
 sapientum, 9, 47, 59. 
 Musaceae, 7. 
 Musca? volitantes, 116. 
 Muscardine, 1 52. 
 Musci Hepatici, 168. 
 
 frondosi, 174. 
 Mycelium, 151. 
 Mycoderma, 83, 145- 
 
 Aceti, 82, 492. 
 Myosurus, 223. 
 Myriceae, 22, 332. 
 Myrtaceae, 277, 387. 
 
 of New Holland, 266, 
 
 Nageli, 32, 570. 
 Naiadaceae, 92. 
 Najas, 64, 94, 1 10, 245, 346. 
 
 major, 94. 
 Nandin, 256. 
 Narcissus, 273, 331, 333, 336, 339. 
 
 ketus, 333. 
 Navicula viridis, 15O. 
 Neckera crispa, 175. 
 Nectarium, 321. 
 Nelumbium, 74, 22O. 
 
 speciosum, 75. 
 Neottia Nidus Avis, 35, 91, 174. 
 
 picta, 353, 41 8. 
 
 Nepenthes, 238, 268, 279, 498. 
 Nerium Oleander, 28, 72. 
 Nerves of leaves, 276. 
 Nicandra, 441. 
 Nigella, 364, 437. 
 Nitella, 92, 162. 
 Nitrate of potassa, 36. 
 Nitrogen, 3, 8, 83, 481, 486. 
 Nodes, 198, 260. 
 Norantea, 268. 
 Nostochineae, 145. 
 Nostoc, 109. 
 Nucleoli, 32. 
 Nuces, 452. 
 
 Nucleus, 178, 389. 
 Nucula, 452. 
 Nuculanium. 448, 452. 
 Nutrition of the cell, 108. 
 
 process of, 468. 
 
 of plants and animals, 475. 
 
 of plants, 504. 
 Nuphar, 278, 378. 
 
 luteum, 95, 224. 
 Nux, 452. 
 Nyctago, 378. 
 Nymphasa, 54, 278, 343. 
 
 alba, 219, 425. 
 
 Oak, 55, 237. 
 Oats, 514. 
 
 Oat, leaf of the, 272. 
 Obovatus, 1 30. 
 Obtusus, 131. 
 Octosporidia, 138. 
 CEdogonium vesicatum, 141, 
 OZnothera, 76. 
 
 grandiflora, 95. 
 
 rhizocarpa, 415. 
 Oil-palms, 484. 
 Onagracea?, 99, 355. 
 Oncidium altissimum, 47. 
 Operculum, 179. 
 Ophioglossum, 195. 
 Opuntia, 7, 74, 128, 261, 276, 547. 
 
 cylindrica, 49. 
 
 peruviana, 43. 
 Organs of plants, 128. 
 
 of reproduction, 557. 
 
 of vegetation, 555. 
 Organisation, 80. 
 Organology, 2, 454. 
 
 special, 555. 
 
 Orthotrichum crispum, 176, 186. 
 Orchis, 331. 
 
 latifolia, 293, 415. 
 
 militaris, 362. 
 
 Morio, 293, 362, 412. 
 Orchidaceaa, 69, 261, 278, S4O. 
 
 stem formation, 248. 
 
 tropical, 218. 
 Orobanche, 330. 
 Orobus albus, 273. 
 Orontium aquaticum, 42O. 
 Oryza sativa, 15, 121. 
 Oscillatoria, 542. 
 Osmundaceas, 195. 
 Oxalate of lime, 5, 6, 87. 
 
 crystals of, 424. 
 Oxalis, 290. 
 
 sensitiva, 552. 
 Oxalic acid, 5. 
 Oxidation, 87. 
 Oxygen, 3, 8, 85, 481. 
 
 absorption of, 507. 
 
 compounds with, 4. 
 Outer bark, 236. 
 Ovatus, 129. 
 Ovule, 212, 296, 389, 558. 
 
INDEX. 
 
