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EASY LESSONS 
 
 IN 
 
 Vegetable Biology; 
 
 OR, 
 
 Outlines of Plant Life. 
 
 REV. J. H. WYTHE, M.D., 
 
 Author of "The Science of Life," "The Microscopist," "Agreement 
 of Science and Revelation," etc. 
 
 CINCINNATI: 
 WALDEN & STOWE. 
 
 1883. 
 
Cfttt 
 
 Copyright 1883, by 
 PHILLIPS & HUNT, 
 
 New York. 
 
PREFACE. 
 
 This work has been prepared for the students of the 
 Chautauqua Literary and Scientific Circle. It is also 
 adapted to use in schools. 
 
 It begins with the simplest and most elementary 
 facts of Biology, and progresses gradually to things 
 more intricate. It uses no unnecessary- technicalities, 
 is condensed into the smallest possible compass, and 
 but few words are spent upon theories. The Chris- 
 tian philosophy of life, which the author believes to 
 be the only true philosophy, is clearly stated ; but he 
 aims to present only facts, and the plain inferences 
 from facts, to the attention of the inquirer. 
 
 ^^ Of XBDB^^S 
 
 [BHIVBRSITY] 
 
CONTENTS. 
 
 CHAPTER PAGK 
 
 I. What Biology Teaches 7 
 
 II. Living Matter 12 
 
 III. Differences between Living and Non-living Matter 17 
 
 IV. Different Kinds of Living Matter 23 
 
 V. Individual Vegetable Cells 27 
 
 VI. The Vegetable Cell as a Member of a Group 33 
 
 VII. Protophytes, or the Simplest Forms of Plants 40 
 
 VIII. Thallogens, or Division of Labor in Plants 46 
 
 IX. Acrogens, or Plants which Grow at the Summit.. . . ; 50 
 
 X. Endogens, or Inside-growers 58 
 
 XL Exogens, or Outside-growers u 
 
 XII. The Vegetable Clothing of the 
 Glossary and Index 
 
 World 80 
 
 85 
 
 [UITIVBBSITY] 
 
^£2 
 
 EASY LESSONS 
 
 IN 
 
 VEGETABLE BIOLOGY. 
 
 CHAPTER I. 
 
 WHAT BIOLOGY TEACHES. 
 
 1. The word Biology is made up of two Greek 
 words — bios, life, and logos, a discourse. It means the 
 study of living things. 
 
 A few years ago all the living and non-living ob- 
 jects in the earth — minerals, plants, and animals — were 
 embraced in one department of knowledge, called 
 Natural History, but it is now usual to study living 
 and non-living objects in different departments. A 
 knowledge of Biology involves much more than the 
 ability to distinguish the different kinds of living 
 beings so as to be able to label dead specimens in a 
 cabinet. This science uses the terms of Botany and 
 Zoology only as the builder uses a scaffolding for the 
 erection of an edifice, or as a postmaster the boxes of 
 his office for a more convenient classification. 
 
 2. Biology includes in its survey both animals and 
 vegetables, and considers their forms and peculiarities, 
 
8 Easy Lessons in Vegetable Biology. 
 
 the parts of which, they are composed, their relations 
 to each other, and the uses which they serve. It takes 
 in the entire life-history of every living thing, with 
 the changes which occur in health and disease. If 
 fully recorded, the world would hardly hold the books 
 which might be written about these things, since there 
 are many thousands of species, or different kinds, 
 both animal and vegetable; and the influences to 
 which they are subject are quite innumerable. Yet 
 many observations and comparisons have shown that 
 one kind agrees with another in certain particulars, 
 so that the general principles which underlie their 
 forms, changes, structure, and uses may be under- 
 stood. The consideration of these general principles 
 and correspondences makes up the chief part of the 
 study of Biology. 
 
 3. Biology studies only living beings. The general 
 forces of nature and the changes in non-living matter 
 are the subjects of Physics and Chemistry. Biology 
 only refers to these changes as they affect living 
 things, or are modified by the presence of life. 
 
