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REPORT ON THE PROGRESS 
 
 OF 
 
 VEGETABLE PHYSIOLOGY 
 
 DURING THE YEAR 1837. 
 
 BY 
 
 F. J. F. MEYEN, M.D. 
 
 PROFESSOR OF BOTANY*TN THE UNIVERSITY OF BERLIV. 
 
 TRANSLATED FROM THE GERMAN 
 
 BY WILLIAM FRANCIS, 
 
 ASSOCIATE OF THE LINN^AN SOCIETY. 
 
 LONDON: 
 
 R. AND J. E. TAYLOR, RED LION COURT, FLEET STREET, 
 
 Printers and Publishers to the University of London. 
 
 1839. 
 
Lti? 
 
 ADVERTISEMENT. 
 
 THE present Translation was undertaken as a contribu- 
 tion towards the supply of a want of information, felt 
 and acknowledged in this country, respecting the la- 
 bours of Continental Naturalists, and especially those of 
 Germany. In sending it forth so long after its an- 
 nouncement, the Translator feels that an apology is 
 due to his Subscribers ; but his undertaking has met 
 with an encouragement insufficient to render it probable 
 that the publication of the work can pay its cost. 
 Should it, however, obtain this measure of success, he 
 wil] feel pleasure in devoting some portion of his time 
 to the translation of future Reports. He has already 
 received a reward which he cannot too highly prize, 
 in being brought into communication with the able 
 and kind friend who has devoted a portion of his va- 
 luable time to the revisal of the work during its pro- 
 gress. 
 
 In the translation, the German has been closely ad- 
 
 M37H1O 
 
IV ADVERTISEMENT. 
 
 hered to, and when French or English papers have 
 been reported on, the originals have been consulted. 
 For those errors which may have escaped him, the 
 Translator requests the indulgence of his Reader^ and 
 has only to hope that his undertaking may assist his 
 countrymen in exploring a field of science rich in in- 
 terest, and which amply repays the time and labour 
 spent in its cultivation. 
 
 W. F. 
 
 Oct. 1, 1839. 
 
REPORT 
 
 ON 
 
 VEGETABLE PHYSIOLOGY. 
 
 IHE study of Vegetable Physiology advances with rapid 
 steps, the small number of its labourers annually increases, 
 each year adds to the importance of its results 5 and we already 
 look forward to the time when a decided separation of vege- 
 table physiology from descriptive botany must take place, for 
 it appears that these two sciences cannot simultaneously be 
 pursued by one and the same botanist to such an extent as 
 the present time demands. The number of anatomico-phy- 
 siological publications of the past year is extremely great ; and 
 it is morphology especially which has engaged during that 
 period the largest share of attention ; at present a contest 
 awaits it similar to that which previously vegetable anatomy 
 had to undergo, where not a single observation was admitted 
 without opposition. So also morphology must not be the 
 work of speculation, but should be founded wholly and solely 
 on the observation of nature ; studied in this way, it will be- 
 come a doctrine easy to comprehend, which will enlarge to a 
 great extent our knowledge of the nature of plants. 
 
 From the active interest which has been taken in vegetable 
 physiology, and from the immense increase of materials, this 
 report becomes from year to year a more arduous undertaking; 
 as, however, it is of some utility for the diffusion of the sci- 
 ence, the reader will kindly overlook those faults with which 
 such a thankless task must always be accompanied. The in- 
 
terest evinced with regard to these reports both in England 
 and in France by translations*, as well as by the kind transmis- 
 sion of some memoirs, which otherwise would not have come 
 so early under our view, convinces us that the naturalists of 
 those countries will feel a greater desire to possess a more 
 general knowledge of our very numerous German labours in 
 this branch of science than heretofore. 
 
 I shall endeavour in future that the report may always ap- 
 pear sooner, perhaps in the month of March ; by which some 
 periodicals, it is true, which are constantly in arrear, will be 
 left over. In the present report we have been able to avail our- 
 selves of the valuable Annales des Sciences Naturelles only as 
 far as the September Number for 1837 5 for to the 6th of May 
 1838 we did not possess in Berlin the later numbers. I must 
 also remark, that of the larger general works which appeared 
 during the past year on vegetable physiology, such detailed 
 reports have not been given as of the smaller publications and 
 separate memoirs ; since this would have been a task beyond 
 the powers of the reporter. 
 
 On the Spiritual Life of Plants. 
 
 M. v. Martiusf has published his views on the soul of plants, 
 with which I may commence the present year's report. It 
 appears, observes M. v. Martius, as if natural philosophers 
 were in general not inclined to admit in the essence of the 
 plant these two spheres, body and soul, as if they would con- 
 cede a soul only to animals and man. It is usual to regard 
 as the essential predicate of the soul, perception such as it 
 appears in animal life ; and, as in the vegetable kingdom, we 
 are acquainted with very few phasnomena which admit of our 
 concluding upon a power of perception in plants, they have 
 been declared not to possess a soul. Von Martius points out, 
 that even animal forms sink so low in the scale of organiza- 
 tion, that all the characteristics of animal life disappear in 
 them ; on the other hand indications of vegetable life display 
 
 * The English translation here referred to was puhlished in the 68th, 
 69th, 70th, and 71st Numbers of the London and Edinburgh Philosophical 
 Magazine, to the pages of which Journal 1 shall have frequent occasion to 
 refer the reader. TRANSL. 
 
 f Reden mid Beitrage iiber Gegenstande aus dem Gebiete der Natur- 
 forschung, Stuttgard und Tubingen, 1838. 
 
themselves ; whilst in the more highly developed vegetable 
 forms, phsenomena occur which belong to animal life, such 
 for instance, as the manifold various motions which have been 
 observed in plants : in fact that animal life and vegetable life 
 appear in no way to be so decidedly separated from each other, 
 and for that reason, therefore, a soul cannot be admitted in 
 animals alone and denied to vegetables. Even the predomi- 
 nant growth and the propagation of plants appear to indicate 
 that they are not confined to the circle of rigid necessity; and 
 we must recognise in them a kind of predetermination, a 
 tendency to the ideal, consequently a higher vital principle, 
 a soul. The soul of plants is much less complex than that of 
 animals ; it is in fact, in itself, of a more obscure and unde- 
 fined nature. Perception, imagination, consciousness, sensa- 
 tion, desire, volition, appear here to have sunk into the night 
 of a gloomy, confined existence, and the narrow path of ana- 
 logy and induction towards this subject, unattainable by our 
 inquiries, is open to us but for a short distance. The vege- 
 table soul must not however be compared with the soul of man., 
 or with that of the higher animals, but rather with the nucleus 
 or that point of the axis only, around which the life of the low- 
 est and most simple animals revolves. Von Martius thinks 
 that we can admit of no organ of soul in plants ; yet we may 
 probably succeed, as I think, in our time in discovering this 
 organ even in plants ; the nervous system has, as is well 
 known, been already observed in vegetables by some learned 
 botanists, although others, it is true, have not been able to 
 convince themselves of the fact. 
 
 A series of phenomena are moreover enumerated, such as 
 the specific susceptibility of plants for the actions of light, 
 heat, air, moisture, &c., which, without a certain degree of 
 sympathy and of perception, without a kind of internal con- 
 sciousness, could not possibly have effect. Perhaps in them 
 all the various grades of spiritual action combine to produce 
 one single obscure idea. The more general and intense the 
 irritation which acts upon plants, the more powerful is the 
 perception. The sleeping and waking of plants, as also their 
 hybernation, correspond exactly to the similar phenomena 
 in animals, only that these states in plants are involuntary. 
 The soul of the plant is diffused throughout it ; in so far how- 
 
 B2 
 
ever as the vegetable soul acts according to its nature forma- 
 tively, plastically, one might say that it is situated in the 
 more highly organized plants principally in the node, in which 
 the vegetable powers slumber. 
 
 This latter opinion might however be disputed,, as might ge- 
 nerally the entire current doctrine of the composition of plants 
 of internodes, on which subject we shall subsequently have 
 occasion to speak more in detail. With respect to the rest 
 I agree perfectly with M. von Martius ; nay, it is to me incon- 
 ceivable how all those phenomena of the vita sensitiva of 
 plants can be thought to be explained by the indefinite expres- 
 sion of irritability. 
 
 Von Martius next enumerates the other manifold processes 
 which the vegetable soul has to superintend when the plant is 
 propagating by sexual intercourse, and concludes these obser- 
 vations with the following words : " Among intricate percep- 
 tions and ideas, a dark sensibility and consciousness, a sym- 
 pathy, a stimulus, an increase of this to affection, probably 
 also a kind of memory in the repetition of certain physical 
 actions ; all this we may deduce from the various habits of 
 plants, if we compare them with analogous relations in animal 
 life. We are not however able to trace in them a higher sense, 
 understanding, or free will/* 
 
 With the preceding is immediately connected a memoir by 
 M. v. Martius*, which treats of the immortality of plants. 
 The idea of the immortality of plants is the next step to the 
 proof of the existence of a vegetable soul; but M. v. Martius 
 himself observes in the introduction, that it is true that many 
 scientific men, to whom the power of comprehending the tran- 
 scendental has been imparted in a lower degree, will regard the 
 consideration of such a subject as a digression ; he however 
 believes that the greater part of mankind are so organized, 
 that they will adopt conclusions, and acquiesce in conse- 
 quences, which rise above the \vorld of sensible contempla- 
 tions and perceptions into the higher world of the spirit. The 
 conviction of the immortality of plants can however in no 
 case be deduced from any proof derived from the nature of 
 plants, but it must be peculiarly the conception of the indi- 
 vidual mind. 
 
 L. e. p. 261286. 
 
" In the corporeal life of the plant there exist intention, 
 tendency, and means for their attainment ; nay, we even see 
 this controlled by the fitness of time, in the same way as in 
 more highly endowed man. The plant, like the animal, has 
 inward intentions to fulfil outwardly, fulfils them like the lat- 
 ter, and indeed, in the same way, more or less perfectly, ac- 
 cording to the various conditions of which they consist. There 
 is therefore only a difference of degree between the unknown 
 unity which predominates over all this activity, and which in 
 man is termed his soul, and the spontaneous power analogous 
 to this soul which the plant exhibits in action during its whole 
 life," &c. We do therefore an injustice to the plant when we 
 consider it as not being like the animal endowed with a common 
 primary force, penetrating through all parts and directing them 
 all to certain actions. From these views, however, it would 
 result, that all inorganic bodies are also endowed with a soul, 
 a thought, which has been already asserted in the most an- 
 cient times ; nay, Von Martius arrives at the conclusion, that 
 everything earthly, and therefore also the plant, possesses a 
 soul, and the numberless fraternity of similar creatures which 
 act so prominent a part in the universal life of our planet, are, 
 according to their scale, governed by a soft peaceful spirit, an 
 Anima blandula, trepidula. 
 
 On the Phenomena of Nutrition and Growth in Plants. 
 
 M. E. Ohlert* has published some observations on the 
 structure and growth of the fibrils of the root ; but deserving 
 of more especial attention are those experiments which he 
 performed on the function of the spongioles, and of the lateral 
 surfaces of the fibrils. The decortication of the spongioles 
 was also observed by M. Ohlert in various plants ; it is more 
 evident in roots which are developed under water. In other 
 cases these membranes split into small rags, which still for 
 some time adhere to the spongioles of the roots. M. Ohlert 
 very rightly observes, that the decortication of the spongiole 
 begins first at the upper end and then further downwards ; at 
 last the loosened membrane holds merely to the apex. I 
 know however of instances where the loosened epidermis has 
 
 * Einige Bemerkungen iiber die Wuvzelzasern der hbhcren Pflanzen. 
 Linnaea, 1837, p. 609 631. 
 
quite peeled off at the spongiole and become destroyed, while 
 further upwards it still adheres firmly ; a similar case also came 
 under M. Ohlert's observation. The calyptrae upon the 
 spongioles of the thick aerial roots of the Pandani, to which 
 DeCandolle first drew attention,, are frequently to be seen in 
 the Botanic Garden of Berlin ; they are for the most part 
 thick membranes, consisting of several layers of cells, which 
 are here torn off from the hinder part of the root by the rapid 
 growth of the spongiole ; after some time this decortication is 
 repeated in the part of the root which has grown subsequently. 
 M. Ohlert's experiments respecting the elongation of the 
 fibrils have completely confirmed Du HamePs discovery that 
 this elongation takes place only at the extremities. 
 
 He has endeavoured to prove by observations, that the cur- 
 rent opinion, that the roots absorb exclusively by the spon- 
 gioles and not with the lateral surfaces, is erroneous, or at 
 least, that the reasons brought forward to prove this are not 
 sufficient. Young plants of Pisum sativum, Lupinus luteus and 
 Calendula offidnalis were so placed with their roots in water 
 that only the radicles were immersed about three lines deep 
 in it. Even after a few hours the roots were withered, and 
 after a few days quite dry ; only that part of the root which 
 was inserted in the water retained its turgescence. Upon this 
 a quantity of plants were so placed in water, that the extre- 
 mities of the fibrils projected out of the water, while the en- 
 tire lateral surfaces were immersed. Also when the apex was 
 coated with gum-lac varnish, the plants continued to grow 
 extremely well if the entire surfaces of the fibrils were under 
 water. From these experiments he concludes, that the fibrils 
 do not absorb the moisture by the spongioles, but at the sides, 
 or over the entire surface. I can however hardly agree with 
 this conclusion ; for I can also bring forward experiments 
 which prove that the apex is, and indeed very actively, engaged 
 in the process of absorption ; this subject, as also my observa- 
 tions on the structure of the spongioles, are accurately detailed 
 in the second part of my Vegetable Physiology, in which are 
 refuted the received opinions respecting the so-called spon- 
 gioles of the root, which do not exist in nature. It must cer- 
 tainly be admitted that plants absorb with the whole surface 
 of their roots ; this surface however is in many cases, and espe- 
 
cially at certain places, so changed, that the absorption is there 
 diminished and gradually disappears entirely. 
 
 M. de Mirbel* has also in a few words treated of the struc- 
 ture of the terminal ends of the fibrils, and has controverted 
 the spongioles being peculiar organs of the apices of the roots. 
 
 M. Dutrochet f has given in the complete edition of his 
 physiological works, a very valuable memoir on endosmosis, 
 which, from its highly important results, is of the greatest va- 
 lue to vegetable physiology. 
 
 M. Dutrochet endeavoured in the first place to determine 
 what effect various degrees of temperature would have upon 
 the endosmosis of one and the same solution. The caecum of 
 a fowl was fixed to a glass tube, and this filled with a solution 
 of gum in 10 parts of water, and placed in distilled water, at 
 a temperature of 4 Reaum. ; the solution of gum had at- 
 tracted within 1J hour so much water that the apparatus in- 
 dicated an increase in weight of 13 .grains ; and in a water 
 at 25 to 26 the increase in the same space of time amounted 
 to 23 grains. In order to be able to give the results of such 
 observations with the greatest certainty, he constructed a pe- 
 culiar apparatus, which he calls Endosmometer ; by means of 
 this instrument the velocity of the endosmosis in various sub- 
 stances w r as measured, or rather the quantities of the fluid 
 which ascended in the endosmometer during a fixed time. 
 For instance, sugar-water of the specific gravity 1*047 at- 
 tracted in 1 hour so much water into the endosmometer, that 
 the instrument indicated 3^. On the other hand, a solution 
 of sugar of 1-258 spec. grav. indicated in the same time 19i. 
 The result of these experiments was this that the velocity of 
 the endosmosis produced by the various densities of the same 
 inner fluid, is in proportion to the excess of the density of the 
 inner fluid over the density of the exterior water. 
 
 M. Dutrochet also determined by a series of experiments 
 the force with which the endosmosis takes place in various 
 substances, and at various densities of these substances ; 
 and it is the results of these experiments which are of such 
 importance to vegetable physiology. The apparatus with 
 
 * L'Institut. 1837. p. 311. 
 
 f M6moires pour servir a 1'histoire anatomique et physiologique des V6- 
 g^taux et des Animaux. A vec un Atlas de 30 planches. Paris, 1837. 2 vol. 
 
which these experiments were performed is very similar to 
 those twofold bent glass tubes employed by Stephen Hales, 
 when he endeavoured to determine the force with which the 
 crude sap ascends in the vine : the end of the shank must here 
 however be blown out in a funnel or bell shape, in order thus 
 to present a larger surface of membrane to the endosmosis. In 
 the first bend of the tube an aperture must be made, which may 
 be closed by a glass stopper, through which the various fluids 
 employed for the experiments may be poured, and a scale is 
 fixed to the outer long shank. Now when the endosmosis is 
 allowed to proceed in this instrument, the fluid contained in it 
 rises by the absorption of the external water; and if some 
 mercury has been placed in the two exterior shanks of the 
 glass tube, this mercury is pressed downwards in the inner 
 shank by the raised column of air and forced upwards in the 
 exterior shank, which can then be nicely measured by the 
 scale there fixed. By similar observations M. Dutrochet 
 arrived at the result, that the force with which water is ab- 
 sorbed in the endosmosis, is more powerful according to the 
 proportion in which the density of the fluid in the interior of 
 the instrument stands to the exterior water. Sugar solu- 
 tions of 1 '035, 1*070, and of 1*140 spec. grav. were prepared; 
 the latter consisted of about one part of sugar and two of water. 
 The excess in density of these fluids above the density of the 
 water was in the proportion of 1, 2, 4. The solution of sugar 
 of 1*035 spec. grav. sucked up into the instrument so much 
 water during twenty-eight hours, that the column of mercury 
 was raised 10" J"'. The second solution caused the mercury 
 to rise in thirty-six hours to 22" 10"' ; and the third solution of 
 1*140 density, in forty-eight hours to45" 9"'. The observations 
 were made at a temperature of 16^ Reaum., and it is evident 
 from them, that the force of the endosmosis is subject to the 
 same law as its velocity. Similar experiments w r ere now per- 
 formed with several other substances; and M. Dutrochet ar- 
 rived at the result, that a solution of albumen exhibits the 
 most powerful endosmosis; after this sugar, then gum, and 
 last and weakest of all, gelatin ; these substances indeed, with 
 respect to the strength of their endosmosis, are expressed in 
 numerals in the following proportion : solution of albumen 12, 
 sugar 11, gum 5'l,and gelatin 3. 
 
After these highly interesting discoveries of M. Dutrochet, 
 it is hardly possible to doubt that the force with which the 
 crude sap ascends in the vine and other plants is nothing 
 more than the action of endosmosis, which is carried on by 
 the innumerable cells of the extremities and hairs of the root 
 with their saccharine juices upon the moisture of the soil. 
 
 M. Dutrochet * has in a subsequent memoir announced a 
 change in his views respecting the conducting organs of the 
 sap ; formerly he regarded the spiral vessels as such, at pre- 
 sent the fibrous ligneous cells. The structure of these ele- 
 mentary organs, he observes, is peculiarly adapted to serve for 
 the ascent of the fluids. These fibrous tubes terminate at both 
 ends in extremely fine points ; their cavities are the finest ca- 
 pillary tubes, and the end of the lower tube is articulated with 
 the end of the upper tube. M. Dutrochet states that he is 
 convinced that the ends of these tubes possess free apertures, 
 and in this manner communicate one' with the other. These 
 supposed apertures at the ends of the ligneous tubes have as 
 yet been observed by no German phytotomist, and I am ra- 
 ther inclined to doubt their actual existence ; nay, it even ap- 
 pears that such apertures are quite superfluous ; for it is well 
 known that the crude nutritive sap does not proceed from be- 
 low upwards through the tubes of the ligneous body, but 
 that it can even, and indeed almost as quickly, permeate late- 
 rally, where M. Dutrochet has not yet observed these aper- 
 tures. 
 
 I will cite a passage in opposition to this view from M. 
 Unger's contributions to our knowledge of parasitical plants t, 
 where this illustrious physiologist has also laid down his be- 
 lief respecting the function of the elementary organs of plants, 
 which almost perfectly coincides with my own. The spiral 
 vessel, he says, and the prosenchymatous cell in some degree 
 allied to it, is certainly rather destined originally to conduct 
 the nutritive fluid than to preserve it and prepare it for che- 
 mical changes ; while the parenchymatous cells must rather be 
 regarded as reservoirs of nutrition. The parenchymatous cells 
 
 * Recherches sur les conduits de la seve, et sur les causes de sa progres- 
 sion. Mem. pour servir a 1'histoire anat. et phys. des Veget. et des Anim. 
 i. p. 368. 
 
 f Ann. des Wiener Museums, ii. p. 25. 
 
10 
 
 are, however, in my opinion, not merely reservoirs of the nu- 
 tritive substances, but the nutritive substances are formed in 
 them, and then proceed from them through all the forma- 
 tions. 
 
 M. A. Poiteau* has also published some observations on 
 the efflux of the sap from the divided stem of scandent plants, 
 which may be entirely explained in the present state of the 
 science. He cut the stem of a climber right through, and no- 
 ticed that at neither of the two surfaces of section did water 
 exude; if, however, apiece of the stem, about 4 feet in length, 
 was cut off, the water contained in it flowed out immediately f. 
 I have already frequently remarked that this water is contained 
 in the metamorphosed spiral vessels, which in the stems of 
 climbers, as in the vine, are so large that they can no longer act 
 as capillary tubes, and therefore the efflux of the sap from the 
 divided ends of the stem of such plants is entirely subject 
 to the pressure of the atmosphere ; it takes place instanta- 
 neously if the end of the cut stem is placed vertically, on the 
 contrary, very slowly if this lies in a horizontal position. If, on 
 the other hand, we separate the upper part of the stem, which 
 is still clothed with its leaves, from the root end, no water 
 can flow* out of the end of the first portion, because the trans- 
 piration of the leaves, when their number is sufficiently great, 
 developes a force by which the water is retained in the large 
 spiral vessels. This fact has been proved by numerous expe- 
 riments in the second part of my Vegetable Physiology. The 
 reason still remains to be explained why no water proceeded 
 from the surface of the section of the lower end of the stem 
 of the climber, as M. Poiteau observed to be the case. It has 
 been proved by numerous observations, that the tears of vege- 
 tables, i.e. the efflux of their crude nutritive sap above the 
 level of the wounds which are inflicted on the stems of such 
 plants, are to be ascribed entirely to the endosmosis of the 
 fibrils, and that this phenomenon only takes place if the plants, 
 as during the production of leaves and buds, require a large 
 quantity of nutriment. 
 
 On the circulation of the sap in Chara a paper by M. Du- 
 
 * Note sur la Liane des voyageurs. Ann. des Sciences Naturelles, Avril 
 1837, p. 233. 
 
 f Lond. and Edin. Philosophical Magazine, vol. xi. p. 525. 
 
11 
 
 trochet* has appeared, which, together with phaenomena long 
 since known, contains also many new facts. Notwithstanding 
 all the numerous observations which have been published in 
 Germany respecting the structure of the Charce, M. Dutrochet 
 commences with a description of this remarkable genus of 
 plants, from which no one certainly would obtain a just notion 
 of it. Mention is made of a central and of a cortical system 
 of the Chara, which latter, in order to be able to observe the 
 circulation in the central system of C. flexilis^ must be taken 
 off. It is hence evident that M. Dutrochet has had before 
 him a Cham with compound cuticle, probably C. vulgaris, but 
 certainly not C. flexilis^ a case which also occurred to a cele- 
 brated philosophical botanist of Germany, who has written a 
 great deal respecting the circulation of sap in plants. 
 
 The artificial removal of the outer cuticle in Ch. vulgaris 
 has long been known ; and if the plants be kept during win- 
 ter in a room, these membranes generally disunite of them- 
 selves and fall off in great pieces. M. Dutrochet also observed 
 that the course of the sap-current in the cells of the Char& is- 
 indicated by the position of the green globules, which are ar- 
 ranged in lines one after the other on the inner surface of the 
 cells ; and is at present of M. Aimer's opinion, that those 
 green globules are the seat of the motion which is observed 
 in the cells of these plants. M. Dutrochet has however seen, 
 (which is likewise not new) that there is a circulation of the 
 sap in such cells of the Charce as possess no green globules 
 on their inner surface ; and this is the case in all other plants 
 where hitherto these motions in the sap of the cells have 
 been observed ; therefore the source of the motion cannot be 
 sought for in those green globules. He has entirely over- 
 looked the fact that a similar circulation occurs in all the 
 cells of the so-called cortical layer of the Charce ; but it seems 
 as if, of all the innumerable memoirs which have appeared 
 on the Charge and the circulation of their sap, M. Dutrochet 
 had read no other than that of M. Amici. 
 
 M. Dutrochet bound round the lower part of the cell of 
 
 * Observation sur la Chara flexilis. Modification dans la circulation de 
 cette plante sous 1'influence d'un changement de temperature, d'une irrita- 
 tion m^canique, de 1' action des sels, des acides, et des alcalis, de celle des 
 narcoliques et de 1'alcool. Comptes Rendus, etc. Nos. 2. 3. 4. Dec. 1837. p. 
 77o. 
 
12 
 
 a Chara, and noticed the separation of the general circulation 
 thus caused ; an internode tied in three places exhibited four 
 distinct circulating currents, which even continued when the 
 adjacent parts were cut off. 
 
 M. Dutrochet examined the influence of various tempera- 
 tures on the circulation in the Chares, and likewise noticed 
 that it still continues at the freezing point of water, but pro- 
 ceeds very slowly. But Corti had previously observed that a 
 cold of 2 to 5 killed the plants ; in general, however, we may 
 say that actual freezing kills the plants and causes the circu- 
 lation to stop. M. Dutrochet observed that the circulation 
 increased in rapidity with higher degrees of temperature, which 
 was the case up to 27 Cels. ; but he did not remark that not 
 only at one and the same temperature this motion varies ex- 
 ceedingly in the several cavities according to their different 
 ages, but that even in the cells of the so-called bark and in 
 those of the interior cavity the velocity in the circulation dif- 
 fers. On the application of a higher degree of heat, says M. 
 Dutrochet, the motion is at first somewhat slower, but gra- 
 dually rises, and finally arrives at the usual rapidity; but 
 water at 45 Cels. killed the plants irrecoverably. 
 
 M. Dutrochet endeavours to show that the influence of light 
 is indispensably necessary to the preservation of the current 
 in the Charts, reasoning from views according to which light 
 is considered as the means for the fixing of the carbon from 
 the carbonic acid of the air. Light appears to me to exercise 
 no immediate influence on the circulation of the sap in the 
 cells of the Chara?, for I kept for several months plants of 
 Chara in a dark situation, carefully covered, but observed in 
 them, at a temperature of 7 to 8 Reaum., motions quite as 
 active as these plants exhibit in summer, even at a higher 
 temperature. M. Dutrochet placed several Charce in a per- 
 fectly dark situation, at a temperature of 14 to 20 Cels., 
 and observed that the motions of the sap became in most of 
 them slower, indeed discontinued completely within twenty- 
 four to twenty-six days in the younger plants, which had at 
 the same time faded. According to my own observation, this 
 fading of the Charce is quite peculiar ; the fact is, that the 
 cells of the outer cuticle decay and fall off, and then only 
 the inner membrane remains, which in C^. vulgaris exhibits 
 
13 
 
 but very few small green globules on the inner surface, and 
 therefore has then a faded appearance. The terminal joints 
 of these plants are still, however, as beautifully green as the 
 fresh plants, let them remain ever so long in darkness ; and the 
 motion in their cells ceases only at death. 
 
 M. Dutrochet placed a Char a in water from which the air 
 had been extracted, and closed the tube under mercury ; the 
 circulation continued even under these circumstances for 
 twenty-two days, and ended only with the life of the plant ; 
 the effect therefore was almost analogous to that produced by 
 a complete absence of light. Corti had previously observed 
 that the circulation of the sap in Chares became slower when 
 the plants were placed in oil or in milk. Corti placed some 
 Charce in the receiver of an air-pump, and, rarifying the air 
 as far as possible, left the plants in this situation during forty- 
 eight hours. The circulation had discontinued ; but after the 
 plants had been placed in fresh water, it began anew in the 
 space of from eight to twelve hours. 
 
 M. Dutrochet has also attentively observed the influences 
 of mechanical causes on the circulation in the Chares. Every 
 pressure and every mechanical irritation of the cells produce 
 a momentary decrease in quickness, and even a complete cessa- 
 tion of the circulation, which is, however, soon restored, the 
 effect being entirely proportioned to the force of the action. 
 Actual injury of the membrane, even by the point of a needle 
 only, causes a sudden cessation of the motion, w r hich then 
 never returns. Injuries have precisely the same effect on 
 Charce as on other plants in whose cells similar circulations 
 occur. If we cut off a single branch of a Char a, the motion 
 ceases for a long time in the adjacent cells ; in Vallisneria in- 
 deed this frequently lasts for ten to twelve minutes, until the 
 motion in the cells of the prepared section again recom- 
 mences with perfect activity. M. Dutrochet states that he 
 has also observed that the simple cell of the Chara exhibits 
 slight convulsive motions if one of the knots of an internode 
 be pierced, and when the outer cortical membrane is pared 
 off. In these cases also, the series of green globules are as- 
 serted to be the cause of the motion, for they are said to con- 
 tract at times in a zigzag direction, similar to muscular fibre, 
 while the membrane of the cell takes no part in this. I have 
 
14 
 
 riot yet had an opportunity of verifying the correctness of 
 these statements. 
 
 A very interesting series of observations has been insti- 
 tuted on the effects on the circulation of the sap in Chara of 
 chemical substances, whose actions on the excitability of ani- 
 mals are known. A portion of a Chara was placed in a solu- 
 tion of caustic potash, containing about ^innr f tms substance; 
 the motion at first became slow, but five minutes afterwards 
 it was again very strong. After twenty-five minutes the mo- 
 tion again became slower, and in thirty-five minutes entirely 
 ceased. Lime-water increased the motion in the cells of Chara 
 in from two to three minutes : this remarkable result I am 
 able to confirm. Momentary immersion of the Charce in lime- 
 water did them no harm, but if suffered to remain in it from 
 four to five minutes the circulation ceased. In a solution of 
 tartaric acid (1 part to 50 of \vater) the circulation continued 
 in the cells for ten or twelve minutes only ; in a weaker solu- 
 tion of this acid (1 to 1000 water) the motion became very slow; 
 but five minutes afterwards it regained its activity by the re- 
 action of the vital forces. After three quarters of an hour the 
 circulation became feeble, and after one hour entirely ceased. 
 
 A similar result was obtained with a solution of sea salt, and 
 M. Dutrochet came to the conclusion, that strong doses of 
 salts and of acids put a decided end to the circulation in Chares, 
 but that the same substances in smaller quantities causes it is 
 true a stoppage in the beginning, but that subsequently this 
 injurious action is overcome by the vital forces of the plant, 
 and the motion is to be observed afterwards as before. Mean- 
 while the case is exactly similar with the vegetative pro- 
 cesses of other plants. The motion in the cell of a Chara 
 which had been placed in a solution of extract of opium (1 part 
 to 14 of water) ceased entirely six minutes after immersion. 
 After a quarter of an hour it recommenced very slowly, but 
 after half an hour it was entirely suspended. In a weaker so- 
 lution of opium (1 part to 288 of w r ater) the effect was similar, 
 but after ten minutes the circulation again returned and con- 
 tinued, it is stated, with increased velocity for eighteen hours. 
 In a solution of opium, only half as strong, the circulation be- 
 came somewhat slower, but subsequently returned with great 
 vivacity. 
 
15 
 
 The action of alcohol on the circulation resembles that of 
 opium. Similar observations have also been made on other 
 plants: these will chiefly be found in a Dissertation by Schii- 
 bler and Zeller*. 
 
 M. Becquerel f has performed a series of interesting experi- 
 ments with the view of discovering the nature of the force which 
 causes these circulating currents of the sap in the cells of 
 the Charce. M. Amici and many others regarded this activity 
 as one similar to the galvanic power, produced by the piles 
 of green globules with which the inner surface of these cavi- 
 ties is lined. The discharge of small piles through Chares 
 twisted in a spiral form produced no change in their circulation; 
 whence the conclusion \vas drawn, that the motion in the 
 Charce is not caused by electricity, but by some other force, 
 with whose nature we are as yet entirely unacquainted. On 
 the other hand, the observations on the effect of continued 
 currents on the circulation in the Chavez lead to other interest- 
 ing results. The passage of electricity causes at first a torpid- 
 ity of the motion, which adapts itself entirely to the strength 
 of the charge, and acts at the same time on both currents, 
 i. e. on the ascending and descending. When the pile has 
 been rendered by a certain number of plates so strong that its 
 action immediately stops the circulation, this, after a short in- 
 terval, recommences under the influence of the electric cur- 
 rent, and returns to all its former activity. If we double the 
 number of pairs of plates, the circulation again stands still, 
 and this may be continued in such a manner that by the ac- 
 tion of a powerful pile the circulation will stop for several 
 hours. By a gradual removal of the plates the circulation re- 
 turns so much the quicker ; however no disorganization is 
 caused by the passage of an electric current. Thus then the 
 action of electricity on the circulation of the sap in the Char 
 coincides with that of heat, excepting that no acceleration 
 was caused by the electricity, which is observed under the ac- 
 tion of heat ; however, I am inclined to think that this is only 
 indirect, as the vegetation of the plant is hereby raised in in- 
 
 Ueber die Einwirkung verschiedener Stoffe auf die Vegetation, &c. 
 Tubingen. 1826. 
 
 f Influence de 1'electricite sur la circulation du Chara. Comptes Ren- 
 dus, 1837, p. 784. 
 
16 
 
 tensity, at least the velocity of the motion in the cells does 
 not depend on the degree of heat. 
 
 M. Morren* has published sx>me views on the circulation 
 of the sap in Dicotyledons, in which he observes that Mohl's 
 discovery of an intercellular substance must lead to a more 
 correct idea respecting the organs of circulation. But it has 
 many years ago, in my opinion, been proved by several phy- 
 siologists that the intercellular passages of plants only convey 
 air, and these occur only in such plants where the close union 
 of thickened septa is said to take place by the so-called in- 
 tercellular substance. In last year's report this subject was 
 treated of at great lengthf, and I am convinced by recent ob- 
 servations still more decidedly, that the intercellular substance 
 is no distinct substance, but consists of the thickened su- 
 perposed cellular septa. I recommend for such observations 
 old leaf-petioles of species of Rheum and the old stems of cu- 
 curbitaceous plants. 
 
 M. Morren regards the pleurenchymatous cells of the wood 
 as the route of the ascending crude nutritive sap, for which 
 some explanation may be necessary, as this denomination is 
 not yet generally adopted in Germany. I proposed the word 
 pleurenchyma to designate the tubes of the liber in 1830, 1 sub- 
 sequently discovered that the so-called ligneous cells possess 
 a similar structure with the tubes of the liber, and distin- 
 guished in the first part of my Vegetable Physiology short 
 pleurenchymatous cells and elongated pleurenchymatous cells; 
 the latter comprise the tubes of the liber, the former the lig- 
 neous cells, which in Germany are more frequently desig- 
 nated by the name of prosenchymatous cells, by which 1 
 understand the ligneous cells of the Conifer. M. Morren 
 has very correctly mentioned the fact, that the crude nu- 
 tritive sap ascends in the wood not only from below upwards, 
 but also passes in a horizontal direction and even obliquely 
 through the wood, exactly in the same way as the circulation 
 of the sap takes place from cell to cell in the diachyma of the 
 various organs. M. Morren is, however, a^so of opinion, that 
 these short pleurenchymatous cells are of the same origin and 
 
 * Considerations sur le mouvement de la seve des Dicotyledones. Bullet, 
 de PAcad. de Scienc. de Bruxelles, 1837, p. 300. 
 
 f Lond. and Edin. Philosophical Magazine, vol. xi. p. 435. 
 
17 
 
 purport as the other cells, and are produced as it were .from 
 spheroid cells, the so-called merenchyma, and therefore the 
 fibrils of the root must also be considered as such cells which 
 take their origin in the root-stem, &c. Much may, however, be 
 objected to this notion ; the fibrils are exceedingly delicate pa- 
 renchymatous cells, and parenchyma and pleurenchyma differ, 
 not merely in the form of their cells, but also in their func- 
 tions. Pleurenchyma rather serves merely to conduct the saps; 
 the short pleurenchyma conveys the crude nutritive sap in its 
 ascent, the long pleurenchyma (tubes of the liber) conducts an 
 elaborated formative sap from above downwards. In the pa- 
 renchymatous cells the assimilation of the absorbed nutritive 
 substances takes place : they respire through the intercellular 
 passages, while in the pleurenchymatous cells no respiration 
 can exist on account of the want of intercellular passages. I 
 have enumerated in my Vegetable Physiology several cases 
 where intercellular ducts occur even between the tubes of the 
 liber, for instance, in Asclepiadece and Apocynece ; and that in 
 these cases the tubes at the same time convey a milky fluid, 
 which abounds in globules ! The origin of the radicular fibrils 
 from the parenchymatous cells may easily be observed. 
 
 M. Morren next enters into a special consideration of an 
 inversely grafted branch of a Camellia) in order to show that 
 the direction in the ascent of the sap may not only be inverted 
 for some hours, but even for the whole lifetime of the plant. 
 The first, as is known, was long since scientifically proved by 
 Stephen Hales, and I have also endeavoured to show * that 
 the ascent of the sap in separated branches is caused entirely 
 by the transpiration of the leaves, &c., consequently the di- 
 rection of the sap may be varied at the will of the experimenter. 
 The ideas of ascent and descent in the motion of the crude 
 nutritive sap are evidently not altogether correct ; the crude 
 sap is always conducted to those parts of the plant which 
 are in want of it, and therefore it is also conveyed to the bud 
 of a cutting, even when this is grafted inversely on to the 
 stock. The vacuum which must arise from the transpiration 
 of the young bud and of its leaves is immediately filled with 
 the fluid which lies nearest to it, and in this way the crude 
 
 * Pflanzen-Physiologie, vol. ii. Berlin, 1838, 
 C 
 
18 
 
 sap ascends from the stock through the wood of the scion into 
 the eye, which may be proved by experiments. 
 
 M. Mirbel* has laid before the French Academy a highly 
 interesting treatise on cambium and the mode of formation 
 of cells and vessels in vegetables. The earlier statement,, that 
 cambium is a cellular mucilaginous mass of extreme delicacy, 
 is therein confirmed, and M. Mirbel is of opinion that his doc- 
 trine of the origin of vessels (probably spiral vessels are in- 
 tended),which originate from cells whose diagonal septa are de- 
 stroyed, is generally adopted, which, however, is not at all the 
 case. I shall not go further into the contents of this commu- 
 nication at present, as M. Mirbel will probably very soon pub- 
 lish this work in a more complete form ; it contains very beau- 
 tiful drawings of the formation of the new ligneous cells from 
 the cambium, and the thickening of their sides by the forma- 
 tion of new layers from the latter. 
 
 M. Girou de Buzareinguesf has on the other hand produced 
 a memoir on the structure and growth of the new woody layers 
 of dicotyledons, which it is true is full of new observations and 
 views, but will hardly gain much credit. I at least cannot 
 concur with him in one single point. In last year's report J I 
 had occasion to notice a paper of M. Girou's, in which the 
 most erroneous observations and false views on well-investi- 
 gated subjects of vegetable physiology were contained ; it is 
 much the same with the present memoir. M. Girou writes 
 and works constantly without any regard to the labours of his 
 predecessors, and this neglect of the observations of others is 
 the cause that the results of his own are as if vegetable phy- 
 siology had first been studied last year. 
 
 M. Dutrochet has laid before the French Academy of Sci- 
 ences some observations on the nature and development of 
 cork, without being acquainted with the observations of M. 
 Mohl, which were noticed at p. 58 || of last year's report. M. 
 
 * Observations sur le cambium et sur quelques modes de formations utri- 
 culaires ou vasculairea dans les vegetaux. Compte Rendu, 1837, p. 295. 
 L'Institut, 1837, p. 311. 
 
 f Mem. sur 1'accroissement en grosseur des exogenes. Ann. des Scienc. 
 d'Hist. Nat. 1837, Mars, p. 129 166, avec 3 planches, 
 
 J Lond. and Edin. Philosophical Magazine, vol. xi. p. 526. 
 
 L'Institut de 1837, p. 10. 
 
 || Page 53, &c. of the translation in Lond. and Edinb. Phil. Mag. for 
 January 1838. TRANSL. 
 
19 
 
 Dutrochet mentions a species of ash, whose branches, from 
 eight to ten years old, develope cork ; after this time the deve- 
 lopment of cork ceases. I have published similar observations 
 on the Metrosideri *, and have indicated the structure as also 
 the development of the suberose layer in relation to the other 
 cortical layers. The other statements of M. Dutrochet were 
 previously known. 
 
 M. Decaisnef presented to the Acad. des Sciences a memoir 
 on the family of the Lardizabalece, which contains some in- 
 teresting observations on the structure of the stems of dicoty- 
 ledons, especially with reference to the Menispermece and Ari- 
 stolochice. As the memoir will probably very soon appear, 
 we delay our notice, as the abstract in the Institut is too short 
 for our purpose. The remarkable structure of the stem of the 
 genus Cissampelos has also been noticed by me in my Vege- 
 table Physiology, p. 3 74. 
 
 M. Link has published the second part of his Anatomico- 
 Botanical Drawings for elucidating the fundamental doctrines 
 of botany J; they are accompanied with Latin and German 
 text. In last year's report I drew attention to this useful un- 
 dertaking, which must add much to the general diffusion of 
 phytotomical doctrines. The drawings are very neatly and 
 beautifully executed on stone, and in the present part there 
 are several which render the distinctions between monocoty- 
 ledons and dicotyledons, Coniferce, Cycadeae, and so forth, very 
 prominent, and on that account may be recommended to the 
 attention of geologists. 
 
 M. Morren endeavours to show that the priority in the 
 discovery of the increase of cells by simple division belongs to 
 him, as he had published already in 1830 the observation, that 
 every fourth part of his beautiful genus Crucigenia (an Alga), 
 on being magnified, again subdivided into four smaller cells, 
 and so on. In last year's report this subject was treated of 
 at length, p. 20 1|, &c., and I stated M. Dumortier to be the 
 discoverer of this interesting fact, which was published in 
 
 * Pflanzen-Physiologie, i. p. 411, &c. 
 t L'Institut, 1837, p. 317. 
 I Berlin, 1837, fol. 
 
 Bulletin de 1'Acad. Royale de Science, &c. de Bruxelles, 1837, p. 300. 
 || Page 386 of the translation in the Lond. and Edinb. Philosophical Ma- 
 gazine for Oct. 1837. TRANSL. 
 
 c 2 
 
20 
 
 1832. He was at least the first botanist who recognised the 
 importance of the facts from which we might conclude with 
 certainty on the increase of the cells by separation ; and M. 
 Mohl has noticed this important subject more fully in Con- 
 ferva glomerata. Suppositions and simple conjectures that 
 cells increased in such a way had frequently been given out, 
 but there is a very great difference between the origin of new 
 cells in the way stated, and the formation of the pollen vesicles, 
 which originate in a manner similar to the albumen of seeds, 
 and M. Morren can hardly lay claim to the discovery of these 
 facts. It was well known for instance that all the cells in a 
 Conferva, proceed from the few cells of the spore, but never- 
 theless we did not then know in what manner the increase 
 of the cells took place ; we were acquainted with the elongation 
 of the spores in severalHyphomyceteSyand the extension of these 
 spores to the development of the young plant ; but yet we had 
 no distinct idea of the process contemporaneously in action. 
 