 611 
 
 Paleae of ferns, 193. 
 Palms, 55, 276, 423. 
 
 stems of, 257. 
 Pampas, 477. 
 Pandanus, 219. 
 Panicle, 309. 
 Panicum miliaceum, 397. 
 Papaver, 440. 
 Papilla of a leaf, 273. 
 Papilla?, 69, 377, 436. 
 Papyrus antiquorum, 239. 
 Paracorolla, 364. 
 Parapetala, 364. 
 Parasites, roots of, 220. 
 Parenchyma, 5i, 111, 220. 
 
 cells, 59. 
 
 spherical, 57. 
 
 spongiform, 52. 
 
 of leaves, 277. 
 
 Parietaria judaica, 122, 552. 
 Parmelia, 128. 
 
 parietina, 160. 
 Partes, 130. 
 
 palmata?, 133. 
 Partitus, 130. 
 Passiflora, 356. 
 
 alata, 154. 
 
 alba, 431. 
 
 princeps, 35. 
 Pastinaca, 302. 
 Patellceformis, 131. 
 Peas, 490. 
 Peckea, 423. 
 Pedicel, 300, 304, 446. 
 Pedicularis, 365. 
 
 palustris, 34, 395. 
 Peduncle, 300, 304, 446. 
 Peireskia, 261. 
 Pelargonium, 319. 
 Peliosanthes Theta, 328. 
 Pellia epiphylla, 172. 
 Peltidea canina, 161. 
 Peltigera canina, 40. 
 Penicillium, 152, 154. 
 Peperomia, 277, 360. 
 Pepo, 448. 
 Perennials, 258. 
 
 bark of, 241. 
 Perianth, 1 70, 333, 338. 
 Perianthial leaves, 333. 
 Peristoma, 179. 
 Perula, 286. 
 Petals, 333 . 
 Petiole, 266. 
 Petroselinum, 302. 
 Peziza, 103, 145. 
 Phalaris, 26. 
 
 cocrulescens, 340, 365. 
 Phanerogamia, 7, 27, 64, 57, 95, 
 
 202, 212, 270, 297, 558. 
 Pharmacy, Botany in relation lo, 2. 
 Phascum, 136, 174, 184. 
 Phaseolus, 15, 400. 
 Phoenix dactylifera, 38. 
 Phormium tenax, 34, 120, 291. 
 
 165, 
 
 Phosphates, 83. 
 
 Phosphorus, 3, 490. 
 
 Phragmites communis, 219- 
 
 Phycologia generalis, 10, 146. 
 
 Phyllanthus, 128, 226, 389. 
 
 Physiology, Botany in relation to, 7. 
 
 Phytolacca decandra, 6. 
 
 Phytelephas, 462. 
 
 Pili, 69. 
 
 Pili urentes, 69. 
 
 Pilularia, 203. 
 
 fruit of, 207. 
 
 globulifera, 54, 205. 
 Pimelea decussata, 367. 
 Pinnate, 1 34. 
 Pinus, 35, 47, 160, 277. 
 
 sylvestris, 40, 241. 
 Piperacese, 332. 
 Piper obtusifolium, 280. 
 Pisonia, 238, 250. 
 Pistia, 427. 
 
 commutata, 406. 
 
 obcordata, 406. 
 
 obovata, 246, 419. 
 
 Stratiotes, 94. 
 Pistil, 314, 368. 
 
 modifications of form, 375. 
 
 stem, 368. 
 
 structure of, 376. 
 
 superior, 368. 
 Pisum, 15. 
 
 sativum, 257, 314. 
 Pitchers, 268. 
 
 Pitcher-shaped leaves, 131. 
 Pith, 111,237, 242. 
 
 of the stem, 18. 
 Plantae compositas, 127. 
 
 simplices, 126. 
 
 agamicae, 139. 
 
 aerea?, 144. 
 
 aquaticae, 144. 
 
 athalamicae, 139, 203. 
 
 cellulares, 141. 
 
 thalamicas, 21 1. 
 
 vase ul ares, 141. 
 Plantago, 276. 
 Plantain, 476. 
 Plant-cell, 31,83. 
 Plants, life of, 458. 
 
 movement of parts of, 544. 
 
 alkaline, 492. 
 
 chalk, 492. 
 
 climbing, 544. 
 
 contents in ashes of some, 564. 
 
 death of, 536. 
 
 digestion of, 493. 
 
 food of, 470. 
 
 in relation to the atmosphere, 503. 
 
 phosphatic, 492. 
 
 reproduction of, 524. 
 
 sleep of, 455. 
 
 siliceous, 492. ^ 
 
 turf-moor, 491. 
 Plate-shaped leaves, 131 
 Pluerothallis ruscifolia, 280. 
 