 4. Those astronomers who still hold to the Nebular 
 hypothesis — the theory that the sun and planets de- 
 veloped themselves out of a sort of fiery vapor or 
 nebulous matter — teach us that only a few of the 
 planets of our solar system are capable of sustaining 
 life, and chemical analysis shows that only four out 
 of nearly seventy elementary or simple substances, of 
 
What Biology Teaches. 9 
 
 which the world is composed, are found essentially 
 connected with living beings. Geology also shows us 
 that there were vast periods in the past history of the 
 earth when no life existed. These periods are hence 
 called azoic, or without life. At the present time, 
 the ice-fields of the poles, and the great deserts, are to 
 a large extent lifeless. It is plain, therefore, that life 
 is not an essential part of creation. Suns and planets 
 would shine ; gravity, light, heat, and electricity 
 would operate ; and chemical changes take place, if 
 there were no living beings. From this consideration 
 we see clearly that Biology embraces something more 
 than the study of the laws and phenomena of non- 
 living matter. It is the science of life. It concerns 
 itself with every thing pertaining to life. 
 
 5. The question, What is life ? has given rise to vari- 
 ous speculations in every age of history to the present 
 day. Some of the Greek philosophers taught that 
 it was the result of the harmony or agreement of the 
 different parts of the body ; and this view is repeated 
 in modern times by those who claim that life is the 
 result of organization. It requires but little thought 
 to see that this is no explanation at all. Since all 
 organization depends on living matter, as we shall 
 more fully perceive hereafter, one might as wisely 
 say that an architect or carpenter was the result of a 
 house, as to say that life results from organization. 
 
 Some have claimed that life is a sort of refined 
 
10 Easy Lessons in Vegetable Biology. 
 
 matter ; a gas, or ethereal vapor. Heat, oxygen, and 
 galvanism have all had their advocates, and at the 
 present day, when teachers of physical science show 
 that one kind of force (as motion, light, heat, or elec- 
 tricity) can be converted, or changed, into another, 
 some are found to say that physical force can be 
 changed into life, or vital force. But this theory is 
 insufficient to explain what life is, since it does not 
 show what is meant by " physical force," nor what 
 changes its form. Life must either be the power of 
 matter or spirit, for we can only conceive of these two 
 forms of existence. This theory is also insufficient, 
 since it does not account for the living germ through 
 which (according to the theory) heat or other form of 
 force passes in order to be converted into vitality. 
 
 6. Writers who have endeavored to define life in 
 accordance with the teaching of materialism — which 
 makes matter explain every thing — have involved 
 themselves in unsatisfactory and often absurd con- 
 clusions. The teaching of the Bible and of all the re- 
 ligions of mankind, the belief of the most eminent 
 philosophers, the doctrine held by the early Christian 
 fathers, and maintained by the majority of scientific 
 and unscientific men, is that the difference between a 
 living body and the same body after death arises from 
 the union of matter and spirit. In other words, a 
 living thing is a spiritual essence which clothes itself 
 with material particles after a form and according to 
 
What Biology Teaches. 11 
 
 an order (or law) of its own kind. Dr. Noah Porter, 
 President of Yale College, in his work on the " Hu- 
 man Intellect," devotes an entire chapter to prove 
 that life and soul are synonymous words, and apply 
 to all living things. The writer of the present work, 
 in the volume entitled " The Science of Life," regards 
 life, not as identical with soul, but as the sum of the 
 activities resulting from the union of mind and mat- 
 ter. Those who desire to study the subject more 
 thoroughly are referred to those works. 
 
12 Easy Lessons in Vegetable Biology. 
 
 CHAPTER II. 
 
 LIVING MATTER. 
 