 M. Morren has since then continued his observations on the 
 separation of the cells in the Conferva, and thinks he has suc- 
 ceeded in recognising in Conferva dissiliens all the circum- 
 stances at the formation of the diagonal partitions ; he observed 
 in this plant that the cells were elongated, and the mass therein 
 contained was divided in the centre into two parts by a trans- 
 parent free space, which was formed of a mucous fluid, which 
 from its destination he supposes to be an intercellular sub- 
 stance, and names it inter-chromula (inter- or meta-chromu- 
 laire or Metendockromique). The condensation now begins 
 from the periphery of this substance, by which the union with 
 the common cell is at the same time effected, and as this ad- 
 vances more and more towards the centre, the double mem- 
 brane thus formed takes the place of the transparent fluid sub- 
 stance, so that now each single portion of the endochrom pos- 
 sesses its distinct membrane. 
 
 M. Dutrochet's memoir on the respiration of plants, which 
 was but shortly noticed in last year's report, p. 56*, has since 
 been published entire t ; the results of this work coincide how- 
 ever very little with the views of many other physiologists, 
 
 * Page 536 of the translation in the Lond. and Edinb. Philosophical Ma- 
 gazine for Dec. 1837. TRANSL. 
 
 f Recherches sur les organes pneumatiques et sur la respiration des v6- 
 getaux. In the collective edition of the Memoirs of M. Dutrochet, i. p. 320. 
 
21 
 
 and quite as little with those I have endeavoured to diffuse on 
 this subject ; so that a more detailed elucidation of the state- 
 ments from which these results are drawn is quite necessary. 
 
 M. Dutrochet complains of those botanists, who think that 
 animal life has nothing in common with that of plants ; ac- 
 cording to his opinion, with which in so far I entirely agree, 
 life is not different in its fundamental phaenomena in all be- 
 ings. It has frequently been admitted, that those phaeno- 
 mena, which in vegetables are comprehended under respira- 
 tion, are exactly opposed in their results to the respiration of 
 animals : M. Dutrochet does not take this view, but accord- 
 ing to him the respiration in plants consists as in animals in 
 a fixation of the oxygen, while I have endeavoured to show in 
 my Physiology (ii. p. 150.), that the respiration of plants, like 
 that of animals, consists in a carbonization of substance, as in 
 both oxygen is inspired and carbonic acid expired. 
 
 In examining the organs of plants which carry on the pro- 
 cess of respiration, M. Dutrochet relates the opinions of 
 MM. Link and Amici, according to which the spiral vessels 
 and their appendages should be regarded as the pneumatic 
 apparatus of vegetables. However M. Link is not at all of this 
 opinion in his recent works, but states that aggregations of 
 air are even found in the intestinal canal of animals, yet this 
 exists for very different purposes. The conveyance of air is 
 evinced very decidedly in the cells of the pith, and nothing 
 can be more certain than that the medulla serves to convey 
 and elaborate the absorbed sap for the young shoots. M. Du- 
 trochet was formerly of opinion that the large spiral vessels in 
 the wood of the vine conducted the nutritive sap, and even at 
 the present time considers this to be correct, but thinks that 
 it is to be attributed solely to this cause, that so long as the 
 leaves are wanting, no transpiration is indicated, and that the 
 sap consequently collects in the spiral vessels. 
 
 The spiral vessels are therefore said to be the pneumatic 
 organs in the wood, while distinct large cells are found in 
 the bark conveying air, which are supposed to be situated in 
 the interior of the bark, and to communicate one with the 
 other. I must confess that I have no idea of these cells, which 
 are said to carry on the process of respiration in the interior 
 of the bark, wholly leaving out of view, that it is not probable 
 
22 
 
 that nature would employ the spiral vessels in the wood and 
 distinct cells in the bark to effect the respiration in plants. 
 
 In my Vegetable Physiology, I have, on the contrary, endea- 
 voured to show that the intercellular system serves for the re- 
 spiration in plants ; and it is only those elementary organs, sur- 
 rounded by intercellular passages or large air cavities situated 
 in the immediate vicinity, in which an actual assimilation of 
 the absorbed nutriment takes place ; for as the respiration in 
 animals produces an amelioration of the blood, i. e. of the 
 elaborated nutritive and formative sap, so in vegetables the re- 
 spiration causes an amelioration of the nutritive sap, which is 
 elaborated in every cell of the parenchyma : and, if we com- 
 pare the structure of animals with that of plants, we shall at 
 once perceive that a respiration, which is to agree in its re- 
 sults with that of animals, can take place in plants in no other 
 way. If we follow up the connexion which exists between 
 the intercellular passages, air cavities, stomata, and the spiral 
 apertures of the cuticular glands, the view which I take in 
 common with M. Unger, that the intercellular passages carry 
 on the process of respiration in plants, will become more than 
 probable. When the cuticular glands are covered with resins, 
 as is frequently the case in the Conifera, this must be regarded 
 as a purely accidental aggregation of the excretion in the ca- 
 vity of the epidermis. 
 
 The leaves are, however, the organs which possess in the 
 greatest number the above-mentioned arrangements for respi- 
 ration. M. Dutrochet notices the difference of opinion respect- 
 ing the destination of leaves with reference to their function ; 
 some botanists have compared them as absorbing organs to 
 the aerial roots, others on the contrary have declared them to 
 be the lungs of plants. To this latter opinion M. Dutrochet 
 adheres in common with many other botanists. The leaves of 
 plants exert on the nutritive sap contained in them a similar 
 action to that of the act of respiration in the lungs of animals 
 on the blood ; and the sap descending from the leaves, the for- 
 mative sap is that which in some degree may be compared to 
 the blood of animals, as of it the new masses are formed. 
 
 Observations have long since shown that plants during the 
 greatest part of the day-time absorb oxygen : to explain this 
 phenomenon M. Dutrochet draws attention to the important 
 
23 
 
 discovery of M. Theod. de Saussure, that porous bodies, and 
 especially such as abound in carbon, possess the property of 
 attracting and compressing certain gases : thus, for instance, 
 carbon can absorb 9^ times its volume of oxygen. It is pos- 
 sible that the absorption of oxygen in plants takes place in 
 a similar way, at least the quantity of oxygen consumed coin- 
 cides with the number of stomata and air cavities in certain 
 plants. All porous bodies however do not possess this pro- 
 perty of compressing gases ; magnesia and lime for instance 
 are exceptions. 
 
 The contents of the remaining portion of this work have 
 partly been published in earlier papers, and we have moreover 
 partially noticed the essential points in our last year's report*. 
 
 Dr. Schleidenf has published some observations on the 
 luxuriant development of various plants in water containing 
 carbonic acid. The springs in the valley of Gottingen abound 
 in free carbonic acid, especially the basins near the Wehnder 
 paper-mill, and there is here found a rich and luxuriant vege- 
 tation, which in spring appears several entire weeks earlier 
 and continues in autumn much later than at other spots of 
 the same district. Dr. Schleiden thinks that the free carbonic 
 acid in the water exercises a favourable influence on the ve- 
 getation, which certainly may be the case ; for observations 
 have shown, that during the vegetation of plants in solar light, 
 the addition of a very small quantity of carbonic acid in the 
 surrounding atmosphere produces a much more powerful dis- 
 engagement of oxygen than takes place in the common atmo- 
 sphere. 
 
 In the memoir on the soul of plants, M. v. Martius J has 
 stated his views on the nutrition of plants. The whole force 
 of vegetable life evinces itself most prominently in its indica- 
 tions of assimilation, as here inorganic matter must be con- 
 verted to organic, and have form given to it. This is an essential 
 character, in which plants differ from animals, as these for the 
 most part take up only organized nutriment. The plant, says 
 M. v. Martius, derives its nourishment from the earth, the 
 water, and the atmosphere ; but I think I am able to prove 
 
 * See Lond. and Edinb. Philosophical Magazine, vol.xi. p. 536. 
 
 f Notiz iiber die Einwirkung freier Kohlensiiure auf die Ernahrung der 
 Pflanzen. Wiegmann's Archiv, p. 279, 1837 ; and Annals of Nat. Hist. p. 
 235. No. IX. 
 
 I Reden und Vortrage, &c., p. 244. 
 
24 
 
 with much certainty that plants are also nourished by the re- 
 ception of organic substances, and that the reception of these 
 as well as of inorganic substances, which are presented to the 
 roots in a dissolved state, is effected entirely according to the 
 fixed laws of physical forces. 
 
 [By a long series of experiments it has been proved that 
 plants will not grow in a soil of inorganic substances ; if, how- 
 ever, organic substances be presented to them for nutrition they 
 vegetate, and fix in their green-coloured parts by the influence 
 of solar light the carbon from the carbonic acid of the air ; it is 
 chiefly the leaves which perform this function. After the fall of 
 the leaves they are converted into humus, and this again pre- 
 sents to the roots of the plant the necessary nutriment. REP.] 
 
 M. v. Martius supposes that plants, in all the operations of 
 their vegetable life > act according to a certain law of preference, 
 therefore with that power which in the human mind becomes 
 will. The plants are thus said to choose from the manifold 
 nutritive substances at their disposal those to which they are 
 especially partial ; however, I am of opinion that ah 1 correctly 
 performed experiments, from which at least we must reason 
 until more recent ones shall have proved otherwise, tend to 
 show that vegetables cannot choose their nutriment. 
 
 The Rev. J. B. Reade * has published several elementary 
 analyses, which would lead us to admit a very remarkable dif- 
 ference in the chemical composition of cellular membrane and 
 of spiral vessels in the same plant. The analyses were per- 
 formed in the laboratory of Mr. Rigg, but unfortunately the 
 method is not stated. Mr. Reade extracted from the roots 
 of the Hyacinth the spiral vessels from the surrounding cel- 
 lular tissue by rubbing them between the fingers, and then 
 both substances were subjected to separate analyses. He ob- 
 tained : 
 
 Spiral vessels. 
 
 Carbon 41-8 
 
 Hydrogen .... 1*1 
 Nitrogen .... 4*3 
 
 Water 51 -8 
 
 Residuum . 1*0 
 
 100 
 
 Cellular tissue. 
 
 Carbon 39'2 
 
 Oxygen. ..... 7' 14 
 
 Nitrogen .... 3' 9 
 
 Water 48'5 
 
 Residuum . TO 
 
 100 
 
 * On the Chemical Composition of Vegetable Membrane and Fibre. 
 Loncl. and Edinb. Philosophical Magazine, vol. xi. p. 421. 
 
25 
 
 These results are in many respects so remarkably at variance 
 with all that we are as yet acquainted with respecting similar 
 subjects, that we must at the outset doubt their correctness. 
 The small quantity of carbon of these substances, which ac- 
 cording to his statements would even be less than that in starch 
 and in gum, is in itself highly improbable, even if no similar 
 analyses had yet been made. According to these statements, 
 the cellular tissue is said to contain an overplus of oxygen and 
 the spiral vessels an overplus of hydrogen, which, however, is 
 not confirmed by analyses in German laboratories. Mr. Rigg is 
 also said to have long ago discovered that the perigonium of the 
 hyacinth contains oxygen in abundance, while the pistil and 
 pollen show a surplus of hydrogen, so that Mr. Reade thence 
 arrives at the conclusion that fibre (probably spiral fibre is here 
 intended !) contains hydrogen, and cellular membrane oxygen 
 in abundance, and indeed in such proportions that these gases 
 form water when the organs are analysed together. 
 
 With respect to the analyses of the spiral vessels and cellu- 
 lar tissue from the root of the hyacinth, I must observe that 
 it is a most difficult, and in the hyacinth even an impossible 
 undertaking, to prepare the spiral vessels in so great a quan- 
 tity, i. e. entirely freed from every kind of cellular tissue, as is 
 necessary for any elementary analysis : besides, the spiral ves- 
 sels snap very easily in the hyacinth, and at the utmost we 
 could only succeed in preparing some pure fibre. Moreover 
 we are not informed in what manner Mr. Reade convinced 
 himself of the purity of the substances employed. Each in- 
 dividual cell of the cellular tissue must be separated piecemeal, 
 and then cleansed several times with alkalis, acids, alcohol, 
 aether, and water, if we desire to obtain a result on the compo- 
 sition of membrane. Thus also the considerable amount of 
 nitrogen, which these analyses indicate, is probably only to 
 be ascribed to the nitrogenous substances contained in the 
 cells ; for the numerous careful analyses of cellular tissue, of 
 wood, &c., hitherto performed, give no nitrogen at all, or at 
 least only so much that it may justly be regarded as a foreign 
 constituent. Mr. Rigg has even made various analyses of the 
 different parts of the flower of the hyacinth ; he thus first sepa- 
 rated the epidermis, then the cellular tissue situated immediately 
 beneath the epidermis, the spiral vessels, and the longer cells 
 
26 
 
 which traverse the parenchyma in bundles, and subjected each 
 of these four substances to separate analysis, which, remarkably 
 enough, have given results exactly corresponding to the ex- 
 pectations. I may be excused, however, for giving my own 
 opinion repecting the division of the flower into these four 
 substances. It would I think be impossible to obtain such 
 quantities as would be necessary for the analysis, even were 
 the division to be made under the microscope and a whole 
 year devoted to the purpose. And if the substances for ana- 
 lysis have not been employed perfectly separated, it does 
 not attain its end. Above all, however, the antithesis in the 
 composition of cellular membrane and spiral fibre, which is 
 said to be indicated by predominant hydrogen and oxygen, 
 is inadmissible. 
 
 In support of some of the above-mentioned suppositions, I 
 will notice some elementary analyses which Prof. Mitscherlich 
 has instituted with the greatest accuracy ; flax fibres, pure cel- 
 lular tissue from the interior of the pith of the elder, and pure 
 spiral fibres from the flower of a Musa were employed. All 
 these substances were previously cut small, then purified in 
 every respect from foreign ingredients, and constantly tested 
 with the microscope, so that no doubt might remain as to the 
 substances which were to be subjected to analysis being as pure 
 as possible. According to these analyses, the flax fibre con- 
 tained in 100 parts 45*98 carbon ; the pure spiral fibre of the 
 Pisang 48-88, and the cellular tissue of the elder pith 50-65 
 carbon. Hydrogen and oxygen were present in the same 
 proportions as in water ; yet, unfortunately, all the analyses 
 indicated some superfluous hydrogen, which proved less the 
 more accurately the analysis was made. Nothing was ob- 
 served of any superfluous oxygen or nitrogen. The perfect 
 combustion of the substances had to be effected by passing a 
 current of oxygen, as an accurate mixture of them with the 
 oxide of copper could not be effected ; and probably the oc- 
 currence of superfluous oxygen is to be ascribed to this me- 
 thod, which it is intended to ascertain by further experiment. 
 
 In a second paper* Mr. Reade has endeavoured to prove 
 
 * Further observations on the structure of the solid materials found in 
 the ashes of recent and fossil plants. Loud, and Edinb. Philosophical Ma- 
 gazine, vol. xi. p. 413. 
 
27 
 
 that potash, lime, and silica enter as organizable substances 
 into the structure of plants. The reasons which Mr. Reade 
 mentions in support of this consist, properly speaking, only in 
 the observation, that we find in the white ash of coal the form 
 of the elementary organs of those vegetable parts which have 
 been burnt, and that this skeleton consists partly of potash, 
 lime, and silica. As far back as two years ago M. Goppert* 
 made mention of a potash and lime skeleton, which remains 
 after the combustion of plants, and exhibits completely the 
 perfect form of the cells and of the other elementary organs. 
 This occurrence of potash and lime in the form of the ele- 
 mentary organs after their combustion, is however not at all 
 of the same character as the siliceous case, which is so very 
 striking in many land and water plants ; for if those alkalis 
 and earths are present in the interior of the elementary organs, 
 they must be precipitated, on the evaporation of the moisture, 
 upon the sides, and after the combustion retain the form of 
 the cells, spiral vessels, &c. The more accurately the cells of 
 plants are divided and purified by acids, alkalis, &c. the less 
 ashes do the membranes and fibres present after combustion, 
 as frequently repeated experiments have shown: however, even 
 if the adherent alkalis and earths are separated as far as pos- 
 sible, yet all cellular membrane, and even the extremely de- 
 licate spiral fibres, exhibit a trace of ashes, and this presents 
 itself in the form of the burnt elementary organs. Thus 
 Prof. Mitscherlich found that the delicate flax fibres which I 
 had divided and purified in every possible way produced al- 
 most one-tenth per cent of such ash, which presents itself in 
 the form of extremely fine membranes partly indicating the 
 form of the fibre. The cellular tissue of the elder pith, which 
 is more difficult to purify, as the single cells cannot be com- 
 minuted by attrition, gave a far greater quantity of ash, for 
 0*5945 parts of pith produced 0*0105 of ash. In the ashes of 
 the flax, Prof. Mitscherlich found a trace of silica and also 
 potash and lime : the ashes of the elder pith contained on the 
 contrary no silica, but much lime and traces of potash and alu- 
 mine. It may therefore be admitted now almost as certain 
 that these alkalis and earths occur in the substance of the 
 parietes of the elementary organs ; but it does not there- 
 * Poggendorff's Annalen, vol. xxxviii. p. 568. 
 
28 
 
 fore follow, as Mr. Reade supposes, that these substances 
 must be regarded as constituent parts of the elementary or- 
 gans. M. Morren many years ago (1830) suggested the sup- 
 position that silica must be considered as a constituent sub- 
 stance of the cellular membrane, but this met with no recep- 
 tion ; for it is easily conceived that the presence or absence of 
 these alkalis and earths in the membrane depends entirely on 
 the contents of the inclosed fluids. 
 
 The most important points respecting the occurrence of 
 crystals in plants may at present be considered as known. I 
 have given a very detailed account*, and M. Unger has also 
 published a memoirf on the same subject, accompanied with 
 a plate of beautiful drawings. M. Unger has confirmed the 
 statement, that the crystals are not formed in the intercel- 
 lular passages, but in the interior of the cells. I, on the other 
 hand, have observed several cases in which exceptions to 
 this rule occur. M. Unger states for instance, that the cry- 
 stalline glands, which are situated on the walls of the air- 
 cavities of Myriophyllum spicatum, are contained in distinct 
 projecting cells, and he has even figured these cellular walls ; 
 however, in all the cases which have come under my notice, 
 I have not been able, even with the most recent instru- 
 ments, to see the cellular walls which inclose the crystalline 
 glands ; this has also happened to Treviranus and Mirbel. 
 As however I can see with my instruments even the single 
 crystals of which those glands consist much more correctly 
 than M. Unger has represented them, I am inclined to think 
 that the cellular membrane figured as surrounding the cry- 
 stalline glands does not exist. 
 
 In the work above cited I have enumerated several similar 
 cases where the deposition of crystalline masses takes place at 
 the exterior of the cells, and have drawn attention to the man- 
 ner in which the formation of crystals is to be understood. In 
 some cases, as in the Charce, the crystals form externally by 
 mere precipitation of the basal carbonate of lime, the carbonic 
 acid which held these in solution being absorbed by the plant. 
 If we place Conferva in lime water, small calcareous crystals 
 
 * Neues System der Pflanzen-Physiologie, i. p. 212246. 
 f Ueber Krystallbildungen in den Pflanzenzellen. Annalen des Wiener 
 Museums, iii. p. 1. 
 
29 
 
 form on their surface, the carbonic acid being extracted from 
 the plant and combining with the lime. All the cases in 
 which it may still be doubtful whether the solitary crystals 
 are surrounded with a cellular membrane or not, have been 
 fully treated of; but it would occupy too large a space in this 
 limited report, were I to enumerate the new facts from the 
 memoirs published by me during the past year. I shall there- 
 fore only touch on my own labours of that period when the 
 facts therein contained stand in contradiction to the observa- 
 tions of others. 
 
 In M. Unger's observations on the frequency of crystals in 
 plants, he remarks, that it is not strictly determined whether 
 the age and locality of the plant contribute essentially to this, 
 although it may certainly be admitted. I think, however, that 
 physiology is at present pretty clear as to this point ; for we 
 know, that plants absorb all that the soil offers them in a 
 dissolved state, that the quantities of the various substances 
 which are absorbed bear an exact proportion to the degree of 
 solution in which these exist, and also to the quantity of the 
 solution which passes through the plants. The solid sub- 
 stances remain in the plants, for the water is evaporated ; and 
 then the various acids produced in the plants, as also those 
 which are imbibed, can carry on the process of their affinity. 
 The age of the plant, the age and vital condition of the single 
 parts, the transpiration which is different at the various parts, 
 and the degree of solubility of the substances to be crystallized, 
 are all circumstances which explain the manifold occurrence 
 of crystals in vegetables. In the cells containing oxalic acid, 
 oxalate of lime will be formed. No amylum can have ex- 
 isted if the oxalic acid was contained in the cell previous to 
 the existence of the lime, for this is converted by the slow 
 action of acids into sugar, &c. And thus might we explain the 
 remarkable phenomenon mentioned by M. Unger (1. c. p. 5.) : 
 " Amylum, green-coloured cellular sap globules, coloured cel- 
 lular sap, cells with crystals, &c., all these occur frequently in 
 single but neighbouring cells, and in the cells themselves we 
 do not see the reason of these various formations. " 
 
 M. Unger notices the difficulties which are opposed to the 
 observation of the crystalline forms, but has figured the va- 
 rious forms of the crystals contained in several plants, for in- 
 
30 
 
 stance, those of Strelitzia Regina, Papyrus antiquorum, Rheum 
 undulatum, Yucca gloriosa, Musa paradisiaca, and M. coccinea, 
 and those of Maranta zebrina, and has treated this point more 
 crystallographically. Many of these statements do not agree 
 with my observations, but a short time will prove the correct- 
 ness of the one or the other ; it appears however to me that a 
 rich field is here opened to the crystallographer, for frequently 
 the most beautiful crystals with all their variations are innu- 
 merable in the same plant. The crystals of obtuse form, which 
 M. Unger has figured from Strelitzia Regina, as well as most 
 of those in Maranta zebrina, and in the pith of the Peperomics 
 and species of Piper, consist of gypsum; in the latter plants I 
 have found tjiem along with crystals of oxalate of lime. 
 
 As an appendix to the memoir on the crystalline formations 
 of plants, M. Unger has published some notices on the milk sap 
 or vital sap vessels (proper vessels) of plants, and at the same 
 time promises on some future occasion to show how the cir- 
 culation of the sap, which takes place in these vessels, is gene- 
 rally carried on. Probably M. Unger will be able to explain 
 this phenomenon which has hitherto remained problema- 
 tical. He also thinks he has put an end by his observa- 
 tions to the dispute respecting the independence of the milk 
 sap vessels by the following statements : " The milk sap ves- 
 sels are only a portion of the vascular fasciculi (those bundles 
 of organs are here intended which in most plants become 
 lignified, and on that account are termed ligneous fasciculi) : 
 they form, it is true, one system of sap-conducting canals, 
 connected by frequent anastomosis, but nevertheless appear 
 to be more closely allied to the parenchyma than to the sy- 
 stem of vascular fasciculi." This view is said to be favoured, 
 first by the position of these vessels in the bark or medullary 
 substance,and secondly by the genesis of thevessels themselves. 
 The origin of the vessels however rests on the following obser- 
 vations : M. Unger observed in a longitudinal section from 
 the medulla of Ficus bengalensis, which is represented in fig. 1. 
 of the memoir on the crystalline formations in plants, several 
 parenchymatous cells placed perpendicularly on one another, 
 differing from the adjacent cells by their contents, which re- 
 sembled that of the other milk sap vessels. This, says M. 
 Unger, can evidently be regarded as nothing else than the 
 
31 
 
 commencement of a proper vessel, which probably in this case 
 endeavours to produce a new anastomosis between two trunks 
 having a longitudinal course, and the horizontal cellular walls 
 still appearing in the form of delicate intermediate parietes, as 
 those parts which in the further progress of development are 
 gradually obliterated. Subsequently he calls these statements 
 and suppositions a history of the development of the proper 
 vessels, and thinks that the formation of the spiral tubes is 
 exactly similar. My observations on this subject are quite op- 
 posed to the suppositions of M. Unger. In the earlier stage, 
 the walls of these vessels are not yet perceptible, and the milky 
 sap is found as it were between the cells in uninterrupted cur- 
 rents : at a later stage, the sides of these vessels gradually in- 
 crease in thickness and become more and more distinct from 
 the adjacent cellular walls ; nay, in some parts of plants, as for 
 instance, in the root, &c., they are furnished by the adjacent 
 cells with more or less strong constrictions, so that even forms 
 similar to those designated by C. H. Schultz as articulated 
 vessels arise. 
 
 ec Since these vessels," observed M. Unger, " are developed 
 from cells, the peculiarities in respect to the structure of 
 their parietes may also necessarily be applied to these vessels. 
 As we may regard the parietes as formed of two more or less 
 adherent lamellae (or, according to my opinion, as originally a 
 simple membrane gradually dividing into two lamellae), we can 
 scarcely deny to the proper vessels one constituent part of its 
 external boundary peculiar to them alone," &c. 
 
 I have in my memoir on the Secreting Organs of Plants 
 (Berlin, 1837, 4to.) and in my Vegetable Physiology (ii. p. 
 370 428), expressed myself in more distinct terms on this 
 subject ; I think that botanists must admit the peculiar pa- 
 rietes of the milk sap vessels, because they really exist in na- 
 ture, and are evident to every one who searches for them ; if, 
 however, M. Unger has not yet observed the circulation of the 
 sap in the vessels of Ficus bengalensis, he will probably notice 
 it hereafter, for it really exists. 
 
 M. Mandl* has published some results of his observations 
 on the milky sap of plants, which highly deserve the attention 
 * L'Institut de 1837, p. 127. 
 
32 
 
 of naturalists. M. Mandl fancies he has discovered that the 
 milky sap of almost all plants contains Infusoria of various 
 forms. In the Euphorbice these Infusoria are said to be highly 
 developed, but unfortunately the description indicates that 
 M. Mandl has not seen Infusoria, but those minute spiculae 
 previously discovered by Rahn *, which mostly consist of amy- 
 lum. The motions and contortions of these amylaceous spi- 
 culae which M. Mandl pretends to have seen do not however 
 exist in nature. I have recently figured the most remarkable 
 forms of these amylaceous spiculae of the Euphorbia^. 
 
 Some notices have recently been published by E. Solly, 
 jun. J on the milky sap of the cow tree of South America. 
 Gigantic cow trees were found in the neighbourhood of Ca- 
 racas, the smooth stems of which rose to the height of 60 
 feet, while the crown, 40 feet above the ground, spread forth its 
 branches, 24 feet in length, on all sides. If incisions were made 
 in the bark, down to the wood, the snowy stream flowed out 
 very rapidly, so that within a quarter of an hour a flask might 
 be completely filled. The vessels conducting this milk are 
 situated in the interior brown layer of the bark. The milk 
 from one of these trees was forwarded to England, and care- 
 fully examined by Mr. Solly ; it was however evidently spoiled, 
 and consisted of 62 parts of water and acetic acid, 30'5 ga- 
 lactin and some gum, gluten, &c. Mr. Solly has designated 
 by the name of galactin the waxy substance which is con- 
 tained in so great a quantity in the milk of the cow tree ; it 
 was regarded as common vegetable wax, but differs from bees' 
 wax in several very remarkable properties. Galactin is dis- 
 solved by cold sulphuric acid and decomposed by warm ; it 
 does not form oxalic acid with nitric acid. 
 
 M. Aug. de St. Hilaire has published an extract from M. 
 C. H. Schultz's memoir on the proper vessels, which the 
 French Academy of Sciences honoured with the prize in 1833. 
 The extract contains little more than what has previously been 
 published by M. Schultz, and as we may look forward to the 
 
 * Meyen's Report for 1835, p. 32. 
 f Pflanzen-Physiologie, ii. tab. ix. 
 
 I On the Palo de Vacca, or Cow Tree, of South America. Lond. and 
 Edinb. Philosophical Magazine, 1837, xi. p. 542. 
 Ann. des Scienc, Nat. 1837, i. p. 257. 
 
appearance of this celebrated and original memoir in the pre- 
 sent year, I consider it more advantageous to reserve my views 
 on its results for the next report. 
 
 It is well known what importance M. Schultz attaches to the 
 milky sap or proper vessels, but it is still better known that 
 other botanists do not concur in his views ; we find that the 
 most distinguished physiologists of our time have entirely con- 
 tested the most important points of these doctrines. Hitherto 
 I was the only observer who defended against unjust attacks 
 the statements respecting the circulation of the sap and the 
 existence of a distinct vascular system, as M. Schultz and se- 
 veral others had previously taught. I did not proceed further 
 into this theory of the circulation in plants, for my own ob- 
 servations differed almost constantly from those of M. Schultz. 
 Notwithstanding this general opposition of physiologists, M. 
 Schultz still asserts, that the vegetable kingdom can, properly 
 speaking, be naturally divided only in accordance with his dis- 
 coveries respecting the circulating system as laid down in his 
 system of plants. I perceive this at least from a eulogium of 
 this system, which a scholar of M. Schultz, a student from En- 
 gland, by name Ch. S n, has published under the form of 
 
 a review of Meyen's New System of Vegetable Physiology, i. 
 Berlin, 1837, in the November Number of 183? of the Jahr- 
 buchfur wissenschaftlichen Kritik. In this anonymous produc- 
 tion it is plainly stated that my system of vegetable physiology 
 does not fulfil its object, because no notice is taken of the 
 application of M. Schultz' s discoveries to the basis of a na- 
 tural system of plants. I need only remark by way of ex- 
 planatory appendix, that M. Schultz has a considerable share 
 in the editing of the above Journal. 
 
 As to the utility of a system of plants, be it founded on 
 actual or alleged anatomical or physiological discoveries, the 
 opinion of systematists alone can decide, and these (I will 
 only mention M. DeCandolle,) have declared themselves totally 
 against the system of M. Schultz. 
 
34 
 
 Anatomical Observations on the Elementary Organs of Plants. 
 
 M. Unger* has observed in the genera Helosis and Langs- 
 dorffia extremely thick-sided parenchymatous cells with large 
 and ramified dotted ducts; in Helosis brasiliensis thirteen 
 layers of such thickened cellular walls were enumerated, and 
 in Langsdorffia hypogea even to the amount of thirty layers, 
 which are traversed by dotted ducts, whose diameters mea- 
 sured between O001 7 and 0'0652 ; they are very neatly figured. 
 The ramification of such dotted ducts was however published 
 by me some time previous. M. Unger is of opinion that such 
 thick-sided cells occur in most plants, while I can find them 
 only in a proportionately very small number. Some cases 
 where these thick-walled parenchymatous cells make their 
 appearance under very remarkable circumstances, I will here 
 enumerate. I have observed t that the hard masses of the 
 so-called stories in the inside of pears consist of larger or 
 smaller aggregations of such thick-sided cells, similar to those 
 discovered by M. Mohl in Hoya carnosa. The parietes of 
 these cells increase at times so much in thickness that their 
 cavities almost entirely disappear, and the mass becomes 
 harder than horn and is indigestible. Du Hamel (Book, 
 III. cap. 2.) has already given a very diffuse but elaborate re- 
 port 011 the occurrence of stones in pears. According to him, 
 the stones are diffused through the whole substance of the 
 pear, and their presence is said not to be accidental. The oc- 
 currence of these hard masses is fully discussed by Du Hamel, 
 but in my opinion more elaborately than exhibited in nature. 
 This substance, he remarks, appears to fall into fine white 
 granules which remain somewhat transparent, so that some of 
 the vessels which ramify in them can be observed. Now these 
 fine granules are the simple cells with thickened walls, and 
 the ramified vessels present themselves under modern micro- 
 scopes in the shape of ramified canals in the substance of the 
 cellular parietes. The circumstance of the soft cellular tissue 
 around the hard masses being more or less radiately arranged, 
 is especially worthy of attention. 
 
 * Beitrage zur Kenntniss der parasitischen Gewachse. Annalen des 
 Wiener Museums, ii. p. 38. 
 
 t Neues System der Pflanzen-Physiologie. Berlin, 1837. I. S. 25. 
 
55 
 
 The septa of the parenchymatous cells of Eriophorum va- 
 ginatum in full-grown specimens are generally very thick to- 
 wards autumn, but at the extremities of the rays of this ra- 
 diate cellular tissue, which form the oblique septa in the air- 
 ducts of this plant, other distinct expansions are found, con- 
 necting the extremities of the rays* ; and a number of simple 
 and ramified dotted ducts also occur in these, by which the 
 communication in the adjacent cells is facilitated. The forms 
 of this radiate tissue, which originate from these expansions 
 of the radial extremities, are among the most interesting 
 hitherto observed. 
 
 Thickened parenchymatous cells occur even in the interior 
 of the soft substance of the petals, and they are very abun- 
 dant in dots and are frequently very irregularly formed, for 
 instance, in Magnolia grandiflora. 
 
 Similar cells with thick walls, only somewhat elongated, were 
 found by M. Unger at the margins of the ligneous bundles of 
 Helosis and Langsdorffia; he calls them prosenchymatous cells, 
 yet I think that they are only protended thick-sided cells of 
 the parenchyma, similar in every respect to those which occur 
 at the sides of the ligneous bundles of common Monocotyle- 
 dons : I do not however recognise them as cells of the liber. 
 In Langsdorffia five to eight only of such thick-sided cells are 
 united into a bundle, but in Helosis they are situated in the 
 form of a half-moon at the inner sides of the bundles, while in 
 Langsdorffia they are abundantly diffused through the entire 
 stock, both within and at the exterior of the vascular circle. 
 M. Unger supposes that for this reason a similarity in the struc- 
 ture of the stem of Helosis and Langsdorffia with that of the 
 stems of ferns may be inferred. I have also found in the stem 
 of Pandanus anastomosing ligneous bundles peculiar to these 
 parasites. 
 
 The occurrence of spiral tubes in all true parasites is at pre- 
 sent well ascertained ; and M. Unger has also convinced him- 
 self of their occurrence. The spiral tubes of the Rhizantheae 
 belong mostly to the reticulated and porous, and have short 
 articulations. 
 
 I have published a memoir on the epidermis of vegetables f, 
 
 * Neues System der Pflanzen-Physiologie, Berlin, 1837, i. p. 5. 
 t Wiegmann's Archiv, 1837, p. 211228. 
 D2 
 
36 
 
 in which I have principally brought together all that we ac- 
 tually know respecting the structure of this substance at the 
 present day. I showed that even Ludwig was acquainted 
 with the cuticle and first started this term ; that further, this 
 term must, it is true, be retained in vegetable anatomy, but 
 that the cuticle is decidedly no distinct membrane enveloping 
 the surface of the cells of the epidermis, and much less can it, 
 as M. Valentin endeavoured to demonstrate, be considered 
 as an intercellular substance. I referred to cases in which it 
 might be distinctly seen, that even the cuticle, be it ever so 
 thick, is composed of the upper sides of the cells of the epi- 
 dermis, for the lateral lines of union of those cells are seen to 
 traverse the cuticle, and indeed quite to the surface. This is 
 best seen on any well-prepared horizontal section of the 
 leaves of Aloe candicans. I have also drawn attention to an 
 aperture peculiar to the cuticle*, and which is situated imme- 
 diately above the true stomates of the epidermal glands. In 
 the genera Aloe and Agave this peculiar formation is very com- 
 mon. I call it a prostomate (Vorspalte)', between it and the 
 true stomate of the epidermal gland there exists a greater or 
 less space, which is also filled with air, and is continued through 
 the stomate into the respiratory cavity. 
 
 I also drew attention f to some peculiarities in the epidermis 
 of various Orchidea. In Pleurothallis and Stelis the epidermis 
 of the leaves exhibits peculiarly formed funnel-shaped cavities, 
 which traverse the whole layer of the cells of the epidermis, 
 and project as deep again into the subjacent cellular mass. 
 Pleurothallis and Stelis offer epidermal glands with stomata 
 only on the under surface of the leaf; these cavities, however, 
 occur on both surfaces, on the upper surface more frequently 
 than on the under. The cells, more immediately connected 
 with the formation of these cavities, mostly contain large drops 
 of oil, which are sometimes found in almost all the cells of 
 the epidermis of the upper surface of the leaf. As I imagined 
 I had observed that these cavities were not closed, but open, 
 and might thus effect a free communication between the atmo- 
 spheric air and the diachyma of the leaf, I regarded them as 
 representatives of the stomata. M. Schleiden, in the following 
 
 * Pflanzen-Physiologie, Tab. V. fig, 1. 
 f Wiegmann's Archiv, 1837, p. 421. 
 
37 
 
 number of the Archiv, which, however, appeared only this 
 year, demonstrated that most of these observations were in 
 some respects erroneous, in others incomplete. He observed 
 that the cavities were not open, but closed by a membrane 
 somewhat above their centre ; he further saw that the cells 
 of the epidermis, contiguous to the cavities, were peculiarly 
 arranged; and lastly, that the cellular parietes adjacent to the 
 cavities had a reticulate porous appearance which is repre- 
 sented in his drawings. 
 
 M. Schleiden connects these formations with the cavities 
 which originate in various plants by the falling off of the hairs, 
 with which the leaves are so frequently clothed in the bud. 
 He says that I had long since found quite similar formations 
 on the under surface of the leaves of Nymphcea odorata, but 
 the history of their development had been followed by him in 
 1833. M. Schleiden found that the leaves of Nuphar luteum, 
 so long as they remain in the bud, are clothed with long silky 
 hairs which subsequently fall off, and then exhibit open cavi- 
 ties, which have the appearance of round scattered cells. I 
 have at this moment no leaves of that plant at hand, but un- 
 fortunately this explanation of Dr. Schleiden is not applicable 
 to the leaves of the Nymphceae examined by me, as N. odorata, 
 ccerulea, alba (also the small variety). The round cells on the 
 under surface of the leaf of these Nymphaece may be observed in 
 the buds, and their outer side, somewhat vaulted, projects 
 above the surface of the epidermis ; a similarly formed cell is 
 situated immediately below each of these round tabular cells, 
 and both together have in general the same longitudinal dia- 
 meter as the adjacent cells of the epidermis. I compare these 
 round cells on the leaves of the Nymphcea with those similar 
 cells observed by me on the leaves of Zea Mays*, of Saccha- 
 rum officinale, &c., which sometimes grow into hairs, but in 
 most cases remain undeveloped. And this is undoubtedly the 
 case in the Nymphace, for some of them exhibit in their de- 
 veloped state hairy under surfaces of the leaf. 
 
 The examination of the leaves of Pleurothallis ruscifolia in 
 
 various stages of development, which I have only lately been 
 
 able to perform, taught me to correct my error, but also 
 
 showed, that M. Schleiden may in his otherwise highly valuable 
 
 * Pflanzen-Physiologie, i. Tab. V. fig. 20. 
 
38 
 
 observations commit oversights. Those peculiar formations 
 on the epidermis of the leaves of Pleurothallis, the closing of 
 which by means of a cross septum had escaped me, and had 
 thus given a false indication of their probable design, originate 
 in simple petiolated glands, which first appear as simple cells of 
 the cellular layer situated immediately beneath the epidermis. 
 The epidermis is in these cases actually broken through, even 
 the cuticle accompanies the surface of the funnel-shaped hol- 
 low, which has originated in this rupture, far down into the 
 hollow, but not to the bottom, as M. Schleiden has repre- 
 sented it. Just as in other cases similar ruptures in the cel- 
 lular layer of the epidermis are closed by epidermal glands 
 with their stomata, so in Pleurothallis the closing of these 
 funnel-shaped ruptures is accomplished by means of the sim- 
 ple glands. At its first appearance on the young leaf the 
 gland presents itself as a simple cell, which is only a little 
 longer than the vertical height of the cells of the epidermis, 
 and at the end projecting beyond the surface of the epidermis 
 is swollen into a club : its form is then similar to the gland of 
 Helleborus fcetidus. This club-shaped swelling subsequently 
 separates by the formation of a diagonal septum, which still 
 remains for some time as a vesicular cell, sometimes it is divided 
 a second time by a longitudinal partition, but subsequently 
 always falls off, upon which the peduncle remains in the 
 funnel-shaped rupture of the epidermis, and its cellular sep- 
 tum subsequently becomes intimately united with the sur- 
 rounding surface of the cuticle. Not unfrequently this cell, 
 which has served as a pedicel, divides again by the formation of 
 diagonal walls into two or even into three smaller cells, which 
 latter case however is very rare. The secretion of an oily sub- 
 stance takes place more or less abundantly in the remaining 
 pedicels, as also in the contiguous cells ; and the peculiar ar- 
 rangement of some small cells around the base of the glan- 
 dular pedicels (which always originate from the subsequent 
 separation of the larger) is similar to that which occurs at the 
 base of many hairs, where they are raised with these above the 
 surface of the plant. I also found on a very young leaf an 
 entire glandular apparatus, such as is commonly situated be- 
 tween the cells of the epidermis of Pleurothallis, projecting 
 beyond the surface of the leaf. 
 
39 
 
 M. Mohl has published a memoir on the structure of the 
 porous vessels of dicotyledons*, and I have also treated of this 
 subject in the fifth chapter of my work, but I have called these 
 porous vessels dotted spiral tubes. 
 
 M. Mohl adopts two varieties of dotted spiral tubes ; in the 
 one the walls are lined equally on both sides with dots or 
 pores, according to M. MohPs statement ; the oak, alder, &c., 
 offer examples ; while in the other variety the tubes exhibit 
 a totally different structure at various parts, as in the lime, 
 the Italian poplar, and in many other woods. In the lime, the 
 walls of these ducts, which abut on the ligneous cells, have all 
 the appearance of spiral tubes capable of unrolling, while the 
 other walls, by means of which these vessels cohere among 
 themselves, exhibit the series of dots, which are always situated 
 between two convolutions of spiral fibre. It is evident, there- 
 fore, from these observations, says M. Mohl, that the dotted 
 spiral ducts belong to the system of spiral tubes, and the most 
 essential part of their formation consists in this : that between 
 the coils of the spiral fibre there is a dilated membrane, on 
 which, between every two fibres, a series of dots is situated. 
 According to my view all the coils of spiral fibres are clothed 
 with a fine membrane, and the coils of fibre take some part in 
 the formation of the dots by reciprocal cohesion. In proof 
 that the dotted spiral tubes belong to the system of true spi- 
 ral tubes, I have mentioned a case in the stem of a gourd, 
 where at times the large spiral tubes are not metamorphosed 
 into dotted tubes, which in this plant is otherwise very fre- 
 quently the case. 
 
 M. Mohl does not consider it as improbable that the thick- 
 ening of the membrane of spiral vessels may be effected by the 
 deposition of new layers upon their inner surface, exactly as 
 with the thickening of cellular membrane ; and I have actually 
 observed this in several cases, representations of which are 
 given in my Vegetable Physiology, plate III. figs. 15 and 16. 
 
 M. Mohl and I also agree in the explanation of the struc- 
 ture of the dots, namely, that they are formed precisely in 
 the same way as the large dots of coniferous and cycadeous 
 wood ; this indeed could not but be expected with the use of 
 
 * Abhandlungen der mailiem. physik. Klasse der Akad. der Wissensch. 
 zu Munchen, 1837, i. p. 415. 
 
40 
 
 such perfect instruments ; for most of the incorrect observa- 
 tions of former times can only be ascribed to the defective mi- 
 croscopes of that period. 
 