 R R 2 
 
612 
 
 INDEX, 
 
 Plumbagineae, 379- 
 Plum, 435. 
 Plumula, 270. 
 Plumule, 418. 
 Poa annua, 501. 
 
 vivipara, 314. 
 Podocarpus, 385. 
 Podostemon, 169, 300, 355. 
 
 Ceratophyllum, 406. 
 Pollen, 296, 467. 
 
 cells, contents of, 358. 
 
 formation of, 355. 
 
 grains, 109, 530. 
 
 granule, 357, 408. 
 change of, 402. 
 
 membrane, 357. 
 
 tube, examination of, 408. 
 
 tubes in contact with nectar, 408. 
 
 tubes, branched, 408. 
 Polygala, 331. 
 Polygonaceas, 271, 272. 
 Polygonum divaricatum, 393. 
 
 Fagopyrum, 497. 
 
 tinctorium, 26. 
 Poly ides lumbricalis, 548. 
 Polypodium ramosum, 58. 
 Polyporus, 152. 
 
 igniarius, 538. 
 Polysperma, 7. 
 
 glomerata, 104, 146. 
 Polytrichoideae, 182. 
 Polytrichum, 171, 186. 
 Pomeae, 369. 
 Pomegranate, 227. 
 Pomum, 449. 
 Pontederia crassipes, 278. 
 Poplar, 46. 
 Populus, 319. 
 
 dilatata, 263. 
 
 Position of plants on soil, 259. 
 Potamogeton, 64, 94. 
 
 lucens, 418. 
 Potassium, 4. 
 Potato, 18, 111, 292. 
 
 starch, 11. 
 
 effects of heat on, 1 3. 
 Potentilla, 259, 319, 345. 
 Pothos, 27 1. 
 
 adventitious roots of, 218. 
 
 crassinervis, 75. 79. 
 
 reflexa, 419. 
 Pouches, 266. 
 Punctatus, 135. 
 Punctum vegetationis, 57. 
 Punica granatum, 428. 
 Pyrenomycetes, 145, 157, 159. 
 Pyrenothalami, 1.59. 
 Preissia commutata, 92, 174. 
 Primary cell, 121. 
 Primulacea?, 314, 384. 
 Processes, 180. 
 
 form of the, 494. 
 Pro -embryo, 174, 198. 
 Prolifera rivularis, 4 1 . 
 Propagation, 80. 
 
 Prosenchyma, 56. 
 Proteaceae, 73. 
 Protein, 23, 24, 37, 81, 85. 
 Protococcus, 128, 136, 145. 
 
 cell, 103. 
 
 viridis, 82. 
 Protoplasma, 568, 
 Pruina, 188, 498. 
 Prunus domestica, 95. 
 
 Padus, 50, 257. 
 
 spinosa, 234. 
 Pseudo-tubers, 293. 
 Ptelea trifoliata, 282. 
 Pteris aquilina, 192, 231. 
 
 chinensis, 1 95. 
 
 speciosa, 193. 
 Pubescens, 135. 
 Puccinia, 151. 
 Pulvinus, 551. 
 Pulp, 430. 
 Pulsatilla, 440. 
 Pyrus, 226, 319. 
 Pyxidium, 447. 
 
 Quadrangular is, 129. 
 Quekett, E., 570. 
 
 John, 577. 
 Quercus Robur, 241. 
 
 Suber, 53, 69. 
 Quince, 10. 
 
 Raceme, 300, 308. 
 Racemose, 134. 
 Rachis, 304. 
 Radical organs, 216. 
 Radix, 217. 
 
 adventitia, 218. 
 
 Ivarancusae, 17. 
 
 tuberosa, 296. 
 