 1. A careful study of any living thing, either 
 vegetable or animal, will show that it is not all alive. 
 Some parts are dead, although they may retain the 
 form impressed on them by vitality, as in the case of 
 a dry branch of a tree, and may serve various pur- 
 poses in relation to the rest of the body, like resin in 
 some plants and milk in animals. When we clip the 
 hair, or pare the nails, we cut merely the dead, in- 
 sensitive part ; but at the root of the hair or nail we 
 find the " quick " — the living part. By the use of 
 the microscope it has been found that every part of 
 every living body, or organism, has scattered through 
 it little particles of living matter. In the skin, flesh, 
 bones, and nerves of animals, and in all the different 
 parts of vegetables, these small particles of living 
 matter may be seen by a good instrument. It is the 
 presence of this living matter which entitles any thing 
 to be called a living being. Without this a man, a 
 horse, a tree, or a flower, would be as dead as a piece 
 of iron or chalk. 
 
 2. This living matter, seen through the microscope, 
 looks like a bit of jelly or albumen. It is generally 
 
Living Matter. 13 
 
 transparent, and is neither quite solid nor fluid. 
 When it was first discovered it was thought to be in- 
 closed in a sort of membrane like a bladder, and it 
 was called a cell. It is now known that it has not al- 
 ways an outside membrane. It is often called proto- 
 plasm, or first formation. It is also called by the 
 better term hioplasm, or living formation. Some re- 
 cent discoveries with the microscope render it likely 
 that the real living matter in each cell, or piece of 
 bioplasm, is arranged like a net-work, and communi- 
 cates with neighboring cells so as to make a continu- 
 ous living structure throughout the body, either of 
 plant or animal. 
 
 Those who have access to a good microscope may 
 find an example of this living matter, or bioplasm, in 
 the white blood-cell. Prick your finger, and put a 
 small drop of blood, about the size of a full " stop " 
 — printer's type — upon the thin glass cover of a mi- 
 croscopic slide, then quickly put the cover in its 
 place, so that the drop may spread by capillary attrac- 
 tion, and observe the globules in the field of view of 
 the instrument. In about every three hundred of the 
 ordinary red blood-disks you will see one of the white 
 disks. If you keep it warm by a heated stage, or if 
 you examine the blood of a cold-blooded animal, as a 
 frog, instead of your own, you will be able to see its 
 peculiar motions and other phenomena. 
 
 3. From such simple, jelly-like particles all animals 
 
 . 
 
14 Easy Lessons in Vegetable Biology. 
 
 and vegetables originate, and by such particles are all 
 organic structures built up. Bone, muscle, nerve, and 
 skin, in animals, and fiber, wood, and vessels, in vege- 
 tables, are all constructed from such elements. It is 
 the province of biology to find out how this is done. 
 
 4. The particles of bioplasm, or living matter, al- 
 ways look alike, no matter where they belong. There 
 is no difference under the microscope between the bi- 
 oplasm of a blade of grass or a whale, of an oak, a 
 rose, a dog, or a man. The bioplasm of skin cannot 
 be distinguished from that of flesh, or of the blood, 
 yet there is a wonderful difference in the power and 
 products of these different kinds, although the differ- 
 ence is not visible even with a microscope. 
 
 Chemical examination also shows that all living 
 matter is composed of the same elementary materials. 
 Oxygen, hydrogen, carbon, and nitrogen enter into 
 the construction of every piece of bioplasm. Some- 
 times lime, or iron, or sulphur are also found, but 
 these are accidental, and not essential or necessary. 
 
 5. The jelly-like living matter which has been de- 
 scribed, like any other jelly, is permeated or satu- 
 rated with fluid, which may be considered apart from 
 the rest of the structure. All organic substances con- 
 tain considerable water. A human body weighing a 
 hundred and fifty pounds can be dried in an oven 
 until it weighs only seven and a half pounds. The 
 water in a piece of bioplasm may also contain other 
 
Living Matter. 15 
 
 substances in solution which may serve the living mat- 
 ter as food. In the spaces between the minutest parti- 
 cles or net-work of bioplasm we may also find mate- 
 rial which has been formed by it. So that in every 
 bioplast, or living particle, we recognize matter in 
 three different states : (1) Matter not yet alive, but 
 about to become so, called Pabulum, or nutriment. 
 
 (2) Living matter in the strictest sense, or Bioplasm. 
 