 M. Mohl compares the development of the porous vessels 
 with that of cells, as series of thin-sided cell-like cavities con- 
 stitute their base, in which the spiral fibres are then formed. 
 M. de Mirbel had already started a similar notion, that vessels 
 are formed from cells, and the observation of the porous tubes 
 in the earliest stages of their development is said to prove this. 
 About this time the individual cells are frequently found per- 
 fectly closed, and the thin membranous diagonal partitions 
 subsequently disappear, while they remain in many cases 
 during the whole lifetime of the plant, but take a structure 
 quite different from that of the lateral partitions, which has 
 already been demonstrated in various plants. I am well ac- 
 quainted with the cases which might lead observers to the 
 above views, but I also know of numerous cases in which the 
 very opposite may be observed, where both the simple as well 
 as the metamorphosed continuous spiral tubes separate in the 
 course of development more or less completely by constric- 
 tion, and form articulations arranged in series. 
 
 The cross partitions of the single articulations of the meta- 
 morphosed spiral tubes are either broken through by a very 
 large aperture or by a number of fissures and longitudinal 
 pores : nay, even the oblique partitions of the large dotted 
 tubes in the wood of some species of Ephedra are pierced, 
 and that by the large round holes, which generally occur in 
 them arranged in two parallel rows. M. Mohl observes that 
 phytotomists have considered these horizontal sides as lateral 
 sides of the tubes, which was also probably owing to bad 
 instruments, for the inclination of these horizontal walls to 
 the lateral is so exceedingly small, that they may even be re- 
 garded as inclined terminal surfaces of the prosenchymatous 
 cells, with which the superposed cells stand in connexion ; 
 I at least have declared in favour of this latter opinion. The 
 disappearance of the horizontal walls in the dotted spiral 
 tubes is, as M. Mohl thinks, to be compared to the formation 
 of the vessels of the latex, which also are said to originate from 
 cells standing above one another, as M. Unger (see p. 30) has 
 tried to render probable by a drawing. The most varied views 
 
41 
 
 exist however on this subject, and are as diametrically op- 
 posed to one another as those on the metamorphosis of the spi- 
 ral tubes. According to M. Schultz, constrictions and the for- 
 mation of articulations of the proper vessels originate with the 
 advancing age of the plant ; in the young state these vessels 
 were still unarticulated. According to my observations, the 
 proper vessels are neither in their youth nor old age provided 
 with cross partitions, but exhibit in the latter state some con- 
 strictions which are independent of external circumstances. 
 According to M. Mohl, the continuous vessels of the latex ori- 
 ginate from cells, whose cross partitions disappear, to which, in 
 consequence of numerous researches on this subject, I am 
 decidedly opposed. 
 
 The distinction between dotted and reticulated spiral tubes 
 consists, according to M. Mohl, in this ; that in the latter the 
 organic matter used for the further development of the vessels 
 does not deposit itself in the form of a membrane between the 
 coils of the spiral fibre, but goes to increase the spiral fibre 
 itself, both with respect to its thickness as well as to its 
 breadth. In the dotted (porous) spiral ducts of dicotyledons, 
 on the contrary, this substance is deposited in the form of a 
 membrane between the coils of the spiral fibre on the original 
 membrane of the vessel. 
 
 Neither can I concur in these statements : the thickening 
 of the walls of both those stages of metamorphosis of the spiral 
 tubes takes place in quite a similar manner ; the principal 
 reason for the change into reticulated and into dotted spiral 
 tubes is to be found only in the arrangement of the individual 
 coils of the spiral fibre. If the coils are widely apart they 
 may fall merely into annular tubes or be metamorphosed into 
 reticulated spiral tubes ; on the contrary, if the coils are close 
 together, only striped and dotted spiral tubes and not reticu- 
 lated can originate. This is very easily confirmed in stems of 
 Cacti, in the inflorescence of Musa, &c. 
 
 On the occurrence of spiral fibre and of pores in the cellular 
 septa of the leaves of Sphagnum much has already been written ; 
 but, as it appears, this subject will be first cleared up in the 
 present year (1838), and that by my having now discovered 
 the cause which gave rise to the different views of various ob- 
 servers on this subject. Even many years ago there existed a 
 
42 
 
 great difference in the observations and in the views on the 
 structure of the leaves of Sphagnum ; several other botanists 
 and myself regarded the fibrous formations occurring on the 
 inner surface of the cellular walls of those plants as spiral 
 fibres, similar to those which occur in the cells of anthers ; 
 and M. Mohl, who, on the contrary, declared these spiral fibres 
 to be partial thickenings of the cellular walls, has at pre- 
 sent also adopted the former view, the correctness of which 
 can no longer be doubted. It is however very different with 
 respect to the observations on the occurrence of large round 
 apertures on the partitions of the cells in Sphagnum : Molden- 
 hauer was the first to observe them ; I denied their existence, 
 which however was again confirmed by M. Mohl. Although 
 I again took in hand my plants of Sphagnum, and observed 
 with a microscope by Ploessl, yet I could never find the al- 
 leged pores, but either perfectly symmetrical septa, as I have 
 correctly figured them in my Vegetable Physiology, i. pi. III. 
 figs. 10 and 11, or such as possessed circular, verrucous pro- 
 minences, which seen from the side projected beyond the sur- 
 face of the cells ; but seen from above, presented mere cir- 
 cles, indicating the circumference of those verrucous promi- 
 nences. These circles were regarded by Moldenhauer and 
 Mohl as open apertures, whereas I had always observed them 
 closed, even when I had coloured the cellular partitions brown 
 by means of iodine. M. Mohl * replied to these statements 
 very fully and forcibly in a separate Inaugural Dissertation, and 
 maintains the existence of pores in the septa of the cells of 
 Sphagnum-, however, as I first noticed during the past summer, 
 both conflicting parties are right and wrong. A very great 
 quantity of forms of Sphagnum, and among them principally 
 Sphagnum acutifolium, which grows about Berlin in very beau- 
 tiful specimens, exhibit quite smooth and unruptured septa, 
 and I have never found pores in them, although I have made 
 frequent observations on them. Other forms, on the contrary, 
 exhibit the verrucous circular prominences; and others, among 
 which is the common Sphagnum palustre, present large circular 
 pores in the septa, which originate in the falling off of the 
 
 * Anatomische Untersuchungen iiber die porb'sen Zellon von Sphagnum, 
 Inaug. Dissertation von Ph. Schlayer. I regard Prof. Mohl as the author 
 of this, as well as of all other dissertations occurring in this report. MEYEN. 
 
43 
 
 little warts*. An observer must be very unskilful, who having 
 such a Sphagnum before him should overlook the pores. It 
 follows from the above, that it cannot be laid down as a gene- 
 ral rule, that the septa of Sphagnum are perforated by great 
 pores, for there are some which remain to the very end of their 
 life destitute of them. 
 
 At the end of the above dissertation M. Mohl has pub- 
 lished various observations against the metamorphosis of spi- 
 ral fibre into annular fibre, a phaenomenon which he desig- 
 nates as one founded upon no fact and purely hypothetical, 
 while I have again defended this alleged hypothesis. The 
 annular spiral ducts originate only from those simple spiral 
 tubes whose sides consist of a single or of few spiral fibres ; 
 thus I observed in a common bean an annular duct, which 
 belonged to a spiral tube of two spiral fibres. In order to 
 show the improbability of this division of the spiral fibre 
 into definite portions, M. Mohl asks by w r hat force could such 
 a division of the spiral fibre be effected. However, this ques- 
 tion may easily be answered ; for can we not actually observe 
 in a thousand other cases a similar division of simple thread- 
 like formations into pieces of a like size, especially the con- 
 striction of such into articulations and sporangia? But even 
 the separation of the spiral fibre is actually to be seen in some 
 places, as for instance, in Cactus cylindricus, where the spiral 
 fibres, which there generally occur separated in rings, are very 
 large ; it is only necessary to assist here a little with the knife, 
 and the spiral fibre breaks or falls into the proper position, 
 which always corresponds to the other free extremity, so as to 
 form with this a perfectly closed ring. The reason that the 
 division of the spiral fibre does not take place under our eyes, 
 as is the case with many similar phaenomena, is evidently 
 this ; because this process happens at the very earliest forma- 
 tion of the spiral tubes, and hitherto no one has observed 
 the formation of spiral fibre. If we examine long portions of the 
 beautiful simple spiral tubes in the stem of Tradescantia and of 
 the common bean ( Vicia Faba) we observe that in the course 
 of the complete spiral tube some small places occur where the 
 spiral fibre has become converted into rings ; nay, below these 
 rings, there exist again frequently some, which still consist of 
 Pflanzen-Physiologie, ii. 52. 
 
44 
 
 two or three coils of spiral fibre ; and this very appearance 
 seems to indicate that they have been formed by dissolution 
 from the common spiral fibre. 
 
 M. Corda* has made the interesting discovery, that the 
 sporangia of the genus Trichia possess the same structure as 
 the elaters of the Jungermannia, that therefore they are elon- 
 gated cells on -whose inner side spiral fibres coil ; hitherto no 
 formations of spiral fibre were known in the fungus tribe. 
 These elaters form the hairy tissue of the genus Trichia, and 
 are situated between the rounded masses of spores. The 
 number of the spiral fibres varies in the elaters of the different 
 species of this genus ; in Tr. varia it is simple or even dou- 
 ble ; in Tr. nitens there are more than ten fibres, in Tr. 
 chrysosperma ten to eleven, in Tr.fallax and Tr. clavata six 
 to seven, in Tr. Lorinseriana and rubiformis five such fibres 
 wound spirally and parallel. The epidermis of the elater-cell 
 is simple, smooth, folded, or furnished with warts, which fre- 
 quently disappear at the ripening of the spores. 
 
 From these observations M. Corda proceeds to general con- 
 siderations on the resemblance in form of the spiral fibrous 
 cells and of the spiral vessels. Attentive observation of nature, 
 observes M. Corda, will recognize with us in the spiral fibrous 
 cell of the lower forms the rigid image of a constant and ne- 
 cessary form of organ in its higher members (the spiral vessels). 
 M. Corda found in Nepenthes destillatoria the spiral fibrous 
 cell, as such, at its highest stage of development ; it is dif- 
 fused in great quantity in the parenchyma of all parts of this 
 plant and conveys air ! This important discovery is only a 
 confirmation of the view, according to which cellular mem- 
 brane is composed of spiral fibres, in favour of which I am at 
 present acquainted with hundreds of facts. M. Corda how- 
 ever errs very much if he thinks that the short articulated 
 spiral tubes are without enveloping membrane, a subject 
 which is treated of at length in my Vegetable Physiology, i. 
 399. M. Corda once more recommences the dispute respect- 
 ing the destination of the dotted ducts, for he fancied he had 
 demonstrated, on his tour through Germany, that these ducts 
 are vessels by passing a hair through their cavities ! (?) Un- 
 
 * Ueber Spiralfaserzellen in dem Haargeflechte der Trichien. Prag. 
 1837. 
 
45 
 
 fortunately he gives no definition of vessel and cell ; were this 
 done, it would be possible to show directly, that in this case 
 it is merely a dispute about words, which I have endeavoured 
 to put an end to in my Physiology, i. p. 78, &c. 
 
 M. Biot* has coloured the flowers of white hyacinths red, 
 by absorption of the sap of Phytolacca decandra, an experi- 
 ment performed more than a hundred years ago, and which 
 since then has been frequently repeated by various observers, 
 but not always with success. 
 
 Anatomico-physiological and Chemical Researches on the 
 Colours of Vegetables. 
 
 We have also obtained in the past year very important ad- 
 ditions to the doctrine of the colours of plants. M. Mohlf has 
 especially examined in an anatomical and physiological point of 
 view, the winter colours of those plants which retain their leaves 
 during this period of the year ; he divides these plants, in re- 
 ference to the preservation of their leaves, into several, although 
 not very accurately defined, groups. In one portion of the 
 plants growing wild, or frequently cultivated in the neigh- 
 bourhood of Tubingen, all or most of the leaves developed in 
 summer pass not only through the winter, but also the follow- 
 ing or even several summers. These plants form the first 
 group, to which belong most of the Conifera, Hedera Helix, 
 Iberis sempervirens,Sempervivum, most of the species ofSedum, 
 Empetrum nigrum, Azalea, and all other plants with coriaceous 
 and evergreen leaves. 
 
 A second class of leaves, which remain green during winter, 
 is formed by those biennials, or even perennials, which have 
 rosettes formed from the so-called radicle leaves, which are 
 developed in the course of the preceding summer or autumn 
 in the plants grown from seeds, or from buds which shoot 
 out from the rhizoma. The rosettes retain their freshness 
 during the winter but die off in spring, and this takes place 
 from without inwards ; frequently the inner leaves only par- 
 tially die off. The life of these leaves extends only to the 
 next period of vegetation, and under this group are classed 
 
 * L'Institut, 1837, p. I. 
 
 f Untcrsuchungen uber die wintevliche Farbung der Blatter. An In- 
 augural Dissertation, Tubingen, 1837. 
 
4G 
 
 the species of Plantago, Dipsacus, Echium vulgare, Verbascmn 
 Lychnitis, Thapsus, nigrum, &c., many Syngenisistce and Um- 
 bellifera, species of Lychnis and Potentilla, Fragaria vesca, 
 &c. 
 
 The third class contains partly annuals, which have germi- 
 nated in autumn, but flower in the following spring, and partly 
 perennials, which have developed new branches in autumn. 
 They differ from the plants of the second group, properly 
 speaking, only in this respect, that their leaves form no ro- 
 settes spread out on the soil, but have a longer stem which is 
 covered with leaves in every stage of development. Un- 
 der this section M. Mohl includes a great portion of the 
 grasses, for instance, Bromus mollis, many Euphorbice, Vero- 
 nica, Antirrhinum majus, Cerinthe minor, Senecio vulgaris, 
 Sonchus oleraceus, Hypericum perforatum, &c. The leaves of 
 these plants live very rarely through a whole year. 
 
 The first question M. Mohl endeavours to solve is, whether 
 the red colouring of the leaves in winter is a phenomenon in- 
 dependent of the autumnal colouring of dying leaves, and of 
 the red colouring of leaves in the process of development, or 
 whether it must not rather be ascribed at times to the one, at 
 times to the other of these causes ? A number of plants are 
 enumerated whose leaves are perfectly green in summer, but 
 during winter assume a more or less deep red tint and in sum- 
 mer again become green, which for instance may be observed 
 in various species of Sedum, Sempervivum, and also on the ivy. 
 In the leaves of the second and third divisions we must 
 ascribe the origin of the red colour to the influence of the win- 
 ter cold, as here the leaves in all stages of development take 
 this reddish or brownish tint. As, however, we find, says M. 
 Mohl, on the same plants, leaves which have this red colour 
 in the winter but die in the spring, while other leaves become 
 red-coloured in the same way, and do not die in the spring 
 but again become green and continue to grow, &c., we are 
 justified in denying this connexion between the production of 
 a red colour and the dying off of the leaves, and must admit 
 that the production of the red colour in leaves in autumn and 
 in winter is owing to a change in the physiological functions 
 of the leaves occurring at this season, but that the falling off 
 of the leaves is only accidentally contemporaneous with that 
 
47 
 
 period, while in others it takes place many months afterwards. 
 The red colour is generally produced by the perforations of 
 insects and by the development of Entophyta, where the leaf 
 merely suffers an interruption in its normal development, but 
 which is not accompanied with death. 
 
 M. Mohl, on the other hand, points to a resemblance which 
 appears to exist between the production of the red colour in 
 leaves and that in fruits ; this might perhaps be compared 
 with the process of ripening of the juicy envelope of fruits. 
 M. M ohl supposes that the formation of red colour in fruits is 
 independent of nutrition, as fruits even ripen when separated 
 from the plant in an immature state : much however might 
 be adduced against the adoption of this view, and I cannot 
 concur in it. 
 
 In leaves, it is the cold, observes M. Mohl, which interrupts 
 their vegetative process, and causes, when light acts on the 
 leaves, red colour to be formed in them. In pericarps, the de- 
 velopment of which is a more complicated process, it is the 
 warmth which favours the perfect development, arid thus 
 hastens the last period of life. As the result of these observa- 
 tions it may be admitted that the formation of colours accom- 
 panies various interruptions of the normal process of vegeta- 
 tion of the leaves and of their elaboration of the crude sap ; 
 on the other hand it must be considered as merely accidental 
 that it occurs in those cases in organs near death, since it hap- 
 pens, as I have stated above, frequently in leaves which con- 
 tinue to live for some time and again become green. 
 
 If leaves which have become red in winter be examined, we 
 find the chlorophylle little or not at all changed, but perceive 
 together with this a red colour in the cells, which, for the 
 most part, is situated in the cells of the epidermis. I have 
 however frequently observed red -coloured cellular sap con- 
 taining green-coloured globules, even in the green cortical 
 layer. It is more seldom that red cellular sap is developed 
 only in the outer layers of the diachyma of leaves ; in this case 
 also, says M. Mohl, it is found in leaves which recommence 
 their vegetation in spring more confined to the outer cells, as 
 in Chelidonium majus, Hedera Helix, &c., while in leaves which 
 die off in spring the formation of colour affects nearly all the 
 cells of the diachyma, as in Isatis tinctoria. 
 
48 
 
 M. Mohl justly doubts, on second thoughts, whether the 
 origin of the red cellular sap*can be explained in the cases 
 above-mentioned by a dissolution and change of the chloro- 
 phylle, as the green globules of the sap occur in the red sap 
 as beautifully coloured as in general. 
 
 M. Berzelius * has examined the autumnal colour of plants 
 in a chemical point of view ; he only observed red leaves in 
 trees and shrubs whose fruits are red. However this does not 
 stand good for the whole vegetable kingdom, for M. Mohl and 
 many others have mentioned various plants in which red 
 leaves occur with fruits of a different colour. M. Berzelius 
 examined the foliage of the cherry tree, and especially that of 
 the red currant, which frequently appears as red as the ripe 
 berries. The colouring matter was extracted with alcohol, 
 which after distillation left behind a red fluid, that had first to 
 be filtered from the precipitated resins and fats. The colour- 
 ing matter is soluble in water, and agrees therefore probably 
 with the red substance which M. Marquart extracted from red 
 flowers, and declared to be an acidulated anthocyan. M. Ber- 
 zelius terms this red colouring substance Erythrophylle, Leaf- 
 red, and is opposed to the view of this red colour being only 
 an acidulated blue ; he found it however in the fruits of the 
 cherry tree and black currant, so that it is evidently closely 
 related to Marquart^s acidulated anthocyan. 
 
 Of considerable interest are M. Berzelius' s observations on 
 the yellow colour of leaves in autumn; this substance does not 
 coincide with Marquart's anthoxanthin, but is a peculiar fat, 
 an intermediate body between fat oils and resins, which re- 
 taining its property of being of difficult solution in alcohol, and 
 smeary and greasy, may be bleached. He calls this substance 
 Xanthophylle, Leaf-yellow, and prepared it by cold infusion 
 of the yellow leaves in strong alcohol, continued for forty- 
 eight hours. When the infusion is evaporated to less than 
 one-eighth of the quantity, a granular substance settles on cool- 
 ing, and by continued distillation a yellow soft smeary sub- 
 stance is obtained, which, like the granules above-mentioned, 
 presents the colouring substance of the yellow leaves. The 
 
 * Ueber die gelbe Farbe der Blatter im Herbste und iiber den rothen 
 Farbestoff der Beeren und Blatter im Herbste. Ann. der Pharmacie, vol. 
 xxi. p. 257264. 
 
49 
 
 solution of this substance in alcohol is so precipitated by water 
 that a pale yellow milk is formed. Xanthophylle is dissolved 
 by aether and becomes brown in concentrated sulphuric acid. 
 Respecting the formation of the xanthophylle from chloro- 
 phylle M. Berzelius observes, " We have every reason to sus- 
 pect, that with the disappearance of the green colour and its 
 change into yellow, the xanthophylle is produced from the 
 chlorophylle by a change of the organization of the leaf ef- 
 fected by cold, and the alteration in the organic process thus 
 caused." It was not possible to produce this change artificially. 
 
 The brown colour of the foliage has nothing, says M. Ber- 
 zelius, in common with the yellow ; it is produced by an ex- 
 tract at first colourless, which becomes brown by the action 
 of oxygen ; yet it may also be observed in this latter case, that 
 all the cellular membrane of the leaf has acquired a brown 
 colour which cannot be extracted even by digestion in weak 
 alkaline solutions. The various proportions in which this brown 
 extract occurs with the xanthophylle give the autumnal co- 
 lours of the leaves a number of tints. 
 
 Notwithstanding all the beautiful researches which have 
 been made of late years on the formation of colours in plants, 
 both in anatomical as well as chemical respects, we are yet very 
 far from the solution of this enigma, as we shall perceive im- 
 mediately from the following observations. 
 
 M. J. Decaisne* has published a very elaborate examina- 
 tion of Rubia tinctorum, and allied species, which are cul- 
 tivated for the purpose of obtaining the madder or red colour. 
 I shall have occasion to notice this work frequently, but shall 
 here only mention those observations which relate to the for- 
 mation of the well-known colouring matter of these plants. 
 
 M. Decaisne is convinced from numerous observations that 
 the colouring substance in Rubia tinctorum, and in general in 
 the Rubiacece, does not occur in peculiar vessels or secretory 
 organs, but in the interior of the elementary organs. It is 
 usual to employ only the root in the preparation of the colour- 
 ing substance, in which it occurs in great abundance ; if how- 
 
 * Recherches anatomiques et physiologiques sur la Garance, sur le de*- 
 veloppement de la matiere colorante dans cette plante, sur sa culture et sa 
 preparation, suivies de 1'examen botanique du genre Rubia et de ses especes. 
 Bruxelles, 1837, 4to. avec 10 pi. 
 
 E 
 
50 
 
 ever the stem of full-grown plants be examined, larger or 
 smaller spots are here and there found, where the cells and 
 spiral vessels are filled with it. 
 
 In the living root of the Madder only yellow colouring mat- 
 ter is observed, which fills in its dissolved state the various 
 elementary organs. In very young roots the colour is still 
 weak, but the older the plant the more intense it is. Here 
 therefore the yellow colouring matter is dissolved in the cel- 
 lular sap, an observation which I made some years ago in a 
 different plant in its young state. This yellow substance is 
 evidently of quite a distinct nature from Marquart's anthox- 
 anthin, which is mostly a resinous extractive of very difficult 
 solution. As soon as the yellow sap of the Madder root comes 
 in contact with the atmosphere it takes a red colour, and a 
 granular substance forms in this red sap. Even the cotyle- 
 dons, as soon as the young plant has come forth, contain in 
 their cellular tissue a yellow sap, which, on their being cut, 
 very soon took a deep red appearance. This change of the 
 yellow cellular sap, in fine sections placed under the micro- 
 scope for observation, M. Decaisne has elucidated by a num- 
 ber of drawings. The cells are seen with fainter or deeper 
 yellow saps, and in other cells this sap has taken a faint rosy 
 tint, while frequently some of the intermediate cells are still 
 quite yellow ; at other places the red sap has already become 
 deeper, and has formed a granular precipitate in the cells. 
 When recent roots of the Rubia were perfectly dried and then 
 microscopically examined, he observed that, although all 
 moisture had disappeared, the cells still exhibited a yellow 
 colour ; whence he concluded, that the colouring substance is 
 a solid, which was previously in a dissolved state in the sap, 
 yet he could not observe it as a distinct body. I have not, 
 it is true, examined the roots of the Rubia, but in the yellow- 
 coloured cells of the stalk the same may be observed ; and here 
 the yellow colouring substance, after the water of the sap has 
 been evaporated, is partly absorbed by the sides, while the re- 
 maining portion rests on their surface. 
 
 M. Decaisne also performed various experiments in order 
 to learn more accurately the causes which changed the yellow 
 sap of the fresh RubitE, as soon as it came in contact with at- 
 mospheric air, into red. He placed fine sections of the root in 
 
51 
 
 boiled water, and observed that they retained their yellow 
 colour in perfectly closed vessels. Other sections were then 
 exposed to the direct influence of various gases and isolated 
 under quicksilver : the result of these experiments was, that 
 oxygen and some degree of moisture must be looked upon as 
 the causes producing the change of the yellow substance into 
 red ; oxygen alone, i. e. without moisture, produced no change 
 in the colour. The red colour of the Madder is therefore, as 
 M. Decaisne observes, a chemical product, entirely independ- 
 ent of the vitality of the plant, to which, however, belongs the 
 formation of the yellow sap. It results at least from these in- 
 teresting observations, that our knowledge of the bases of ve- 
 getable colours is not yet very far advanced. We have in this 
 case an instance of the transition of a perfect yellow colour 
 into the most beautiful red, and this produced by the influ- 
 ence of oxygen and the presence of water. 
 
 The roots of young madder plants afford but little colouring 
 matter; from the age of eighteen months they may be used with 
 advantage, but their colouring substance keeps on increasing 
 to an age of three years. 
 
 M. Decaisne also performed a series of experiments to in- 
 vestigate the influence of light on the production of the colour- 
 ing substance in madder plants ; for this purpose he grew 
 young plants exposed to various degrees of light. They were 
 placed in glass cases which were covered with cotton, others 
 in coloured glasses, as under red, yellow, or green glass. 
 Another plant was grown under white glass ; a third remained 
 exposed to the open air, and a fourth was buried in the earth 
 and covered to the height of 3 feet with loose soil. The plants 
 which had been covered with cotton had in eight days lost so 
 much of their colour as to appear quite pale ; the plants under 
 red glass exhibited this change of colour in a still greater de- 
 gree, and those under other glass were in a similar condition. 
 In general, these experiments on the growth of plants under 
 coloured glasses afforded as few results as those enumerated 
 in my first year's report (1835). According to Osann's obser- 
 vations, only 34 rays of light pass through red glass, while 
 966 are held back ; light green glass transmits 630 and re- 
 tains 340. We hence see how varied is the quantity of light 
 which arrives at the plants grown under such coloured glasses ; 
 
 E 2 
 
52 
 
 but we already know from other experiments by Alex. v. 
 Humboldt, DeCandolle, and others, what a small quantity 
 of light plants absolutely require, and that the formation of 
 vegetable colours does not proceed from the direct influence 
 of light. 
 
 The plant, which had been grown under ground, exhibited 
 a change of the yellow colouring substance, namely, of the sap 
 globules coloured by chlorophylle into the yellow colour, which 
 was dissolved in the cellular sap ; M. Decaisne has even ob- 
 served this change of the chlorophylle at various periods, and 
 has thus been enabled to follow it up more accurately ; he has 
 also elucidated these observations by several highly instructive 
 coloured illustrations. I have observed this change of the 
 chlorophylle into a yellow colouring substance, soluble in the 
 cellular sap, in young plants of Vicia Faba, which had been 
 grown immediately on their appearance in a dark situation ; 
 at the same time cells with red coloured sap also occurred. 
 All these colours disappear if the plants are exposed for some 
 time to light. 
 
 We have finally to notice M. Mohl's * observations on the 
 occurrence of chlorophylle in the green coloured cellular sap 
 globules, a subject which is for the first time specially men- 
 tioned in this memoir. About the same time a separate section 
 of my Vegetable Physiology (i. p. 200) was devoted to the same 
 subject : "Occurrence of coloured cellular-sap globules." The 
 results of these observations are as follows : M. Mohl and I 
 agree that the chlorophyUe appears in the cells of plants partly 
 in an amorphous and partly in a granular form. This and 
 other facts respecting this questionable subject were pub- 
 lished by me some years agof to refute Treviranus' view, 
 that the cellular sap is never of a green colour, which is now 
 confirmed by M. Mohl. The occurrence of amorphous chlo- 
 rophylle in the cells of Conferva is noticed by Mohl, and a 
 number of perfect plants are enumerated in which amorphous 
 chlorophylle occurs together with granular in the cells. In 
 Phanerogamae, observes M. Mohl, amorphous chlorophylle 
 is generally met along with granular chlorophylle in the 
 
 * Untersuchungen liber die anatomischen Verhaltnisse des Chlorophyll's. 
 An Inaugural Dissertation. May 1837, Tubingen. 
 
 t Year's Report for 1 835. Wiegmann's Archiv., part III. 1836, p. 90. 
 
53 
 
 same cells, forming an appendix to the granules, or greater 
 masses, presenting an amorphous gelatine in which the chloro- 
 phylle granules are immersed, &c. These various forms are 
 found for instance in the parenchymatous cells of leaves of 
 many cellular plants, as in Sedum, SempervivumjPinusStrobus, 
 &c. I showed * that these amorphous masses are spread over 
 the inner walls of the cells, and are frequently accompanied 
 with common green globules. In the cells of the vertical layer 
 of leaves this occurrence of amorphous chlorophylle is espe- 
 cially common, so that, for instance in the Cycadece, the entire 
 walls of these cells are at times clothed with it. 
 
 M. Mohl attempts to fix distinctions between the granules, 
 which lie in the chlorophylle and the chlorophylle granules 
 themselves, although it appears probable to him that they 
 stand in very close connexion with each other. Here my ob- 
 servations do not agree with those of M. Mohl ; for the chloro- 
 phylle is properly speaking neither granular nor amorphous, 
 but it adheres in the granules to a semi-solid mass which is 
 penetrated by it, and the amorphous chlorophylle is conse- 
 quently a gelatinous semi-fluid mass more or less coloured by 
 chlorophylle. Of what this gelatinous substance, the basis of 
 the amorphous chlorophylle, consists, it is difficult to deter- 
 mine, the quantity at the disposal of the operator being too 
 small. The case is quite different with the substance serving 
 as substratum to the granules coloured by the chlorophylle, 
 which M. Mohl erroneously terms chlorophylle granules. 
 Both M. Mohl and Dr. Schleiden f endeavour to prove in op- 
 position to my views that they are not granules, but solid 
 masses, which however I published two years ago {. 
 
 The case of granular masses being mistaken for vesicles 
 occurred very frequently, even till within a few years, and the 
 microscope alone was the cause, showing in some similar glo- 
 bules so strong a shadow round the object, as to lead to the 
 conclusion of the presence of a distinct enveloping membrane, 
 which even occurred to M. Mohl at that period respecting the 
 amylum granules. 
 
 We come now to the most important subject treated of in 
 
 * Physiologic, i. p. 202. 
 
 f Beitrage zur Keimtniss der Ceratophylleen. Linnaea, 1837, p. 331. 
 
 : Year's Report for 1835. Wiegtnann's Archiv., 1836, p. 90, &c. 
 
54 
 
 M. Mohl's memoir. He observed, in Char a flexilis, from 
 one to four well-defined granules situated in the interior of 
 each of the green globules which clothe the inner surface of 
 the cells, and which were coloured blue by iodine, and con- 
 sequently consisted of amylum ; the surrounding green enve- 
 lope became on the contrary brown. This fact I confirmed, 
 having observed it accidentally during the past year on Char a 
 flexilis, and indeed on cells that were in a state of decomposi- 
 tion ; but I also found that it is very variously circumstanced 
 in different individuals, not only in C. vulgaris, but also in 
 Charce with simple cuticle, which had grown for years in my 
 room. In most cases the green cellular sap globules were co- 
 loured brownish by iodine, especially in the young thriving 
 branches ; in other individuals, and even in single cells, there 
 might frequently be seen a very regular division of these green 
 elliptic granules into two or three smaller ones and of a rounder 
 form ; the green enveloping mass, of which at first the whole 
 consisted, at the same time gradually disappeared, and it was 
 now evident that the newly originated globules were coloured 
 blue by iodine. Although I constantly grow Charce in my 
 room, yet I have never been able to discover the causes by 
 which the formation of the amylum granules in the green glo- 
 bules which clothe the inner surfaces of the cells of the Charce, 
 is effected ; in Chara vulgaris it might frequently be observed 
 in old cells growing in the dark, where the outer cellular layer 
 had separated by decomposition from the membrane. We 
 however know that new branches are developed from the axes 
 of such old plants though the individual continues to live ; it 
 therefore appears to me that the occurrence of the amylum in 
 such cells is destined for the nutrition of the young plants ; 
 but in no way can it be laid down as a general rule, that the 
 green cellular sap globules of the Charce have amylum gra- 
 nules for nuclei. I can at any time show Charce whose green 
 globules indicate not a trace of amylum. 
 
 M. Mohl also found that the larger green globules which 
 so frequently occur in various Conferva, contain a nucleus 
 which is coloured blue by iodine ; but neither is this found at 
 all times in Confervce, as I have shown by repeated observa- 
 tions*. M. Mohl's further observations go to prove the oc- 
 
 * Note. Amylum is also present at times in the Closlerice under similar 
 
55 
 
 currence of amylum even in the green globules of the more 
 highly developed plants, which is very easy in many water 
 plants and also in some succulent land plants; it was observed 
 in Tradescantia discolor and in Vallisneria spiralis, where each 
 globule exhibits a large amylum nucleus. Dr. Schleiden (1. c. 
 p. 531.) observed the sap globules of Ceratophyllum, and states 
 that they consist of amylum surrounded by chlorophylle. Si- 
 milar observations were made and published by me eleven 
 years ago on Vallisneria, and three years back on Trades- 
 cantia, Zanichellia 3 &c., but explained in a different manner, 
 and as it appears more correctly ; I observed that the amylum 
 granules in Vallisneria and in the other plants mentioned, 
 where they occur in the cells situated near the surface, were 
 coloured by chlorophylle, and this metamorphosis of amylum 
 into chlorophylle begins at the surface and increases the more 
 the globules are exposed to the influence of light, or in fact to 
 the influence of a more powerful process of carbonization. 
 This is the case with the occurrence of amylum granules in the 
 so-called chlorophylle globules, which in nature do not exist ; 
 as Dr. Schleiden also very correctly observes, that chlorophylle 
 is always an homogeneous, amorphous, waxy substance, but 
 I can certainly not agree with his subsequent statement that 
 it is spread over the amylum granules and cellular partitions. 
 Chlorophylle, this waxy substance, is formed by the plant in 
 very different ways, sometimes of amylum, at others of semi- 
 fluid, slimy substances, which are produced in the cellular 
 sap, at times of those more solid substances which most ge- 
 nerally constitute the base of the green sap globules, and which 
 assume a brownish tint with iodine, and as I suspect, consist 
 of coagulated nitrogenous nutritive substances. These sub- 
 strata are also formed in those cases w r here the development 
 of chlorophylle is suppressed, but they themselves are subject 
 under such circumstances to be dissolved and converted into 
 other substances. 
 
 M.Mohl also found similar chlorophylle globules containing 
 amylum which becomes blue by iodine in separate portions of 
 many plants, for instance, in the cells of the cuticular glands 
 
 conditions, in which I have several times coloured the larger green glo- 
 bules, as well as all the smaller with which the Closterium was filled, blue or 
 violet-blue, by means of iodine. Rep. 
 
56 
 
 (termed by him porous cells), in the cells of the epidermis of 
 Aspidium exaltatum, of Calla athiopica, in the diachyma of 
 Abies pectinata, Pinus alba. Camellia japonica, &c., and I have 
 observed them in the elementary organs of the medullary 
 sheath and in the cells of the medullary rays of various trees 
 and climbers*. 
 
 A second variety of chlorophylle globule, immediately con- 
 nected with the form just described, possesses, says M. Mohl, 
 sharply defined outlines in common with the preceding, but 
 is distinguished from it by each chlorophylle grain containing 
 several amylum granules. The envelope of these granules 
 appears sometimes smooth-edged and sometimes crenulate 
 when it adheres to the circumference of the individual amy- 
 lum granules. Similar grains are met with in the diachyma 
 of Aspidium exaltatum, Sempervivum tectorum, and in the 
 cells of the pith of Stapelia maculosa, &c. 
 
 Another form of the chlorophylle grain incloses several, 
 but very minute globules of amylum, the blue colour of which 
 on their combination with iodine is not easily perceived, the 
 embrowned coating of the chlorophylle being too thick. Such 
 chlorophylle grains are found, says M. Mohl, between those of 
 the former form passing into them through several interme- 
 diate stages, for instance, in the leaf-petioles of Pothos lanceo- 
 lata, and sometimes in other cellular layers, as in Orontium 
 japonicum, Sedum anglicum, &c. 
 
 The latter form constitutes those which are generally rather 
 large, but less sharply defined than those described : under a 
 high magnifying power a number of very minute particles 
 may be discerned in them, which are coloured by iodine of a 
 deep brownish-yellow. Nevertheless, M. Mohl thinks that 
 these minute granules also consist of amylum, in which opi- 
 nion however I cannot agree ; for after previous extraction of 
 the chlorophylle with aether a yellowish white mass remains, 
 which is coloured brown by iodine, and the cellular sap glo- 
 bules coloured by chlorophylle occur in most plants in this 
 form. 
 
 M. Mohl now starts the question, whether the amylum gra- 
 nules are formed first and the coating subsequently deposited 
 around them, or whether the chlorophylle is first formed and 
 * Physiologic, i. p. 372, &c. 
 
57 
 
 the granules subsequently originate in it. M. Mohl decides 
 the question in accordance with his observations of nature ; 
 in some cases the chlorophylle is first formed, and the amy- 
 lum granules subsequently developed, as for instance, in the 
 Spirogyrce, Link, and in the Chara, as I have previously men- 
 tioned ; but in other cases the amylum is found first, and then 
 the formation of the chlorophylle takes place. The third case, 
 and which is the most frequent, M. Mohl has not noticed, 
 where the formation of the chlorophylle stands neither pre- 
 viously nor subsequently in connexion with the formation of 
 amylum, where it has for substratum a semi-solid yellowish- 
 white substance which is coloured brown by iodine. 
 
 But even in the Conferva and in the Spirogyrce it may pretty 
 generally be stated that the formation of the chlorophylle pro- 
 ceeds from the amylum ; for it is the amylum granules which 
 are dissolved at the formation of the seed in the Spirogyrte, 
 unite with the green mass present, and produce the substance 
 for the formation of the two membranes which surround each 
 seminal grain of these plants ; they then again condense, and 
 adopt even in the seed a spiral position at the germination of 
 the young plant which proceeds from a prolongation of the 
 third or innermost membrane, but are again employed to pro- 
 duce the substance for the formation of amorphous masses 
 coloured by chlorophylle. What is the physiological object 
 which nature probably attains by this disposition of amylum 
 in leaves ? M. Mohl is rather inclined to answer, that it is a 
 reserved nutriment destined to be employed in those plants 
 which flower but once for the development of the fruit ; and in 
 the perennials, plants losing their leaves in autumn, is carried 
 into the stem and there deposited as material (?) at the expense 
 of which the buds are said to develop in the succeeding spring. 
 
 M. Payen* has prepared lichen starch from Icelandic moss, 
 and after having dried it at a temperature of 100 subjected 
 it to an elementary analysis, which gave C 12 , H 10 , O 5 , a com- 
 position very approximate to the amylum of the higher plants. 
 Great difference in the composition of amylum and moss- 
 amylum was not to be expected ; it was however hitherto ge- 
 nerally supposed that the latter was coloured yellowish-brown, 
 the former blue by iodine ; I have however frequently found 
 * L'lnslitut de 1837, p. 128. 
 
58 
 
 that the amylum in fresh Lichens was coloured blue by iodine, 
 and in fact lichen-amylum does not exist in the form of glo- 
 bules in Lichens, but forms the membranes and the contents 
 of their elementary organs. 
 
 In a subsequent note* read by M. Payen before the So- 
 ciete Philomatique, he observes that he had been able to see 
 with the microscope the amylum of the Iceland moss united in 
 small balls ; M. Payen however did not notice that the septa 
 of the cells of those plants are also coloured blue by iodine. 
 
 Monographic revisions of various Families of Plants in a 
 Physiological point of view. 
 
 From M. Ungerf we have received a very excellent work 
 on parasitic plants, which especially treats very fully of the 
 inrooting of the parasites on the stock plants. The inquiry 
 relates to parasites, which are independent and individualized 
 plants, which although not independent of other plants at 
 their origin, are nevertheless so in the duration of their life, 
 and in which they are, as it were grafted, and from which they 
 almost exclusively derive their nourishment. From this pe- 
 culiar vital process, more than from their form and their struc- 
 ture, these plants are united into a distinct group. A want of 
 roots or root-like organs is peculiar in a higher or lower de- 
 gree to all parasites, and M. Unger observes, that although 
 we find in some of the more perfectly developed species a true 
 rhizoma, nay, even ramified roots, this indicates far more the 
 evident general tendency of nature to attempt variations of 
 formation in every possible manner, within the limits of cer- 
 tain vital laws, than a deviation from the general rule. 
 
 The vast abundance of materials at M. Unger's disposal in- 
 duced him to form a division of the parasitical plants into va- 
 rious groups, founded on the mode of connexion existing be- 
 tween the parasite and its stock. Nine such groups are esta- 
 blished, the genera forming them enumerated, and their in- 
 rooting in the stock plants more or less completely described. 
 The following are the groups. 
 
 1. The parasite originates immediately upon the wood of 
 
 L'Institut de 1837, p. 145. 
 
 f Annalen des Wiener Museums, vol. ii. p. I. 
 
59 
 
 its supporter, and anastomoses by its vascular system with the 
 vascular system of the nourishing plant. To this section be- 
 long Rafflesia, Brugmansia, Pilostyles, Apodanthes, Cytinus ? \ 
 
 2. The parasite endeavours to form a kind of rhizoma, by 
 which it suspends itself to the stock, and from which it sends 
 forth several floriferous branches, for instance, Hydnora, Scy- 
 balium. 
 
 3. By an increased reaction (founded probably on the 
 mode of germination), a portion of the vascular system of 
 the nourishing plant is received in the rhizoma of the pa- 
 rasite, and a body formed which belongs to both plants. 
 Under this section are classed the genera Balanophora, Cy- 
 nopsole, Sarcoptyte, Cynomorium, Lophophytum (?), Ombro- 
 phytum (?). 
 
 4. The parasite forms a rhizoma, the fibres of which ad- 
 here to the stock plant : for instance, Helosis, Langsdorffia. 
 
 5. No rhizoma but branched roots which are connected 
 with the stock plant by suckers, as Lathrcsa. 
 
 6. Ingrafting of the parasite, as in the first group, but 
 having roots which are sometimes provided with tubercles, 
 sometimes have none. To this section belong the genera Oro- 
 banche, Phelipaa, Conopholis, Hyobanche, Epiphegus, jEginetia, 
 Obolaria. 
 
 7- The roots of the parasite are intermatted with the roots 
 of the stock plant into a kind of tuberose mat. Monotropa and 
 Corallophyllum. 
 
 8. The parasite is developed somewhat independently, only 
 intromitting here and there from the stem fleshy tubercles into 
 the stock plant, as in Cuscuta and Cassytha. 
 
 9. Highly ramified roots which at times pass under the 
 bark of the supporters, and are, as it were, infiltrated into 
 them. Viscum, Loranthus, and Myzodendron. 
 
 In forming this arrangement, M. Unger thinks that he has 
 established a law, according to which the lower or higher 
 developed nature of the parasite constantly rises to greater in- 
 dependency and freedom parallel with the successive series of 
 its independent relations in the inrooting. 
 
 He also divides the so-called false parasites with regard to 
 their connexion with the soil into various groups. To the first 
 
60 
 
 belong Hedera Helix, Ampelopsis quinquefolia, Bignonia radi- 
 cans, &c. These plants attach themselves by means of small 
 crampons to neighbouring objects without deriving their nou- 
 rishment from them. Similar crampons (Haftwurzeln) are also 
 observed in some semi-parasitical plants, as in Cuscuta and 
 Cassytha ; M. linger even believes that the tubercles in La- 
 thraa, Orobanche, &c., should be regarded as such formations, 
 in which view I cannot concur. 
 