 Rain, its influence on vegetation, 509. 
 Raja Pastinaca, 190. 
 Ranunculaceas, 329, 365. 396. 
 Ranunculus, 331. 
 
 acris, 337. 
 
 procerus, 320. 
 Rays of sun-light, 86. 
 Receptacle, 446. 
 Receptaculum, 148. 
 Red snow, 458. 
 Reniform, 130. 
 Reniformis, 132 
 Reproduction, 467. 
 
 asexual, 531. 
 
 irregular, 531. 
 
 of a cell, 527. 
 
 of plants, 524. 
 
 organs of, 128, 557. 
 
 regular, 531. 
 
 sexual, 531. 
 
 various modes of, 534. 
 Reseda, 433. 
 
 alba, 387. 
 Resins, 30, 87. 
 Resorption, 516, 523. 
 
INDEX. 
 
 613 
 
 Respiration, 89, 471. 
 Rhamnus, 77. 
 Rhegma, 448. 
 
 Rhipsalis salicornioides, 35, 356. 
 Rhizina;, 144, 158. 
 
 Rhizocarpeae, 70, 169, 190, 203, 209, 212, 
 244. 
 
 structure of, 209. 
 Rhizoma, 235. 
 Rhizophora, 423. 
 
 Mangle, 65, 237. 
 Rhizomorpha subterranea, 542. 
 Rhus, 53, 240. 
 Ribes, 241. 
 Riccia fluitans, 168. 
 Ricciese, 167. 
 Rice, 476, 484. 
 Richard, L. C., 417. 
 Ricinus, 398, 427. 
 Rime, 498. 
 Rimosus, 135. 
 Rivularia, 109. 
 Root, 88, 166, 167. 
 
 function of the, 219. 
 Rootless Agamae, 168. 
 Root-sheath, 69. 
 Roots of parasites, 220. 
 Rosa, 226, 319. 
 
 divarica, 321. 
 
 Rosaceae, 242, 271, 272, 339. 
 Rosulate, 134. 
 Rotundata, 132. 
 Rotundatus, 131. 
 Rotundus, 129. 
 Rubiacese, 390, 426. 
 Rumex crispus, 278. 
 Ruscus, 128, 226, 236, 282. 
 
 aculeatus, 245. 
 Rush-halm, 228. 
 
 Sacculus, 203. 
 Sago, 13. 
 
 Sagus Rumphii, 18. 
 Salicacea?, 332. 
 Salix, 332. 
 
 alba, 548. 
 
 capraea, 282. 
 
 male flowers of, 306. 
 Salvinia, 69, 72, 203. 
 
 fruits of, 208. 
 
 natans, 208. 
 
 seed-buds of, 208. 
 Salts, 5, 87. 
 
 of ammonia, 489. 
 
 crystallization of, 36. 
 
 decomposition of, 87. 
 Salver-shaped, 130. 
 Salvia Horminum, 281. 
 
 officinalis, 394. 
 
 patula, 341. 
 
 verticillata, 71. 
 Samara, 448. 
 
 Sanguinaria canadensis, 308. 
 Santalacea.% 401. 
 Santalum album, 412. 
 
 Sap, circulation of, 78. 
 
 crude, 504. 
 
 currents of, 109. 
 
 experiments on the motion of, 97, 
 
 115,515, 520. 
 Sapindaceae, 252. 
 Saponaria officinalis, 425. 
 Sarcostemma viminale, 66. 
 Sargassum, 146, 165. 
 Sarracenia, 268. 
 Sarsaparilla, 17. 
 Saururus, 303, 332. 
 Saxifraga, 7, 498. 
 
 granulata, 15. 
 
 sarmentosa, 72, 280. 
 Scabiosa, 345. 
 
 atropurpurea, 395. 
 Scandix Pecten, 302. 
 Scapus, 229. 
 Scattered buds, 216. 
 Schaffner, 572. 
 
 Scheuchzeria, embryo of, 419. 
 Schimper, Dr., 266. 
 Schistostega osmundacea, 543. 
 Schleiden, 256. 
 Scholia latifolia, 9. 
 
 speciosa, 9, 113. 
 Schwann, 466. 
 Scindapsus, 65. 
 