 (3) Formed material, or matter which was alive, but 
 is so no longer. 
 
 Owing to the constant action of the air and other 
 influences, the formed material is constantly decay- 
 ing, or becoming effete, and thus returns to the inor- 
 ganic world from which it originated, so that we may 
 say of the body of any living thing — though not of 
 the life — u Dust thou art, and unto dust shalt thou 
 return." 
 
 6. Physical forces, like gravity, heat, light, and 
 electricity, and chemical agencies, affect all living 
 matter as well as the non-living, but not always in 
 the same manner. Some forces, as gravity, for ex- 
 ample, act in the same way on the living and the non- 
 living. The passage of liquid out of or into a porous 
 or membranous vessel is similar in a living or non- 
 living thing. In other instances the presence of life 
 greatly modifies the influence of inorganic force. 
 Thus, water generally freezes at 32 deg. F., and boils 
 at 212 deg.; but bioplasm, or living matter, resists the 
 
16 Easy Lessons in Vegetable Biology. 
 
 extremes of lieat and cold as long as the life remains. 
 There are differences in this respect in different or- 
 ganisms. The motions of some simple forms of ani- 
 mals are arrested by ice-water, and recommence on 
 increasing the temperature, but the development of 
 trout's eggs proceeds well in ice-water, while in a 
 warm room they soon die. Many kinds adapt them- 
 selves to a considerable change of temperature if it be 
 gradual. Men will endure the cold of an Arctic win- 
 ter, and, on the other hand, the workers in plaster 
 will bear for a considerable time the heat of an oven 
 raised to 500 deg. F. The influence of light, heat, and 
 electricity upon bioplasm varies according to the spe- 
 cies, some requiring a greater amount than others for 
 natural growth. As to chemical changes, the life 
 power has greater modifying power than any thing 
 else in nature. A vast variety of products in both 
 animals and vegetables are due to the controlling 
 influence of life. In a few instances the skill of a 
 chemist has imitated the product in his laboratory, 
 but the majority can only be found as the result of 
 life. Among them may be named albumen, starch, 
 sugar, and gum. Many others will occur to us as 
 we proceed in our studies.* 
 
 * See " Science of Life," Chap. IY. 
 
Living and Non-living Matter. 17 
 
 CHAPTER III. 
 
 DIFFERENCES BETWEEN LIVING AND NOtf-HVING 
 MATTER. 
 
 1. The jelly-like bioplasm described as existing in 
 all kinds of vegetables and animals, and forming all 
 sorts of organic materials, is so different in power 
 from non-living matter as to compel us to believe 
 that it contains something more than mere matter. 
 Each kind, or species, of living being can do some- 
 thing which is peculiar to itself, yet there are certain 
 particulars in which all kinds agree, or things which 
 all sorts of bioplasm can do, but which no matter can 
 do which is not alive. 
 
 2. All bioplasm has spontaneous motion. Most 
 vegetables are fixed to one spot, but the living matter 
 in their tissues is just as much in motion as the bio- 
 plasm of the most active animals, so that the same 
 things may be said of either animal or vegetable bio- 
 plasm. Non-living matter is passive. It has inertia* 
 It can neither originate, suspend, nor destroy motion. 
 It can only transmit motion, or be moved. But bio- 
 plasm, or living matter, has primary energy, and can 
 overcome inertia. Its motions are spontaneous, or 
 
 * A property of matter which causes it to remain in a state of rest 
 or of motion. 
 2 
 
18 Easy Lessons in Vegetable Biology. 
 
 spring from its own internal energy. So far from 
 being caused by external influence, its movements are 
 often in direct opposition to gravity, or any other 
 force which we may imagine to act upon it. 
 The motions of bioplasm are of three kinds : 
 