 Under the second group of false parasites are classed Bro- 
 melia, TillandsicB, Epidendra, and other Orchidea, as also 
 Mosses and Lichens : the roots of these plants, in so far as 
 they possess such, are capable of vegetating only in vegetable 
 mould, or in the continually decaying outer bark of woody 
 plants. In the third group of false parasites, in which the last 
 state of limitation is found, are enumerated the twiners. 
 
 The grouping of the true parasites above-mentioned, ac- 
 cording to M. Unger, appears to me to be too much subdi- 
 vided; I for instance, should combine the three first groups, and 
 propose various other modifications. I can in this place how- 
 ever only mention the most prominent points of the new ob- 
 servations on which M. Unger establishes his divisions. In 
 the history of the development of the parasites of the first 
 group, Dr. Blume's observations on the germination of Brug- 
 mansia are related, but it appears to me as if these observations 
 were made subsequently to the time when Dr. Blume sent me 
 a bud of Brugmansia for examination. M. Unger thinks that 
 R. Brown's notion of an intermediate production derived from 
 the root of the Cissus on which Rafflesia Arnoldi is situated is 
 erroneous ; the error however is on the other side. In the 
 Brugmansia, which is fixed on the root of Cissus tuberculatus, 
 I found this intermediate body, which had entirely proceeded 
 from the substance of the root, of very considerable size, just 
 as I have figured it from a cross section in the Flora Javae, Tab. 
 VI. fig. 1. This intermediate body forms with its parenchy- 
 matous margins a cup in which the opened flower is seated as 
 in a calyx. Hence it follows that at least the first two groups 
 should be united. Whether the intermediate body is somewhat 
 larger or smaller does not signify at present. 
 
 No rhizoma exists in Lathraa, but a highly ramified root 
 
61 
 
 which is connected with the stock plant by tubercles. M. 
 Unger intends to publish his observations on this subject in 
 a separate memoir. 
 
 Highly interesting is the peculiar connexion existing be- 
 tween the roots of Monotropa hypopithys and the roots of the 
 stock plant (Pinus Abies, L.). According to M. Unger's dis- 
 covery, it is a rhizoma-like, tuberose, irregular body, from 
 which the inflorescence of the plant proceeds, and this body 
 consists of a convolution of intimately matted fibrils which 
 belong partly to the parasite and partly to the stock. This 
 root mat is externally somewhat loosely penetrated by earthy 
 masses, but towards the centre increases so much in closeness 
 of texture, that the masses almost entirely disappear, and 
 nothing is left but a tissue of roots which cannot be unra- 
 velled. The contact of the two roots, easily distinguished 
 from each other by form, colour, and consistency, is very in- 
 timate, although no tubercles or similar organs exist, by 
 which a direct union, an interpenetration of both, might be 
 effected. The parasite is therefore nourished in this case by 
 the exudation of the spongioles of the root. It must not be 
 thought that this nourishment consists in the excrements 
 of the roots, for I think I have proved that these supposed 
 excrements are precisely in the same situation as the whole 
 doctrine of spongioles of the root and tuberosities, of which 
 nothing exists in nature. 
 
 M. Unger has also published some very interesting obser- 
 vations on the growth of the Cuscuta. These plants are easily 
 raised if their seeds be sown among green plants already 
 developed. During the first period the young plant daily 
 lengthens about an inch, the original embryo becoming dry up 
 to that point of the stem where the first tubercle makes its 
 appearance. The young germs w r ould not succeed on the green 
 leaves of Sedum album, although the tubercles of the Cuscuta 
 had already become fixed to them. A young Cuscuta with 
 its stock was placed under a glass and kept moist by the va- 
 pour of the water : during three days it increased in size, then 
 made 1 coil round itself and produced tubercles at this very 
 place. The lower part of the plant now ceased to grow, while 
 the tubercles penetrated of themselves into the substance at the 
 entwined spots. M. Unger observed the metamorphosis of an 
 
62 
 
 original tubercle into a shoot. He also made some observations 
 on the germination and the formation of the root of Viscum ; 
 but the observations of Du Hamel, Gaspard, and many others 
 have left little unknown on this subject. M. linger has how- 
 ever observed in several tropical species of Loranthus, that the 
 roots having a horizontal direction are not fixed in the bark 
 but on it, intimately surrounding the branches, and even ad- 
 hering to them with their extremities. 
 
 In a second part, M. Unger gives his anatomical observa- 
 tions on the parasites, whose mode of insertion into the stock 
 plant has been previously described ; he concludes, that the 
 whole of the parasitical plants may be divided in a system- 
 atical point of view into three sections. The first comprises 
 those parasites, whose imperfect vascular bundles, having for 
 prototype Langsdorfia, are arranged in a circle and are con- 
 nected with each other by anastomoses. This section is placed 
 parallel with the formation of the stem in Ferns. A second 
 group is formed by those parasites in which the vascular bun- 
 dles are also imperfect, but in which it appears that a periphe- 
 rical formation of roots is added to that at their apices. This 
 section comprises the genera Orobanche, Lathr&a, Monotropa, 
 Cuscuta, Cassytha ; and M. Unger thinks that these plants, 
 with respect to their anatomical structure and mode of growth, 
 can be compared with none of the larger vegetable divisions ; 
 while the genera Viscum, Loranthus, &c. belonging to the third 
 section possess perfect vascular bundles and resemble dicoty- 
 ledons in their mode of growth. 
 
 This mode of subdividing parasitical plants will probably 
 meet with little acceptation ; in fact I am not acquainted with 
 anything from which it can be proved that Orobanche, Lathraa, 
 Monotropa, Cuscuta, &c. differ essentially in their structure 
 and growth from other dicotyledons. It is true that Rafflesia 
 and Brugmansia exhibit a similar deposition of ligneous bun- 
 dles, or vascular bundles as they are here termed, on one an- 
 other, as in ferns ; but I can also produce stems of Cactus, in 
 which something similar occurs ; and therefore the drawing 
 an analogy between the genera of parasitical plants and ferns 
 cannot be justified. M. Unger thinks that his views on the 
 arrangement of parasites are strengthened from the structure 
 of their seed ; this supposition is however quite as erroneous 
 
63 
 
 as the unfounded doctrine of the growth of true parasitical 
 root plants without actual seed, which I have already lamented 
 for many years as one of the errors of my youth. When I 
 examined Dr. Blume's Brugmansia, the specimen which was 
 said to have ripe seed was more than half decomposed ; hence 
 the hymenomycetous fungi in and near the seed in the figure 
 (fig. 17.) : probably too the embryo was also wanting, although 
 the change in form of the seed allowed of the conclusion of 
 a fecundated condition. On the young, yet unopened flowers, 
 I have observed the seed quite normal with its nucleus and 
 simple coat, and have figured them in fig. 16. PL II. of the 
 Flora Javae. It must however be remembered that these obser- 
 vations were made in February 1837 5 and consequently before 
 the appearance of the celebrated memoir on the ovule of plants; 
 but even if R. Brown had not already observed the embryo 
 in the seed of Rafflesia (of which M. Unger is ignorant), I 
 should now, from the mere appearance of the seed in compa- 
 rison with a non-fecundated ovule, no longer doubt the exist- 
 ence of the embryo. The Rhizanthea have therefore an em- 
 bryo in their seed, and its form and development indicate in the 
 most decided manner that they belong to the dicotyledons. 
 
 It might be imagined, says M. Unger, that the parasitical 
 forms were only the shadows of types which presented them- 
 selves in a more noble independent and perfect form in another 
 direction of the vegetable kingdom ; but if he had arranged 
 the various parasites in the natural families represented by 
 those types, the organographical portion of this memoir, so 
 abundant in material, would have been of a much more per- 
 manent value for systematic purposes. 
 
 The six lithographic quarto plates annexed to the memoir, 
 contain an abundance of beautiful and faithful representa- 
 tions. 
 
 In the excellent monograph of the Riccia which Dr. Lin- 
 denberg* has published, there is a section which treats of the 
 structure, growth, and generation of the Ricciae } and contains 
 numerous and highly valuable additions to vegetable physio- 
 logy. The author states, that only those species of Riccice are 
 
 * Nova Acta Acad. C. L. C. Nat. Curios, xviii. p. 1. Vratislaviae et Bonnse, 
 1837, p. 361504. c. Tab. XIX. 
 
64 
 
 destitute of roots, which grow entirely in water, and only so long 
 as they are entirely surrounded by this element, but they send 
 forth roots so soon as they come in contact with the soil. The 
 roots of the Riccia are simple, very rarely branched, and their 
 number varies, as in other plants, in different individuals. 
 These roots of the Riccice consist in mere simple radical fibrils, 
 as is the case in all mosses ; yet in Riccia natans, where several 
 deviations in form are already evident, these fibrils which are 
 developed in the earth are both articulated and unarticulated. 
 Such small variations occur even in more perfect plants ; now 
 and then even ramified fibrils are met with. But besides these 
 delicate rootlets, M. Lindenberg has also observed in some 
 species, in R. purpurascens and natans, stronger and more rigid 
 radicles, which at their extremity are incrassated in an oval, 
 clavate, or globular form, and then again emit from all sides 
 small slender fibres. He terms these roots sprouting roots, 
 and the thick tuberosities at the extremities are developed ac- 
 cording to his observations into new plants ; but they are in- 
 correctly designated as radical buds ; they are evidently gems, 
 the occurrence of which at the extremities of the roots of such 
 imperfect plants is very remarkable, as in Lemna alone has 
 anything similar been observed. In R. natans they are formed 
 even at the extremities of the simple radical fibrils, but the de- 
 tails have not been completely demonstrated. 
 
 M. Lindenberg regards the Riccice as those inferior plants, 
 in which perfect cellular tissue first occurs, which can only be 
 admitted in a certain sense ; for not only in the Fungi, but also 
 in Algae, we find not merely very regularly formed cells, but 
 also a regular deposition of these cells on one another, ex- 
 actly as in the more perfect plants ; these cells differ from the 
 perfect cellular tissue merely in their contents and in the firm- 
 ness of their walls. M. Lindenberg thinks he has found in 
 the structure of the Riccice a confirmation of M. Kieser's 
 theory, " that the ideal primitive form of vegetable cells, forced 
 to deviate from their original form of a sphere or ellipsoid 
 in consequence of their being united into an uninterrupted 
 tissue, is the rhomboidal dodecahedron." All the cells, he ob- 
 serves, in the parenchyma of the Riccia are of this form, or 
 may be reduced to it, although at the same time the constant 
 
65 
 
 tendency of the cells to retain as much of the globular form 
 or to return to it as nearly as the reciprocal pressure, &c. al^ 
 low, is very apparent. 
 
 This supposition, however, requires at least, that those cells 
 of the parenchyma of the Riccics should be in their origin 
 spherical, and have been subsequently compressed. But can 
 this be observed in the RICCICB ? I think I may answer the 
 question negatively, for in the Marchantice where the cellular 
 tissue is exactly similar to that in the Riccice, it may be ob- 
 served that the development of the form of the cells is not 
 effected in the way above described. The mathematical deve- 
 lopment of Kieser's hypothesis on the origin of the form of the 
 cell is nevertheless quite correct, and even Stephen Hales de- 
 monstrated very decidedly that round bodies of uniform size, for 
 instance common peas, when caused to swell in a firmly closed 
 space filled with them, were changed by reciprocal pressure 
 into dodecahedrons. This form, produced by external circum- 
 stances, cannot however be regarded as the ideal primitive 
 form of those originally round bodies; and it is founded on 
 very erroneous observations, if it be supposed that the ideal 
 rhomboidal dodecahedral cells can round off at their edges 
 and corners and pass into the various other forms. If the re- 
 ciprocal pressure ceases, which sometimes, from the unequal 
 expansion of certain parts, occurs, the separated cells re-as- 
 sume the spherical form from which they had departed. 
 
 M. Lindenberg has given a very detailed account of the sub- 
 ject in question, in which we find the following observation ; 
 " that in sections of cellular tissue other forms besides the 
 hexagonal occur, which does not prove against, but in favour 
 of Kieser's view," i. e. that the form of the cells is that of 
 the rhomboidal dodecahedron. However I have only been 
 strengthened by continued observations in my views on this 
 subject (see Phytotomie, p. 216.), nay, I could at present bring 
 forward more detailed observations than at that time. And, in 
 fact, it is surprising, that even now mention is made in many 
 manuals of botany, of the rhomboidal dodecahedral form of the 
 cells, whilst good longitudinal and cross sections place the true 
 form of the cells immediately before the eye; I will also mention 
 that cells of the continuous parenchyma whose form resembled 
 
66 
 
 a regular rhomboidal dodecahedron have never occurred to 
 me : I do not even think that there is any actual similarity. 
 
 The Riccice, like all plants having a tissue consisting of se- 
 veral layers, possess a cuticle, i.e. an upper cellular layer, and 
 M. Lindenberg observes very justly that it is merely a dis- 
 pute about words, whether the epidermis ought to be consi- 
 dered as a distinct organ or merely as the upper cellular layer 
 of the parenchyma. The form of the cells of the epidermis 
 of the RiccicB is more or less regular dodecahedral, of which, 
 however, I could not convince myself. The cells of the epi- 
 dermis are filled with green sap globules when the frond is 
 quite thin, but uncoloured when the frond is more consider- 
 able, and the green cells then gleam through the interior of 
 the frond, and in this way originates the greyish green colour, 
 when dried silvery grey, which for instance is peculiar to R. 
 glauca. At times the marginal cells are provided with cellu- 
 lar sap and even amylum granules occur in them. The rough 
 surface of the Riccice is caused by small verrucous swellings 
 of the upper sides of the cells. " Frequently," observes M. 
 Lindenberg, " these vesicular prominences are and remain 
 closed ; not unfrequently however they open on the further 
 development of the plant ; either quite irregularly, as in R. 
 hortorum, crystattina, the upper cellular sides disappearing al- 
 most entirely, and thus irregular cavities of various size and 
 open above originate ; or by the disintegration of some cells 
 round or oval fissures are formed, as in Corsinia marchan- 
 tioides ; or lastly by some cells raising themselves higher and 
 in the shape of warts, and these apparent papillae open above as 
 in Ricciafimbriata." In Oxymitra the apertures are surround- 
 ed regularly by smaller round cells. All these observations are 
 exceedingly interesting, especially on account of the similar 
 appearances which have here and there already been noticed 
 in plants. I compare the apertures, with and without pa- 
 pillae-like prominences of the adjacent cells of the epidermis, 
 which M. Lindenberg has observed, to the so-called stomata 
 of the Marchantice ; the papillae of Riccia fimbriata especially 
 bear the greatest resemblance to the open prominences on the 
 fronds of the Marchantia, in which the true cuticular glands 
 which present the stoma in the centre of their two semicir- 
 
67 
 
 cular cells are entirely wanting, on which subject I have re- 
 cently offered some remarks*. It appears as if these aper- 
 tures served to convey the moisture of the air into the interior 
 of the tissue of these plants ; theRiccice grow under similar cir- 
 cumstances as the Marchantice ; at times they have too much 
 moisture, at others too little, and these arrangements might 
 in both cases aid in regulating the proportions. Besides, the 
 vesicular projections on the surface of the Riccite do not always 
 open, a phenomenon quite similar to that of the occurrence 
 of the holes so frequently mentioned on the sides of the cells 
 of some species of Sphagnum, on which subject we shall sub- 
 sequently have occasion to treat more fully. 
 
 Although the cellular tissue of the Riccice is very compact, 
 exactly as in the Marchantice, so that only very rarely inter- 
 cellular passages occur between the cells, yet the substance of 
 the frond, when it occurs but moderately, is abundantly tra- 
 versed by air-receptacles. They arise from a gradual disinte- 
 gration of the cells, are often present only here and there in 
 the frond, and frequently quite irregular, and in the species 
 growing in water they are found to exist constantly. When 
 the frond is thick several series of such air-cavities originate 
 one above the other as in the gibbosity of Lemna gibba. 
 
 All the species of Riccice which have a more fleshy frond 
 present in the centre a still denser layer, consisting of hori- 
 zontally elongated cells. In several species the under surface 
 is moreover covered with a coloured cuticle, which consists of 
 a single or at times even of numerous layers of small coloured 
 cells ; in old age this membrane frequently falls off of itself, 
 and produces, by mere shining through, a colouring of the 
 surface. This coloured layer, says the author, is chiefly the 
 cause of all the red and violet colouring of the Riccia y with 
 the exception of the margin, which in some cases is inde- 
 pendently coloured. Where the margin is involute this co- 
 loured under side occurs above. 
 
 In most species of Ricciae not a trace is found of a vein in 
 the leaves ; in some however bundles of pleurenchymatous 
 cells are gradually formed. These traverse the frond longi- 
 tudinally and send out ramifications on both sides; they are 
 not met with in any species which is not provided with air- 
 
 * Ueber einige Eigenthiimlichkeiten in der Epidermis verschiedenen Or- 
 chideen. Wiegmann's Archiv. 1837, p. 423. 
 
 F2 
 
68 
 
 cavities. I regret that the author has not explained this sub- 
 ject more accurately and elucidated it by drawings, as at 
 present I have no fresh Riccice at hand ; it appears to me 
 however as if these veins consisted only of elongated paren- 
 chymatous cells, and as such form the sides of the air-cavities 
 which gleam through the upper cellular layer. In Corsinia 
 he however observes, that there exists a large bundle of such 
 fibrous cells situated close together, only here and there tra- 
 versed by elongated almost prosenchymatous cells, and send- 
 ing out true ramifications, likewise consisting of several series 
 of cells. 
 
 The occurrence of such veins in the Riccia would be highly 
 remarkable, as the Marchantice evidently stand much higher 
 and yet exhibit no such veins ; in the latter, their place is oc- 
 cupied by bundles of beautiful fibrils, which run exteriorly, 
 surrounded only by ridged elevations. 
 
 M. Nees von Esenbeck had the kindness to forward to me 
 a specimen of Corsinia for examination ; it was dry, but it ap- 
 peared to me to show plainly that those bundles of brown 
 fibrous cells belong no more to the Corsinice than to other 
 Riccice. I found however on one specimen, between the de- 
 licate fibrils, a brown fibre, which agrees with the description 
 of the fibrous cells given by M. Lindenberg ; but I can af- 
 firm that this fibre, which also presented ramifications, did 
 not belong to the Corsinia. However, only the examination 
 of fresh specimens can decide this point. 
 
 The RiccicB are otherwise so nearly allied to the Marchantice 
 in the appearance of their organs of fructification that they 
 can hardly be considered as a distinct natural family. 
 
 Dr. Schleiden* has published a monograph of the genus 
 Ceratophyllum, containing much that is new, notwithstanding 
 all that has already been written on this subject. It is clearly 
 shown that Ceratophyllum must be separated from the Naiades 
 and reckoned among the Dicotyledons. The embryo has two 
 large fleshy cotyledons and a highly developed plumula ; it is 
 inclosed in albumen, and consists of a circle of leaves, which 
 at times is separated by an apparent internode from the cotyle- 
 dons, of a whorl of six undivided leaves, and lastly of two to 
 three whorls of forked leaves. M. Schleiden observed the em- 
 bryo sac in the axis of the nucleus long before impregnation, 
 Beitrage zur Kenntniss der Ceratophylleen. Linnaea, xi. p. 513. 
 
69 
 
 in the form of a cylindrical cell, in whose apex (micropyle-end) 
 were contained some small cells. The ovule is pendulous and 
 provided with an integument, the pollinic cell was followed to 
 the micropyle, and here it penetrates the aperture of the in- 
 tegument, expands into an irregular saccate dilatation vary- 
 ing in size, and then passes from thence into the nucleus un- 
 til it reaches the embryo sac : immediately upon this the first 
 trace of an embryo is visible. During this time the cells of 
 the endosperm have expanded considerably until they have 
 reached the chalazar extremity and quite fill it. In these en- 
 dosperm cells he discovered the interesting phenomenon of 
 the rotatory current \vhich existed in each cell ; it was a yellow- 
 ish slimy fluid, intermixed with small globules, which was in 
 motion. The current ascended from the base of the cell, in 
 its axis, resembling an artesian spring, to the very top, where 
 it separated into innumerable, minute^ scarcely perceptible 
 currents, which fell down the sides in all directions, in order 
 to reunite below with the main current. The direction of the 
 central stream is in all cases alike, namely, from the embryo 
 towards the chalaza. 
 
 From the development of the embryo, as also from the di- 
 latation of the lower cells, the upper ones become compressed 
 and die from above downwards. 
 
 The stem of the Ceratophylla consists of bark covered with 
 epidermis, of a ring of bundles of elongated cells, and of pith. 
 The genus Ceratophyllum has no spiral vessels. Dr. Schleiden 
 here remarks that he had discovered spiral vessels in Lemna 
 as early as 1835. However, L. Treviranus had many years 
 ago figured the spiral vessels in the roots of Lemna ; I myself 
 denied the fact, not being able to confirm it with my older 
 microscope, but with the instrument of Ploessl I could also 
 see the vessels. In Zannichellia the spiral vessels are said 
 to disappear in the old articulations. I recollect having seen 
 in the summer of 1835 spiral vessels both in the young and 
 old internodes of this plant. 
 
 Whether the Ceratophylla are perennial or not is not yet 
 ascertained ; they flower from July to the middle of Septem- 
 ber. In the beginning of September flowers and nearly ripe 
 fruit are found on the same stem. The plants contained nearly 
 90 per cent, water, and the ashes f alumina, f silica, &c. 
 
70 
 
 The geographical distribution of this genus is very general ; 
 it is not merely confined to the northern hemisphere, for I my- 
 self saw Ceratophylla in Chili *, and other travellers have also 
 observed them there. 
 
 Dr. Schleiden admits only one species of Ceratophyllum) and 
 calls this C. vulgare ; a long series of observations are enume- 
 rated to prove this view. 
 
 Asa Grayt has also recently written on the affinities of the 
 genus Ceratophyllum ; it appears to him that a great similarity 
 prevails between the embryos of the genera Ceratophyllum and 
 Nelumbium, which he endeavours specially to demonstrate, and 
 then places the Ceratophyllacece in the immediate vicinity of 
 the Cabombacece and Nelumbiacece. The memoir contains 
 no new observations, nor do I find anything respecting the 
 structure of the Ceratophyllacece. 
 
 On the Propagation of Vegetables, and on the Organs that 
 contribute to it. 
 
 Mr. Felix Dunal, of Montpellier J, has made us acquainted 
 with some interesting observations on the organs of fructifica- 
 tion of a Marsilea, which have been made by M. d 5 Esprit 
 Fabrewith great accuracy. The specific name of Fabrihas been 
 assigned to this Marsilea ; there can, however, be little doubt 
 as to its being the same species described byTenore as Marsilea 
 pubescens ; this latter name must consequently be retained ! 
 
 The generative organs of this Marsilea are in some respects 
 of a different structure from those of our common Marsilea : 
 their functions are, however, more easily recognised than 
 in this. At the base of the petiole are situated the capsules, 
 each on the involute side of the termination of a conical 
 pointed pedicel, which is partly inclosed by the inferior mar- 
 gins of the two valves, forming the capsuliform involucrum 
 of the inflorescence or the organs of fructification : the in- 
 closed part therefore constitutes the receptacle, from which 
 proceed on both sides vascular bundles which surround all the 
 organs of fructification. As soon as the involucrum has opened, 
 
 * Meyen's Reise, &c., i. p. 370. 
 
 f Remarks on the structure and affinities of the order Ceratophyllacece. 
 Ann. of the Lyceum of Nat. Hist, of New York, 1837, iv. p. 41 . 
 
 J Observations d' Esprit Fabre sur la structure, le de" veloppement, et les 
 organes generateurs d'une espece de Marsilea trouvee dans les environs 
 d'Agde. Ann. des Scien. Nat., Avril 1837, p. 22 l,avec planches xii. etxiii. 
 
71 
 
 a mucilaginous thread makes its appearance, which bears at 
 its side from six to ten sessile, racemose, elliptically formed, 
 annularly curved (roules en anneau] bodies. In the imper- 
 fectly developed state of this thread the vascular bundles which 
 arose from the sides of the receptacle, encircle the thread and 
 are connected with the racemose bodies, which are the male 
 and female reproductive organs of the plant. All these state- 
 ments, which are nearly complete as to the development and 
 structure of this mucilaginous thread, are elucidated by admi- 
 rable drawings. With the further development of the inflo- 
 rescence the point of the thread quits the involucrum and is 
 unrolled to a straight erect thread, which on each side bears 
 from three to five of the organs of reproduction. The end of 
 the thread is always naked ; it is composed of an extremely 
 delicate and almost transparent cellular tissue, the cells of 
 which abound in mucus and contain some very minute sphe- 
 rical globules. 
 
 The reproductive organs are from 2 to 3 lines long and 1 
 thick, enveloped in a kind of mucous membrane ; they contain 
 two different kinds of bodies, which are said to be ovules or seed 
 and anthers. In general they occur in the same organ, the 
 ovules on one side, the anthers on the other, but so arranged 
 that the ovules are constantly situated above and the anthers 
 immediately beneath. In each single organ are from ten to 
 fifteen ovules, which exhibit at one end a small yellow wart 
 surrounded by a circular prominent capsule. The ovules are 
 filled with a semi-transparent fluid, in which numerous glo- 
 bules float ; the wart of each ovule is always directed towards 
 the anther. The anthers are formed of a transparent membra- 
 nous sac, in which are evident numerous pollen granules of 
 spherical and elliptical form, which when crushed give out 
 spermatic granules of great tenuity. The sexual difference be- 
 tween the two bodies described, the ovules and the anthers, is 
 completely confirmed by M. Fabre's observations. The im- 
 pregnated ovules emit roots and germinate with one cotyledon. 
 
 These observations on Marsilea pubescens are, especially at 
 the present time, of particular interest ; I am inclined to be- 
 lieve there can be no doubt that these reproductive organs 
 must be regarded as modified leaves, and that here therefore, 
 in a case where spores and pollinic vesicles are formed in the 
 
72 
 
 same leaf in a natural way, an actual impregnation takes place, 
 although there does not exist that difference which the other 
 higher plants exhibit between stem and leaves. At the same 
 time these observations confirm M. MohPs view, that the 
 spores of Cryptogamia and all lower plants in general, are 
 produced, like the pollen granules of the higher plants, from 
 modified leaves. 
 
 M. Link* has published the second part of his Elements 
 of Botany, which contains (p. 44 331) the important chap- 
 ter on the inflorescence and fruit of plants. This second 
 part is also as rich in observations as the first, and above 
 all I must direct attention to the morphological views of the 
 author expressed in this work ; they are the result of many 
 years' study of nature. 
 
 The observations of M. Fritzsche t on the structure of pol- 
 len, which we mentioned in our last year's report J, have now 
 been published entire. The work is divided into two sections : 
 the first treats of the structure of pollen in general, the second 
 on the tunics of the pollen. The whole is written without 
 any mention of the literature on the subject, as the perspi- 
 cuity of this difficult subject would in M. Fritzsche's opinion 
 have been thereby endangered. 
 
 The exposition of the first memoir on pollen in general be- 
 gins with the examination of the anthers of Chara, which it 
 is well known deviate very much from the general rule. The 
 coats of the anthers of the Chares are in general composed of 
 eight flat-pressed triangular cells, each four of which form a 
 hemisphere; the superior hemisphere is closed, the inferior 
 one on the contrary has at the spot where it is attached a round 
 aperture, which is formed by semicircular excisions of the tri- 
 angle that take part in its formation. The structure of these 
 triangular cells is very fully described ; they contain a clear un- 
 coloured mucus (this mucus is stated to be coloured probably 
 from a misprint) and the inner surface of the parietes situated 
 towards the centre of the anthers is covered with a layer of red 
 granules, which again exhibit in their substance a quantity of 
 
 * Elementa philosophise botanicse, torn. ii. Edit, altera, Berolini, 1837. 
 f Ueber den Pollen. Mit 13 colorirten Steindriicken. St. Petersburg, 1837. 
 4to. Printed separately from the Memoirs of the Royal Academy. 
 J Lond. and Edinb. Philosophical Magazine, vol. xi. p. 165. 
 
73 
 
 very minute dark bodies. This arrangement of the coloured 
 and uncoloured part of the triangular anther- cells explains the 
 occurrence of the Arillus diaphanus with which the anthers of 
 the Chares are surrounded. The septa are noticed, which 
 extend in these triangular cells from the circumference to a 
 third of the diameter. They are placed vertically between the 
 upper and lower surfaces of the triangle, and consist of two 
 cellular walls (because they are mere folds. Rep.}, giving this 
 multifid cell some resemblance to a stellate cell, only that the 
 interstices are wanting in them. In Chara with compound 
 cuticle, as in C. tomentosa, &c., M. Fritzsche has discovered 
 small spiculae, which are situated at regular distances between 
 the two membranes of the septa. He has also found in the 
 interior of each anther a bottle-shaped body, consisting of 
 single cells, which projects into the centre of the anther and 
 there supports all the other parts : this formation has hitherto 
 been overlooked by all observers, but the connexion of the 
 other cells and of the polleh thread with the surrounding in- 
 tegument has been known years ago, and we possess since 
 1832 and 1833 some of /the most beautiful drawings of the 
 confervoid pollen thread of the anthers of the Chara, although 
 M. Fritzsche thinks that they have hitherto never been 
 figured correctly. There is in fact nothing more easily per- 
 ceptible with our present microscopes than this transparent 
 delicate thread, but all earlier amplifications were insufficient 
 for this purpose, although even with them the remarkable 
 motions of the Spermatozoa of these plants were discovered 
 by Bischoff, as was mentioned in last year's report*. 
 
 M. Fritzsche has observed the formation of the anthers of 
 the Charae from a simple cell which was filled with a transpa- 
 rent colourless mass, which I am able to confirm, but the for- 
 mation of septa which should then follow is limited only to the 
 thickness of the triangular cells, which subsequently form the 
 coat of the entire organ, and this formation I found to resem- 
 ble that of the outer cellular layer on the Chares with com- 
 pound epidermis. 
 
 After these remarks on the structure of the anthers ofChara, 
 M. Fritzsche speaks of the contents of the pollen in general : 
 the same observations and views which have already several 
 
 * Lond. and Edinb. Philosophical Magazine, vol. xi. p. 165. 
 
74 
 
 times been asserted against the Spermatozoa or spermatic cor- 
 puscules, are again brought forward ; they are said to be fecula 
 or drops of oil, in which view 1 do not concur ;. I have, how- 
 ever, already stated my opinion on this subject in last year's 
 report. Starch occurs only in imperfectly formed pollinic 
 vesicles ; not rarely in Coniferce and in some water plants. I 
 have also been able to observe in Muscari moschatum that in 
 such imperfectly developed pollinic vesicles the masses of fe- 
 cula which occur in them are converted into a gummy sub- 
 stance arid decompose into small molecules which have a very 
 lively motion, resembling in every respect the phenomenon de- 
 scribed by me in the cells of Marchantia polymorpha *. In 
 some cells of this plant there occur instead of the common 
 green cellular sap globules some large balls of a yellowish 
 brown substance, which have been already observed and fi- 
 gured by Mirbel. I followed up the formation of these masses 
 from the globules of starch, which deliquesce and are then 
 converted into a gum. When these globules are perfectly 
 developed and of a yellowish brown colour, they decompose 
 on the smallest touch into innumerable minute brownish mo- 
 lecules, which for days exhibit the most lively motions,, having 
 an appearance similar to the motions in solutions of indigo, 
 gum-arabic, &c., only somewhat more active. 
 
 The second section treats of the coats of the pollen. A sim- 
 ple membrane and one of a more compound structure are to 
 be distinguished on the pollinic vesicles. Some plants exhibit 
 but one tunic, others on the contrary three and even four. 
 Most frequently but two tunics occur, and they are termed 
 the inner and the outer coat; but where a duplication of one 
 or both these membranes exists these names do not suffice, 
 and on that account he proposes for the entire series of mem- 
 branes, when they are all four present, the terms Intine, Ex- 
 intine, Intexine, and Exine, which however cannot be admitted, 
 for the fact is quite different to what M. Fritzsche supposes f. 
 
 The inner tunic is from its simplicity easily distinguished 
 from the outer membrane, and chemical agents afford ample 
 means for separating them. Concentrated sulphuric acid de- 
 stroys the inner membrane, but the outer one with its ap- 
 
 * Wiegmann's Archiv, 1837, part iii. p. 428. 
 
 [f Similar views are however entertained by H. Giratid. See his paper 
 in the Annals of Natural History, vol. ii. p. 399. W. F.] 
 
75 
 
 pendages is merely coloured by its action, frequently of a 
 purple-red. The membrane and its coating are generally si- 
 milarly affected, but in some cases, as in Beloperone oblon- 
 gata, the membrane is coloured purple-red and its coating yel- 
 lowish-brown by sulphuric acid. The outer tunic is coloured 
 of a dark brown by iodine, and the inner membrane is said to 
 take no colouring from a solution of iodine, like cellular mem- 
 brane in general (which, however, cannot be generally asserted. 
 Rep.}. The membrane of the outer tunic is sometimes of 
 greater, sometimes of less consistence, not only in various 
 plants, but at times even at different parts of the same vesicle, 
 for instance, at the apertures ; but the coatings with which the 
 membrane is covered vary considerably. This subject is 
 treated in a very elaborate manner, and by employing high 
 powers of a good microscope M. Fritzsche has succeeded in 
 bringing to light a vast number of new and interesting facts 
 which are illustrated in the annexed plates in large and beau- 
 tiful drawings. It is not possible for me to enumerate in this 
 short report the essential facts respecting these coatings of the 
 outer tunic ; I can only communicate the most important, and 
 for the remainder I must refer to the memoir itself. 
 
 In several Malvaceae the outer membrane is equally densely 
 covered with a layer of transparent, cylindric, apparently solid 
 granules, standing erect, side by side, which give it a granular 
 appearance ; the granules seem to be connected by a distinct 
 substance ; in other plants however this is not the case. In 
 Chrysanthemum carinatum a membranous coating distinct from 
 the granules occurs. At times the granules do not cover the 
 entire surface of the membrane, at times they are placed re- 
 gularly and connected with one another by bands, at others 
 they are free and more or less regular. In Plantago capensis 
 the granules are irregular, and also in irregular position. Free 
 large equidistant granules have been observed in Jatropha 
 pandurcefolia. When the granules are united by ligaments, 
 pollen-like connexions originate on the surface of the outer 
 membrane, as in Ruellia formosa. The occurrence of spines 
 on the membrane is connected with this granular coating. In 
 Malvaceae the spines are sometimes seated on the cylindrical 
 granules, and may be separated from them ; it is probable that 
 they have no direct connexion with the outer tunic. In some 
 
76 
 
 cases cavities or canals were found in the larger spines, and 
 MohPs supposition that they are cellular formations which se- 
 crete oil is confirmed. These spinous formations are most re- 
 markable in the group Cichoracece ; they stand in single regu- 
 lar rows, and can only be observed with advantage from the 
 side. Among these spines of Cichoracece a connexion exists 
 which seems to be effected by a membranous mass clothing 
 the membrane ; the series of spines appear from this cause 
 like broad bands, and present, when observed from the side, 
 an umbraculiform appearance. 
 
 In another class of vegetables, regular pentagonal and hex- 
 agonal figures, circumscribing walls, have their origin on the 
 outer tunic ; these are again interrupted as in Cobcea scandens, 
 and appear like piers of a bridge. In Geranium and Pelar- 
 gonium verrucous bodies are situated, like statues, on the 
 arches connecting the buttresses. (The history of the occa- 
 sional formation even of some imperfectly developed pollen 
 grains of these plants shows that all the elegant formations on 
 the surface of the pollen granules arise from similar erect gra- 
 nules in juxta-position, as they so frequently occur in the Mal- 
 vaceae. Rep.) 
 
 In some plants the surface of the outer tunic presented the 
 appearance of net-work, as in Polemonium coeruleum, Gilia 
 tricolor, Metrodorea nigra, &c. 
 
 A separate chapter treats of the intermediate bodies which 
 occur between the inner and outer tunics. They are most 
 easily seen in Astrap&a, and have there in an isolated state the 
 form of a plano-convex lens, of which the side turned towards 
 the outer coat is covered with granules resembling the external 
 surface of the outer coat. In other plants these granules do 
 not exist on the outer surface of the intermediate body, or 
 there is merely a simple ring present, as in Ruellia formosa. 
 The intermediate bodies are situated in general at those spots 
 where apertures exist in the outer tunic which are closed by 
 them, and these intermediate bodies have a far greater extent 
 than the apertures, on which account they cannot be consi- 
 dered as belonging to the outer membrane. In Alcea rosea, 
 where these apertures in the outer membrane are very nume- 
 rous, their inner surface is clothed with densely juxta-posed 
 globular granules, which are said to be the intermediate bo- 
 
77 
 
 dies. In Campanula Medium and in Cucurbita Pepo they are 
 also found; and M. Fritzsche starts the opinion that they 
 should be regarded as diseased pollen granules. In Scabiosa 
 pubescens he found two such intermediate bodies, which ap- 
 peared to be encased one in the other. (These intermediate bo- 
 dies of M. Fritzsche are cells and their contents, which occur 
 in the pollen vesicles of numerous plants, and have been over- 
 looked by him. When these cells in the interior of the vesi- 
 cles have large cellular nuclei, as in many Liliacece, such a 
 case as is related of Scabiosa pubescens becomes intelligible. 
 Rep.) The intermediate bodies, however, also occur in some 
 forms of pollen which have no apertures, as in Pinus and La- 
 riX) where the pollinic vesicle has two outer linings. The 
 drawing given of the pollen of Pinus sylvestris is one of the 
 most unsuccessful; in nature it has quite a different aspect. 
 
 The subject of the second part of M. Fritzsche's memoir is 
 the form of the pollen. He first treats -of the pollen masses 
 and then of the pollen grains ; the former occur in the Or- 
 chidece, Asclepiadece, and in the genus Inga, which was pre- 
 viously known. The individual grains, of which the pollen 
 mass of the Orchidece consists, possess but one tunic, and there- 
 fore the inner one according to M. Fritzsche, yet the struc- 
 ture of this membrane but too plainly evinces that it is nearly 
 related to the outer ones of other kinds of pollen. In the 
 grains of the genus Asclepias he has not only observed two 
 tunics but even an exintine. 
 
 Then follows a natural division of the pollen grains, ac- 
 cording to the number of tunics. 
 
 1. Pollen grains with one tunic. To this section belong 
 Cauliniafragilis, Zanichellia pedunculata, Zoster a, and Najas 
 major. The confervoid pollen described in Zostera was dis- 
 covered, described, and figured many years ago by my friend 
 Nees von Esenbeck. 
 
 2. Pollen grains with two tunics. Under this section are 
 classed almost all the forms of pollen, and we may properly 
 speaking regard those cases where fewer or more than two 
 membranes occur as exceptions. They divide themselves into 
 two groups, according to the presence or absence of the aper- 
 tures in the outer coat ; cohesions occur in both cases. 
 
 A. Grains without apertures. The peculiar geniculated 
 
73 
 
 pollen grains of Ruppia are here described. Then follows 
 the ellipsoid form of many Monocotyledons, which M.Fritzsche 
 has drawn with a fold, as in Lilium, Pancratium. Cohesions 
 of two, as in Lilium candidum, and of four, as in Phillydrum 
 lanuginosum and Anona tripetala, are enumerated. More rarely 
 two opposite folds occur, as in Tigridia Pavonia ; on the con- 
 trary, frequently symmetrical longitudinal folds, as in Plum- 
 bago capensis. Globular pollen forms are more rare. Stre- 
 litzia exhibits them with an homogeneous outer coat ; Canna 
 presents small spines, and regular warts appear in Jatropha 
 panduraefolia. In Sowerb&a juncea the groove goes quite 
 round the vesicle, and the outer coat is thus divided into two 
 halves. Allied to this is the interesting form of the pollen of 
 Thunbergia fragrans and several species of Berberis. In 
 Commelina coelestis a large tabular piece takes off, which lies 
 on the aperture as a lid, and several such lids occur in the 
 genus Passiflora, where again a number of varieties originate 
 by the division of the lid, which are all minutely described 
 and figured. That portion of the outer tunic where the aper- 
 tures are closed by distinct lids is termed the skeleton of the 
 tunic. In Scabiosa the lid appeared as if merely formed by 
 the granular lining of the outer tunic. 
 
 B. Grains with apertures. These forms are again subdi- 
 vided into two sections, according to whether the apertures 
 consist in fissures of various lengths, or form circular holes. 
 Three fissures, as in Geissomeria longiflora, is the smallest 
 number observed. In many Cyperacea four to five unsym- 
 metrical fissures are found ; the form of Car ex prcecox is fi- 
 gured where the inner tunic presents peculiar thickenings. 
 
 The position of the fissures on the tetrahedral forms of the 
 pollen of some species of Corydalis and Basella is very re- 
 markable. The pollen of Talinum patens exhibits twelve fis- 
 sures, and Polygonum amphibium many more, the outer tunic 
 forming twelve regular pentagonal fields, each of which is sur- 
 rounded by five regular fissures. 
 
 The group of pollen grains with round apertures presents 
 a greater variety of forms ; one aperture in the Graminece, 
 two apertures in Banksice and Justicia Adhatoda. Three aper- 
 tures are most frequent and occur in many plants in connexion 
 with three longitudinal grooves, which in general hide the 
 
79 
 
 apertures. Rarely three apertures without grooves, as in 
 Morina persica. A number of peculiar forms are here fully 
 described which had partly been previously published. Some 
 cases are also mentioned where all the grooves are not provi- 
 ded with apertures, yet in this case the pierced grooves stand 
 in a definite proportion to the unpierced. 
 
 Lastly, there are forms with a cellular (?) texture of the 
 outer pollen membrane ; in some cases only a part of these 
 fields which have the cellular appearance are provided with 
 apertures, as in Phlox ; in others, on the contrary, all the 
 fields have apertures, as in Gomphrena globosa. 
 
 3. Pollen grains with three tunics. Where a greater 
 number of tunics exist than in the second division, the addi- 
 tional ones must not be regarded as new tunics, but duplica- 
 tions either of one or the other. In the pollen of the Coniferte 
 the inner tunic is doubled, in the Onagrece the outer one ; nay, 
 M. Fritzsche alleges that he has observed a duplication of the 
 inner tunic in Clarkia elegans. (If the pollen of Pinus, Larix, 
 TaxuSy and Juniperus, be observed comparatively in this re- 
 spect, we may easily be convinced that no reason exists for the 
 admission of such duplications. Rep.} 
 
 4. Pollen grains with four tunics. Clarkia elegans, spe- 
 cies of CEnothera and Encharidium concinnum are here enu- 
 merated. 
 
 I have published some observations on the Spermatozoa of 
 Jungermanniae*, which exactly resemble those described by 
 M. Unger in the anthers of the genus Sphagnum. I noticed 
 the occurrence of these Spermatozoa of the Jungermannia in 
 the interior of lenticular compressed vesicles (ceUs ?) ; in 
 each vesicle there was a single worm-like creature with thick 
 cephalic extremity and thin tail, and situated quite at the 
 margin of the vesicle, so that the filiform tail can run round the 
 margin of the entire vesicle and again touch the head. These 
 cells containing the Spermatozoa are very large and in great 
 quantity in the anthers ; and in some genera of mosses they 
 are enveloped in gelatinous mucus, which swells by absorp- 
 tion of water, causes the anther to open and expels the whole 
 mass from it. On the solution of the gelatine in water these 
 
 Wiegmann's Archiv, 1837, i. p. 430. 
 