 Scitamineaa, 7, 16, 48, 55, 327. 
 Scitosiphon, 146. 
 Scleranthus perennis, 395. 
 Scolopendrium, 195. 
 Scorpion, 190. 
 Scrophularia, 410. 
 Secale, 16. 
 
 cereale, 421. 
 
 cornutum, 152. 
 Secretions, 80, 86, 523. 
 Sectus, 130. 
 Secunda?, 134. 
 Sedum, 128,276. 
 Seed, 437. 
 Seed-bud, 296, 367, 385, 389, 391, 588. 
 
 arched, 391. 
 
 development of, 423. 
 
 straight, 389. 
 
 structure of, 399. 
 Seed-leaves, 280. 
 Seed, solitary, 447. 
 
 of plants, 444. 
 Seeds, naked, 437, 447. 
 Segmenta, 130. 
 Semecarpus, 436, 
 Semen of plants, 444. 
 Seminium, 452. 
 
 Sempervivum tectorum, 27, 263. 
 Sensitive plant, 27, 552. 
 Sepals, 314, 332. 
 Septa, false, 432. 
 Sessilis, 133. 
 Serrate, 132. 
 Set.t, 69, 179. 
 Sexual plants, 201, 244. 
 Silenacea?, 391. 
 
614 
 
 INDEX. 
 
 Silica, 4. 
 
 Silicium, 3. 
 
 Silicula, 448. 
 
 Siliqua, 448. 
 
 Silkworm, 152. 
 
 Siphonodon celastrineus, 322, 372. 
 
 Siphonia elastica, 28. 
 
 Sleep of plants, 455. 
 
 Stnithia sensitiva, 552. 
 
 Snow, 487. 
 
 Snowberry, 95. 
 
 Snow, red, 458. 
 
 Sodium, 4. 
 
 Soil, 509. 
 
 of the fields, 512. 
 
 of the garden, 512. 
 
 products of, 476. 
 
 temperature of, 513. 
 Solan ia, 86. 
 Solanin, 27. 
 Solanum, 283, 429. 
 
 tuberosum, 34, 95, 292, 429. 
 Solenia, 146. 
 Sonchus asper, 32 1 . 
 Sorbus aucuparia, 27 1 . 
 Sori, 194. 
 Sorosis, 448. 
 Spadix, 308. 
 Sparsae, 134. 
 Spatha, 338. 
 Spathe, 30O. 
 Spathulate, 130. 
 Spergula arvensis, 497. 
 
 pentandra, 394. 
 Spermophore, 382, 384, 443. 
 Spermatozoa, vegetable, 99, 359. 
 Sphacelia segetum, 152. 
 Sphaeriae, 145. 
 Sphagnum, 51, 176, 184. 
 
 leaf of, 188. 
 
 Sphalerocarpium, 447,449. 
 Spicatae, 134. 
 Spike, 300, 308. 
 Spikelet, 308. 
 
 Spikes with woody bracts, 449. 
 Spiral filaments, 97. 
 
 fibres, 43. 
 
 forms of the, 43, 137. 
 
 formations, 156. 
 
 twisting of an axis, 233. 
 
 name and origin, 42. 
 Spirodela, 236. 
 Spirodela polyrrhiza, 70. 
 Spirogyra, 25, 32, 90, 95, 1 47. 
 Splachnum, 180. 
 Sporangium, 139, 144. 
 Spore-case, 144, 155. 
 
 cells of, 99, 162. 
 
 leaf of, 194. 
 Spores, 109, 144. 
 Sporocarp, 139, 144, 178, 211. 
 Sporocybe, 144. 
 Stalks, 249. 
 Stamen, 348. 
 Stamen of the Cryptogamia, 349. 
 
 Stamens, 345. 
 
 accessory, 364. 
 Stapelia, 548. 
 Starch, 9, 10, 18, 90. 
 Starch, granule, development of, 567. 
 
 granules, 19, 38. 
 
 under a microscope, 12. 
 
 in various forms, 14. 
 
 with cold water, 13. 
 
 works on, 19. 
 Stem-germen, superior, 370. 
 
 leaves, 280. 
 
 pistil, 370. 
 
 origin of, 372. 
 Stemonitis, 152. 
 Stems, 166, 215,228,249. 
 
 of climbing plants, 251. 
 
 of grasses, 2fc9. 
 Stigma, 178. 
 Stings, 69. 
 Stipelles, 271. 
 Stirps, 228. 
 Stock, 228. 
 Stock, leaf of a, 73. 
 Stoma, 180. 
 