 (1) Inherent motions of the individual particles 
 among themselves. Each particle is as much alive as 
 the whole mass, and the movements of each are spon- 
 taneous. If a thread or filament of bioplasm be ex- 
 amined in a powerful microscope, the motions of the 
 particles may be observed by the granules of formed 
 material (Sec. 5, Chap. II) which may be scattered 
 through the mass. " As the passengers in a crowded 
 street may go the full length of the street, or turn 
 back, or stop and double, as many times as they wish, 
 so do the particles move in the mass of bioplasm. 
 Up, down, across, backward, and in all directions. — 
 even through each other — do these molecules move, 
 each impelled by its own inherent energy." * 
 
 Observe another motion of bioplasm : 
 
 (2) Constant change of shape. A piece of bio- 
 plasm never remains at rest. If unconfined, its exter- 
 nal appearance or shape is continually changing. 
 This has been called amoeboid motion, from the name 
 given to one of the simplest forms of living beings 
 known, the Amoeba. 
 
 Fig. 1. This appears to be simply a piece of bio- 
 
 * •• Science of Life." 
 
Living and Non-living Matter. 10 
 
 plasm, or living jelly, yet it is a complete organism. 
 Its organs, however, are all extemporaneous. It 
 never retains the same outline or form, and it can 
 project any part of its substance in the shape of an 
 
 Fig. l. 
 
 arm or branch, and if it touches any thing which 
 may serve it as food, the rest of the body will flow 
 around it and digest it. Indigestible parts it discards 
 by flowing away from them. It literally swallows 
 without a mouth, digests without a stomach, and 
 moves without muscles, while a small fragment of its 
 substance is capable of repeating the same things as an 
 independent organism. Such living Amoebae are found 
 in stagnant pools of water and many other places. 
 Since every piece of bioplasm has similar changes of 
 shape, it is agreed to call such changes amoeboid. 
 
 (3) Wandering movements. As unconfined bio- 
 plasm can flow along an arm or branch of its own 
 body around its food, it can in the same manner 
 change its position from place to place. In this way 
 
20 Easy Lessons in Vegetable Biology. 
 
 the white blood-cells, described in Sec. 2, Chap. II, 
 wander out of the blood-vessels in order to construct 
 the various parts of the body as they may be needed. 
 (Fig. 2.) 
 
 3. Another peculiarity of living matter is the 
 power of nutrition and growth. The non-living in- 
 creases in size by external additions, but bioplasm 
 selects appropriate material from its food, (or pabu- 
 lum,) changes the chemical relations of this material, 
 
 Fig. 2. 
 
 and appropriates it to its own structure in such a way 
 that it grows from within. It is altogether different 
 from the enlargement of a crystal, or of the increase 
 of any thing without life. 
 
 4. Bioplasm can generate or reproduce its own 
 kind of living matter. No living being exists which 
 did not originate from living matter of a similar 
 kind. Some persons have thought that they have 
 seen the beginning of life in some forms of simple 
 beings, originating by what has been called sponta- 
 
Living and Non-living Matter. 21 
 
 neons generation, bnt a careful examination proves 
 them to have been mistaken. Microscopic living 
 beings appear after a time in water where vegetable 
 or animal matter has been left to decay, but we now 
 know that their eggs or seeds, in the shape of very 
 minute particles of bioplasm, are to be found in great 
 numbers floating about in the air and in every collec- 
 tion of water, and that these seeds or eggs retain 
 their life-powers after having been subjected to boil- 
 ing heat. Of course there was a first animal or vege- 
 table of each kind, and some learned men think it 
 w T as the offspring of another kind, not quite like it, 
 by some sort of change of form or of activity, so 
 that the more complicate forms sprang from more 
 simple ones. This doctrine of " evolution," as it is 
 called, has never been proved by facts, although the 
 varieties existing in the same species, as the different 
 kinds of dogs or pigeons, give it a sort of probability 
 to some persons. All kinds of living beings, how- 
 ever, spring from similar parents, and none have ever 
 been known to change into other forms. The forms 
 pictured upon the monuments of early Egyptian his- 
 tory are similar to those of the present day. New 
 varieties, not new kinds, may be produced by culture, 
 as in the case of roses and other flowers, but such will 
 return to their original form if allowed to grow wild. 
 5. The power of a living thing to preserve its own 
 identity amid all the material changes which take 
 