80 . 
 
 cells are set free and then commence a constant rotation round 
 their axis, sometimes to the right at others to the left. The 
 enveloping vesicle appeared at times to be absent, and I then 
 thought I could perceive that the Spermatozoa moved in a 
 spiral direction. As these observations were made on a tour 
 to the Tyrol, the last circumstance could not be exactly made 
 out ; subsequently, however, I have convinced myself that in 
 the Jungermannice and in mosses the Spermatozoa quit the 
 cells at a certain period of their development and then move 
 in numerous ways, but generally determined by the spiral ro- 
 tation of their tail. The Spermatozoa of the species of Sphag- 
 num which have been so accurately observed by M. Unger are 
 also developed, as I have noticed, in the cells ; but I have not 
 been able to perceive their division as stated by M. Unger, al- 
 though I have recognized it in the Spermatozoa of animals. 
 
 In the splendid work of M. Lindenberg* there is also a 
 chapter on the development of the female organs of fructifica- 
 tion of the Riccice, whence it is concluded that the Riccia have 
 no distinct permanent disk, but the whole frond must rather 
 be considered as such, and the last cellular layer beneath the 
 epidermis is the spot where the fruit at the time of maturity 
 momentarily dwells, or as in the Corsiniae arrives there even 
 previously. The formation of the fruit begins quite deep, 
 immediately above the under epidermis of the frond a small 
 dark spot originates which appears as a cavity, around which 
 the cellular tissue is compressed. This spot soon exhibits a 
 distinct yellowish-white membrane which forms a globular 
 sac, and is provided with an apex. In this sac are deve- 
 loped the disk-like bodies, whence the spores originate. The 
 fruit, however, in its further development gradually ascends, 
 while the cavity which was occupied by it in its earlier stages 
 is again closed by the expansion of the cellular tissue. The 
 fruit of the Riccics consists of two membranes, an inner the 
 true sporangium, and an outer the pericarpium, which, like a 
 calyptra, falls off when the spores have become ripe. In 
 Sphterocarpus and Oxymitra the outer tunic separates entirely, 
 it becomes a distinct coat, and the calyptra then again ap- 
 pears as a membrane coherent with the sporangium in the in- 
 terior of that tunic. At the formation of the spores in the 
 * 1. c. p. 392404. 
 
81 
 
 Riccia M. Lindenberg found the number 13 predominant, 
 while M. Mohl considers 14 to be the general rule. 
 
 The following observation was made on the germination of 
 the spores of R. crystallina, glauca, andfluitans. In the first 
 fourteen days merely a swelling of the margin of the spores 
 could be perceived; between the fourteenth and twentieth days 
 this margin expanded at one, or simultaneously at several 
 places. The expansions finally formed cells, but the further 
 development could not be observed. The fructification of the 
 spores is effected by the turbid fluid which proceeds from the 
 apertures of the anthoid organs, and flows over the surface of 
 the fronds. 
 
 M. Martens* has observed in the Botanical Garden of Lou- 
 vain, a hybrid between Gymnogramma calomelanos and G. chry- 
 sophylla, to which Bory de St. Vincent f proposes to apply the 
 name of G. Martensii. At the same time the latter gentleman 
 observes, that this hybrid formation appears to occur quite 
 commonly in nature, for he had received several well-preserved 
 specimens of this plant through I/Herminier from Guade- 
 loupe, where it grows among the two above-mentioned Gym- 
 nogrammce. He also enumerates several other ferns that 
 might be considered as hybrids, which it is true is merely 
 founded on suppositions, to which however I am partially in- 
 clined to assent. 
 
 The experiments on the artificial propagation of plants by 
 leaves have also been extended. In a memoir by E. Otto, 
 W. Brackenridge, C. Plaschnick, and C. BoucheJ, gardeners 
 in the Royal Botanical Garden of Berlin, several new observa- 
 tions of the kind are enumerated ; the work originated in a 
 prize question which had for many years been proposed by the 
 Horticultural Association, as to the best mode of increasing 
 plants by cuttings, and it obtained the prize as the best of 
 the answers communicated. The memoir is divided into four 
 parts, which treat of the propagation of plants by true cut- 
 tings, by root cuttings, by gem cuttings, and by leaf cuttings. 
 In the latter section it is stated that several species of Theo- 
 
 * Hybridite dans les Fougeres. L'Institut, 1837, p. 228. 
 f L'Institut de 1837, p. 280. 
 
 I Verhandlungen des Vereins zur Befdrderung des Gartenbaues in den 
 Konigl. Preuss. Staaten. xiii. I 8 Heft. Berlin, 1837, p. 7. 
 
 G 
 
82 
 
 phrasta, Aloe, Echeveria, Gloxinia, and Cotyledon, may be pro- 
 pagated by leaves; healthy leaves of these plants are chosen, 
 they are cut off close to the stem, and then placed singly in 
 small pots in a light sandy soil. The leaves are covered with 
 a bell-glass which must be open at the top. In the course of 
 eight weeks the leaves become cartilaginous, put forth roots, 
 and then very soon a young plant appears above ground. 
 
 It is desirable that this subject should soon be more fully 
 investigated, for we know at present that the emission of 
 young plants from leaves may take place in several ways ; first 
 by a production of true buds, as in Bryophyllum, and partly also 
 in Ceratopteris ; and secondly, by a previous formation of 
 gems, as in Ornithogalum thyrsoides, Ranunculus bulbosus, 
 cabbage leaves, &c. In M. DeCandolle's Vegetable Physi- 
 ology, (ii. p. 118.) M. Keeper has brought together several 
 other cases of the kind. 
 
 I have again drawn attention to the increase of mosses by 
 gems*, in which way, at least, several species of mosses propa- 
 gate quite as plentifully as by true spores ; Mnium androgy- 
 num., L., is the most known in this respect. A drawing an- 
 nexed to the article of the extremity of a similar gemmal pe- 
 tiole exhibited a number of petiolated gemmae which subse- 
 quently drop off from the stalks which become brown. Mr. 
 G. Dickie has also published several observations on the 
 same subject f; he saw in the gemmae of Bryum (Mnium) 
 androgynum on their first appearance nothing more than 
 simple minute transparent vesicles of an oval form. I per- 
 ceived in them immediately after their first appearance ex- 
 tremely delicate greenish masses which were converted into 
 globules, and were again partially employed in the interior for 
 the formation of new parietes. Mr. Dickie says, that these 
 gemmae in their mature state contain a substance of granular 
 appearance, but no mention is made of their cellular struc- 
 ture ; the drawings unfortunately can hardly be termed recog- 
 nizable. According to my subsequent observations, there is 
 first formed in the simple elongated vesicle which occurs as the 
 
 * Einige Worte iiber das Vorkommen von Brutknospen bei den Laub- 
 moosen. Wiegmann's Archiv, 1837, i. p. 424. 
 
 f Observations on the Gemmae of Bryum androgynum. Magazine of 
 Zoology and Botany, vol. ii. p. 226. 
 
83 
 
 first state of the gem, one or several horizontal walls, and 
 then these newly originated cells are more or less regularly 
 divided by longitudinal septa into smaller cells : during this 
 time the circumference constantly increases until the whole 
 formation is completed. Mr. Dickie also repeated the expe- 
 riments on the germination of the gemmae, which had been long 
 before instituted, described, and figured in Germany ; he saw 
 the first radicle make its appearance at the side of one extre- 
 mity, and it appeared as if it had proceeded from the interior 
 and had broken through the membrane. 
 
 Mr. Berkeley's* observations on the second membrane in 
 the Asci of some Fungi, as in Spharia populina, pedunculata, 
 &c., will require new observations to be made on this subject 
 with the aid of modern microscopes. 
 
 M. Schwannf has published a series of interesting experi- 
 ments on vinous fermentation, which appear to give another 
 direction to the answer of the question 'respecting equivocal 
 generation. He discovered that vinous fermentation is con- 
 stantly connected with the development of a peculiar fungus, 
 which he proposes to name Saccharomyces, Sugar Fungus. 
 He had also accurately observed the development of a si- 
 milar fungus in beer-yeast, when this subject was published 
 in the Institut du 23 Nov. 1836, by M. Cogniard-Latour. I 
 did not enumerate the latter observations in last year's Report, 
 in order to compare them simultaneously with those of M. 
 Schwann, as these interesting discoveries evidently belong to 
 both naturalists. M. Cogniard-Latour observed that the mash 
 an hour after the addition of yeast exhibited some single 
 globules resembling those contained in the yeast; an hour 
 afterwards some of these globules had doubled, while it ap- 
 peared as if the second globule had been expelled from the 
 first. The second globule soon became of the same size, and 
 subsequently no single globules were found ; nay, finally al- 
 ways three, four, or more such globules were found adhering. 
 M. Cogniard-Latour came directly to the conclusion that the 
 
 * On the existence of a second membrane in the Asci of Fungi. Maga- 
 zine of Zoology and Botany, vol. ii. p. 222. 
 
 t Vorlaufige Mittheilungen betreffend Versuche iiber die Weingahrung 
 und Faulniss. PoggendorfPs Ann. der Phys. und Chem. vol. xli. p. 184. 
 
 G 2 
 
84 
 
 globules of the mash had originated from seed in the globules 
 of the yeast ; he also states that twice he observed the flowing 
 of some fluid out of those globules of the yeast. M. Schwann's 
 observations on this subject are however much more accu- 
 rate, and I am able to confirm them were there any need of it. 
 He saw in the beer-yeast most globules cohering in series ; 
 they were partly round, but for the most part oval granules 
 of a yellowish white colour (they are perfectly colourless in 
 achromatic instruments. Rep,), which partly occur singly, 
 but generally in series of 2 8 or more. Usually one or more 
 distinct series branch off obliquely on such a series. In short, 
 the whole is an articulated and ramified plant. M. Schwann 
 observed, that the new articulations grew forth at the ends of 
 the terminal articulations, as the articulations to form new 
 branches were emitted laterally. During the fermentation of 
 the expressed juice of the grape similar plants were observed, 
 which presented but a small difference from those of the beer- 
 yeast, only that such long threads as are perceptible in the 
 latter were not noticed in the vinous fermentation. In the re- 
 cently expressed juice nothing of these plants is perceptible ; 
 at 20 they may be observed in thirty-six hours, and M. 
 Schwann could observe the increase of their volume under 
 the microscope in the interval of from half an hour to an en- 
 tire hour ; they are here more globular, and generally only two 
 are adherent together. 
 
 I have also been able to observe the growth of new articu- 
 lations from the ends of older ones in plants from beer-yeast 
 and also in vinous and apple ferments. The process is very 
 interesting and may be followed completely ; the individual 
 articulations subsequently separate and again grow on under 
 favourable circumstances. Each articulation of this plant is 
 a distinct independent plant, which immediately continues to 
 grow when disturbed in its adherence; or each articulation must 
 be regarded as a spore of the plant. If the single articula- 
 tions, in which state the plants in the thick beer-yeast are ge- 
 nerally found, are mixed in the mash, they continue to grow, 
 and in thinner fluids the plants become very large; their 
 branches extend radiately in all directions. I boiled the plants 
 from beer-yeast for ten minutes, and yet I observed their fur- 
 
85 
 
 ther development when again brought under the microscope ; 
 and M. Cogniard-Latour* exposed them to various degrees 
 of cold ; but even after the action of a cold 90 cent, they still 
 retained the property of decomposing sugar. 
 
 Similar plants occur in cider ferment ; they are articulated 
 and ramified in the same way as in the beer-yeast, but their 
 joints are mostly three times as broad as long, and I also ob- 
 served on them an increase by mere separation, although 
 rarely. 
 
 M. Schwann demonstrates the connexion between the fun- 
 gus described and vinous fermentation : however it is proba- 
 bly yet too soon to explain the phaenomena of fermentation 
 from their development ; first, because the formation of the 
 fungus is carried on much earlier than the development of 
 carbonic acid in the fermenting fluid, and then there are se- 
 veral other plants which are developed more or less at the same 
 time with them in the fermenting fluid, several of which, in 
 connexion with the former, are described under the unte- 
 nable genus Mycoderma, Persoon and Desmazieres ; nay, if the 
 supposed species of Mycoderma had not been figured by Des- 
 mazieres f we certainly should never have had a clear notion 
 of them. Desmazieres described a Mycoderma vini y glutinis 
 farinulce, malti-juniperi, malti-cerevisice y and ceremsice ; but 
 here two entirely distinct things are constantly united which 
 do not at all belong to one another ; namely, the small articu- 
 lated fungus previously mentioned, which we call Saccharo- 
 myces after M. Schwann's proposal, and form at present the spe- 
 cies Saccharomyces vini, cerevisice and pomorum, occurring in 
 all fermenting substances, together with a larger confervoid 
 one, the formation of which is also in many respects highly re- 
 markable. To this place belongs the confervoid fungus which 
 Amici observed in the sap of the weeping vine, the growth of 
 which also takes place very rapidly, so that the elongation can 
 be observed in a few minutes. This confervoid fungus is more 
 or less shortly articulated in various fermenting substances, 
 frequently unarticulated and unramified for some length, and 
 then the articulations form at the branches, frequently over 
 the whole thread at more or less regular distances, and then 
 again, especially towards the end of the branch, the articula- 
 
 * L'Institut, 18 Feb. 1837. No. 199, p. 73. 
 t Ann. Scienc. Nat., torn. x. 
 
86 
 
 tions swell to a globular form, subsequently disunite, and again 
 develop to new plants ; yet rarely will two fluids be found in 
 which these plants are quite similarly circumstanced. In the 
 expressed juice of a Borsdorfer apple, a fungus of this kind, of 
 great beauty, was formed together with the Saccharomyces; 
 several large, almost globular flocks, frequently of the size of 
 a pea, were present in the fluid, which were separated from 
 one another, and always consisted of a very large, or rather in- 
 numerable coils, of such single confervoid fungi, at the basis 
 probably adherent. I observed this very interesting form for 
 many weeks, and placed a single flock in a watch-glass with 
 pure water, and so that the branches came to lie close at the 
 surface ; to prevent the evaporation of the water the whole was 
 covered with a plate of glass. In the lapse of from eight to ten 
 days new radiate bundles were evident, and among these might 
 be observed several which proceeded from the globular sepa- 
 rated articulations of the original confervoid fungus, while 
 others had developed fruit and represented nothing else than 
 Mucor Mucedo when growing in water. 
 
 This form of the Mucor growing in water is but slightly 
 different from the aerial form, and even the outer membrane 
 of the sporangium may be observed on it. Mr. Berkeley* 
 has observed the origin of this confervoid fungus in currant 
 wine, and also noticed that it developed the organs of fructi- 
 fication of Mucor clavatus. The drawings which Mr. Berke- 
 ley has given prove sufficiently that in both cases we have 
 observed one and the same species ; I however consider the 
 Mucor as M. Mucedo, and am of opinion, from actual fre- 
 quently repeated observations, that M. clavatus is merely a 
 small variety of M. Mucedo, and cannot be regarded as a di- 
 stinct species. 
 
 From this observation, which I repeated, I conclude that 
 iheMycodermes are undeveloped vegetable forms, and, as some 
 other observations show, belong to the genera Mucor, Penni- 
 cillum and Aspergillus"\ . And here also belong the greatest 
 
 * On a Confervoid State^of Mucor clavatus, Lk. Mag. Zool. and Bot., 
 vol. ii. p. 390. 
 
 f Note. I would here especially enforce upon botanists the necessity of 
 at last directing their observations to the development of the lower forms of 
 Fungi, a subject which will be in the highest degree rewarded although the 
 number of the so-called species and genera of recent times will frightfully 
 disappear. Dr, Meyen, 
 
87 
 
 number of species of Agardh's supposed genus Hyyrocrocis, 
 as H. acida, vini, rosce, atramenti, salvice, &c. 
 
 In the fermenting fluids occur however several other things 
 of difficult determination ; thus I noticed in the beer-yeast 
 excessively delicate confervoid forms, which are generally 
 somewhat longer than the single articulations of the Saccha- 
 romyces, but are at the most only one-tenth in breadth ; they 
 are not of like length, and increase by division into still smaller 
 threads. They are only sufficiently evident with a magnifying 
 power of 300. In the expressed juice of the grape I observed, 
 besides the two above-described plants, a delicate white sedi- 
 ment, which adhered to the glass at the margin of the fluid ; 
 it was formed of innumerable perfectly round and equally 
 sized bodies, which were about one-tenth the size of the arti- 
 culations of the SaccharomyceSy and in the course of from 
 three to four days disappeared entirely. 
 
 The number of vegetable forms which occur in the ferment- 
 ing juices of fruits is consequently very great, and whether 
 the phenomena of fermentation depend on the one or the 
 other cannot be decided. M. Schwann instituted some obser- 
 vations with the vinous fermentation, whence he concluded 
 that in vinous fermentation as also in decomposition it is not 
 the oxygen of the atmospheric air which produces it, but that 
 it is a substance destructible by heat contained in the atmo- 
 sphere. A solution of sugar was mixed with yeast, exposed 
 .for ten minutes to the temperature of boiling water, then 
 brought into a small bottle under mercury, and some heated 
 air (one-fourth to one-third of the volume of fluid) conducted 
 into it. The bottles with the heated air were then closed with 
 a stopper and placed aside in a temperature of 10 to 14; they 
 evinced however no phenomena of fermentation, while other 
 bottles with the boiled fluid, into which however no heated 
 air had been conducted, were in the course of four to six weeks 
 broken into pieces from the development of the gas. The 
 phenomena widen M. Schwann observed in these experiments 
 are in effect very remarkable, but they might probably be ex- 
 plained in some other way : the temperature of boiling w r ater, 
 it is true, does not destroy the Saccharomyces as previously 
 stated ; but we also know that even the germination of the 
 seeds of higher plants does not take place in perfectly boiled 
 water, although exposed to the atmosphere. 
 
88 
 
 M. Trog*, of Thun, has published some general observa- 
 tions on the propagation of fungi by Mycelium and by spores, 
 confirming several statements previously published in various 
 works. The recent observations on the occurrence of spores 
 in the higher fungi were not then known to M. Trog. The 
 question how the sowing of the spores of fungi is effected in 
 nature is treated of at great length : it appears highly probable 
 to the author, that the spores of the Hymenomycetes are partly 
 suspended in the air, carried everywhere by the wind, and ad- 
 here to all bodies, or as it were are precipitated from the air 
 by rain. Thus for instance after some rainy days numbers of 
 MyceneS) dung fungi, &c., are seen to shoot forth, which had 
 been probably sown in this manner. Some examples are also 
 enumerated to give weight to the notion that the spores of fungi 
 float partly in the air ; for instance, if the divided membrane 
 of a laminated fungus be placed with the lamellae downwards 
 on paper, the spores, as is commonly known, fall on the paper ; 
 as soon however, says M. Trog, as the lamellae, from sinuosity 
 or from becoming vaulted, are not in contact with the paper, 
 these spots on the paper appear without any spores, because 
 the current of air is sufficient (even in closed rooms) to carry 
 them away. I repeated this experiment, but found the expla- 
 nation nearer at hand : the falling down of the spores is me- 
 chanically prevented when the lamellae are pressed together 
 by their lateral surfaces. The second statement is very re- 
 markable : place a Peziza or Helvetia on dark paper, and from 
 time to time, especially on a little shaking, it will be per- 
 ceived how many of the asci empty themselves all at once 
 with rapidity of their spores, a smoke being seen to ascend 
 from their hymenium, which however immediately disappears, 
 and even after several hours no considerable traces of their fall 
 can be noticed around the fungus ; consequently they have 
 remained in the atmosphere or have been carried away by it. 
 The other statements have long since been proved to be in- 
 sufficient. 
 
 M. Schwabef has published some observations on the Oscil- 
 latorice of the hot springs of Karlsbad, which correct in seve- 
 ral points the labours of his predecessors. He too feels the 
 
 * Ueber das Wachsthum der Schwamme. Flora 1837, No. 39. 
 t Ueber die Algen der Karlsbader warmen Quellen. Mit 2 Tafeln Abbil- 
 dungen. Linnaea, 1837, p. 109127. 
 
89 
 
 great want existing at the present day in the systematical defi- 
 nition of this genus and its species; for the most opposite things 
 have been described under the name Oscillatorice, and again 
 frequently the most similar forms have been enumerated as 
 distinct species. When one has observed for years the growth 
 of the Oscillatoriae daily in one's study, and noticed the mani- 
 fold changes of form in one species, it is really almost impos- 
 sible to conceive how travellers venture, during a short stay at 
 Karlsbad, to describe twenty, thirty, and even more new species 
 of this genus, a case which really occurred recently. 
 
 M. Schwabe has limited his observations only to some few 
 of these plants of the sources of Karlsbad, and he has there- 
 fore succeeded in observing something useful respecting their 
 structure and propagation. The separation of the genus 
 Mastigonema from Oscillatoria cannot however be adopted ; 
 for the very plant belonging to it, is to be regarded as the 
 representative of the true Oscillatorice. It is interesting to 
 see that the sporangia or spore-threads of Nostoc anisococ- 
 cum, Spr., have been described and figured as four distinct 
 species of Spharozyga,', these supposed species of Sphcerozyga 
 stand in the same relation to the Nostoc as the Oscillatoria 
 Flos agues to our common small Nostoc. The complete history 
 of the development of the Alga, which M. Schwabe has figured 
 and described as Fischera thermalis, is of great interest ; this 
 probably is presented to us by the same M. Fischer to whom 
 natural history is indebted for one of the most interesting 
 discoveries of recent times*. 
 
 M. Morrenf gives, with an accurate description of the struc- 
 ture of Conferva dissiliens, his views on the various generative 
 functions which are said to belong to this plant. He says that 
 the cells of this Conferva contain an almost homogeneous mass, 
 an endochrome, in which some distinct globules occur which 
 are converted into transparent vesicles yellower than the rest 
 of the mass, and exhibiting in their interior dark spots of a 
 brown or red colour. These larger globules which occur in 
 all true Conferva and have hitherto been regarded as similar 
 to the cellular sap-globules in other plants, are considered by 
 
 * The discovery here alluded to is probably that of the shields of some 
 Infusoria being composed of silex. W. F. 
 
 t Bulletin de 1'Acad. de Bruxelllcs, 1837, p. 303. 
 
90 
 
 him to be the male generative system, which performs on the 
 other portion of the endochrome a true impregnation. This 
 view would appear however to be a mere hypothesis, when we 
 observe the formation of the spores in the Spirogyrce by con- 
 jugation, as in these plants all the cells contain the larger glo- 
 bules, which M. Morren regards as the male generative sy- 
 stem, and yet germinating seeds are only formed in the con- 
 jugated cells. 
 
 I have published* some observations on the brownish ve- 
 sicles which characterize the cavities at the extremities of the 
 Closterice by their active molecular movement. Gruithuisen 
 discovered this motion twenty-six years ago, and he subse- 
 quently observed a current of minute globules which occur at 
 the margins of the Closteria, and may be compared to that 
 in the Charae. I pursued these observations somewhat fur- 
 ther, and remarked that they consist in two currents of mi- 
 nute globules proceeding in opposite directions, and are evi- 
 dent both on the concave and convex sides of the Closterice. 
 Other observations showed that these brownish vesicles pass 
 out of the cavities at the extremities of the horns, and that 
 they can change from their constant and lively molecular 
 movement into a merely progressive one, and vice versa ; for 
 they re-assume their molecular movement so soon as they 
 have returned from their progressive motion into the cavity 
 of the extremity. The observations for this view are spe- 
 cially given in the work above-mentioned, and I have subse- 
 quently made several similar observations on the cellular sap 
 globules of higher organized plants, which are enumerated in 
 the second volume of my Vegetable Physiology, in the chapter 
 on the rotatory current in cells. 
 
 Sir W. J. Hooker t has brought together numerous obser- 
 vations of great interest on the duration of the germinating 
 power of seeds, on which subject various, and frequently almost 
 incredible notices have appeared of late years. In the first place, 
 the observations of Ch. des Moulins, from the memoirs of the 
 Linnaean Society of Bordeaux, (which unfortunately are not at 
 
 * Wiegmann's Arcliiv, 1 837, p. 426. 
 
 f Information respecting seeds which have been found in Roman tombs, 
 and which have retained their powers of germination, &c. Companion to 
 the Botanical Magazine, 1837, vol. ii. p. 293. 
 
91 
 
 my disposal in Berlin) are related, according to which some 
 Roman graves were opened in the Commune de la Mouzie- 
 St. -Martin, Canton Laforce (Dordogne), which contained in 
 their coffins seeds of various plants, almost all retaining 
 their powers of germination : they were seeds of Heliotropium 
 Europceum, Medicago lupulina, and Centaurea Cyanus* Next 
 follow the observations of Dureau de la Malle, according 
 to which, seeds of birch, ash, brooms, Digitalis, &c. can 
 retain their powers of germination after a hundred years and 
 more under ground ; arid birch and mustard seeds can lie for 
 20 30 years under water without losing this power. Finally, 
 Sir W. J. Hooker communicates a letter from W. Burroughs, 
 in which is announced that seeds of Centhranthus ruber were 
 found in an old tomb at Wymondham Abbey, which germi- 
 nated and produced flowering plants. The seeds were found 
 in a small coffin of baked earth, closed air-tight ; they were 
 packed together with salt and odoriferous shavings with a 
 foetus and wrapped in linen, which was coated with pitch. 
 The tomb, in all probability, dated from the middle of the 
 twelfth century. 
 
 In October, 1834, there was also a notice in London's Gar- 
 dener's Magazine on the opening of a British tomb ; on which 
 occasion, in a portion of the contents of the stomach, a quan- 
 tity of small seeds were found which were declared to be seeds 
 of the raspberry. These seeds germinated in 183 6 and brought 
 forth excellent fruit*. Mr. Lindley immediately concluded 
 that the raspberry, at the time the tomb was placed there, 
 somewhat about 2000 years ago, grew wild in England. 
 
 MM. Edwards and Collin f have instituted a series of expe- 
 riments on the influence of vapour on vegetation : they placed 
 various seeds under exactly similar circumstances to germinate; 
 only the amount of vapour in the surrounding media was dif- 
 ferent, in order to observe directly its influence on vegetation. 
 It was observed that the influence of vapour was exceedingly 
 great, and that it very much hastened the vegetation in this 
 first period. The favourable circumstances which accelerate 
 the germination of seed are, the presence of as much moist- 
 
 * London's Gardener's Magazine, 1 836, p. 695. 
 
 t Influence de la vapeur sur la vegetation. L'Institut, 1837, p. 193. 
 
ure as the seeds are in want of for absorption, an atmosphere 
 which is almost completely saturated with vapour. This is 
 also applicable to the other periods of vegetation (as is shown 
 by the vegetation in the moist tropical forests. Rep.}. And 
 it thence follows, that in the hot-houses of our gardens the 
 influence of vapour on vegetables should be employed to a 
 far greater extent than has hitherto been the case. 
 
 The Feuilleton du Temps, 18 Avril 1837, contains a more 
 detailed communication of the memoir by MM. Edwards and 
 Collin, from which I will mention some of the results obtained. 
 In the open atmosphere, even when it is very moist, the seeds 
 of plants are said not to germinate. I have, however, only in 
 last year's Report mentioned exceptions to this rule. The 
 seeds of grain germinate in an atmosphere saturated with 
 moisture ; under water they require eight times the length of 
 time. With a simultaneous action of water and vapour, the 
 seeds germinate earlier when the atmosphere is saturated with 
 moisture. 
 
 Morphology. 
 
 From the great number of memoirs which appeared in the 
 course of 1837 treating of the morphology of plants, I shall 
 first select that of M. von Martius*, as the subject is there 
 treated in a more general way. 
 
 First Lecture. The plant, observes von Martius, is an or- 
 ganized body expanded between heaven and earth, free above, 
 but below fettered in the bands of the earthly. The plant 
 lengthens upwards and downwards, and differs in this twofold 
 growth, the descending and the ascending, so completely, that 
 the appearance of its two large systems is accompanied with and 
 incloses totally distinct formations. The root is essentially 
 the simple uniform portion (shut up as it were within itself) 
 of the plant. It constantly persists in its downward direction ; 
 it increases in length and in breadth ; can ramify by division ; 
 but neither is it as a whole, nor are its individual parts, ca- 
 pable of transformation. The ascending axis of the plant is its 
 solar and aerial system ; it is diametrically opposed to the 
 
 * Die Metamorphose der Pflanzen. Four lectures. Reden und Vortrage, 
 &c., p. 111-223. 
 
93 
 
 root. In all of the more highly developed plants the ascend- 
 ing axis soon separates into two formations, differing essen- 
 tially from each other, which, undergoing constant change, 
 represent in various forms the whole super-terrestrial life of 
 the plant. They are the axis or the stem and the leaf. The 
 stem is the persistentpart of all the super-terrestrial forma- 
 tions ; it is opposed to the leaf as the bearing part ; it forms 
 the centre, the axis ; the leaf on the contrary appears as a pe- 
 ripherically secreted part, which can be imagined to be sepa- 
 rated here and there from the stem. M. v. Martius thinks 
 that the leaf may also be considered as a secondary and re- 
 ramified axile formation, but that with respect to its inner 
 form it is asymmetrical. 
 
 The axile formation increases in length and in breadth, 
 and after some time divides into branches, thus resembling 
 exactly the descending axis. But an essential distinction 
 between the growth of the stem and that of the root is 
 said to consist in the first being developed at fixed periods, 
 while the root is less subject to periods of terrestrial life, and 
 is therefore in a constant state of growth at all times of the 
 year. 
 
 The leaf is developed by unfolding itself: it is not merely an 
 extension and elongation, but an increase in breadth ; and this 
 vital principle is the cause of its deviating from the perpendi- 
 cular position of the axile formation. The common leaves are 
 destined to increase and ameliorate the saps by the absorp- 
 tion and secretion of gaseous fluids : not so when the leaves 
 have changed their form, when they have become metamor- 
 phosed ; a phaenomenon which constantly accompanies the 
 production of the germ. A sexual function is the end of all 
 leaf-metamorphoses : the pistil-leaf on the female side, the 
 pollen-leaf or anthers on that of the male, wind up the beau- 
 tiful play of metamorphosis. These sexual leaves do not im- 
 mediately succeed the green ones, but a series of changes of 
 other leaves intervene, which, however, also belong to the ge- 
 nerative system. They differ from the foliage by their form 
 and colour, and may be termed coloured leaves. The trans- 
 formation of common leaves into coloured and into sexual 
 leaves is called the ascending metamorphosis; the retrograde 
 metamorphosis designates on the contrary the change of me- 
 
94 
 
 tamorphosed into green leaves. In the flower the axile forma- 
 tion seems to disappear entirely and presents itself as the re- 
 ceptacle. The transformed leaves now stand no longer one 
 above another, but side by side, and are therefore developed 
 nearly cotemporaneously. 
 
 There are three essential points in the ascending growth, in 
 the development of which the whole formative principle is in 
 action ; node, leaf, and internode. If we inquire into the ori- 
 gin of leaves, we find a thickening of the axis and a conver- 
 gence of its vessels in the node, just beneath the lateral inser- 
 tion of the leaf. Above a node the vessels again resume 
 their regular ascending course ; they return to perfect order 
 and symmetry, until at the end of the internode they come to 
 a new node and foliaceous formation, and thus several inter- 
 nodes stand one above another in the axile development. The 
 formation of each collateral axis is also stated to be preceded 
 by that of nodes and leaf. 
 
 Second Lecture. Leaves with distinct sheath processes, 
 with petiole and with the peculiar foliaceous expansion, are 
 regarded by M. von Martius as perfect leaves ; however, all 
 leaves do not possess these three parts, but sometimes the 
 one, sometimes the other exhibits a predominant develop- 
 ment. From these differences three kinds of leaves may be 
 distinguished : sheath leaves (Coelophylla), petiole leaves 
 (Steleophylla), and surface or broad leaves (Placophylla). The 
 succession of the green leaves from the root to the leaves of 
 the inflorescence is of high importance for the history of 
 the development of the plant. In general the formation of 
 leaves commences with Coelophylla, further upwards on the 
 stem both the other dimensions of the leaf occur, and when it 
 comes to a ramification of the axis one or the other of these 
 stages of the leaf is again lost. These changes are still 
 more remarkable when a flower proceeds from the axis in- 
 stead of a leaf-bearing branch. These are the bracts, called 
 ante-leaves or bearing leaves, the functions of which still co- 
 incide with those of the common leaves. But the changes 
 which the petals and sexual leaves exhibit are far more de- 
 cided in form and colour. At the metamorphosis of the 
 leaf into stamen the formation of the pollen proceeds in its 
 interior. This metamorphosis takes place in the upper or 
 
95 
 
 superficial parts of the leaf, which has become converted into 
 the anther, while the filament corresponds to the petiole of the 
 common leaf. The fruit leaf is the upper and last stage of leaf- 
 metamorphosis, and here we find the three dimensions of the 
 leaf each changed in a peculiar way ; the sheath portion is 
 converted into the germ, the petiole into the style, and the 
 superficies into the stigma. The fruit leaf is in general not 
 situated at or near the axis, but exactly upon it, and conse- 
 quently the elongation of the axis is herewith at an end. 
 The axile formation takes part in the formation of the fruit 
 only in so far as it frequently ascends along the suture, which 
 is formed by the cohesion of the margins of the coelophyllum, 
 and becomes part of it. This is most evident when the pistil 
 is formed of several leaves. When the margins of each leaf co- 
 here inter se and with the intermediate ascending substance 
 of the axis, several cavities are formed in the germ ; but when 
 the margins of each single fruit leaf .do not cohere inter se 
 but with the margins of the neighbouring leaves, one cavity 
 is produced. The flower does not give rise to collateral axes 
 which remain adherent to the plant, but produces axes of pe- 
 culiar structure, which separate from the primitive axis and 
 commence an independent life ; these are the seeds whose de- 
 velopment before and after impregnation is treated of at some 
 length, according to the facts at present known. 
 
 The leaves belonging to the series of the calyx and corolla 
 are to be regarded as leaves of two impulses following closely 
 one upon another. They are the peripherical parts of two 
 continuous portions of the stem which here indicate its me- 
 tamorphosis by the considerable contraction of the axis and 
 by the change in the form and colour of the leaves. The 
 calyx consists mostly of leaves which correspond only to the 
 inferior or sheath parts. They stand perhaps in the same 
 relation to the following more finely organized leaves as the 
 scales of the leaf-buds to their leaves. In a higher stage of 
 development the leaf becomes coloured ; in the young bud 
 the colour of the petals is generally of a light green. The 
 petal is however not a leaf metamorphosed in all its three di- 
 mensions, but it is especially the lamina or surface portion of 
 the leaf which is most developed, and the petiole is reduced to 
 the unguis in its development. When the petals are united in- 
 
96 
 
 to a single piece, the ungues form the tube, and the surfaces 
 the limb of the monopetalous corolla. Thus \ve have seen, 
 concludes von Martius, that the flower is that portion of the 
 ascending axis, in which the leaf, having undergone a four-fold 
 metamorphosis, ascends by degrees to its ultimate destination. 
 It is a four-times metamorphosed shortened branch, which has 
 departed from the nature of the leaf-bearing branch, &c. 
 
 Third Lecture. On closer consideration of the formative 
 processes of the flower, several laws become apparent, such 
 as, 1st, the succession of four great stages of formation, the 
 whorl of calyx, corolla, stamens and pistil. In accordance 
 with the second law, the calyx and corolla consist each of one 
 whorl of leaves, on the contraiy, the series of the stamens 
 of two whorls. The third law is founded on the number in 
 the structure of the flower, as in regular flowers the num- 
 ber of the members of all whorls is the same. The num- 
 bers three and five appear most frequent in the whorls of the 
 flower : three prevails in Monocotyledons and five in Dico- 
 tyledons. Calyx and corolla generally remain constant to this 
 number, i. e. duplications occur rarely. When these whorls 
 consist of fewer members the case may be regarded as an ex- 
 ception. The series of the stamens is however more subject 
 to duplications. The numerical relation of the last whorl or 
 that of the pistil undergoes frequent reductions, especially in 
 Dicotyledons, where instead of five frequently only one or two 
 pistils occur ; at times it is also increased. The difference in 
 the numerical relation in the series and in the members of 
 the whorl of the fructification is exceedingly great in various 
 plants, sometimes the typical numbers remaining equal from 
 the calyx to the whorl of the pistil, or increasing towards the 
 centre of the flower, or decreasing in that direction. The 
 position of the members in the various whorls of fructifica- 
 tion depends on the consideration of the numerical law. It 
 is said, the members of the next succeeding whorl are so ar- 
 ranged that they alternate with one another, whence it re- 
 sults that the position of each leaf in the flower is a regular 
 one. The most general types of the flower, therefore, the 
 Monocotyledons and Dicotyledons, may be represented by 
 two diagrams, and M. von Martius then considers how this 
 formation may be compared to the process in operation at the 
 
97 
 
 production of leaves and of branches, for it was demonstrated 
 that the sepals and petals are only leaves and the flower a 
 shortened branch. 
 
 Since the leaves are arranged either opposite or in a spiral, 
 these two types may also be admitted in the process of the 
 formation of the flower, namely that of whorls and of spirals. 
 The latter case is the most frequent, and it is proved by an 
 examination of the doctrine of the position of leaves that na- 
 ture acts after the same laws in the formation of the flower. 
 Now since the flower is a shortened branch, the leaves united 
 to form a whorl cannot always stand next one another so as 
 to be in contact in their regular succession ; for were this the 
 case with a whorl of five members, each leaf would only be at 
 a distance from the next of one-fifth part of the circle, while 
 they are in reality two-fifths or three-fifths of the circle from 
 one another. The arrangement of the sepals and petals is ge- 
 nerally distinguished by their imbrication, those leaves being 
 superposed which first separated from the stem, exactly as in 
 the leaf-bud. We have already seen that the members in the 
 successive verticils of the flower alternate, and this may be 
 explained by the supposition that a different proportion is in 
 action between the different whorls ; a proportion, which is 
 one half greater than that which prevails between the mem- 
 bers of the same period. 
 
 When the number of the members in the whorls does not 
 remain constant through the whole flower, we may suppose 
 two possibilities to explain it ; either a reduction occurs in the 
 members of one or more whorls which agree in proportion 
 with the rest, or the several series of the flower follow differ- 
 ent proportions. In both cases a dissimilarity occurs in the 
 numerical relations, and frequently connected with it an ir- 
 regularity of form also. The latter arises from unequal ex- 
 pansion and elongation. 
 
 Fourth Lecture. Von Martius endeavours to demonstrate 
 in this last lecture the general morphological laws which were 
 developed in the preceding one in their special relations ; those 
 of the flower are first entered upon, and he then treats of the 
 top, the bottom, the front, the back, the left and the right of a 
 plant : the gradual passage of the carpel into fruit is treated 
 of more at length, butjhis I can merely indicate. 
 
 H 
 
98 
 
 Shortly previous to this sheet going to press, I received 
 through the kindness of Alex, von Humboldt the splendid 
 work on the metamorphosis of plants, which M. Turpin has 
 recently published *. It contains only seventy-nine pages, but 
 of very small print, and in the largest folio ; three plates ac- 
 company it, designated by 3, 4, 5, and drawn by M. Turpin, 
 and on their account very probably the inconvenient folio size 
 has been chosen. 
 
 We are already acquainted with M. Turpin from the c Ico- 
 nographie Vegetale/ as a botanist who has his peculiar no- 
 tions on the metamorphosis of plants, which however have 
 met with great opposition, especially in Germany. In the 
 present work he has brought forward the same views, only in 
 a somewhat different form, without paying the least attention 
 to the many valid objections made by E. Meyer in the seventh 
 volume of the Linnaea. Upon the first plate M. Turpin has 
 represented a typical or ideal plant to prove the ee unite de 
 composition organique" as well as the radiate or centrifugal de- 
 velopment and the original identity of all the appendiculated 
 parts. It is divided into a Systems terrestre and a Systems 
 aerien ; the former appears to me particularly incomplete, al- 
 though it is correctly represented as an immediate continuation 
 of the stem. The pith of the stem proceeds through the whole 
 of the main root to its apex, while the collateral roots take 
 their origin in the wood. The axis of the aerial system of the 
 ideal plant is terminated by the embryo, which in one case is 
 situated with its radical apex on it, and in the second case is 
 attached to it by a kind of umbilical cord. On the second 
 plate are represented a beautiful series of splendid monstrosi- 
 ties of various parts of the inflorescence, several of which may 
 be quite new, and some of which I shall subsequently enume- 
 rate, without agreeing with M. Turpin as to their signification. 
 
 On the last plate three beautiful proliferous centifolial 
 roses are figured with great art, the sepals have become con- 
 verted into common leaves, and moreover the gradual change 
 of the petal into anther is demonstrated. I regret from want 
 
 * Esquisse d'Organographie vegetale, fondee sur le principe d'unite et de 
 composition organique et devolution rayonnante ou centrifuge pour servir a 
 prouver 1'identite des organes appendiculaires des vegetaux et la metamor- 
 phose des plantes de Goethe. Paris, 1837, fol. 
 
99 
 
 of space not being able to go more deeply into the doctrines 
 of this work, which shall be done in next year's report, if in 
 the mean time no other person shall have taken up the sub- 
 ject. 
 
 The profound researches of L. and A. Bravais * respecting 
 the arrangement of the leaves have excited in the past year 
 particular attention, especially on account of the difference in 
 the exposition and in the results from the similar inquiries of 
 German botanists. Several new terms have been added to 
 the existing nomenclature in reference to this subject which I 
 shall commence with. Secondary spires are those multiple par- 
 allel spires which by their union embrace all the leaves ; the 
 number of these spires is called the secondary number, and the 
 divergence separating two consecutive leaves of one of these 
 spires, the secondary divergence ; thus, when parallel and equi- 
 distant spires suffice to embrace all the leaves, eight will be 
 the secondary number of these spires. By ; encyclical number is 
 understood the number of circumvolutions requisite for the 
 primitive spire to pass from one leaf to the next following of a 
 secondary spire. For the sake of shortness the expressions dex- 
 trorsum and sinistrorsum are frequently replaced by their ini- 
 tials D. and S. : thus 2 S. represents a system of two parallel 
 spires comprehending all the leaves and proceeding from right 
 to left ; 3 D. a system of three dextrorsal spires, and so forth. 
 
 Although the leaf and the vital node are two decidedly di- 
 stinct organs, yet they are not here separated ; and frequently 
 the word insertion is employed, which has the advantage of 
 being equally applicable to the leaf and to the various foliaceous 
 organs, such as the scale, bract, &c. derived from it. Mother- 
 leaf is that leaf in the axilla of which any of these parts may 
 have originated. The authors divide the leaves into two differ- 
 ent groups; 1. curviseriate, arranged on all sides in spiral lines, 
 never forming vertical series, each leaf being the only one on 
 the vertical containing it ; 2. rectiseriate, capable of forming 
 series parallel to the axis of the stem. 
 
 The memoir is divided into two chapters ; in the first the 
 geometrical laws of the spirals are developed, and in the second 
 
 * Essai sur la disposition des feuilles curviseri^es. Annal. des Scienc. 
 Nat. Bot. p. 42- 120. 
 
 H2 
 
100 
 
 the position of the curviseriate leaves treated of; both are of 
 such extent and go so deeply into the minutiae, that we must 
 here content ourselves with communicating the results which 
 the authors themselves have drawn from then* observations. 
 
 At the commencement of the first chapter the following sup- 
 positions are made before entering into a more accurate ex- 
 position of the question relating to the multiple spires : the 
 point of the insertions forms a cylinder : the secondary spires 
 are geometrical helices : the coils are all parallel to each 
 other and equidistant. In the resume it is further stated, 
 that it frequently happens that the spires of an aggregation 
 of leaves or of vital nodes are raised or depressed, and cease 
 in consequence to be spirals in the most rigorous acceptation 
 of the word. Nevertheless this arrangement can hardly be said 
 to invalidate the results ? 
 