 Stomachs in animals, 493. 
 Stomata, 279. 
 Stomata on mosses, 188. 
 Stomates, use of, 189. 
 Strata, 444. 
 Stratiotes aloides, 94. 
 Strawberry, 436. 
 Strelitzia, 7. 
 
 farinosa, 22, 26, 118. 
 Strobilus, 447, 449. 
 Stroma, 151. 
 Style, 178, 368. 
 Stylidium adnatum, 552. 
 
 graminifolium, 552. 
 Suber, 69. 
 
 Substantia intercellularis, 111. 
 Sugar, 9, 21, 81, 476, 483. 
 
 cane, 21. 
 
 solutions of, 83. 
 Sulcatus, 135. 
 Sulphate of lime, 6. 
 Sulphates, 83. 
 Sulphur, 3, 490. 
 Suture, 434. 
 Syconus, 448. 
 Symphoricarpos, 95. 
 Synanthereae, 22. 
 Syncarpium, 448. 
 Syringa, 239- 
 
 vulgar is, 282. 
 Syrrhopodon, 177. 
 
 prolifer, 177. 
 
 Tamarind, 462. 
 Tamarindus, 9 
 
 Indica, 113. 
 Tamarix gallica, 21. 
 Tannic acid, 27. 
 Tannin, 27, 87, 114. 
 
INDEX. 
 
 615 
 
 Taroo, 18. 
 Tartaric acid, 27. 
 Taxus, 302, 350, 382. 
 baccata, 317, 393. 
 Tegmenta, 280, 386. 
 Tela contexta, 68. 
 
 epidermoidea, 68. 
 fibrosa, 64. 
 
 Telephora hirsuta, 157. 
 Telmatophace gibba, 219, 421. 
 Temperature of soil, 513. 
 Teres, 1 28. 
 
 Terminal bud, 216, 270. 
 Terminology, 258. 
 Testa, 433, 461. 
 Tetraspora, 138, 183. 
 
 gelatinosa, 101. 
 Tetratheca, 36O. 
 Teucrium, 325, 343. 
 Thallus, 151. 
 
 crustaceus, 157. 
 Theca, 145, 179. 
 Thesium, 412. 
 Thorns, 69. 
 Thyrse, 310. 
 Tierra colorada, 479. 
 Tilia europEea, 44, 65. 
 Tillandsia amoena, 389. 
 Tissues, 51, 130, 459. 
 Tmesipteris, 190. 
 Topinambour, cultivation of, 563. 
 Tomentosus, 135. 
 Trabecular, 181. 
 Trachea, 54. 
 
 Tradescantia. 6, 43. 
 crassula, 48, 70. 
 discolor, 70, 74. 
 rosea, 95. 
 stem of, 229. 
 virginica, 97, 314. 
 
 Tragopogon, 357. 
 
 Transition, 142. 
 
 Trapa, 367. 
 
 natans, 423. 
 
 Trees, age of, 538. 
 
 Tree Carnation, 120. 
 fern, 192. 
 
 Trichia, 156. 
 
 Trichiacese, 152. 
 
 Triglochin, 128. 
 
 Trillium erectum, 397. 
 
 Triqueter, 128. 
 
 Triticum, 16. 
 
 Trollius, 364. 
 
 Tropa^olum, 414. 
 majus, 542. 
 
 Truncatus, 131. 
 
 Trunk, 221. 
 
 Trunks, epidermis of, 237. 
 
 Try ma, 448. 
 
 Tschornoisetn, 477. 
 
 Tube-shaped leaves, 131. 
 
 Tubes mixtes, 49. 
 
 Tuber-buds, 292. 
 
 Tubercles, 292. 
 
 Tubers, 292. 
 Tubus, 131. 
 Tubiliformis, 131. 
 Tulipa Gesneriana, 95. 
 Typha latifolia, 425. 
 