22 Easy Lessons in Vegetable Biology. 
 
 place, is entirely different from the power of mere 
 matter. In Chap. II we learned that oxygen, hydro- 
 gen, carbon, and nitrogen are found in every par- 
 ticle of bioplasm, and that sometimes a few other 
 chemical elements occur accidentally. Now these 
 things do not remain quiet in living matter. Atom 
 by atom they quickly pass through it. They are 
 seized by the bioplasm as food, transformed into its 
 own structure, and then are changed into formed 
 material, as starch, wood, gum, oil, etc., in vegetables, 
 and blood, muscle, bone, and nerve in animals. The 
 formed material decays atom by atom and is cast off, 
 to mingle again with the inorganic elements of the 
 world. During all these changes the living being 
 preserves its identity and power. Thus it is possible 
 that an atom of oxygen or hydrogen may be cast off 
 from some of the bioplasts of our own bodies, be 
 wafted by the air to the sides of the Andes, be ap- 
 propriated to the use of the bioplasm in one of the 
 cinchona-trees, and return to us in the form of qui- 
 nine, perhaps to cure us of ague. The possibilities of 
 science exceed the most romantic imagination. The 
 preservation of its identity shows that the life of bio- 
 plasm differs from the atoms which come to and go 
 from it. It does not depend upon the new ones, for 
 it existed without them, nor upon the old ones, for 
 it remains without them. Life is not matter, but 
 matter's master. 
 
Different Kinds of Living Hattek. 23 
 
 *&* Of THU^^S 
 
 pIJVMSITy] 
 
 OHAPTEE IV.^ 
 
 DIFFERENT kinds of living matter. 
 
 1. We have learned in former lessons that the ele- 
 mentary particles of living matter look alike and have 
 the same essential composition, although they may 
 belong to different kinds of living beings, and may 
 serve very different purposes. 
 
 2. Different bioplasts produce different forms of 
 living things by the special instincts (or tendencies) 
 belonging to each kind. These different forms are 
 arranged, or classified, in Botany and Zoology, not 
 only for convenience of study, but as far as possible 
 in accordance with the plan of Creative Wisdom, 
 which has assigned to each its place in the order of 
 nature. 
 
 3. The thousands of different kinds of vegetables 
 and animals could not be remembered ; but by group- 
 ing certain kinds together, which are in some respects 
 similar, and by combining these groups with others, 
 naturalists are able to form something like an orderly 
 system. Such a system will be a natural system if the 
 grouping be according to existing resemblances or true 
 affinities, otherwise it will be an artificial system. An 
 illustration of a natural system of classification may be 
 
24 Easy Lessons in Vegetable Biology. 
 
 found in a house, considered as a building. Let us 
 suppose that all kinds of houses may be referred to one 
 or other of three types, or general plans — the Oriental 
 type with a dome roof, the Grecian type with a flat 
 roof, or the Gothic type with a pointed roof. We 
 select a house of the Grecian type. But there are 
 several classes of the same type, as made of wood, 
 iron, or stone. Our supposed house is a wooden one. 
 But there are several orders in each class. Thus 
 we may have Pine, Oak, Mahogany, etc. The house 
 we are considering is built of oak. In each order 
 there are other groups, or genera. The doors may be 
 at the front or at the side. Of the kind, or genus, 
 having the door at the front, there are more specific 
 kinds, according to the resident. In our supposed 
 case, the specific house is John Smith's. Thus, if we 
 have rightly classified we have learned that John 
 Smith's kind, or species, of house, is of the genus, or 
 group, which has front doors belonging to the larger 
 group, or order, of houses built of oak. This again 
 is grouped in the class of wooden houses under the 
 Grecian type. 
 
 In a similar manner naturalists try to group to- 
 gether living things according to their real relation- 
 ships. All systems, however, are imperfect, on ac- 
 count of our imperfect knowledge, and we need not 
 be surprised to find one naturalist referring a form 
 to a group very different from that to which it is 
 
Different Kinds of Living Matter. 25 
 
 referred in the scheme of another, since men differ 
 greatly, not only in knowledge, but in opinion. 
 