 It is quite certain that some unknown cause at times disturbs 
 in a greater or less degree the uniformity of the successive in- 
 ternodes ; but this does not destroy the divergence. Just as 
 the most depressed spires, for instance the primitive spires, are 
 the most favourably disposed to allow of our appreciating by 
 means of their deviations, the least variation in the vertical 
 heights of the insertions, in the same way the most elevated 
 spires, those approaching most to the vertical, being placed 
 under quite opposite circumstances, will also be most advanta- 
 geously situated to allow us to appreciate the least change in 
 the secondary divergences, as these variations of different kinds 
 occur in each of the two cases in the direction of a line which 
 is almost perpendicular to the spiral. Now we find as a con- 
 stant fact of observation, that the more the spires are of a higher 
 order, the more regular are their forms and directions. When 
 an insertion is driven out too much to the right or to the left 
 by some alteration in the vegetative power it is only a local fact, 
 an apparent deviation from the law, and the succeeding in- 
 sertions do not generally participate in this displacement. 
 Let us suppose that the place of the insertions is no longer a 
 cylinder but a conical surface, which is even more conformable 
 to nature, the secondary spires become Archimedean spirals 
 on the plane of convolution. But it may also happen that the 
 spires do not exactly follow the law of the spiral above ex- 
 pressed, they may either be too much raised or too much 
 
101 
 
 depressed in various portions of their course ; it will be with 
 these flexuosities, generally inconsiderable, as with those 
 treated of above in the case of the cylinder, and we shall still 
 be right in concluding generally on the constancy of the primi- 
 tive divergence from that of the secondary divergence. And 
 finally, in the general case, when the place of the insertions is 
 conical, nothing prevents our conceiving it to be divided into 
 horizontal sections, each of which would belong to various 
 cones ; and our results, true for each section, must also hold 
 good for the whole. 
 
 With respect to the parallelism and equidistance of the se- 
 condary spires among themselves, this is a supposition ren- 
 dered sufficiently evident by the direct observation of the plant; 
 it is only occasionally changed by that force which at times 
 disturbs the normal height of the insertions ; and as soon as 
 this normal height is re-established, the parallelism again 
 makes its appearance. 
 
 These results (those namely of the preceding paragraphs) 
 may be considered as general and independent of the geome- 
 trical form of the place of the insertions, and even of the re- 
 gularity of the secondary spires. 
 
 The torsion of the stem must however not be neglected : 
 sometimes it takes place in an opposite direction to the pri- 
 mitive spire, and then diminishes its divergence in appearance ; 
 at times it occurs in the same direction, and in this case the 
 primitive divergence is on the contrary increased. This force 
 rarely produces, in the opinion of the authors, any great effects; 
 nevertheless it is highly important, in all cases where it is pos- 
 sible, to take into account this source of error. 
 
 The second chapter of this memoir contains the special con- 
 sideration of all the cases occurring in the curviseriate leaves, 
 to which I must refer the reader. The general results are how- 
 ever the following. 
 
 1. When an aggregation presents several spirals whose se- 
 condary numbers are prime to each other, the insertions are 
 arranged on a single primitive spire, and are separated from 
 each other by a constant divergence from one extremity of 
 the aggregation to the other. 
 
 2. If the secondary numbers have 2, 3, or 4 for their com- 
 mon divisor, the insertions are arranged in whorls of 2, 3, 
 
102 
 
 or 4 leaves ; and these whorls cross one another at a constant 
 angle of divergence from one extremity to the other of the 
 aggregation. 
 
 3. In the greater number of plants with alternate inser- 
 tions the divergence of the primitive spire is an irrational 
 angle equal to 137 30' 28", which is but the small segment 
 of the circumference divided into mean and extreme propor- 
 tion : this angle corresponds to the series 1, 2, 3, 5, 8, 13, &c. 
 
 4. Other arrangements may occur, but much more seldom, 
 in which the divergence, still irrational, may equal 99 30' 6", 
 
 and correspond to the series 1, 3, 4, 7, 11 ; 77 57' 19", 
 
 and correspond to the series 1, 4, 5, 9 ; 151 8' 8", 
 
 corresponding to the series 2, 5, 7> 12, &c. 
 
 5. The constancy of each of these angles is not affected, at 
 least in its mean value, by the inequality in height of the suc- 
 ceeding internodes and other local disturbing causes. 
 
 6. The insertions may present false whorls when they are 
 grouped in twos or threes at the same height of the stem. 
 
 7. The primitive spiral is prolonged down to the subter- 
 ranean stem, retaining the same invariable divergence, and 
 sometimes even to the organs of the flower. 
 
 8. The direction of the spiral generally appears indifferent 
 on the central stem and on the branch ; it seems to be in no 
 certain relation to the direction of the convolution of the 
 voluble stems or to the torsion of the fibres on themselves ; 
 but on the branch this direction is determined by the posi- 
 tion of the first leaf to the right or to the left of the primitive 
 leaf. 
 
 9. All the series above cited may give rise to bijugate sy- 
 stems more or less frequently, and which will most frequently 
 be present on plants with opposite stem leaves ; the ordinary 
 system may also give rise to corresponding trijugate aggrega- 
 tions. 
 
 10. The phenomenon of the convergence of two spirals 
 into one must be explained by the partial abortion of one of 
 these spirals, or by the cohesion of the two into one ; a whole 
 series may also suffer complete abortion ; and this remark ren- 
 ders the existence of most of the recurrent series, which do not 
 appear to belong to the scries above enumerated, very doubt- 
 ful. 
 
103 
 
 A second memoir of MM. Bravais* treats of the symme- 
 trical arrangement of inflorescences ; a work which is still more 
 comprehensive than the first. On account of limited space 
 I am merely able to communicate the summary which the 
 authors have given at the end of the various paragraphs, be- 
 lieving that in this manner the results which they think they 
 are able to draw from their laborious researches, will most pro- 
 minently appear. 
 
 With reference to the inquiries respecting the uninodal cyme 
 of Monocotyledons, we find the following summary. 
 
 1. The uninodal cyme is the type of the cymes presented 
 by monocotyledonous plants. 
 
 2. The pedicel of each flower is furnished with a single 
 bract, susceptible of abortion, whence a second pedicel does 
 or may originate. 
 
 3. This bract indicates the spiral order of the pedicel. 
 
 4. The cyme may be helicoid, scorpioid or distichous, ac- 
 cording to whether the pedicels are homodromous or antidro- 
 mous or distichous. 
 
 5. It may be prolonged or contracted according to the 
 state of the pseudothallus, with sessile or pedicellate, simple 
 or double flowers ; this last case happens when it is dichoto- 
 mous at its origin. 
 
 6. It may be terminal or axillary, and in this second case 
 the inflorescence is generally a thyrsus ; as yet however we 
 have not met with a terminal cyme among the scorpioids. 
 
 7. The double helicoid cymes have their two halves homo- 
 dromous. 
 
 8. The double scorpioid cymes appear on the contrary to 
 have their first pedicels antidromous to one another. 
 
 The following results have been taken from the paragraphs 
 on the bracts of dicotyledonous inflorescences. 
 
 1. The greater number of dicotyledonous flowers have 
 their pedicel furnished with two lateral bracts, sometimes de- 
 veloped, sometimes more or less entirely abortive. 
 
 2. These two bracts are most frequently the first leaves of 
 a spiral proceeding from the primitive leaf and in continua- 
 tion with the sepals ; and when they are inserted at equal 
 
 * Essai sur la disposition symmetrique des inflorescences. Ann. des 
 Scienc. Nat. 1837, pp. 193, 291, 348, and vol. ii. p. 1142. 
 
104 
 
 heights, this circumstance will suffice to indicate whether the 
 pedicel is right-handed or left-handed. 
 
 3. In calyces with free sepals it is often easy to find dut 
 the direction of the calycinal spiral, and the direction of the 
 pedicel spiral may be concluded from their aestivation. 
 
 4. In the Leguminoscc the first sepal is closer than usual 
 to the median line, which modifies the form of the flower with- 
 out disturbing its general relations of organization. 
 
 5. The two bracts may be opposite-decussate : they may 
 also not exist. In paragraphs 5 and 6, the spiral and scorpioid 
 uniparous cyme is treated of, and in conclusion the following 
 summary communicated. 
 
 1. The binodal uniparous cyme is common in dicotyledo- 
 nous plants. 
 
 2. To the upper bracts belongs constantly, or appears to be- 
 long, the germen. 
 
 3. The cyme maybe helicoid or scorpioid according to whe- 
 ther the pedicels are homotropous or heterotropous ; it is disti- 
 chous when the distichous arrangement prevails on the pedicels. 
 
 4. It may be elongated or prolonged according to the state 
 of the pseudothallus, sessile or pedunculated, with sessile or 
 pedicellate flowers, simple or double. 
 
 5. It may be axillary or terminal : in the latter case it may 
 be considered as formed of one or two partial axillary cymes 
 and of a central terminal flower. 
 
 6. In a scorpioid cyme the aestivations of the flower of each 
 series have a fixed relation indicating the nature of the cyme. 
 
 7- The involution is a necessary consequence of the axil- 
 lary angle. 
 
 8. The floral series are organically opposed to the series of 
 fertile bracts, but the excentric inequality approximates them, 
 and separates on the contrary these latter one from another. 
 
 9. The sterile bract is frequently smaller than the fertile 
 bract ; it is frequently abortive ; both may also prove abortive. 
 
 10. The primitive bract frequently coheres with its axil- 
 lary pedicel. 
 
 11. The number of flowers is frequently variable ; it dimi- 
 nishes above in the thyrsus, and the cyme may become uni- 
 florous in consequence of this diminution. 
 
 12. The pedicels have sometimes a torsion in the direction 
 
105 
 
 of the secondary divergence of the fertile bract ; this torsion 
 tends to bring back the planes of the floral symmetry to par- 
 allelism. 
 
 13. An accessory branch may originate beneath the pe- 
 dicel analogous to the central stem : a branch may originate 
 analogous to the axis of the first bract. 
 
 14. Accidental exceptions to the preceding rules are now 
 and then met with ; the vegetables on which this exceptional 
 state is constant are very rare. 
 
 The summary of the four following paragraphs is, 
 
 1. The biparous cyme is essentially descendant or ascen- 
 dant : these two modifications do not appear to be met with 
 together in one and the same natural group. 
 
 2. The biparous cyme is direct or inverse. 
 
 3. The biparous cyme frequently ends by becoming unipa- 
 rous on its last branches ; the direct ascending cyme and the 
 inverse descending cyme then pass over to the scorpioid state ; 
 the inverse descending cyme and the direct ascending cyme on 
 the contrary pass into the helicoid state. 
 
 4. The double uriiparous cyme is a particular case of these 
 modifications. 
 
 5. The central flower of a double scorpioid cyme belongs to 
 the next concentric series to the primitive leaf. 
 
 6. The two partial axillary cymes of a double terminal cyme 
 commence with pedicels parallel to each other : in the Bo- 
 raginece it is the last node that produces the parallel pedicels. 
 
 7- The position of the terminal pedicel in the dichotomous 
 ramifications is determined by the value of the complimentary 
 divergences, and by the more or less excentric state of the 
 pedicels. 
 
 8. The direct ascending cyme is not rare in the Apocynea 
 and Polemoniacece. 
 
 9. The inverse ascending cyme appears to be characteristic 
 of the Ranunculacece ; several Ranunculi make exceptions 
 among the dicotyledonous plants by their uninodal cyme. 
 
 10. The rectangular cyme is usually biparous, but some- 
 times it may be uniparous. 
 
 11. The trinodal cyme is frequently but a variety of the 
 binodal, in which a node above the second, and heterotropous 
 with it, would precede the terminal flower. 
 
106 
 
 In paragraphs 11, 12 and 13 the multinodal cyme and se- 
 rial cyme are treated of, as also the kind of cyme in the chief 
 natural families enumerated, and in conclusion the following 
 consequences drawn : 
 
 1 . The accessory gem originates between a branch and its 
 primitive leaf, proceeds from this branch in the same way as 
 that from the central stem, and its primitive spiral has the 
 same primitive leaf for its point of departure. 
 
 2. The other inferior accessory gems likewise grow the one 
 from the other ; the same leaf serves them in succession as a 
 primitive leaf. 
 
 3. The gem produced between the branch and the axis 
 may proceed from a vital node situated at the base of the 
 branch and normally opposite to that of the angle of the leaf; 
 or the branch is accessory to the gem, this latter remaining 
 more or less stationary or becoming abortive. 
 
 4. The central axis, the principal branch, and the acces- 
 sory branches may cohere in various ways among them- 
 selves. 
 
 5. The serial cyme is composed of peduncles superposed in 
 this way : when these peduncles have their lateral vital nodes 
 sterile, the serial cyme is simple, in the contrary case it is 
 compound. 
 
 6. The accessory peduncle has constantly at least as many 
 vital nodes beneath its flower as the peduncles produced from 
 the first or second node of the central peduncle have beneath 
 theirs : when this number is very considerable, it may be 
 regarded as a leafy branch. 
 
 7. The multiple axillary embryos proceed directly or indi- 
 rectly from a central axillary embryo ; this latter is solitary in 
 the angle of the leaf. 
 
 Finally, in paragraphs 14, 15 and 16, the thyrsus, the sir- 
 mentide, the laws of homodromy and antidromy are explained, 
 from which the following conclusions are drawn : 
 
 1. When the successive axes of centrifugal inflorescences 
 have a small number of lateral nodes, generally two or four, 
 the second node is antidromous with the first, the third with 
 the second, and the fourth with the third, and so on : these 
 antidromes are the less constant as we arrive at axillary gems 
 whose numerical order is higher. 
 
107 
 
 2. There result thence two distinct dispositions, according 
 to whether the first node is homodromous or antidromous : 
 these two kinds divide vegetables into two unequal, gene- 
 nerally speaking very natural groups ; but they may also be 
 met with in nearly allied plants, or even in one and the same 
 plant, according to circumstances of vegetation. 
 
 3. The vegetative ramification does not present any general 
 law similar to the preceding, but in some rare cases, in which 
 some constancy in the order of the spirals is found, the pre- 
 ceding laws determine the order of the first nodes, and the 
 following three may be added to them : 3 . The opposite gems 
 appear antidromous with respect to each other : perhaps the 
 first law is merely a corollary of this. 3 b. The consecutive 
 distichous gems are antidromous with respect to each other, 
 and are frequently given out unilaterally. 3 c. On the curvi- 
 seriate alternate axes, at a sufficient distance from the first 
 nodes, the gems tend to become homodromous with respect 
 to each other; sometimes homodromous, sometimes antidro- 
 mous, to the central stem. 
 
 4. The accessory gems are most frequently antidromous 
 with that which is immediately above them ; this rule is never- 
 theless subject to exception when the gems are peduncles pro- 
 vided with a small number of nodes. 
 
 5. The dextrorsal accessory gems usually project to the 
 right and the sinistrorsal to the left ; the same effect is some- 
 times produced on non-accessory gems. 
 
 I must finally request indulgence if I have not given va- 
 rious expressions in the sense of MM. Bravais, for I freely 
 confess that a great portion of this immense labour has re- 
 mained very unintelligible to me, and it is reported that many 
 other botanists are in the same plight. 
 
 MM. Bravais have also published in a separate memoir the 
 results of the observations of MM. Schimper and Braun on 
 the position of the leaves of plants*. 
 
 M. Zuccarinif has published a very interesting memoir 
 on the formation of leaves and gems in Cactete, which contains 
 
 * Resume des travaux de MM. Schimper et Braun sur la disposition spi- 
 rale des organes appendiculaires. Ann. des Scienc. Nat. 1837. p. 161 
 182. 
 
 f Knospen mid Blatter der Cacteen. Allgemeine Garten-Zeitung von 
 Otto und Dietrich, No. 25. 1837. 
 
108 
 
 a great treasure of positive observations : it is a work the more 
 desired as we have recently obtained so complete a monograph 
 of this family. The Cactece are, says the author, provided 
 either with true leaves (Peireskia) or their rudiments (Opuntia, 
 Rhipsalis, Epiphyllum, Hariota,Lepismium, many Cerei), or are 
 actually leafless (Mammillaria, Melocactus, Echinocactus, the 
 rest of the Cerei). From the axes of the leaves or, when these 
 are wanting, from those places, where according to the laws 
 of the arrangement of leaves they would be situated, bundles 
 of thorns of various forms are developed, which may, accord- 
 ing to analogy, be regarded as buds, and the thorns as thorny 
 scales. In the Peireskice, in which alone true leaves occur, the 
 petiole is separated from the leaf and is regularly thrown off. 
 In the Opuntice the leaves are merely round, unarticulated, 
 pointed or obtuse formations, properly speaking only rudi- 
 ments of leaves, which gradually dry. In Rhipsalis, Epiphyl- 
 lum y &c., they are only small adpressed scales, ciliated at the 
 border, which also subsequently dry. The development of the 
 pulvinus stands in an inverse relation to the occurrence of 
 leaves in the Cactete : thus in the Peireskice it is almost im- 
 perceptible, but appears prominently where there is no forma- 
 tion of leaf. 
 
 The thorns or bundles of spines are situated in, or some- 
 what above the axis of the leaves, whether these occur or not : 
 in the latter case it will be evident from the spiral arrange- 
 ment peculiar to the leaves. It may also distinctly be ob- 
 served on the skeleton of the Opuntice that the ligneous 
 bundles proceed to the thorn-bundles just as they do to the 
 buds in other plants. Attention is also drawn to Barleria 
 lupulina, one of the Acanthaceae, where similar thorny buds 
 occur together with the usual ones. Numerous similar cases 
 however occur among the Syngenesista. 
 
 The thorns of the Cactece, which consequently must be re- 
 garded as metamorphosed bracts, are never hollow, but always 
 solid and of a firm corneous texture. They are smooth or 
 finely and softly haired. In Opuntia exuviata, tunicata, &c., the 
 upper cellular layer disengages itself, beginning at the basis of 
 the thorn, and then covers it as a sheath, which is easily drawn 
 off. The thorns frequently grow for many years, each time 
 advancing somewhat at the base, when the new-grown portion 
 
109 
 
 is easily discernible. In many Cerei, Opunticc, and Peireskitz 
 the number of the thorns in each bundle increases with age, 
 new ones annually shooting forth from the centre. In some, 
 especially in the Echinocacti, there is frequently a central thorn 
 which seems to terminate the growth ; and here the number of 
 thorns is almost universally constant as soon as the plant is 
 full-grown. The thorns are not always arranged in circles in 
 the bundles, but in the Echinocacti with sharp edges stand in 
 the form of an elongated ellipse, at whose upper end gradually 
 the last thorns and lastly the flowers make their appearance. 
 The flowers and new shoots of wood almost always appear 
 above the bundle of thorns, and are consequently not encircled 
 by them, which is even the case in Mammillaria prolifera. 
 The thorn bundles of the Mammillaria usually throw forth 
 neither flowers nor branches, and consequently, with the ex- 
 ception of a few species (Mammillaria vivipara,parvimamma) 
 which sprout from the mammillae but do not flower, are con- 
 stantly abortive ; while in the Mammillarice the flowers pro- 
 ceed from the stem close above the pulvinus. Here therefore 
 sterile or abortive buds and wood- and flower-buds occur on 
 the stem, and M. Zuccarini sho\rs that this double formation 
 of buds is also known in other plants. 
 
 M. J. Wttewaall has published a very elaborate memoir on 
 the nature of the stem in a physiological and morphological 
 point of view*. It is divided into four chapters: the first 
 treats of the development of the annual stem, the second of 
 the further growth of the stem, the third of the subterranean, 
 and the fourth of the difference between root and stem : they 
 are all written with a great knowledge of the subject and of 
 its literature, and will be of great value to subsequent mor- 
 phologists. In the consideration of the development of the 
 annual stem, the author sets out from a view, which enjoys 
 great favour also with us in Germany, viz. that of the compo- 
 sition of the cauliculus from the cohering petioles of the coty- 
 ledons, a notion which is completely refuted by actual ob- 
 servation of the development of those separate parts. It may 
 indeed be replied, that^I ought to give the proof: however, I 
 
 * Jets over het onstaan, den groei, en de vormveranderingen van den 
 stengel. Tijdscrift voor natuurlijke geschiedenis en physiologic, Vierde 
 Deel, 2 e Steek, 1837, p. 42105. 
 
110 
 
 promise to produce it very soon ; moreover it has already 
 been given in part in the recent papers of Dr. Schleiden.* 
 
 That which was assumed for the cauliculus is also consider- 
 ed valid for the separate internodes ; for each of them is said 
 to proceed from the petioles (which have remained in a state 
 of cohesion,) of the leaves becoming free higher up. The unte- 
 nableness of these statements is already sufficiently shown by 
 the observation respecting the division of the ligneous bun- 
 dles of the stem and their course to the actual leaves, yet in 
 this case the young and the old stem must be examined, and in 
 fact, from immediately after its appearance between the cotyle- 
 dons to the flower, &c. But the history also of the develop- 
 ment of the stem, and the leaves which proceed from it, which 
 is constantly effected in a similar way as in the formation of the 
 cotyledons, refutes this view of M. Wttewaall, upon which he 
 has founded the entire history of the development of the stem. 
 The subject is treated very nearly in the same way as in E. 
 Meyer's celebrated memoir in the 7th volume of the Linnaea. 
 
 In the second memoir, on the further growth of the stem, 
 M. Wttewaall also shows the greatest circumspection and ac- 
 quaintance with the literature on the subject, yet he holds 
 more to the side of the French physiologists. The third chap- 
 ter, in which the subterranean stem is treated of, deserves espe- 
 cial attention. The subterranean stem occurs in herbaceous 
 plants as well as in shrubs and trees ; it is thinner than the 
 air stem, and the leaves occur in the form of rudimentary scales 
 which occupy the same position as the leaves on the air stem. 
 If the latter is, as the author says, provided with stripes of 
 the remaining petioles, then we find them also on the subter- 
 ranean stem. True subterranean stems occur in Corchorus 
 olitorius, L., Spiraea sorbifolia, Syringa, Rosa, Clethra aim- 
 folia, where but lately they were regarded as true roots. Al- 
 though the creeping roots of trees and shrubs are able to de- 
 velope buds under favourable circumstances, yet this is pecu- 
 liar in a much higher degree to the subterranean stem, for all 
 its scales have buds in their axes. Not rarely do we find in 
 the trees above mentioned some, the stems of which are sur- 
 
 * [Of the papers here referred to, translations have been given in Nos. 73 
 and 74 of the L. and E. Phil. Mag., and Part VI. of Taylor's Scientific Me- 
 moirs. W. F.] 
 
Ill 
 
 rounded with runners, while others exhibit none ; the first ap- 
 pear to have been grown from cuttings, the latter from seed. 
 
 The subterranean herbaceous stem differs much more from 
 the air stem than was the case in the arborescent ones above 
 mentioned ; under this head are reckoned the anamorphoses 
 of the stem, which have hitherto been described under the 
 names of rhizoma, radix repens, bulbus, tuber, &c. Our au- 
 thor lays down three kinds of this subterranean herbaceous 
 stem; in the first the creeping stem does not increase in 
 thickness, in the second it does, and in the third kind the 
 stem is erect. He also directs attention to the circumstance, 
 that at times the terminal bud in the subterranean stem grows 
 further horizontally, while the lateral buds are developed in 
 the form of air stems in a vertical direction, and then the air 
 stem frequently takes a horizontal direction. A number of 
 excellent examples are enumerated ins upport of the three 
 positions. 
 
 The inquiries relative to the difference between root and 
 stem also abound in interesting observations. 
 
 A learned correspondence has begun between E. Meyer and 
 H. Mohl*, which promises to explain some of the most diffi- 
 cult points of morphology ; it relates to the morphological 
 signification of fibres, which E. Meyer considers, from their 
 position, analogous with branches. 
 
 M. Mohl perfectly coincides with E. Meyer respecting the 
 origin of the stem from leaves, but he does not adopt Meyer's 
 view of the formation of nodes, any more than the statement, 
 that the collum of the plant should be regarded as the first 
 node, and that to each internode would belong the node si- 
 tuated at its lower extremity, which are victoriously contested. 
 It is incomprehensible to me how M. Mohl can dispute this 
 latter statement, agreeing as he does to the first, on the origin 
 of the stem from leaves, for it appears that the one proceeds 
 from the other ; in my opinion, observation shows that the 
 leaves shoot forth from the stem, and this therefore cannot 
 consist of the cohering leaves or petioles. 
 
 M. Mohl regards the fibre as an axis which originates from 
 a descending current of sap, and merely represents the lower 
 portion of the vascular bundle of a perfect axis 5 as on the 
 * Linnoea, for 1837, pp. 106, 487. 
 
112 
 
 other hand, the bud which originates from an ascending current 
 only represents the upper portion of the axis. e( But 1 can- 
 not/ 5 says M. Mohl, " like you, regard the fibre as a series of 
 internodes, and not be of opinion that a fibre can replace any 
 branch ; but I believe that fibre and eyes together form a per- 
 fect axis, but that they are really connected only in the di- 
 cotyledonous embryo ; on the contrary, that they are separated 
 in the lateral position on the primary axis, and that the one 
 half is inserted at the upper end of the stem, the other at its 
 lower end." 
 
 M. Unger has published the results of his continued ob- 
 servations on the development and destination of lenticells *, 
 which we noticed in last year's report, p. 64 f. These in- 
 quiries have shown M. Unger, that in all cases where subse- 
 quently a lenticell is formed, a stoma existed in the green 
 branch. Even in Ulmus suberosa he observed that the obli- 
 terated epidermal pore constantly passed into a lenticell ; on 
 the contrary, all the transitions from the normal pore, through 
 all stages of its expansion, to its rupture through the epider- 
 mis, are seen in the annual shoots of Bignonia Catalpa. M. 
 Unger agrees with M. Mohl in regarding the lenticell as a 
 partial exuberance of the suberose layer of the bark ; I have, 
 on the other hand, proved in my Physiology, and more fully 
 in last year's report, that the lenticells originate from the green 
 cellular layer. They break through the suberose layer of the 
 bark, and observation certainly affords no reason for consider- 
 ing this process as analogous to the original formation of the 
 gemmae, which opinion M. Unger again repeats at the con- 
 clusion of his paper. 
 
 We have obtained from E. von BergJ a small but in many 
 respects very important work on the nature of bulbs. The 
 first chapter contains the observations and views which the 
 author has collected in a morphological respect on bulbs, but 
 the observations on the increase of bulbs are especially inter- 
 esting ; a subject which it is true has already been studied 
 in various ways, but is yet capable of daily affording new re- 
 
 * Flora von 1837, p. 236. 
 
 f Lond. and Edinb. Philosophical Magazine, vol. xii. p. 58. 
 
 1 Uie Biologie der Zwiebelgewachse oder Versuch die merkwiirdigsten 
 Erscheinungen in dem Leben der Ziebelpflanzen zu erklaren. Neustrelkz 
 und Neubrandenburg, 1837. 8vo. 
 
113 
 
 suits. Bulbs are divided into annual and perennial ; with the 
 consideration of the former, the history of the development 
 and propagation of the daffodil, the tulip, the crown impe- 
 rial, the crocus, the common onion, &c., are detailed with the 
 greatest accuracy. The hyacinth is taken as an example of 
 the vital history of the bulbs of perennial duration, and the 
 development of its bulbs very minutely described. The genera 
 Muscari, Ornithogalum, Uropetalum, Amaryllis, Narcissus, 
 Pancratium, Galanthus, &c., resemble the hyacinth. The con- 
 dition of the bulbs of Amaryllis formosissima is specially de- 
 scribed. The lilies form a second chief division of perma- 
 nent bulbous plants, in as much as they have scaly bulbs ; a 
 great number of liliaceous plants, which chiefly belong to our 
 most beautiful plants, have been studied for a series of years, 
 and the development of their bulbs fully described. Of the 
 Allia, Allium Cepa, descendens, fragrans, moly, nigrum, sati- 
 vum, Scorodoprasum and vineale are annual, and Allium acut- 
 angulum, fistulosum, senescens, and Victorialis are perennial, 
 and to the same class belong also some kinds of Iris, Scilla, 
 Gladiolus, Oxalis and others. All these observations are not 
 only highly instructive to botanists, but must also prove very 
 agreeable to the lovers of horticulture. 
 
 The second part of this work contains general observations 
 on bulbous plants, from which I may extract the follow- 
 ing. The regular, more or less rounded form of all bulbs arises, 
 says M. von Berg, chiefly from this circumstance, that in these* 
 plants, more so than in all others, the antithesis between the 
 inner formation and outer development appears most promi- 
 nently, and that both actions begin contemporaneously and 
 almost consist in the same act ! M. v. Berg noticed a curious 
 fact on the bulb of the narcissus, which commenced deve- 
 loping leaves of a bright violet colour like those of the flower ; 
 subsequently they increased considerably in length, but the 
 coloured apices dried up while the larger inferior portions re- 
 mained quite foliaceous. 
 
 A distinct chapter is devoted to the consideration of the 
 individuality and death of plants. The question, whether 
 plants die from age or whether their termination is brought 
 about by accidents, is then treated of, and M. von Berg de- 
 clares in favour of the first view, which in my opinion, how- 
 
 i 
 
114 
 
 ever, must be very much restricted. He even states himself, 
 towards the conclusion of his work, that the bulb may be re- 
 garded as a symbol of immortality, just as much as the dying 
 seed might serve as a general proof of the continuance in death. 
 
 M. Ohlert* has published some highly interesting obser- 
 vations on the position and farther development of the buds 
 of our common trees and shrubs. With the appearance of 
 the young leaves on the bursting of the bud, appear almost 
 contemporaneously in their axillae the young buds for the 
 next year, which are further developed in the summer and 
 autumn ; the scales of the buds are soon perfected, but the 
 inclosed leaves appear still to increase during the winter, which 
 as I have myself observed is at least the case in some plants. 
 The number of scales is quite constant for each species, and at 
 their opening in spring the buds have the same number of 
 leaves. There is a relative definiteness in the number of the in- 
 ternodes, which the annual shoot, i. e. the developed buds, ex- 
 hibits, the number of internodes in the different species never 
 exceeding a certain maximum ; moreover it often coincides 
 with the number of leaves or leaf-pairs which are formed ante- 
 riorly in the bud. M. Ohlert adduces in a table some excel- 
 lent proofs. Thus Fraxinus excelsior has two pairs of scales, 
 five leaf pairs, and at the utmost 3 internodes in the annual 
 shoot ; Msculus Hippocastanum seven pairs of scales, five of 
 leaves, five internodes ; Acer campestre six pairs of bracts, five 
 of leaves, ten internodes ; Sorbus aucuparia three pairs of 
 scales, five of leaves, eight internodes, &c. 
 
 M. Ohlert then observes, that at times, as in Tilia, &c. the 
 axillary bud becomes apparently terminal, but that it is easily 
 recognized on dividing it. 
 
 In the buds of some trees and shrubs more leaves are formed 
 than are to arrive at development, upon which the leaves at 
 the apex of the branch dry and fall off, for instance, in Sy- 
 ringa, &c., consequently no terminal buds originate in this 
 case. In other cases there are fewer leaves in the bud than 
 the young branch developes members, as in Ulmus campestris, 
 Tilia Europcea, &c., where also no terminal buds are formed ; 
 or as in Fraxinus, Acer, Cornus, Quercus, &c., where terminal 
 
 * Einige Bemerkungen iiber die Knospen unserer Baume und Straucher. 
 Limuea, v. 1837, p. 632. 
 
115 
 
 buds arrive at development. Lastly, there are also trees and 
 shrubs whose buds contain as many leaves as the future 
 branch is to have members, as in Cytisus and JEsculus. 
 
 MM. A. Henry and Cl. Marquart have given descriptions* 
 of various monstrosities of the carpel of Salix cinerea, which 
 may most easily be explained according to the view above 
 mentioned of the signification of the carpel. This and similar 
 deformities in the carpel of the willow have been frequently 
 observed and as often explained in different ways. The sepa- 
 ration of the carpellary leaves and their metamorphosis into 
 anthers, while the axile formation nevertheless produces the 
 ovules, would be the most essential fact resulting from the 
 descriptions given of the drawings. 
 
 There is besides, the drawing of a catkin of the same kind 
 of willow, the carpels of which are intended to show the retro- 
 grade metamorphosis of the ovules into leaves. The cavity of 
 the carpel is filled with a number of longitudinally folded leaves, 
 variously serrated at the margin, as shown in the drawing : the 
 ovules are said to be missing, but on this account the occur- 
 rence of leaves permits of a different explanation, and we can- 
 not yet admit that the ovules are metamorphosed into leaves. 
 
 M. Dutrochetf has also published some new observations 
 on abnormal formations of various parts of the plant, and com- 
 pared them with similar ones of other botanists, which is of 
 interest for the theory of the metamorphosis of plants ; how- 
 ever, I must refer the reader to the memoir itself, as the sepa- 
 rate subjects appear to me to be too special for this place. 
 We also find in it the observation, that we have no more rea- 
 son for admitting the petal or the stamen to be a metamor- 
 phosed leaf, than the reverse, that the common leaf is a 
 modification of form of the petal or the stamen. 
 
 M. Dutrochet has made several additions in the new edition 
 of his memoir on the generation of plants J, which are remark- 
 able in several respects. It is well known that Grew described, 
 
 * Ueber abnorrae Bildungen des Fruchtknotens der Salix cinerea, L. 
 Mit einer Tafel Abbildungen. Ersten Jahresbericht des botanischen Ver- 
 eines am Mittel- und Niederrhein, Bonn, 1837. 
 
 f Observations sur les transformations ve'getales. Mem. pour servir a 
 1'Hist. Anat. et Pbysiol. des Vegetaux, ii. p. 163. 
 
 J De la generation sexuelle des plantes et de 1'embryologie vegetale. 
 Mm. pour servir a 1'Hist. Anat. &c. ii. p. 115. 
 
 i2 
 
116 
 
 as early as 1672, a small aperture in the outer epidermis of 
 the seed of various Leguminos<z, which, in his opinion, was 
 destined to convey air to the embryo and to facilitate the pas- 
 sage of the radicle. Subsequent observers declared this small 
 hole to be the aperture through which the ovule was impreg- 
 nated, without, however, giving any positive observations on 
 the subject. In 1806 Turpin proposed a view which also 
 ascribed to the round aperture in the epidermis of seeds the 
 function of receiving the fructifying substance, and called this 
 point of the epidermis the micropyle, a term which has been 
 generally adopted, although it must in the present state of 
 science also give way to a more rational denomination. In the 
 memoir of M. Dutrochet we now learn that Turpin has aban- 
 doned his former opinion respecting the function of the mi- 
 cropyle, and at present supposes that it is an aperture without 
 any physiological function *. 
 
 M. Dutrochet, on the contrary, regards the micropyle as a 
 pneumatic tube which conveys to the interior of the seed the 
 air requisite for respiration, in short he has adopted Grew's 
 old notion respecting the function of the micropyle. I consi- 
 dered it to be my duty to prefix this short historical notice to the 
 subject in dispute, but it must greatly surprise every botanist 
 who is not acquainted with the subject from personal obser- 
 vations, that at the present day such a notion can be advanced 
 by a member of the celebrated Academy of Sciences of Paris, 
 after the most splendid writings have been laid before that 
 
 * In the most recent memoir of M. Turpin (Esquisse d' Organographie, 
 &c., p. 42) we find in fact these statements confirmed ; the micropyle of M. 
 Turpin is nothing further than the aperture which an involute, and at its 
 margins cohering, leaf exhibits at its extremities, therefore it has originated 
 from imperfect cohesion. "This deficiency in cohesion may be," says M. 
 Turpin, " divided into Micropyle foliaire, M. bracteen, M. antherifere, M. 
 ovarien, M. carpellaire, and M. ovulaire" &c. The aperture of the cavity 
 of the leaves of Nepenthes is considered by him as being something similar, 
 and he would term it Macropyle, but he pays no attention to this aperture 
 being provided with a lid. From this and several similar explanations of 
 M. Turpin, we should perhaps be justified in limiting this term micropyle to 
 the point of impregnation of the ovule ; for the aperture in the ovule, through 
 which the fructifying substance passes, is sometimes formed by the envelopes 
 of the ovule, and then either by the outer, or by the inner one, sometimes by 
 the apex of the nucleus, which frequently projects in a most remarkable 
 manner, but sometimes also by the apex of the embryonal sac, which fre- 
 quently projects far outpf the nucleus or the round aperture of the envelopes, 
 and thus grows to meet the fructifying substance, the pollen tube with its 
 contents. DR. MEYEN. 
 
117 
 
 assembly itself, giving a pretty complete explanation of the 
 function of the micropyle and the structure of seeds, leaving 
 out of question the researches of Rob. Brown. There is, it is 
 true, a great deal to be observed on this subject in special, but 
 in general we have so clear a knowledge of it that such a dis- 
 regard of the observations of others must highly astonish us. 
 
 M. Dutrochet describes in the second part of his work the 
 ovule of various plants, e.g. of Amyydalus communis, Evony- 
 mus europaus, Pisum sativum, Fagus Castanea, Galium Apa- 
 rine, Spinacea oleracea, Mirabilis Jalappa, Nymphaa lutea, 
 and Secale cereale, and shows that he is well acquainted with 
 a difference in the number of the envelopes of the seed in va- 
 rious plants ; but he nevertheless employs the terms for these 
 parts invented by M. de Mirbel, which in the present state of 
 observations are no longer suitable. M. de Mirbel has highly 
 advanced our knowledge of the structure of the seed, previous 
 and subsequent to impregnation, as every botanist will admit ; 
 and, though I would no longer recognize the terms which this 
 learned naturalist has advanced to render the subject intelli- 
 gible, it must not be regarded as a censure cast upon those 
 admirable researches. 
 
 At the conclusion of the memoir, M. Dutrochet relates his 
 observations on the formation of ergot ; he does not con- 
 sider it to be a fungus, but a diseased development of the grain. 
 But it appears to him probable, that this diseased development 
 of the grain into ergot is in consequence of the presence and 
 increase of a microscopic fungus, which should be placed by the 
 side of Uredo. I cannot however concur in this view, in con- 
 sequence of my observations on the subject. 
 
 Another important work of M. Mohl* relates to the mor- 
 phological signification of the organs of propagation of those 
 Cryptogamia which are provided with leaves. In these inquiries 
 he starts from the two following morphological positions, as 
 their correctness is of the highest importance in every explana- 
 tion of the organs of fructification of the Cryptogamia. They 
 are: 
 
 1 . That the anther in Phanerogamia is not formed by the 
 involution of a leaf, and that consequently the pollen grains 
 
 * Morphologische Betrachtungen iiber das Sporangium der mit Gefassen 
 versehenen Cryptogamen. Eine Inaugural Dissertation. Tubingen, 1837. 
 8vo. 
 
118 
 
 do not proceed from the surface of the leaf, but that they ori- 
 ginate in primitive cells which are situated in the interior of 
 the metamorphosed leaf, and subsequently again disappear. 
 This doctrine was already shown in last year's report to be 
 well founded, and in the present one it is supported by Dr. 
 Schleiden's observations. 
 
 2. That the carpel also, like the anther, proceeds only from 
 the metamorphosis of a leaf, and that the axile system takes 
 no part in it, but that the ovules always spring from the up- 
 per surface and from the margin of the carpel leaf. This se- 
 cond position is by no means to be considered as proved; nay, 
 we shall some pages further on be acquainted with the obser- 
 vations by which it might be refuted, and consequently several 
 explanations which M. Mohl has given of the sporangium 
 might be resolved in some other way. 
 
 On account of the difference which the sporangium exhibits 
 in various families with respect to structure, the single fami- 
 lies must be considered separately, and M. Mohl commences 
 with the Equisetaceae. The sporidia of these plants are, on 
 account of their origin in primitive cells, and partly from their 
 composition of a double membrane, compared with the pollen 
 grains of phaenogamous plants, and even a similarity in the 
 structure of the sporangium with that of the anther is sup- 
 posed to exist. He also refutes the view according to which 
 each of the angular receptacles in Equisetum is considered to 
 arise from the cohesion of a whorl of leaves ; observations on 
 the fruit-bearing shafts of Equisetum Telmateja are also enu- 
 merated, which presented transitions from the verticillate shaft- 
 leaves, cohering into sheaths, to whorls of fructification, and 
 which left no doubt that the so-called receptacle of Equisetum, 
 covered with sporangia, does not arise from a cohesion of a 
 whorl of leaves proceeding from a branch, but from a leaf of 
 the shaft itself; that it represents as it were the connective of 
 an anther developed to an extraordinary size, and that the 
 sporangia situated on its under surface correspond to the se- 
 parate loculaments of an anther. 
 
 In the consideration of the sporangium of ferns M. Mohl 
 first adduces the proof that the fronds of ferns must be as much 
 regarded as a true leaf, as the leaf of the Cycadece and palms; 
 and the want of buds in the axillae of the leaves of ferns is simi- 
 
119 
 
 larly circumstanced, as in the mosses, Lycopodineae and Cy- 
 cadece. (In these latter plants small buds not unfrequently 
 occur at the base of the stem between the scales. Rep.) 
 
 In the Ophioglossea M. Mohl compares the whole theca, in 
 reference to its organization, with the anthers of a phaenoga- 
 mous plant. The apex represents more or less distinctly the 
 apex of a leaf; the receptacles of the sporidia are mere cavities 
 in the tissue of the leaf, and the axis of the theca corresponds 
 to the middle portion of a staminal leaf contracted to a con- 
 nective. 
 
 InBotrychium the sporangia already become more independ- 
 ent ; they are perfectly separated from each other, a case 
 which M. Mohl compares to the formation of the anther in the 
 genus Geonoma. He also recognizes in the sporangia of all other 
 ferns, which develope their fruit on the under surface of the leaf, 
 an analogous formation with the theca of the anthers. At least 
 it is clearly proved that the morphological functions hitherto 
 ascribed to the capsules in ferns are erroneous, and M. Mohl 
 finds another reason for his view in the formation of sporidia 
 in primitive cells which are subsequently reabsorbed. No great 
 weight can be laid on this last reason, for at present several 
 other cases are known where the formation of new cells takes 
 place in original cells. A series of objections which might also 
 be brought forward against the analogy between the sporan- 
 gium of a fern and the theca of an anther are refuted at length. 
 
 The ingenious idea that the capsules of ferns consist of me- 
 tamorphosed leaves, the midrib of which forms the ring of 
 the sporangium, appears to have been first advanced by C. H. 
 Schultz ; altogether M. Mohl seems to pay too little regard to 
 the writings of that philosophical botanist, from whom the 
 sporangia of the lower plants have already long ago obtained 
 their morphological signification. Thus for instance the spo- 
 rangia in Equisetum have originated from the metamorphosis 
 of the foliaceous members of the stem, as those of the Poly- 
 podia from the metamorphosis of the leaves ; and consequently 
 the former also correspond to the articulation of the stem, the 
 nodes of which have formed the capsule-shields, and the 
 sheaths of the leaves the loculi of the capsule ! 
 