 Ulothrix zonata, 101. 
 Ulmin, 29. 
 Ulva, 128. 
 Ulvaceae, 146. 
 Umbel, 308. 
 Umbellate, 133. 
 Umbelliferae, 54. 
 Umbilicaria, 158. 
 Umbilicus, 389. 
 Undina, 109, 128, 144, 145. 
 Unger, 38, 256, 570. 
 Union of cells, 107. 
 Urania speciosa, 465. 
 Urceolatus, 131. 
 Uredo Maidis, 151. 
 Uredines, 151. 
 Urtica, 78. 
 
 dioica, 396. 
 
 canadensis, 122. 
 
 crenata, 78. 
 
 urentissima, 78. 
 Urticaceae, 40. 339. 
 Utricularia, 77, 268, 279. 
 Utriculi, 38. 
 Utriculus, 447, 451. 
 
 Vagina clausa, 274. 
 
 petiolaris, 272. 
 
 stipularis, 272. 
 Vaginula, 179. 
 Vallisneria, 110, 364. 
 
 spiralis, 92, 93. 
 Vasa, 54. 
 
 lactescentia, 64. 
 
 propria, 59. 
 Vascular bundles, 57, 166. 
 
 bundles, cells of, 414. 
 
 of leaves, 277. 
 Vaucheria, 145. 
 
 clavata, 100. 
 
 Unger i, 41. 
 Vegetable albumen, 81. 
 
 cell, life of, 105. 
 
 cells, motions of, 99. 
 
 chemistry, 2. 
 
 colours, 26. 
 
 jelly, 9. 
 
 mucilage, 9. 
 
 Vegetation, organs of, 555. 
 Velamen radicum, 69. 
 Verbascum thapsus, 302. 
 Veronica, 364, 367, 426. 428. 
 
 fructiculosa, 302. 
 Verruca?, 69. 
 Verrucaria, 144. 
 Verticillate, 134. 
 Vibratile cilia, 98. 
 Vicia Faba, 53, 60. 
 Vierlingsfruchte, 148. 
 
616 
 
 INDEX. 
 
 Vinca, 351. 
 
 Vine, 50,237, 241. 
 
 Vinegar, 82. 
 
 Vinous fermentation, 36. 
 
 Viola, 343. 
 
 Viscin, 28. 
 
 Viscosus, 498. 
 
 Viscum, 10.5, 233, 360, 401. 
 
 album, 28, 234, 282, 316, 393. 
 Vital processes, 110. 
 Volatile oil, 40. 
 Volvox globator, 127. 
 
 Walnut, 435. 
 Warts, 40, 69. 
 Water, 4, 82, 90, 509. 
 
 decomposition of, 86, 89. 
 
 in contact with zinc, 85. 
 Wax, 22. 
 
 Weeping Ash, 215. 
 Wigandia urens, 77. 
 Wild cattle, 477. 
 Willow, 46. 
 
 Willows, weeping, 533. 
 Wolffia, 136, 245. 
 
 Michelii, 235. 
 Wood, 56. 
 
 cells, 57. 
 
 charcoal, 4S6. 
 
 formation of, 238. 
 Wounded parts of plants, 528. 
 
 Xanthorhcea australis, 247. 
 
 Yams, 476. 
 
 Yew, wood of the, 50. 
 
 Yucca, 234. 
 
 gloriosa, 247, 406. 
 
 Zea Mays, 4, 16, 22, 224. 
 Zarnichellia, 332. 
 Zinc, 85. 
 Zingiberacese, 16. 
 Zinnias, 361. 
 Zostera marina, 142, 358. 
 Zygnema quininum, 149. 
 
 THE END. 
 
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 Bldg. 400, Richmond Field Station 
 University of California 
 Richmond, CA 94804-4698 
 
 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS 
 
 2-month loans may be renewed by calling 
 (510)642-6753 
 
 1-year loans may be recharged by bringing 
 books to NRLF 
 
 Renewals and recharges may be made 4 
 days prior to due date. 
 
 DUE AS STAMPED BELOW 
 
 SEP ? 1 2000 
 
 12,000(11/95) 
 
53, 
 
 LIBRARY, BRANCH OF THE COLLEGE OF AGRICULTURE