 Types represent general plans of structure. Classes 
 are formed by the special modification of a type. 
 Orders are groups of the same class related by a com- 
 mon structure. A Family or Genus is a still smaller 
 group having generally the same essential structure. 
 A Species is the smallest group whose structure is 
 constant. Species are so much alike that they may 
 have descended from the same parents. Individuals 
 are the units of organic life, forming a complete ani- 
 mate existence. Peculiarities of races or breeds are 
 called varieties. Vegetables and animals are distin- 
 guished from each other by the term Kingdom, and 
 the types in each kingdom are called Sub-kingdoms. 
 
 4. The names which naturalists use to designate 
 kinds or groups of living things are formed from the 
 Latin or the Greek language. There -are good rea- 
 sons for this. In the modern languages common things 
 have many different names. But the majority of 
 plants and animals are new or rare, and have no name 
 in any modern language. If there must be a new 
 name it may as well be Latin or Greek as any other. 
 Then the latter languages have the advantage of ex- 
 pressing by their combinations some peculiarity which 
 is distinctive, and which is readily recognized by the 
 learned. As to the difficulty of learning these terms, 
 it is only apparent. They can easily be mastered by 
 
26 Easy Lessons in Vegetable Biology. 
 
 application. The terms of natuiftl science are no more 
 difficult than those of geography or of history. 
 
 5. The types, or general plans of structure, found 
 in vegetable Biology may be described briefly as 
 follows : 
 
 1.) Protophytes, (Greek protos, first, and phuton, a 
 plant.) The first or simplest forms of plants — vege- 
 tables composed of a single cell, or mass of bioplasm. 
 
 2.) Thallogens, (Gr. ihallus, a frond, or vegetable 
 expansion, and ginomai, to produce or grow.) Plants 
 composed of a tissue of cells, or bioplasts, but with no 
 clear distinction of stem, root, and leaves. 
 
 3.) Acrogens, (Gr. akra, summit, and ginomai, to 
 grow.) Plants which grow at the summit only, and 
 not in diameter. 
 
 4.) Endogens, (Gr. endon, within, and ginomai, to 
 grow.) Plants whose vessels and woody libers first 
 grow within the stem. The seed has but a single 
 lobe, or cotyledon. 
 
 5.) Exogens, (Gr. exo, outward, and ginomai, to 
 grow.) Plants whose woody fibers grow in outer lay- 
 ers. The seed has two lobes, or cotyledons. 
 
 Under these five types or plans of structure all the 
 multitudes of plants which clothe the earth or dwell 
 in the sea can be arranged. 
 
Individual Vegetable Cells. 27 
 
 CHAPTEE V. 
 
 individual vegetable cells. 
 
 1. The elementary masses of bioplasm (Sec. 2, Chap. 
 II) are usually called cells, even if they are merely 
 pieces of animated jelly, uninclosed by an outside 
 shell or membrane. Some of these cells remain un- 
 connected with others during their entire life, and 
 multiply by self-division. Others have a living or 
 vital connection with neighboring cells, so as to form 
 tissues and organs. In this chapter we shall consider 
 the vegetable cell as an individual — its various ap- 
 pearances and its activities. 
 
 2. It is not easy to distinguish between the cell, or 
 living matter, of an animal and a vegetable. Some 
 cells appear like animals at one part of their lives and 
 like vegetables at another part. After long study 
 learned naturalists have agreed that the principal dif- 
 ference between animals and plants is that the latter 
 can be nourished by simple mineral or chemical (that 
 is, unorganized) matter, while animal nutrition re- 
 quires material which has been organized, or made 
 part of a living being. 
 