 There are greater difficulties in the signification of the spo- 
 rangium in Lycopodium, yet in this case M. Mohl seizes on 
 
120 
 
 the affinity which exists between Lycopodium and Isoetes ; 
 and since in Isoetes the sporangia do not stand isolated in the 
 axis of the leaf but upon it; since further in Psilotum, and more 
 evidently in Tmesipteris, the sporangium is situated on the 
 leaf, it becomes probable that the axillary position of the spo- 
 rangia in Lycopodium also is merely apparent, and that they 
 are rather a product of the leaf than of the stem. Yet these 
 statements are merely ventured as suppositions, for M. Mohl 
 found that the base of the sporangium is connected with the 
 midrib of the leai^ in whose axis it is situated, as well as with 
 the stem, so that we remain in doubt respecting its true point 
 of insertion. Moreover the sporangium of Lycopodium may 
 be much better compared to that of Botrychium, both in re- 
 ference to the form and to the mode of bursting than to the 
 carpel of phaenogamous plants. 
 
 After these researches, the question should be asked: 
 whether the sporangia of the higher Cryptogamia can be re- 
 garded as the same organ as the anthers in Phanerogamia, 
 and the spores as the same organ as the pollen grains. This 
 view was already advanced for various Cryptogamia by the in- 
 genious Agardh, and founded indeed on the mode of germina- 
 tion of the sporidia, in which a similar process was supposed 
 to be recognized as at the formation of the pollen tube. M. 
 Mohl has already previously contested this view, but thought 
 that the growth of the pollen tube was a mere mechanical act 
 produced by the endosmosis and the peculiar structure of the 
 poUen grain. These tubes were said to be projected both 
 in pollen grains, which had been dried for years, and in fresh 
 ones, when moistened by acids and alcohol, statements which 
 were adopted by almost all botanists, but the incorrectness of 
 which I demonstrated ten years ago, and at the same time 
 proved, against M. Brongniart's view, that the pollen tube did 
 not arise from a mere expansion of the inner membrane of the 
 pollen, but from actual growth. 
 
 An elaborate and highly important memoir by Dr. Schleiden* 
 is closely connected with the preceding one ; the author com- 
 mences with the admonition that the doctrine of the metamor- 
 
 * Einige Blicke auf die Entwickelungs-Geschichte des vegetabilischen 
 Organismus bei den Phanero^amen. Wiegmann's Archiv. [An English 
 translation of the entire memoir appeared in the February and March Num- 
 bers of the London and Edinburgh Philosophical Magazine. W. F.] 
 
121 
 
 phosis of the organs of plants can only be advanced by means 
 of observation. The history of the development, which must 
 be pursued from the earliest appearance, alone gives the cor- 
 rect solution respecting the destination of the various organs 
 of plants. 
 
 The embryo in the seeds of plants, says M. Schleiden, ori- 
 ginally consists of an axile formation, which is closed superi- 
 orly but is not limited inferiorly ; the upper end expands in a 
 globular form, and from the sides of this globe the cotyledons 
 proceed, while the apex developes to form a bud. What takes 
 place in the embryo is again repeated in the growth of the 
 leaves on the subsequent stem, and consequently this cannot 
 consist of adherent leaf-stalks. M. Schleiden is of opinion 
 that in investigating the laws of position of the leaves we must 
 set out from originally opposite ones, as exhibited in the coty- 
 ledons. That calyx and corolla are to be considered as folia- 
 ceous organs is generally admitted, and M. Schleiden also ob- 
 served that the monopetalous calices and corollae are in their 
 early stage noncohering, as also that every flower has in its in- 
 cipient development a regular construction. The grasses are 
 mentioned as a highly remarkable example, in which the organs 
 of fructification have, as is well known, been variously ex- 
 plained, since here non-cotemporaneous development, adhe- 
 sion and suppression of individual parts, quite disfigure the 
 original regularity. Nor can any longer doubt exist respecting 
 the formation and signification of the stamens ; they are mo- 
 dified leaves in whose diachyma four (this is the general law) 
 cavities occur filled with pollen. Sometimes, though rarely, 
 the original middle lamella is not developed, and then the di- 
 vision into two lateral cells does not exist, but it then appears 
 bilocular. 
 
 The formation of the pollen takes place in these cavities, 
 and in fact in the interior of primitive cells, in which proba- 
 bly for the most part four other cells are formed, in which the 
 single grains of pollen are produced. The quadruple number 
 is here the more general rule, yet, at times, as in Podostemon 
 ceratophyllum, there are only two grains of pollen found in 
 the large primitive cell. After the development of the pollen 
 the re-absorption of the primitive cells takes place, which in 
 some plants is effected entirely, in others less completely. 
 Nay, even with respect to the re-absorption of the large and 
 
122 
 
 small primitive cells, we find in several plants considerable 
 differences ; in Pinus we may still see in March and April the 
 large primitive cells separated into four distinct loculi. M. 
 Link* assigns to the tissue of these cells a peculiar name ; he 
 calls it Collenchyma, from its similarity with gluten. M. Link 
 also regards the well-known threads in the anthers of the 
 GEnothertz as remains of the membranes of the original cells. 
 
 M. Schleiden considers the placenta to be a formation of 
 the axis, and the carpel leaves to be modified true leaves, 
 which at the commencement are separated, and only cohere 
 subsequently in various ways to form the different kinds of 
 ovaria. In the Graminece and Cyperaceae the ovarium con- 
 sists of a single leaf, in the Conifers it remains open, in the 
 Resedacece three carpel leaves are united above to form one 
 open basin ; frequently the carpel leaves are bent towards the 
 axis, and then again turned backwards. In the palms, the 
 embryo is originally, soon after the impregnation, perfectly 
 erect ; the inner side of the ovarium does not however in- 
 crease in height as the seed advances to maturity : thus the 
 apex of the embryo becomes fixed and serves as a central 
 point, about which the radicula, in the unilateral development, 
 describes a quadrant, and in this manner the embryo horizon- 
 tails lateralis originates. 
 
 M. Schleiden commences his remarks on the ovulum and 
 placenta, with the description of the female flower of Taxus, 
 which is nothing more than the terminal bud of the collateral 
 axis ; the axis terminates in a small protuberance, which is 
 the nucleus of the ovule ; and since subsequently in the act of 
 impregnation a union of this axile formation takes place with 
 the pollen, impregnation consists in nothing more than in 
 the conjunction and balancing of the two most important an- 
 tagonistic forces the plant possesses, viz. those of the hori- 
 zontal (leaves) and of the vertical (axis) structure. 
 
 The nucleus is the most essential part of the ovule ; its en- 
 velopes, which are termed ovular membranes, are only to be 
 considered as collateral formations, and M. Schleiden regards 
 them as amplexicaul integumental leaves, which are here com- 
 bined into a sheath-like envelope. Now the nucleus either 
 mains naked or is provided with a simple or double integu- 
 
 * Philos. Bot. cd. alterna, ii. p. 199. 
 
123 
 
 ment. Since the usual terms testa and membrana interna 
 are not applicable to these envelopes, he proposes that of 
 integumentum simplex for the one case, and those of inte- 
 gumentum externum and internum where the nucleus is in- 
 closed in two envelopes. The difficulty in the investigation 
 of the ovule is chiefly caused by its being in a great number 
 of plants reflected, even long before impregnation, and this 
 reflexion occurs both in the naked ovules and in those which 
 are provided with simple or double integuments. M. Schlei- 
 den ascribes all reflexions of the seeds of plants to the axile 
 formation, and therefore to the nucleus, with which I cannot 
 agree ; he moreover only enumerates the two cases where the 
 axis remains straight (ovulum atropum), and the other where 
 the axis is reflected and produces the ovulum anatropum. In 
 a physiological respect these reflexions are very unimportant, 
 for in many "plants I have found some ovules not reflected, and 
 nevertheless perfectly impregnated; but to systematic botany 
 these reflexions of the ovule are very important, and the third 
 division which even earlier botanists have established, that of 
 the amphitropous seed, is quite indispensable. I shall en- 
 deavour to show in another place that the amphitropous seed 
 must not merely be considered as a transition-form between 
 the atropous and anatropous seeds ; and moreover the frequent 
 reversions of the ovule by a subsequent curvature of the um- 
 bilical cord must be designated by distinct terms. The forma- 
 tion of the integuments of the nucleus is very accurately 
 and minutely described by M. Schleiden, and what I have ob- 
 served on this subject fully coincides with his statements; 
 I also agree perfectly with him that MirbePs quartine does 
 not exist as a distinct membrane. 
 
 Although it is easy in cases with true placenta centralis li- 
 bera or as in the Polygonea., in Taxus, &c. to explain the nu- 
 cleus as the mere apex of the axis, yet it might prove difficult 
 to many botanists in the case of parietal placentae : however 
 M. Schleiden enumerates several examples which give to this 
 view a high degree of probability ; for example, the ovaria of 
 the Fumariaceae and Cruciferts and the cones of the Abietince. 
 
 These views of M. Schleiden will certainly meet with great 
 opposition : hitherto it was generally admitted that the ova- 
 rium consisted of buds which formed at the margins of leaves. 
 
124 
 
 M. Schleiden regards this explanation as a supposition totally 
 unfounded, and thinks that he is able to establish as a general 
 law that a bud is never formed upon a leaf. This law however 
 is easily seen, by direct observation of nature, not to exist ; the 
 very supposition is the weakest point of Dr. Schleiden's ex- 
 cellent memoir, and has led him to many forced explanations. 
 I believe that I am able to prove that, if we base the morpho- 
 logical signification of the ovarium on unprejudiced obser- 
 vation, and do not explain the observations according to pre- 
 conceived views, we must admit a four-fold mode of origin of 
 the ovules; viz. they originate most frequently at the margins of 
 the carpel leaves, next at the sides of the midrib of the carpel 
 leaves, more rarely upon their entire inner surface, and lastly 
 also from the axis, where they occur either at the end of the 
 axile formation, or at the side of the frequently much shortened 
 axis. 
 
 I will here draw attention to some of the splendid monstro- 
 sities figured and described by M. Turpin in the work pre- 
 viously noticed*: the explanation it is true frequently stands 
 quite in contradiction to the figured observations. Fig. 19 is 
 the drawing of a monstrous fruit of Aquilegia vulgaris, the five 
 carpel leaves are almost completely rolled up and their lateral 
 walls covered with ovules and leaves. Figs. 28 and 29 repre- 
 sent monstrous involucra of Trifolium repens ; in one case 
 the ovule-bearing margins of the carpel-leaves are not adhe- 
 rent and are clothed with six small leaves ; in the other partly 
 ovules and partly leaves have shot out from the margins. Im- 
 mediately above, in figs. 20 22, M. Turpin gives his explana- 
 tion respecting the formation of the legumen by the cohesion 
 of the convoluted leaves. 
 
 Now, says M. Schleiden, as in the pollen-bearing organs 
 the cellular tissue is converted by a peculiar modification into 
 pollen, so also we observe in the summit of the axis, the nu- 
 cleus, a peculiar modification of this tissue ; for in it is deve- 
 loped a single long cell which is subsequently converted into 
 the sac of the embryo, and this happens at a period long pre- 
 vious to the so-called impregnation. The manifold varia- 
 tions, to which this sac is subject in various plants, are partially 
 
 * Esquisse d'Organographie Wget., &c. PL IV. 
 
125 
 
 known ; in Lathraa squamaria it was observed in the form of 
 shapeless excavations. However, according to my observa- 
 tions, the sac is not constantly situated in the interior of the 
 nucleus, and in fact M. Schleiden's description of the struc- 
 ture of the ovule previous to impregnation cannot be consi- 
 dered as a general rule, by the conception of which every case 
 of deviation would appear very easily explainable. In nume- 
 rous cases the sac of the embryo is only formed subsequent to 
 impregnation ; and in others, where the nucleus occurs long be- 
 fore in the form of a hollow sac consisting of a simple cellular 
 layer, it then occupies itself the place of the embryonal sac. 
 
 M. Schleiden lastly arrives at the actual act of impregna- 
 tion, the plastic processes of which have hitherto been de- 
 scribed in the writings of Amici, Brongniart, Rob. Brown, and 
 Corda. On the 31st of July 1833, Robert Brown made known 
 that he had followed the pollen tubes in Asclepias phytolac- 
 coides to the apex of the ovule, and therefore to the summit of 
 the nucleus, since in Asclepias this is perfectly naked, which 
 Mr. Bro\vn did not then venture to advance : " to this point/* 
 it is stated in that short paper, ee the tube adheres so firmly that 
 I am inclined to think it actually penetrates, to some depth 
 at least, into the substance of the ovulum," &c. But on Mr. 
 Brown's visit to Berlin, in the first days of September 1833, 
 he had already advanced somewhat further in this inquiry, for 
 he showed me with his accustomed kindness the entrance of 
 the tubes into the summit of the nucleus, which was after- 
 wards seen in Breslau also, although Corda subsequently took 
 no notice of it. In a memoir which M. Corda presented to 
 the Kais. Leopold. Akademie* in September 1834, he gave 
 his observations on the act of impregnation in the Conifera ; 
 he saw the pollen tubes ascend through the cavity of the se- 
 cundine to the opening of the nucula, enter this, become 
 thinner in its cavity, and discharge their contents in the form 
 of a turbid liquid mass. This mass M. Corda observed soon 
 to fashion itself, forming the embryo-sac, but the connexion 
 of the pollen tubes with the embryo-sac continues for some 
 time after impregnation. 
 
 I have prefixed these historical statements in order to render 
 
 See the Jahresbericht for 1835. Wiegmann's Archiv, 2 tem Jahrg. 2 ter 
 Band. 
 
126 
 
 as prominent as possible the new view which Dr. Schleiden 
 has advanced on the act of impregnation in plants. He sup- 
 poses that the course of the pollen tubes from the stigma to 
 the ovule is the general process in the impregnation of Phane- 
 rogamia, and further that one, rarely a greater number, of 
 these tubes penetrate the intercellular passages of the nucleus. 
 The tube which reaches the embryo-sac presses it forwards, 
 indents it, and appears in the form of a cylindrical bag, which 
 forms the commencement of the embryo, which therefore is 
 nothing more than a cell of leaf-parenchyma ingrafted upon 
 the summit of the axis ; consequently it is formed by the 
 membrane of the pollen tube and by the indented embryonal 
 sac. (Much as I value the observations of Dr. Schleiden, 
 and rejoice that many points of vegetable physiology will be 
 considerably advanced by his profound researches to a more 
 rapid solution than otherwise would have been the case, yet I 
 must declare that these statements are not quite correct. The 
 embryo-sac is certainly never indented by the penetrating 
 pollen tube, nay, the embryo is even frequently of considerable 
 size before any trace of an embryo-sac exists. Rep.) In plants 
 which possess several embryos, just as many pollen tubes are 
 present as there are embryos. From these observations, says 
 M. Schleiden, the important consequence proceeds, that the 
 two sexes in plants have been named quite falsely, for each 
 grain of pollen of the nucleus is a new individual, and the 
 embryo-sac on the contrary should be regarded as the prin- 
 ciple which only determines dynamically the organization of 
 the material substratum. 
 
 It will hence be seen that the statements of MM. Corda 
 and Schleiden respecting the plastic processes in impreg- 
 nation in the interior of the ovulum are quite different : the 
 former are, except the penetration of the pollen tube into the 
 nucleus, which was previously observed by Robert Brown, 
 entirely incorrect ; not only does M. Schleiden say so, but 
 Robert Brown also, and I likewise convinced myself of it soon 
 after the publication of the observations ; nay, M. Corda has 
 completely misapprehended the most essential facts in the 
 structure of the ovule previous and subsequent to impregna- 
 tion, notwithstanding the good observations already extant at 
 the time. The question now is, whether the observations of M, 
 
127 
 
 Schleiden on the act of impregnation are correct, and whether 
 we must dismiss in consequence our old views respecting the 
 sexes of plants. I am of opinion (and shall endeavour to prove it 
 in the third volume of my c Physiology') that M. Schleiden's 
 observations have considerably advanced our knowledge re- 
 specting the plastic process in the impregnation of plants; but 
 it will be shown that the old notions of the sexes of plants must 
 be retained as before, even setting entirely aside the formation 
 of bastards, which could not be explained according to the doc- 
 trine that the anther must be considered as a female ovarium. 
 
 We return at present to the consideration of the embryo. 
 Upon its first appearance, says M. Schleiden, the embryo is to 
 be recognized as a membranous cylinder, rounded and closed 
 superiorly, open inferiorly, and filled with organisable matter, 
 which is gradually converted into cells, beginning from above 
 downwards, during which process the cellular nuclei become 
 apparent, which appear at all times to perform a principal part 
 in the formation of cells*. This cylinder M. Schleiden regards 
 as an axile formation, the upper end of which expands into a 
 globe, whence the cotyledons are developed, the apex (that is 
 to say the axis) remaining more or less evidently free, by which 
 it is proved that the axis exists before the leaves. 
 
 The first appearance of the embryo and the formation of 
 its parts is naturally of the highest importance for the mor- 
 phological explanation of the various parts of the grown plant : 
 
 * With respect to the function of the cellular nucleus several important 
 discoveries have been made in the current year (1838), which in many 
 cases perfectly explain the formation of the cellular tissue of plants. I have 
 also observed in many cases that the cellular nucleus makes its appearance 
 originally as a simple globular mucous cell provided with a solid spherical 
 nucleus, and only at a subsequent period is converted into the disc-like forma- 
 tion which is very frequently attached by excessively delicate, and at times 
 also ramified threads to the inner surface of the cell. From the substance 
 of this disc, the first rudiments (the nuclei) of the amylum globules and of 
 the other cellular sap globules, which for some time adhere to the disc and 
 form a circle around the more solid nucleus, are formed. Subsequently the 
 mucous substance of the disc disappears, the starch globules, &c. increase in 
 size and still remain for some time in that circular position, in which the 
 green cellular sap globules are frequently found in the cells of the epi- 
 dermis. In very young potatoes and in some species of Cactus I have been 
 able to follow up this formation. Rep. [Dr. Meyen here evidently alludes 
 to M. Schleiden's admirable memoir on Phytogenesis, which at present oc- 
 cupies so much of the attention of continental botanists, and of which an 
 English translation appeared in the 6th Part of Taylor's Scientific Memoirs. 
 W. F.] 
 
128 
 
 I therefore communicate the results of my observations on 
 this subject, which are somewhat different from those of M. 
 Schleiden. The membranous cylinder from which M. Schlei- 
 den starts is not always present, but where it occurs cellular 
 nuclei are formed in it and cellular walls around them, and 
 thus the cylinder is divided into cells ; the terminal cell, how- 
 ever, expands in a globular form, and from this is 'developed 
 the entire embryo, which sooner or later separates from the 
 articulated thread originating from the older parts of the cy- 
 linder and termed by De Mirbel " bearer ;" it does not belong, 
 as it appears to me, to the essential parts of the embryo. Thus 
 the embryo appears on its first occurrence to be a simple glo- 
 bular cell, and has consequently the form of the most simple 
 of plants. This globular cell forms, from within outwards, into 
 a cellular mass, and it is only after it has attained a certain 
 size that the cotyledons are developed ; but at the same time 
 a growth of the globule takes place towards the opposite end, 
 and consequently the formation of a true axis. I confess, how- 
 ever, although I regard the stem as that part from which the 
 leaves proceed, and have anatomically demonstrated it, that I 
 could not observe the apex of the embryo-globule (punctum 
 veyetationis, Wolff.) to remain free between the projecting 
 cotyledons, I only saw the appearance of the first trace of the 
 future plumula at a subsequent period. 
 
 M. Kunth has shown* by observations on the seeds of 
 Crucifera that the embryo of these plants adopts only towards 
 the ripening of the seed, in consequence of external causes, the 
 various forms which it exhibits in the perfectly developed 
 state ; and that those differences, since the causes which give 
 rise to them must always re-occur in the same plant, afford 
 very constant and important characters. He found in the 
 young seeds of Erysimum cheiranthoides, L., and E. officinale, 
 L., the radicula always situated laterally to the cotyledons, and 
 these only became incumbentes with advancing maturity. In 
 young seeds of Raphanus sativus the embryo was still nearly 
 straight, merely curved at the radicula ; the cotyledons were 
 expanded and of unequal size, by which means the subse- 
 quent relations become intelligible. 
 
 * Ueber den Embryo der Cruciferen. Wiegmann's Archiv, 3ten Jahr- 
 gang, Iten Theil, p. 232. 
 
129 
 
 A similar change of the original position of the parts during 
 the process of ripening was also observed by M. Kunth in 
 the fruit of the Cruciferae. The ovarium for instance is so 
 placed in these plants that the axis corresponds to the dis- 
 sepiment ; but in fruits where the dissepiment expands it is 
 situated laterally with respect to the axis. 
 
 M. Mohl* has given a complete description of a deformed 
 hermaphrodite floral catkin of Pinus alba, which explains va- 
 rious points in the morphological signification of the flowers 
 of the Conifers in a very decisive manner, and which will evi- 
 dently settle the differences of opinion that prevail among bo- 
 tanists on this subject. He found these monstrosities on se- 
 veral female catkins of Pinus alba, on the lower half of which the 
 flowers formed more or less perfect transitions to male flowers, 
 while the upper portion was covered with perfectly normal fe- 
 male flowers, which also commenced, in those specimens that 
 were left for some time longer on the tree, developing very re- 
 gularly into fruit. All those flowers which formed a transition 
 to male flowers consisted, like the normal female flower, of two 
 organs, the bract and its axillary carpellary leaf; each of these 
 parts differed from the normal type, the bract for instance was 
 more or less perfectly converted into a stamen, and the carpel- 
 lary leaf was, the more completely this change of the bract 
 belonging to it had taken place, developed of a smaller size, 
 and less perfectly. The inferior flowers of these catkins were 
 smaller, and the ovules had not developed on their carpel-leaf. 
 In the upper flowers the carpel-leaf was smaller, it was some- 
 what bent forwards superiorly, and had become linguiform. 
 In the highest flowers it represented a scale folded together, and 
 was nearly quite green. In the same proportion as the carpel 
 diminished the bract expanded, not only in respect to size but 
 much more with reference to structure. In the inferior flowers 
 there was on the outer side of the bract, above its base, a round 
 protuberance of a yellowish green colour, which possessed in 
 its interior a hollow cavity filled with pollen grains ; the upper 
 portion of the bract stood, like the carpel-leaf, erect. Upon the 
 upper surface of this bract, along its middle line and from its 
 point of insertion to its summit, proceeded a somewhat raised 
 ridge, which corresponded to the connective of the normal an- 
 
 * Ueber die mannlichen Bliithen der Coniferen. Tubingen, 1837. 
 
 K 
 
130 
 
 ther. At the basis the entire bract was indeed somewhat con- 
 tracted, but not so much so that this part might be called a 
 true filament. In those bracts which approached still more to 
 normal anthers, (and this was the case in most of them) there 
 were upon the outer side two protuberances, containing pollen, 
 of a long oval form and yellow colour, which at their hinder 
 end were partially separated from the bracts as in Araucaria. 
 These formations differed from the normal anthers only from 
 their being smaller, possessing a larger band and exhibiting a 
 total want of the filament. A portion of these anthers burst 
 longitudinally in the sutures, scattered the pollen, and then 
 dried ; others on the contrary remained closed and kept fresh 
 for several weeks, thus again exhibiting their nature as bracts. 
 From the phaenomena which the examination of these her- 
 maphrodite catkins presented M. Mohl deduces the following 
 conclusions : 
 
 1. Each bilocular anther ofPinus and the allied genera has 
 proceeded from the metamorphosis of a single leaf, which is 
 also the opinion of Robert Brown and Lindley. 
 
 2. The anthers of Pinus originate from leaves that belong to 
 the male catkin, and are not, as Mr. Lindley supposed, to be 
 considered as lateral monandrous flowers, and consequently 
 also are not analogous to the carpel-leaves of the female 
 catkin. 
 
 Now it appears therefore necessary that the multilocular 
 anthers of other genera of Conifer should also be considered 
 to have originated from the metamorphosis of a single leaf. 
 M. Mohl is quite right in stating that the presence of a greater 
 number of anther-loculaments cannot be advanced as a reason 
 against this view, for it must not be overlooked that there is no 
 reason why pollen could not be formed in the interior of a leaf 
 as well at twenty different places as at one, at two, or at four. 
 Moreover the male amentum of Juniperus presents in the 
 number of anther-loculaments real transitions to various other 
 genera of Coniferce. For instance, the inferior scales of the 
 amentum of Juniperus very frequently possess only two locu- 
 laments, in which they coincide with Pinus ; the trilocular are 
 similar to those of Cunninghamia, and form the transition to 
 the quadri- and multilocular anthers of other genera. M. 
 Mohl here also touches on the explanation of the multilocular 
 
131 
 
 anthers of many Cycadea, which must evidently be explained 
 in exactly the same way. 
 
 In conclusion, M. Mohl endeavours to decide in a very in- 
 genious manner the question whether the male coniferous 
 amentum should be regarded as a flower or as an inflorescence. 
 The male amentum of the Conifer <z ? he observes, possesses only 
 in outer appearance and in this, that all its stamina with the 
 the axis upon which they stand are deciduous, a resemblance 
 to a true amentum, and is therefore rather to be compared to 
 a flower. The proof of this latter assumption presents, it is 
 true, far greater difficulties than the proof that the view, ac- 
 cording to which the cone of the Conifers is to be regarded as 
 an inflorescence, is incorrect. However, the examination of 
 the female amentum in all stages of transition leads M. Mohl 
 to the view that the male flowers of the Conifer <e exhibit an 
 approximation of the floral formation both to the inflorescence 
 and to the vegetative parts of the plant. The lower stage of 
 development, in which the male flower of the Conifer <z is found, 
 is easily shown by the want of a floral envelope and by the slight 
 shortening of its axis, and the only distinction from the vege- 
 tative axis consists in a short flower-stalk. (In young firs (Pi- 
 nus sylvestris) which flower for the first time, it may very fre- 
 quently be seen that one or more pairs of leaves are converted 
 at the lowest portion of the new shoots into anthers, a phae- 
 nomenon which throws great light on this subject. Rep.) 
 
 Of especial interest also are the considerations on the female 
 flower of Cycas, where the intimate connexion between stem, 
 leaves, and carpellary leaves is far more remarkable than in 
 the flowers of the Conifers ; for in those species of Cycas, says 
 M. Mohl, in which the carpel-leaf still bears pinnules, the 
 forms of both are strikingly similar ; and the carpel leaves more- 
 over retain the nature of stem-leaves in so far that they do 
 not lie close on to one another, and the stem does not lose with 
 their production the power of growing further and producing 
 new leaves, on which account the portion of the axis covered 
 with the leaves of fructification fluctuates, from its nature, be- 
 tween an axis of fructification and of vegetation. 
 
 M. Schleiden's views* on the morphological signification 
 
 * Einige Blicke, &c. English translation in Lond. and Edin. Phil. Mag., 
 vol. xii. pp. 172 and 241. 
 
 K2 
 
132 
 
 of the female cone of the Conifers are very different from 
 those just mentioned; he considers that which has been re- 
 garded since R. Brown as an open ovarium to be merely a 
 scale-like expanded placenta, and R. Brown's bractea to be 
 the actual carpellary leaf. In fact the placenta shows itself to 
 be in the Abietinece a perfectly independent part in its growth 
 from the carpellary leaf, and perfectly distinct. Nay, it here 
 developes itself, when without the least constraint, to such an 
 extent, that at length the carpellary leaf itself (bractea of 
 authors) appears as a mere supplementary part. The detailed 
 exposition of this highly difficult subject M. Schleiden pro- 
 mises at some future time. He too found an hermaphrodite 
 cone of Pinus alba, and states that these views are confirmed 
 by this monstrosity in the most beautiful manner. 
 
 I have very frequently found hermaphrodite cones, and the 
 transformation of the actual spicular leaves into carpellary 
 leaves or into bracts of authors, may most distinctly be fol- 
 lowed on them, as well as the origin of anthers from the leaves 
 which surround the base of the cone. 
 
 On Phenomena of Sensibility and Irritability of Plants. 
 
 In a memoir with the title ** De la tendance des vegetaux 
 a se diriger vers la lumiere et de leur tendance a la fuir", 
 which M. Dutrochet has published in the collective edition of 
 his memoirs*, various very obscure phenomena of the direc- 
 tion and motions of some plants and their parts have been 
 investigated. The learned author begins this chapter first 
 with the consideration of the direction of the roots in the ger- 
 minating mistletoe (Viscum album),, and arrives at results al- 
 ready known. The greatest portion of the memoir is occu- 
 pied with the consideration of the direction of the root in 
 creeping plants, and the causes. M. Dutrochet has observed 
 that some plants, for instance Humulus Lupulus and Convolvu- 
 lus sepium, avoid the light, while others constantly turn to- 
 wards it. The stems of these two plants were placed in a glass 
 with water, and observed near a small window 7 . The apices 
 of the stems were directed in the morning towards the win- 
 dow, but in the course of the day turned from it, while at 
 night they returned to their original position. With the fading 
 
 * Vol. ii. p. 1640. 
 
133 
 
 of the stems they lost their property of avoiding the light. 
 The opposite direction during day and night was observed 
 previously by Bonnet. M. Dutrochet draws from these ob- 
 servations the following conclusions : 1. certain plants avoid 
 light, and this for the purpose of seizing hold of firm and 
 opake objects ; 2. the flexion of the stem towards the light, as 
 also from it, therefore in opposite directions, is the result of a 
 physiological action, and not of a superfluous elongation of 
 one side of the stem by which some botanists have endeavoured 
 to explain it. The roots exhibit no tendency either to grow 
 towards or from the light. 
 
 In the explanation of the causes which give rise to the 
 windings and flexions of the stems of plants M. Dutrochet is 
 very complete, but he starts from points which are purely hy- 
 pothetical, and were demonstrated to be such in last year's 
 report. All flexions of plants are, as M. Dutrochet thinks 
 to have proved, produced by the action of two kinds of tissue, 
 which differ from each other both by their texture and the 
 principle of their action ; these two flexible tissues are the 
 cellular tissue and the fibrous tissue. The cellular tissue 
 bends by the action of endosmosis, and the fibrous tissue by 
 its filling with oxygen, &c. M. Dutrochet thinks that he has 
 observed that the inner cellular layer of the bark is in general 
 thickest in those plants which turn towards the light, and 
 considers the latter to be a natural consequence, that the cells 
 predominating in such bark and becoming smaller and smaller 
 from without inwards, swell by endosmosis. The contrary 
 appearance is said to be exhibited in such plants as turn 
 from the light : here for instance the cortical layer is said to 
 be the thickest. Starting from this notion, M. Dutrochet has 
 endeavoured to explain very completely all the difficult points 
 of this questionable subject, and a number of special observa- 
 tions are enumerated, which however collectively might easily 
 be refuted. 
 
 M. Brunner* attempts to explain the winding of plants to 
 various sides from the different degree of irritability proper to 
 
 them. Suppose a plant A. stand 
 
 B. C, 
 A. 
 
 at equal distance 
 
 * Ganz anspruchsloser Versuch, das Links- und Rechts-winden der vor- 
 kommenden Pflanzen zu erklaren. Flora von 1837. No. 41. 
 
134 
 
 from two supporters directed towards the east, the elonga- 
 tion of the young shoots will move pretty generally in the 
 arc between B and C. (How is it then with those plants that 
 turn from the light ? Rep.) If the plant only possess a high 
 irritability, it will turn towards the early rays of the sun and 
 seek a supporter to the left ; but if the plant require a longer 
 influence of the light to determine its direction the plant will 
 turn to the right. 
 
 If this explanation were correct we should perhaps be able 
 to determine at will the flexion or winding of plants ; it would 
 only be necessary to remove those supporters towards which 
 the plant tends or to place them on the opposite side ; but as 
 observation shows, ah 1 this is of no use. And how would the 
 turning to the right and left on one and the same tendril, as 
 occurs in Bryonia, be explained ? 
 
 In A. Curtis's Enumeration of the plants growing sponta- 
 neously around Wilmington, in North Carolina*, we find a 
 description of the remarkable leaves of Dionaea Muscipula, 
 of which instructive figures have already been published in 
 various works. Sometimes Mr. Curtis found the entrapped 
 fly enveloped in a mucous substance which appeared to act 
 upon it as a dissolving medium, upon which he came to the sup- 
 position that the insect might be employed in the nourishing 
 of the plant. I will merely observe respecting the secretion of 
 the fluid which is observed on the closed leaves, that it is a 
 consequence of the water collected by the transpiration of the 
 leaves and precipitated in the closed space. And this water 
 is, in a climate so warm as that of South Carolina, the cause of 
 the dissolution of the imprisoned insect. 
 
 M. Morren has published f some new observations on the 
 catalepsy of the flowers ofDracocephalumAustriacum and Mol- 
 davicum which are connected with those, respecting which w r e 
 gave a notice in last year's report. The author observed these 
 phaenomena hitherto in Dracocephalum Virginianum, Austri- 
 acumsLudMoldavicum; in the first species the so-called catalepsy 
 is perceptible to a high degree, in the second it is less consider- 
 able, and in the third still less. The outer relations are very 
 completely and accurately described in this memoir, by which 
 
 * Hooker's Companion to the Botanical Magazine, vol. ii. p. 5. 
 f Notes sur la Catalepsie des Dracocephalum Austriacum et Moldavicum. 
 Bullet, de 1'Acad. des Scienc. de Bruxelles, 1837, p. 390. 
 
135 
 
 the phenomenon termed catalepsy is produced in these species, 
 and M. Morren again arrives at the conclusion that this phae- 
 nomenon does not merely depend on a distinct property of 
 the cellular tissue, or on a want of elasticity in the flower- 
 stalks, but must be regarded in toto as a mechanical result, 
 independent of the position of the parts. 
 
 M. Dassen*, who has published the beautiful memoir on 
 the motion of the leaves of plants, of which Prof Wiegmann 
 has inserted an extract in his journal, has drawn the attention 
 of botanists to a phenomenon of leaf-motion hitherto little at- 
 tended to. The leaves of those plants which move are fre- 
 quently provided with swellings at their base ; there are how- 
 ever other leaves which move without these swellings. The 
 motion of these latter again presents in various plants consi- 
 derable differences, which are more particularly described in 
 this memoir ; it consists in the inversion of their natural posi- 
 tion, which is sometimes performed in the space of a day, but 
 sometimes takes a much longer time. M. Dassen displaced 
 some branches of trees and various other plants from their 
 natural position, and bound them fast to the stem, so that 
 they hung downwards : in the course of a few days they had 
 spread themselves out so much, that the upper surface of the 
 leaves was again turned upwards. These experiments were 
 made in June when vegetation was in full force, and the re- 
 sult was the same in all cases. The experiments were then 
 repeated in October, when most of the branches remained 
 motionless ; only those of rose trees, of Robinice, and of her- 
 baceous plants endeavoured to regain their previous position. 
 The following question then presented itself: By what is 
 the motion of the branches effected, whether by a cause seated 
 in themselves, or by the leaves ? To determine this question, 
 M. Dassen repeated the experiments on branches with and 
 without leaves, and observed that those branches which had 
 been deprived of their leaves remained in their unnatural po- 
 sition ; the leaves were therefore regarded as the cause of this 
 motion of the branches. Subsequent experiments were made 
 in order to discover the mechanism producing the motion of 
 
 * Onderzoek aangaande de Bladbewegingen, die niet door aanzwellingen 
 ontstaan. Tijdschrift voor naturlijke Geschiedenis en Physiologie, 1837,1V. 
 1. 2. p. 106 131. 
 
136 
 
 the leaves, whether the nerves of the leaves remained during 
 the process active or passive, &c., and the following results 
 were arrived at : that leaves with simple nerves and without 
 petioles change their position from the unnatural to the natural 
 as well as those with petioles ; and 2ndly, that the parenchyma 
 is the cause and not the nerves. Further observations re- 
 specting the mechanism producing the motion of leaves with 
 and without petioles gave the following results : 1. All leaves 
 with simple veins have the power of self inversion ; 2. The 
 apparently unpetiofated leaves in which the veins are diffused 
 in a different manner, move by a bend in their point of attach- 
 ment; 3. The short and stiff as well as the long and slender 
 petioles are unfavourable to the motion ; 4. When the petiole 
 is not too stiff or long, the inversion of the leaves is produced 
 by a semi-inversion lengthwise and also by a bend of the pe- 
 tiole ; 5. In folia pelt at a the motion takes place partly by a 
 bend of the petiole itself, partly by a change in the direction 
 of the leaf with reference to the petiole. 
 
 M. Dassen then proceeds to the examination of the causes 
 which produce the motion of leaves : various plants stationed 
 in pots were left to grow turned from the light, and some even 
 without light in closed boxes. The result was highly remark- 
 able : the leaves of those plants w r hich could not turn them- 
 selves round died, but the remainder were inverted quite as 
 quickly in the dark as in the light, whence M. Dassen arrives 
 at the conclusion, that light was no more the cause of the di- 
 rection of the leaves upwards than darkness is the cause of the 
 downward direction of the root. Neither can the action of 
 heat or that of moisture be regarded as the cause of this mo- 
 tion. Finally M. Dassen passes in review those motions of 
 the leaves which take place constantly in the course of one day, 
 and even without swellings ; these are the phaenomena which, 
 as is well known, were regarded by Linnaeus as the Sleep of 
 Plants. M. Dassen considers Linnaeus's explanation as an 
 error into which that great man fell, as well as all those who 
 have merely copied almost word for word from him respecting 
 this point. The memoir On the Sleep of Plants, by E. Meyer, 
 which I noticed in my report for 1835, as highly interesting 
 and full of laborious research, is especially attacked. I cannot 
 however agree with M. Dassen : for all the valuable observa- 
 
137 
 
 tions which Meyer had enumerated respecting this phaeno- 
 menon may be explained in a different sense, and in fact more 
 in accordance with nature, if we start from the general point of 
 view, by the periodical occurrence of sleep, which appears to 
 be common to all animated beings. M. Dassen placed a pot 
 containing Impatiens noli tangere during the night in a dark 
 place, and the result was, that the leaves even during the fol- 
 lowing day retained the same direction. Another plant was 
 placed during the day-time in a dark place, and for two entire 
 days the leaves retained the usual direction which is proper 
 to them in the daytime. From these and other experiments 
 M. Dassen concludes that the motions of plants without 
 swellings are caused solely by the process of vegetation, and 
 that this is rendered evident as soon as the leaves are exposed 
 to unnatural external influences. 
 
 I ask then, whether from the examples cited the phaeno- 
 menon of vegetable sleep can be denied ? On the contrary, 
 phaenomena exactly similar may be proved to exist in ani- 
 mals. 
 
 Diseases of Plants. 
 
 I have published some observations on the development of 
 smut in maize*, which demonstrate the origin of this incu- 
 rable disease in the interior of the cells of the affected part. I 
 consider it to be a settled fact, that the smut (Ustilago, Link,) 
 is not a contagious disease, but is inherited, and arises from 
 the stoppage of the saps produced by superabundant manure 
 foreign to the nature of the plant. At one or at several places 
 of the inner surface of the affected cells small deposits of mucus 
 are formed, from which filiform ramified bodies proceed, which 
 are colourless and almost transparent, but contain a quantity 
 of small molecules consisting of a somewhat more solid sub- 
 stance. These mucous filaments, in the interior of the cells, 
 soon present constrictions at various places, first generally at 
 the apices of the small lateral branches ; and these constricted 
 ends take an ellipsoidal and lastly a spherical form, become of 
 a yellow colour, and change into those minute brown vesicles 
 of which the smut consists. The destruction of the cellular 
 walls by dissolution commences with the aggregation of these 
 
 Wiegmann's Archiv for 1837, p. 419. 
 
138 
 
 smut vesicles in the diseased cells, and then these vesicles 
 are found in great masses lying close together, filling entirely 
 the diseased organ and frequently without leaving a trace of 
 the original intervening cellular wall. 
 
 M. Leveille* read a paper before the Philomathic Society 
 of Paris on the Uredines, in which he contests both M. Tur- 
 pin's view and that of M. Unger on the origin and significa- 
 tion of these formations. He considers the Uredines to be 
 true parasitical fungi and not diseases of the plants on which 
 they occur ; they are said to originate from a byssoid tissue 
 beneath the epidermis of the plants. Probably M. Leveille' 
 will publish more detailed communications on this subject to 
 prove his statements, with which, as far as they have been 
 made known, I cannot agree ; but his observations also prove 
 that the view advanced by M. Unger, that these plants should 
 be regarded as diseases of the respiratory organs, is not cor- 
 rect, for they all take their origin in the cells. 
 
 M. von Voithf has described certain abnormal formations 
 which he observed on the wood of the elm ( Ulmus) : they are 
 triangular bodies which proceed from the bark into the interior 
 of the wood. Since the microscope was not at all employed 
 in examining these formations, and I cannot find them in the 
 wood of the elms occurring in the neighbourhood of Berlin, 
 it is impossible for me to come at any correct notion of them 
 from the description, for it is not even stated whether the foreign 
 body consists of bark substance or of wood. I am rather in- 
 clined to suspect that these diseased formations are derived 
 from bark substance and that the cause of this deformity must 
 be sought, as M. v. Voith suspects, in the ascending of the 
 trees with iron points, by which the bark has been squeezed 
 into the wood, but not destroyed. The new annual rings of 
 the wood forced their way afterwards through the apex of the 
 impressed bark, &c. If my suppositions are correct then all 
 the rest is easily intelligible. 
 
 M. Dutrochetfs communication on the formation of the 
 ergot was noticed at p. 117. 
 
 Numerous experiments have again been performed on the 
 
 * L'Institutde 1837, p. 191. 
 
 f Ueber em sonderbares Gebilde in der Ulme. Flora von 1837. No. 17. 
 
139 
 
 action of poisons on plants by M. Miquel* : for the most part 
 sections of plants were employed, and the effect of caustic am- 
 monia, acetate of lead, tincture of galls, camphor, cherry-laurel 
 water, extracts of opium and Hyoscyamus on them observed. 
 The effect of ammonia and camphor in a gaseous form also 
 was noticed, and M. Miquel obtained in general from all his 
 numerous experiments results quite similar to those already 
 established by his predecessors. I will however here add one 
 observation, namely, that the velocity with which the various 
 poisons act upon the severed parts of the plant depends en- 
 tirely on their evaporation, for only in consequence of this does 
 the plant absorb the water with the poison, &c. ; it is conse- 
 quently necessary that in all such observations, if in future it is 
 desired to obtain coincident results, the state of moisture 
 and the warmth of the air be observed. 
 
 Geography of Plants. 
 
 The interesting communications which Alexander von Hum- 
 boldtf has published on his ascent of the Chimborazo, con- 
 tain some important facts relative to the geography of plants 
 which at the same time must be regarded as correcting the 
 statements of Major Hall, published in this journal (Wieg- 
 mann's Archiv) in 1835. Above the height of 9720 feet A. v. 
 Humboldt found the Chimborazo surrounded with large plains 
 which lie step-like one above the other; the first step is 10200 
 feet high, the second 1 1 700, and they are so horizontal that it 
 seems as if one were looking upon the bottom of an ocean. The 
 very extensive downs (las Pajonales) are, on the Chimborazo, 
 as well as everywhere around the high peaks of the Andes, so 
 monotonous that the family of the grasses (species ofPaspalum, 
 Andropogon, Bromus, Deyeuxia, Stipa,) are rarely supplanted by 
 dicotyledonous plants, in which respect the vegetation exhibits 
 great similarity to the Steppes of Northern Asia. Only Cal- 
 ceolaria, Composites, and Gentiance (among which G. cernua, 
 with purple-red flowers) present themselves in those elevated 
 plains among the gregarious grasses, which, for the greater 
 part, belong to North European genera. The mean tempe- 
 rature of these heights also nearly agrees with that of North- 
 
 * Proeven overde Werkingvan Vergiften ofPlanten. Tijdschrift v. Nat. 
 Geschied. en Physiol. 1837, iv. p. 154208. 
 
 t Ueber zwei Versuche den Chimborazo zu besteigen. Schumacher's 
 Jalirbuch fur 1837, p. 176206. 
 
140 
 
 ern Germany in 58 15' lat. The highest point of the peak 
 of Chimborazo reached by v. Humboldt was at a height of 
 18097 Parisian feet; only a few lichens were traced above the 
 limit of eternal snow. The last collected were Lecidea atro- 
 virens and Gyrophorarugosa, Achar., about 2820 toises high. 
 The last moss, Grimmia longirostris, flourished 400 toises 
 lower down. 
 
 M. von Baer's remarkable voyage to Nova Zembla* has 
 filled up one of the greatest gaps in the sources for the study 
 of the true geography of plants. All that we formerly knew 
 of the vegetation in the polar zone above the limits of Europe 
 was limited to a few scattered notices ; at present however, now 
 that a scientific person like v. Baer has visited the unknown 
 Nova Zembla, we possess a description of the relations of ve- 
 getation of this zone, such as but few districts can offer. 
 
 Nova Zembla, it would seem, must be regarded as a conti- 
 nuation of the northern Ural, whence it becomes probable a 
 priori, that the vegetation of those islands may agree with 
 that in the region of the alpine herbs of the southern Ural. 
 However, we will pass on to Von Baer's descriptions of the 
 climate and vegetation of Nova Zembla. Nowhere was a con- 
 tinuous grass-plat observed wiiich might have deserved the 
 name of a meadow, not even a continuous covering of moss ; 
 even the foliaceous lichens flourish but poorly on Nova Zem- 
 bla, while the crustaceous lichens clothe every block of augitic 
 porphyry, and occur also on the other stones, yet less fre- 
 quently. On the other hand, Dry as octopetala, in continuous 
 withered turfs, clothes the dry hilly declivities formed by the 
 loose stones. There is no heath, no Empetrum nigrum, Ar- 
 butus alpina, Betula nana, Sedumpalustre, Rubus Cham&morus, 
 &c. ; in short ah 1 those plants are here wanting which I have 
 mentioned in my Geography of Plants as characteristic of the 
 southern portion of the polar zone, and which I attempted to se- 
 parate under the name of arctic zone from the polar zone. Ab- 
 sence of vegetation, says v. Baer, is characteristic of the deserts 
 of Nova Zembla ; isolated specimens of the genus Draba are 
 found there. The loose masses of solid rock exhibit the in- 
 crusting lichens ; Verrucaria geographica is the most common, 
 Stereocaulon paschale and isolated specimens of Cochlearia 
 and Papaver nudicaule. The rocky rubbish, a more decom- 
 
 * Bulletin scientif. de 1'Acad. imperiale des Sciences de St. Petersbourg. 
 
141 
 
 posed stone, presents plants forming patches, as Silene acaulis, 
 Saxifraga oppositifolia, Arenaria rubella. Among these grow 
 Draba alpina and other species, Arenaria ciliata, Myosotis 
 villosa, Dryas octopetala. The loamy soil, which in summer 
 dries up- and breaks into fissures 1 3 inches broad (more or 
 less regular polygons), exhibits Platypelalum purpurascens, 
 species of Saxifraga, as S. Hirculus, and isolated specimens of 
 Draba verna. The mosses gradually collect in the furrows, 
 and among these grows Salix polaris, the most common of 
 the shrubs, whose branches are very short and only send 
 forth two leaves with the catkin from the protecting envelope, 
 together with some species of Eriophorum. 
 
 As plants of the most sterile soil are enumerated Rhodiola 
 rosea, Erigeron coniflorum, a Vaccinium, which is situated with 
 its woody stem in narrow fissures of rock and only sends forth 
 leaves, Papaver nudicaule, Ranunculus nivalis, which mere- 
 ly requires snow-water, and flowers when the soil is not 
 warmed above 1. Oxyria reniformis is almost as easily 
 satisfied. 
 
 But there are also beautifully decorated spots in Nova Zem- 
 bla, where vegetation breaks forth in all the splendour of co- 
 lours, as it were on the ground, for the beautiful flowers never 
 rise above a few inches high. The purple- coloured flowers of 
 Silene acaulis and Saxifraga oppositifolia, the blue flowers 
 of the tufts of Myosotis villosa, were varied with gold-yellow 
 Ranunculuses and Drapa alpina, mixed with peach-blossomed 
 Parryce, white Cerastia, blue Polemonia, and the sweet little 
 Forget-me-not, and gave the impression of a variegated carpet. 
 Although this vegetation evidently coincides with that of the 
 alpine regions of southern mountains, yet M. v. Baer observes 
 that here the individual plants occur in greater masses, while 
 in Nova Zembla they are more scattered and mixed with one 
 another, so that in a walk of halfawerst almost half the Flora 
 of Nova Zembla is found united. 
 
 Especially favoured spots, entirely clothed with a pretty 
 dense covering of plants, are very rare on Nova Zembla ; the 
 Ranunculuses, with the exception of Ranunculus nivalis, are al- 
 most solely confined to those spots abundant in humus. 
 
 But how is it possible for a larger vegetation to occur in 
 these inhospitable islands, since the warmest month in Nova 
 
142 
 
 Zembla brings with it only as much warmth as October in 
 Drontheim, December in Edinburgh, and January in central 
 France ? M. v. Baer then shows that the idea of the vegeta- 
 tion proceeding very rapidly in the high north is, at least with 
 regard to the extreme north, incorrect, for during a stay of 
 three weeks in one district the progress of vegetation was found 
 to be far slower than in lower latitudes ; but there only such 
 plants occur as require a very short time of vegetation, as for 
 instance with us the spring flowers. The common cress was 
 sown at St. Petersburgh in May, and in July in the latitude of 
 Matotschkin-Schar, and the development at the latter place 
 proceeded three times slower than at the former; it is therefore 
 easily intelligible why scarcely anywhere ripe seeds were found 
 in Nova Zembla towards the beginning of winter. Plants like 
 Tussilago frigida, SalixBrayi, and the Vaccinium above men- 
 tioned, do not even appear to flower, whence one might pro- 
 bably be inclined to conclude that they had transmigrated from 
 the neighbouring coasts. Although M. v. Baer characterizes 
 the assumption of such a transmigration of plants as something 
 scarcely admissible, yet he observes that whoever has travelled 
 through these districts will certainly be determined in favour 
 of it. The coasts generally always abound more in plants than 
 the interior districts, and M. v. Baer regards the ice as being 
 the best means for conveying the wandering seeds. The plants 
 of Spitzbergen are almost without exception found in Nova 
 Zembla, but there are also other plants in these islands which 
 have hitherto been met with only in North America, and con- 
 sequently might also be considered as having migrated to Nova 
 Zembla. 
 
 M. v. Baer then treats at great length of the height of the 
 limits of eternal snow on Nova Zembla, but arrives at the re- 
 sult that it is impossible to fix a general determination, for the 
 local influences are surprisingly great. Notwithstanding the 
 slight degree of warmth, all the snow in the plains melts to- 
 wards the end of July ; in the hollows and valleys it never 
 entirely disappears. In so cold a country, where the mean 
 temperature of the atmosphere is so exceedingly low, the 
 higher warming of the soil by the sun's rays must have the 
 greatest effect on the occurrence of vegetation, and M. v. Baer 
 has devoted particular attention to this subject. By this 
 
143 
 
 higher calorification of the surface of the soil the lower stra- 
 tum of air is in the first place warmed, and then the imme- 
 diately subjacent surface of the soil ; and, as observation shows, 
 the whole vegetation on Nova Zembla occurs in these two small 
 regions. Only very short roots descend into the earth, and 
 the longer roots run just beneath the surface. In general they 
 proceed almost horizontally and form with the stem a right 
 angle. The giant of the shrubs of Nova Zembla is Salix la- 
 nata ; it grows to about a span high, while the roots, orperhaps 
 more correctly the subterraneous stem, is about an inch thick, 
 and was laid bare for the length of from 10 to 12 feet with- 
 out exhibiting the termination. On account of the slight 
 warmth of the air, which, properly speaking, is restricted 
 merely to the lowest stratum, the plants there grow to a height 
 of from 2 3 inches, those of from 4 5 are much less fre- 
 quent, and those of 6 inches very rare. Salioo Brayi seems to 
 show very distinctly that the air at the height of 8 inches does 
 not contain sufficient warmth for it to develop a bud. 
 
 We are also indebted to M. v. Baer for similar interesting 
 observations on the vegetation at various spots of the coasts 
 of the White Sea*, which exhibit the greatest coincidence with 
 those of Lapland, with which we are so accurately acquainted. 
 On the east coast of the White Sea in 65 20' northern lati- 
 tude the declivities of the Winter Mountains were richly 
 clothed with trees and shrubs, and abounded in luxuriant 
 Pteonies (P. intermedia, Meyer,), Aconites, Rosa spinosissima, 
 Hedysarum neglectum, Polemonium cceruleum ; but in heights 
 of from 150 to 200 feet the northern character again returned 
 in all its force. On the south coasts of Lapland (66 10' north 
 lat.) the vegetation was very different from the one just de- 
 scribed. Here the plains were covered with lichens and 
 mosses, interspersed with Rubus Chamcemorus and Vaccinium 
 uliginosum. In 67 lat. M. v. Baer found patches of Diapen- 
 sia Lapponica, Arbutus alpina, Azalea procumbens, Empetrum 
 nigrum, and heath forming extensive turfs. However in the 
 neighbourhood of the coasts there are still some patches of 
 arboreal vegetation to be seen. There is no corn cultivated 
 in these districts. 
 
 * Bullet, scientif. de 1'Acad. de St. Petersbourg, ii. p. 132144. 
 
144 
 
 From A. Ermann's journal of voyage* we select the fol- 
 lowing additions to the geography of plants. In the neigh- 
 bourhood of Tobolsk in 58 northern latitude,, the hilly di- 
 stricts are clothed with dense forests of firs, pines, poplars 
 and very high birch. Near Irkutsk and its environs (52 N. 
 lat.) Pyrus baccata grows, bearing fruit of about the size of a 
 pea, in Kjachta they attain the size of a cherry. Moreover 
 near Neotschinck the true apricot grows with a juiceless peri- 
 carp but well -tasted kernel, and close to it the Siberian Stone- 
 pine. 
 
 M. Ermann gives some very interesting climatological no- 
 tices on Jakutzk (62 lat.) which are of high importance to the 
 geography of plants. The temperature of the soil presented 
 at a depth of 50 feet 6 Reaum. and coincident with this is the 
 mean warmth of the atmosphere f. Every year the tempe- 
 rature falls below 40 Reaum., on the 25th Jan. 1829 even 
 to 46'4 R. The last night-frost occurs on the 1 2th of May, 
 and then the summer lasts till the middle of September. The 
 mean warmth of Jakutzk is in June, July, and August, 1 1, 15, 
 and 13 R., and frequently the thermometer is seen in the 
 shade to mount to 20 R. Several kinds of corn, as summer 
 wheat and rye, are sown in the neighbourhood of the town, 
 and bear 15-, and even in some cases 40-fold, although the soil 
 is thawed only to a depth of 3 feet. In the gardens po- 
 tatoes, cabbages, turnips, and radishes are cultivated, and even 
 cucumbers are forced in dung beds. 
 
 The isothermal lines do not extend from the Lena straight 
 eastwards, but ascend strongly towards the north. Near 
 Antscha, one degree north of St. Petersburg, and 2244 Pa- 
 risian feet above the sea, the vegetation was more luxuriant 
 than the summit of the Brocken in the Hartz. Lofty-stemmed 
 trees (not coniferous) graced the forests. In the journey across 
 the Aldamic Mountains Betula nana was frequently met with, 
 which is more sensitive than the larch to the cold mountain 
 air. At 3444 Par. feet near the end of the Antscha valley 
 several larches were found, by which the relations of tempe- 
 
 * Reise um die Erde durch Nord-Asien und der beiden Oceane in den 
 Jahren 18281830, erste Abtheilung. 
 
 f The ground ice there is said according to recent communications to be 
 382 feet thick. 
 
145 
 
 rature show themselves to be more favourable in the eastern 
 portion of the Aldamic mountains than in the west, where the 
 limit of trees is said to be 1000 feet lower. On the Kapitan 
 mountain there were still larch at a height of 3780 feet; at 
 4000 feet nothing but lichens could be found. M. Ermann ob- 
 serves, that the larch does not form any knee-wood like the 
 Coniferae of our German mountains. In the neighbourhood 
 of the Arka he noticed a peculiar Conifera, the stem of which 
 was 3 inches in diameter and 10 12 feet in length : it grows 
 quite straight and slender, sending several stems from one 
 root, but in winter is bent so much to the earth that it is en- 
 veloped in snow, and thus it is ridden over without its pre- 
 sence being suspected. The cones are about half the size 
 of those of the Siberian Cedar, and likewise contain well- 
 flavoured seeds. 
 
 In the journal of voyage of M. G. Rose* we find the very 
 important notice for the geography of plants, that M. Feder- 
 hoff had ascertained by measurement the summits of the 
 northern Ural to be from 8 to 9000 feet high, and that these 
 are even in 66 N. lat. free from snow. The snow occurs 
 there only in the saddle-shaped hollows between the separate 
 peaks, and on the eastern and northern declivities. 
 
 M. Goeppertf has observed the vegetation on a drift of coal 
 burning beneath the surface near Plaenitz, not far from Zwickau. 
 At some places the drift comes up to the surface, and its ex- 
 tent is defined in winter by the green turf remaining free of all 
 snow, while in summer it is parched. At the chief places of 
 evolution of the hot gases M. Goeppert found it to be from 50 
 to 54 R. ; upon the hilly prominences, principally clothed with 
 moss, 35 36; in the parts covered with grass 14 30 R. He 
 enumerates a great number of plants which grew on this hot 
 soil ; it is true they were also found in the immediate vicinity, 
 but far less developed and not in full vegetation. The warm- 
 est point was a portion covered with a turf six inches thick, 
 which indicated, at a depth of three inches, 45 R. Although 
 
 * Reise nach dem Ural, dem Altai, und dem kaspischen Meere, ausge- 
 fuhrt im Jahre, 1829, von A. v. Humboldt, Ehrenberg, und G. Rose, Berlin, 
 1837, p. 381. 
 
 f Bemerkungen iiber das Vorkommen von Pflanzen in heissen Quellen 
 und in ungewbhnlich warmen Boden. Wiegmann's Archiv, 3ten Jahrgang, 
 p. 101. 
 
 L 
 
14G 
 
 this high temperature of the soil is something unusual in our 
 country, yet similar circumstances occur very commonly in 
 certain tropical regions. On the coast of the island Lantao 
 (China) in August at half-past three P.M., I ascertained the 
 water of some rice fields to be 36 R. : evidently the adjacent 
 sand, which was completely clothed with plants, was still 
 higher, for towards mid-day I had observed the black sides of 
 the vessel to be heated to 49-2 R. 
 
 M. Goeppert has given as an introduction to this work some 
 very complete historical notices of the occurrence of plants in 
 hot sources and in unusually warm soils, which will be of great 
 service to future writers on this subject. 
 
 M. Zuccarini in his monograph of the Cactece* has treated 
 very fully of their geographical distribution. Cactus plants 
 have been observed in the New World from 49 north lat. to 
 the southernmost parts of Chili, and it is to be presumed that 
 they go as far south in the southern hemisphere as they ascend 
 northwards in the northern. Their vertical distribution goes 
 through all regions, from the hot plains of the tropics to the 
 neighbourhood of eternal snow. Some species of this family 
 were collected on the west side of North America in 44 45 
 lat. at great heights, and Nuttall has discovered several Cacteae 
 in similar latitudes on the high mountains in the Mandan di- 
 strict. Opuntiae have been observed up to 41 lat. on the east 
 side of North America. " So extensive a distribution of the 
 family/ 5 says M. Zuccarini, " leads us naturally to expect a 
 great variety in the peculiar habitats of the different species. 
 But it must be observed, that with the exception of cultivated 
 Opuntice and Cerei, all the other species are limited in their 
 occurrence to small districts, and therefore statements like 
 that of Meyen of the occurrence of the Mexican Cereus senilis 
 on the Andes of Chili are probably founded on errors arising 
 from want of comparison." I am glad to be able to give some 
 explanation on this point. I have not seen the Cereus senilis 
 on the Andes of Chili, I do not understand therefore how the 
 author can make such a remarkable statement ; but I saw a 
 Cereus in the Cordilleras of southern Peru, which resembled 
 in habit the Cereus senilis of our hot-houses ; nay, I did not 
 
 * Denkschriften der mathematisch-physikalischen Klasse der kbnigl. 
 Acad. der Wissenschaften zu Munchen, vol. ii. 1837. 
 
147 
 
 even see this quite close in my rapid journey, much less ex- 
 amine it attentively, so that it may very likely be some other 
 species ; yet this must not be asserted too hastily, for the re- 
 lations of climate in which Cereus senilis occurs in Mexico and 
 those of southern Peru, at the height in which I found this 
 plant, are exceedingly similar. Moreover, M. Lehmann has 
 described a Cereus bradypus from Brazil, which M. Pfeiffer 
 considers to be synonymous with C. senilis, Haw. These 
 statements however must be founded on actual comparisons, 
 and even then it would be incorrect to ascribe generally a very 
 restricted occurrence to the Cactece. Besides, plants of very 
 limited stations allow rarely of wide artificial distribution, 
 which we however find to be the case with the Cactece. 
 
 ee The Cactece seem to be pretty indifferent as to the nature 
 of the soil, for the individual species are found without di- 
 stinction on limestone, sandstone, primary formations, and on 
 strata which have been altered by volcanic action." They are 
 even frequently found on the sea-shore, especially Cerei and 
 Opuntice ; but I cannot agree with the author, that all Cactece, 
 with the exception of the Peireskice, require an open sunny 
 situation. All those Cactece which require a permanent warm 
 and moist climate, and frequently occur parasitical, i. e. on 
 the bark of other trees, as the Epiphyllece according to Her- 
 mann's statement, and also many species of Rhipsalis, vege- 
 tate most luxuriantly in the shade ; the Peireskiae on the con- 
 trary that I met with in their native country stood quite ex- 
 posed to the sun. M. Zuccarini further enumerates a series of 
 observations, whence it results, that the climate which suits the 
 various Cactece passes from the heat of tropical countries to the 
 temperature of the colder temperate zone ; that therefore it is 
 impossible in their cultivation to keep all the species, in ac- 
 cordance with nature, under similar external influences, al- 
 though most species allow of considerable latitude. M. v. Kar- 
 winski has given the natural habitats and heights at which 
 they occur, for a great number of Mexican Cactece, and has 
 published them in this work. The Echinocactus macrodiscus 
 occurs there at an altitude of from 9 to 10,000 feet. 
 
 In the consideration of the distribution of the Cactece, not 
 American, M. Zuccarini inclines to the view that Rhipsalis 
 Cassytha is indigenous to the Isle of France and Bourbon, and 
 
 L2 
 
148 
 
 Cereus flagelliformis to Arabia, and that they have not there 
 passed into a wild state. That Opuntia occur in India must 
 be regarded as a well-established fact, but few well-founded 
 notices exist respecting the distribution of Opuntiae in Africa 
 and southern Europe. Desfontaines mentions the yellow- 
 flowered Opuntia for Barbary ; in Greece it is very frequent. 
 In Tyrol the Opuntiae occur up to 47 lat. ; in northern Italy 
 only O. Italica, Tenore, and 0. vulgaris, Miiller, are found, 
 but in southern Italy several species. In Spain the Opuntice 
 are so common that the question almost arises whether some 
 species have not been transported from Spain to America or 
 from America to Spain. The Opuntia Tuna de Castilla is espe- 
 cially cultivated in America on account of its beautiful fruit. 
 
 M. Zuccarini also describes very fully the uses of the va- 
 rious Cacteae. The Opuntice and the tall thorny Cerei are em- 
 ployed for fences and for fortifying entrenchments ; the wood 
 of the Cactece affords a most excellent material for burning, 
 which is used in various ways in lands poor of wood, in the 
 neighbourhood of Copiapo even for the smelting of copper. I 
 have frequently employed the dry wood of the Cerei and 
 Opuntiae for burning, and found it preferable only from its be- 
 ing consumed very quickly in a dry state ; the copper smelting 
 in the province of Copiapo, the northern part of Chili, with 
 Cactus wood has been discontinued, nay, one may frequently 
 journey there for days together without seeing a single Cactus. 
 Probably these plants were so unsparingly exterminated at the 
 time when the working of the copper ore was begun there with 
 the greatest enthusiasm about 100 years ago. On the high Mex- 
 ican plains, the copses, miles in length, of Cerei, Opuntice., and 
 Echinocacti afford in the dry season a means to the herds of 
 horned cattle of quenching their thirst. In Mexico the deli- 
 cate shoots of Opuntia Nopalitio are eaten like cabbage, and 
 the flesh ofEchinocactus cornigerus boiled in sugar like melons. 
 The fruits of the Opuntice are, as is well known, eaten every- 
 where, and in some places with great gusto. The species most 
 sought after in Mexico are the Alfajayuca and the Tuna de 
 Castilla : the first bears fruit of the size of a thick fist, it is 
 of a green or yellowish colour, almost without thorns, and 
 contains a sweet soft flesh. The fruits of the Cerei are also 
 eaten in many districts (the fruits of Cereus chilensis have a 
 
149 
 
 very insipid taste, but are much eaten by the people. Rep.). 
 These fruits are also greatly improved by cultivation. 
 
 We have obtained a similar work from J. Bateman on the 
 distribution of the Orchidacece*. This splendid family of 
 plants contained in Linnaeus's time only 100 species, and has 
 at present increased to 2000. Europe possesses but few Or- 
 chidaceae ; they occur more numerously and beautifully the 
 nearer we approach the torrid zone, in the moist districts of 
 which they appear in astounding numbers of species and 
 splendour of colour, and in this surpass all other families of 
 plants. Africa, Asia and America are probably equal in the 
 present number of Or chidacece, but each of these quarters of the 
 globe seems to possess some characteristic forms peculiar to it, 
 so that the botanist might already tell from the physiognomy 
 of the plant its country. The forms with pendent stems and 
 splendid flowers of many Dendrobia, Aerides and their allies 
 give the character of the beautiful orchidaceous Flora of India, 
 which is strongly contrasted with the forms of the Bulbophylla 
 or the long appendages of the species of Angrcecum of Africa. 
 America presents on the other hand the erect forms of the 
 Epidendrum, the long isolated branches of many Orchidece, 
 and a greater variety of gigantic and more wonderful forms than 
 any other portion of the globe. It is hardly possible at pre- 
 sent to enter into any further statistical investigation of the 
 distribution of the various forms of Orchidece. 
 
 Ph. Writgenf has published a valuable memoir on the geo- 
 graphical relations of the plants of the Prussian province of 
 the Rhine. First the physical relations of the superficies of 
 the district are described, such as position, boundaries, size, 
 climate, and distribution of the mountains, with a statement of 
 their highest points, for which purpose a large number of mea- 
 sured heights are enumerated. The surface of the Rhenish 
 province may be divided, according to the state of cultivation, 
 
 into Acres. Acres. 
 
 Corn fields 4,337,691. Land gone out of tillage 673,467. 
 
 Woods 3,148,713. Roads and rivers 297,573. 
 
 Meadows and pastures 905,313. Gardens and plantations 240,841. 
 
 Wastelands 870,396. Vineyards 44,756. 
 
 10,217,450. 
 
 * The OrchidacetB of Guatemala and Mexico, 1 Fasc., fol. 
 
 f" Erster Jahresbericht des botanischen Vereins am Mittel und Nieder- 
 rhein. Bonn, 1837, p. 62, &c. 
 
150 
 
 From these statements it will easily be perceived, that the 
 Rhenish province, where at present more than one-half of the 
 surface consists in a carefully cultivated soil, where only one- 
 third is now covered with light woods, and only one-eleventh 
 of the lands lies waste, that such a land must have' worn some 
 centuries back quite a different appearance to that of the pre- 
 sent day, and consequently that the character of the vegetation 
 must have changed essentially from the thinning of the woods 
 and the draining of marshes. 
 
 In the consideration of the vegetation of the Rhenish pro- 
 vince in a statistical point of view the author gives a table 
 of the number and of the arithmetical proportions of the wild 
 plants, from which I have selected some statements respecting 
 the chief families. The number of Phanerogamia amounts to 
 1480; the Dicotyledons are to the whole number as 1 : 1'29, 
 the Ranunculacea = 1 : 30'8, the Papaveracets and Polygaleae 
 = 1 : 296, the Crucifera = 1 : 18'5, the Rosaces = 1 : 30'8, the 
 Leguminosa = 1 : 18- 7, the Umbelliferce = 1 : 24'3, the Com- 
 positce = 1 : 10, the Cichorinae being as 1 : 28. The Labiates 
 \ : 21'l,the Scrophularina = 1 : 26*8. The Monocotyledons 
 = 1 : 4'1, the Gramme = 1 : 12*9, and the Cyperacea = 
 1:18. To all these statements are added comparisons with the 
 proportional numbers of the same families in adjacent coun- 
 tries. Besides which there is a table of the duration of life of 
 the Rhenish plants; the 1480 Phanerogamia may be divided 
 accordingly into 30? annuals, 11? biennials, 913 perennials, 
 and 143 woody plants, &c. 
 
 In the third chapter the physiognomy of the vegetation of 
 the Rhenish province is characterized : the woods there are 
 almost entirely formed of deciduous trees, as the red beech, 
 the oak, and the birch, while the white beech, the elm, the oak, 
 the Norway maple and others generally occur only isolated. 
 Among the shrubs may be named the hazel, the alder, chiefly 
 Alnus glutinosa, the common dog-wood, the common maple 
 (Acer campestre). The rocks of the valley of the Moselle pre- 
 sent a peculiar appearance from the immense number of box 
 (Buxus sempervirens), which clothes the declivities with its 
 dark brownish-green, and imparts to this district a foreign cha- 
 racter. The arboreal vegetation was most powerful on ba- 
 saltic soil. From the slight elevations that occur in the Rhe- 
 
151 
 
 nish province, the highest point, the top of the Hochwald, be- 
 ing only 2405 Rhenish feet, all true mountain plants are want- 
 ing ; only the shade-loving wood-plants, such as Corydalis bul- 
 bosa and tuberosa, Anemone ranunculoides, Vinca minor, Den- 
 taria bulbifera, &c., decorate the ground of the higher moun- 
 tain declivities, as well as the woods of the plain. Fir woods 
 present themselves properly speaking only on the highest 
 points of the Hundesriicken, but here they cannot reach, from 
 the nature of the soil, to any great extent. The vegetation of 
 these districts is divided into an upper and lower region ; the 
 highest limit of the cultivation of the vine (about 800 feet ab- 
 solute height) is fixed as the boundary, and numerous plants 
 are enumerated \vhich as it appears do not extend beyond this. 
 
 In examining the influence of the geognostic peculiarities 
 of the soil, M. Writgen arrives at the conclusion that a far more 
 important influence must be ascribed to the temperature, 
 moisture, and aggregate condition of the soil than to its geo- 
 gnostic character. Observations are enumerated to show how 
 differently limestone and slate, in combination with light, 
 warmth, and moisture, act on the development of the vegetation. 
 Cypripedium Calceolus was observed on the slate mountains 
 of the Rhine ! In the Eifel, on the limits of the clay slate 
 and of the limestone, spelt is cultivated on the latter and rye 
 on the first, and the farmer therefore distinguishes spelt ground 
 and rye ground ; but in the valley of the Rhine the cultivation 
 of grain is so especially favoured by the climate and outer pro- 
 perties of the soil that this distinction is not known. 
 
 There are also some interesting communications in this 
 work on the separate distribution of some species of plants. 
 
 M. Siegmund Graf* has communicated some similar ob- 
 servations on the relations of vegetation of the duchy of Krain, 
 and although this country also possesses no well-defined na- 
 tural boundaries, yet such special investigations of small dis- 
 tricts add more or less important facts to the great structure 
 which vegetable geography tends to erect. Krain is a very 
 uneven land, and comprises 1'735'696 Vienna yokes (of 1600 
 square fathoms) of superficies, of which nearly one-third is 
 
 * Versuch einer gedrangten Zusammenstellung der Vegetations- Verbal t- 
 nisse des Herzogthums Krain. Laibach, 1837-8. Also contained in the 
 Linnaeafor 1837. 
 
152 
 
 covered with forests, one-seventh cultivated, and about one- 
 third consists in meadows and pasture land, there being but 
 little unproductive land. The highest mountain in Krain, 
 the Terglon, is 9036 feet high and covered with eternal snow. 
 In the plains of Krain there are vineyards and orchards; in 
 the warmer Innerkrain, even figs, pomegranates, Laurus no- 
 biliSy Zizyphus vulgaris, &c. grow. The chief portion of the 
 wood in Krain consists however of just the same ordinary 
 trees as adorn the woods of Germany ; the heights of these 
 woods are it is true entirely wanting, although this is most im- 
 portant ; yet I suspect that they are situated above 15 to 1600 
 feet, since the greatest number of ascertained heights in this 
 country lie between 2 and 3000 feet ; consequently here, ac- 
 cording to the rules laid dow r n by me, the region of deciduous 
 trees must predominate, and the character of the vegetation 
 accordingly be similar to that on the northern side of the Alps. 
 The underwood, i. e. the shrubs, are also quite the same as 
 those that principally occur in the plains of Germany. 
 
 In the garden at Laibach (46 2' north, lat.) a number of 
 plants of the subtropical zone, such as Magnolice, Laurus Sas- 
 safras, Aucuha japonica, &c. pass through the winter. Krain 
 is so rich in plants that M. Graf has found there nearly one- 
 third of all the plants of Germany, viz. 1654 species. The 
 family of the Composites contains 8*7 of the entire number, 
 the Grammes 13'8, the Papilionacece 15'6, and the former 
 are more numerous in individuals. The Umbelliferae amount 
 to 19'2 of the number, the Cruciferce 20'4, the Personates 
 21*0, the Labiates 21 -2, the Rosacecz 23 '0, the Cyperoidce 25 -4, 
 the Ranunculacece 27*1? and the Caryophyllacece to 27*5. 
 
 M. Graf* has also enumerated a number of plants which 
 flower in various months on the Grosskahlen mountain near 
 Laibach. 
 
 We have obtained a highly valuable memoir from M. Aug. 
 de Saint-Hilaire t on the primitive vegetation of a portion of 
 Brazil, the botanical treasures of which have been so carefully 
 investigated by him. Just as the vegetation in the most cul- 
 tivated lands of Europe must have at present an appearance 
 
 * Der Grosskahlenberg bei Laibach. Flora von 1837. No. 42. 
 f Tableau geographique de la vegetation primitive dans la Province de 
 Minas Geraes, Paris, 1837, 8vo. Extr. des Nouv. Ann. des Voyages. 
 
153 
 
 entirely different from that of 1000 years ago, we observe al- 
 ready at the present day in various parts of Brazil a great 
 change in the character of the vegetation from the influence 
 of the cultivation of the soil. 
 
 A very extensive portion of Brazilian America, says M. de 
 St. Hilaire, has changed its physiognomy; a large Fern (Pteris 
 caudata) and Saccharum Sap& replace the grotesque forests, and 
 in the immeasurable open spaces all the plants appear to fly be- 
 fore the Capim godura (Melinis minutiflord) . European, Afri- 
 can, and North American plants follow on the other hand the 
 steps of man. Nevertheless, the primitive vegetation presents, 
 in the province of Minas Geraes, such great differences, that 
 distinct appellations have been given to them. The whole 
 land is divided into Matos and Campos. The woods are either 
 primitive (Matos virgens] or formed by man. The Catingas 
 are less luxuriant woods which yearly throw off their leaves ; 
 they have been admirably described by M. v. Martius. The 
 Carrascos are lower wood which consists of tall shrubs 3 
 to 4 feet high ; the Carrasquenos form a transition between 
 the Carrascos and the Catingas ; their trees are higher than 
 in the former. The Campos are plains which, covered with 
 herbs, surround the Matos ; they are original or produced 
 by man on the soil of destroyed forests. It must not however 
 be thought that the above-mentioned distinctions of the Bra- 
 zilian vegetation are so accurately defined as is stated in 
 books : we shall everywhere find transitions from the one to 
 the other, and even from the Carrascos to the true Campos. 
 
 M. de St. Hilaire then gives an interesting account of the 
 physiognomy of the vegetation which is presented in the dif- 
 ferent above-mentioned districts of the province of Minas 
 Geraes, of which our German naturalists, who have travelled 
 in those countries, have given such beautiful descriptions. 
 
 In Hooker's Companion to the Botanical Magazine for 
 the year 1837 3 we also find some very important memoirs for 
 the geography of plants, of which, however, I can only men- 
 tion the names, as they enter too much into special details for 
 me to give extracts of them here. Above all, the beautiful 
 memoir of Allan Cunningham* must be mentioned, which 
 
 * Florae Insularum Novae Zelandiae Precursor ; or a Specimen of the 
 Botany of the Islands of New Zealand. Companion, ii. p. 222, 337 and 358, 
 and continued in the Annals of Natural History. 
 
154 
 
 contains an arrangement of all the plants hitherto found in 
 New Zealand according to their natural families. Further, 
 the observations of J. Backhouse* on the Esculents of Van 
 Diemen's Land, among which, the roots of Pteris esculenta 
 play a chief part ; they are often of the thickness of a man's 
 thumb, and go deep below the surface of the earth. The root 
 tubers of some OrchidecB, as Gastrodia sesamoides, form the 
 potatoes there, &c. The natives eat the heart of Cibotium 
 Billardieri and Alsophila australis. The other edible plants 
 are of no importance, and can only satisfy hunger to a certain 
 degree. 
 
 There is also in Hooker's Companion a memoir of the un- 
 fortunate Douglas, consisting of letters which he had ad- 
 dressed to his friends f. There are numerous very useful 
 communications relating to the geography of plants scattered 
 in it ; the most remarkable of all appears to me to be the no- 
 tice of a gigantic Cactus which Douglas observed on the Gal- 
 lopagos : its stem is from 2 to 3 feet in diameter, and 40 to 50 
 in height. It belongs to the genus Opuntia, and has long and 
 large yellow flowers and very long flexible thorns. 
 
 M. Beilschmid J, to whom botany and especially the geo- 
 graphy of plants is indebted, for the greater diffusion of many 
 of the most interesting works, has translated Watson's ( Re- 
 marks on the Geographical Distribution of British Plants, 
 chiefly in connexion with Latitude, Elevation, and Climate,' 
 and appended to it some interesting additions and observa- 
 tions : this work is as it were republished by M. Beilschmid, 
 for hitherto we did not even know of its existence at Berlin. 
 
 We may regard R. Schneider's memoir as a sequel to the 
 publication of the above work ; it contains a very excellent 
 comparison of the vegetation of Silesia with that of Great Bri- 
 tain, and the numerical proportions between the British and 
 Silesian plants, which are arranged in a table side by side, 
 
 * Some remarks on the roots and other indigenous Esculents of Van 
 Diemen's Land. Companion, ii. p. 39. 
 
 f Memoir of the Life of David Douglas, with a portrait. His sketch of 
 of a journey to the North Western parts of America. His letters from the 
 Columbia. His journey across the Rocky Mountains to Hudson's Bay, &c. 
 Companion, p. 79 178. 
 
 J Bemerkungen iiber die geographische Vertheilung und Verbreitung der 
 Gewachse Grossbritanniens, besonders nach ihrer Abhangigkeit von der 
 geographischen Breite, der Hbhe und dem Klima, Breslau, 1 837. 
 
 Vergleichung der schlesischen Flora mit der britischen nach Watsons 
 Angaben. Flora von 1837. Nos. 33, 34. 
 
155 
 
 are very striking. The same author has also published some 
 additions to the Silesian Flora (Breslau, 1837), which however 
 I have not been able to see. 
 
 In a very complete memoir on the Peculiarities of the 
 Flora of the Peat Bogs in the neighbourhood of Greifswald*, 
 M. Hornschuch has specially enumerated all the plants which 
 take part in the formation of peat in that district, and also 
 those which grow preferably on such turf soils. The various 
 peat moors of that district exhibit in their composition great 
 differences, and each one possesses something peculiar which 
 is also expressed in its Flora. The following is the account 
 of the formation of the peat in the turf pits. Sphagnum cus- 
 pidatum gradually covers the whole surface of the water of 
 the pit, sinks from its own weight together with the other 
 plants growing on it, and either fills it up or forms floating 
 islands, and its place is then occupied by Sphagnum acuti- 
 folium. This gradual change in the vegetation in these pits 
 is distinguished by the following stages. The Sphagnum cus- 
 pidatum fixes itself to one side of the pit and densely together, 
 but still swims in, and is surrounded by water, in which Equi- 
 setum limosum and Car ex filiformis vegetate ; while, on the 
 other sides of the pit, Juncus uliginosus begins to spread over 
 the surface of the water, proceeding from the sides. In older 
 pits Sphagnum covers the whole surface ; on and between it 
 vegetate isolated individuals of Schcenus albus, Eriophorum 
 vaginatum, Comarum palustre, Drosera intermedia ; and the 
 submerged rhizomas of Equisetum limosum break with their 
 culms through this covering of plants, &c. 
 
 M. linger read a paper f before the meeting of Naturalists 
 at Prague, in which he brings forward some new statements 
 to defend his view respecting the dependence of certain forms 
 of plants on the nature of the soil J. The new observations 
 have been collected in the neighbourhood of Gratz in Styria ; 
 he there found a number of plants which he designates as al- 
 ways occurring on limestone, and again others which belong 
 to the Kalk-holden . It is sufficiently well known how differ- 
 
 * Flora von 1837. Nos. 47, 48. t Flora von 1837. No. 40. 
 
 J See last year's Report, 
 
 In the German Kalkstete in opposition to Kalkholden. I have some 
 doubt about the meaning of this last word, but if formed of hold loving 
 would be plants preferring limestone but not confined to it. W. F. 
 
156 
 
 ent are the views of botanists on this subject. M. Unger's 
 opponents are however able to mention as many facts against 
 this dependence of plants on the geognostic character of the 
 soil as M. Unger has advanced in support of it. 
 
 I can only mention the interesting and important memoir 
 of Sauter v. Bregenz on the Relations of Vegetation in the 
 district of the Boden lake and in a part of the Voralberg*, 
 as also the descriptions of MM. Tommasinif and Brunner J, 
 as they are more of local interest, and their numerous special 
 statements do not permit a general representation of the re- 
 sults. 
 
 Highly important for future writers on the Vegetable Geo- 
 graphy of the South Sea Islands is M. Guillemin's Zephy- 
 ritis Taitensis : it is most especially adapted, in connexion 
 with M. Endlicher's remarks on the Flora of the South Sea 
 Islands, and the beautiful memoir of Allan Cunningham, 
 mentioned at page 153, on that of New Zealand, to a special 
 statistical research. 
 
 M. F. A. Miquel || has published a memoir on the occur- 
 rence of the Sargazzo in the sea of Sargazzo, named after it, 
 in which there are some points intimately connected with 
 the geography of plants. M. Miquel is also convinced that 
 Agardh's two species S. vulgare and S. bacciferum are iden- 
 tical, and only form one species, for which he proposes the 
 name of S. Columbi, as this enterprising navigator touched on 
 the Sargazzo sea on the 16th Sept. 1492. According to the 
 laws in force among botanists, such a change of names can cer- 
 tainly meet with no good reception ; the plant which floats in 
 this sea was named by Linnaeus Fucus natans, and is identical 
 with Fucus natanSy Turn. ; Gmelin certainly did wrong when 
 he called it Fucus Sargazzo. The generic name has, it is true, 
 been changed, but there exists no reason for altering Lin- 
 
 * Flora von 1837, i. Beiblatter, p. 1. 
 
 f* Ausflug von Gbrz auf die Kron-Alpe tmd in das Reibler-Thal in Karn- 
 then. Flora von 1 837. Nos. 5, 6. 
 
 J Ausflug ill's Zermatt-Thal im Julius, 1836. Flora von 1837. No. 10. 
 
 Enumeration des plantes decouvertes par les voyageurs dans les Isles 
 de la Societe, principalement dans celle de Taiti. Ann. des Scienc. Nat. 
 1837, i. 
 
 |j Over het Sargasso of Zeekroos. Tijdschrift voor Natuurlijke Geschie- 
 denis en Physiologic, 1837, iv. p. 25 41. 
 
157 
 
 naeus's specific name ; this fucus must therefore be called Saf- 
 gassum natans, although it was subsequently found sessile as 
 well as floating. 
 
 M. Miquel treats of the question respecting the origin of this 
 floating fucus, and thinks that if we admit that it has been torn 
 from its place of growth and only remains afterwards living for 
 some time, we should not depart much from analogy. Here- 
 upon various doubts are raised against views advanced by me, 
 who have observed that the small floating specimens show 
 quite distinctly that they have never been sessile, that conse- 
 quently we have not to look for the ground upon which they 
 may have originated, but that the surface of the water on which 
 they float must be regarded as such. The doubts which M. 
 Miquel advances against my actual observations are however 
 very easily obviated ; in every case where he suspects that 
 my observation (I did not advance a mere opinion on this 
 subject, but actual observation. Rep.) is without analogy I 
 have enumerated actual analogous cases, and subsequent ob- 
 servations have increased my knowledge on this point. All 
 the specimens of this floating fucus which M. Miquel has ob- 
 tained from the Sargazzo sea have a short foot-stalk, which ap- 
 pears to me very intelligible, for this fucus floats in masses of 
 greater or less size, some individuals even attaining to a length 
 of 2, 3, 5, and more feet, and each one has hundreds, nay thou- 
 sands, of stalks, branches and shoots *. But it is the large 
 specimens which the sailors fish up to bring home for their 
 friends, and especially those with stalks and branches. I was 
 very soon convinced that the examination of the large speci- 
 mens could lead to no result ; I therefore fished for the small- 
 est, which very soon solved the enigma, and the specimens 
 brought home by me confirm my statements. I did not ob- 
 serve dying or dead specimens in the Sargazzo sea, conse- 
 quently they can only be very rare. 
 
 Since the question of the floating gulph-weed is now an- 
 nually repeated, and very frequently spoken of in the Aca- 
 demic des Sciences of Paris, I forwarded a specimen of this 
 
 * It must not be overlooked that all these parts are only foliaceous for- 
 mations, and that a Fucus has neither stem nor root in the sense of the higher 
 plants ; on which account these are no reasons at all in favour of M. Miquel's 
 view, that this fucus cannot have been developed in a floating state, but must 
 have grown erect. 
 
158 
 
 plant to that celebrated Society, that at least one fact might be 
 established, viz. that this plant had never been sessile. Now 
 although this point was very easy to decide on the specimen 
 sent, yet a learned member of the Academy, evidently without 
 examining the specimen, supposes nevertheless that it may 
 have been torn loose. 
 
 After the establishment of this fact, that the floating perfect 
 fuci in the Sargazzo sea have not been sessile, we arrive at 
 the question, whence then have the seeds of this plant come ? 
 But this question also is not difficult to answer if we consider 
 the powerful currents which prevail in and about this sea, 
 especially as we know that the sessile specimens of the Sar- 
 gassum natans on the American coast, and probably on the 
 coasts of the Azores, &c., bear fruit. 
 
 THE END. 
 
 ERRATUM. 
 
 52, 3rd line from bottom, for flower read flower-stalk. 
 
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