 3. Most vegetable cells produce a membrane, or cell- 
 wall, on the outside, within which the living matter 
 
28 Easy Lessons m Vegetable Biology. 
 
 is, as it were, imprisoned, although certain openings, 
 or pores, may be left in the cell-wall for the pur- 
 pose of communication. There is also a concentra- 
 tion of living matter within the cell, called a nucleus, 
 and sometimes a still further concentration within the 
 nucleus, called a nucleolus, (or little nucleus.) The 
 bioplasm, also, within the cell, differs in density, that 
 next to the wall of the cell being thicker, or more 
 mucilaginous, than the rest. This latter part, or lay- 
 er, has been called the primordial utricle, or original 
 bag. Fig. 3 will give a general idea of the element- 
 ary vegetable cell. 
 
 4. The cell-wall referred 
 to in the last paragraph 
 is composed of a substance 
 somewhat like starch, 
 called Cellulose. This is 
 often thickened by de- 
 posits inside, layer after 
 Fig. 3. layer. When it becomes 
 
 solid it is known as woody tissue. Common wood is 
 made up of a number of these cells arranged side by 
 side. 
 
 5. In cells with thin membranes, the inherent mo- 
 tion of the bioplasm (Chap. Ill, Sec. 2) can often be 
 seen with the microscope. This motion has been 
 called circulation, but it is an irregular motion of the 
 particles, sometimes slower, sometimes advancing, now 
 
Individual Vegetable Cells. 
 
 29 
 
 retreating, now stopping, or beginning again, in a 
 way differing from all non-living matter. (Fig, 4.) 
 
 Fiff. 4. 
 
 6. Sometimes the cell-wall has a deposit of 
 material, (silica}) or of other mineral matter, 
 is often beautifully 
 marked with lines and 
 dots. Different species of 
 plants produce different pat- 
 terns of these deposits, as 
 represented in the figures of 
 Diatoms in Chap. VII. 
 
 7. The cell-wall is often ir- 
 regularly thickened by a de- 
 posit inside, so as to present 
 different appearances in (lif- 
 erent cells. In the Pine and 
 Fir tribe the pores in the wall 
 of the wood-cells are sur- 
 rounded by concave spaces 
 or depressions. (Fig. 5.) Fig. 5. 
 
 flinty 
 which 
 
30 
 
 Easy Lessons m Vegetable Biology. 
 
 In other cases the more solid matter is deposited so 
 as to form dots, or rings, or spiral fibers, on the cell- 
 wall. (Figs. 6 and 7.) 
 
 8. 
 
 Fig. 6. 
 
 Vegetable cells are of 
 
 according 
 
 Fig. 7. 
 
 various shapes, 
 to the purposes which they 
 serve or the pressure to 
 which they have been subjected. They may be glob- 
 ular, oval, conical, prismatic, cylindrical, branched, 
 
 Fig. 8.— Various forms of cells : a. Conical, b. Oval. c. Prismatic, d Cylindric. 
 €. Sinuous. /. Branched, g. Entangled, h, Stellate, i. Fibro-cellular tissue. 
 
Individual Vegetable Cells. 31 
 
 star-shaped, hour-glass shaped, disk-shaped, tubular, 
 many-sided, or of any other form. (Fig. 8.) 
 
 9. The bioplasm within the cell-wall may be trans- 
 formed into a great variety of formed material, mak- 
 ing special cell-contents. These may be solid, as col- 
 oring matter, starch, crystals, and resin ; or fluid, as 
 oil and gum, or solutions of sugar or tannin. The 
 most important of these substances is called Chloro- 
 phyll, (Gr. chloros, green; phyllon, a leaf,) or 
 the source of the green color of plants. It is com- 
 posed of a peculiar coloring matter intimately united 
 with separate particles of bioplasm, which, under the 
 influence of sunlight, causes the absorption of car- 
 bonic acid gas from the air, which is necessary to 
 nourish the plant. Starch is also an important prod- 
 uct of vegetable cells, even more widely distributed 
 than chlorophyll. It seems to be stored up in the 
 cells as a reserve food-material for the use of the new 
 cells which are subsequently formed, hence it oc- 
 curs in large quantities in seeds, 
 bulbs, and tubers. (Fig. 9.) 
 
 Crystals of oxalate of lime 
 often occur in cells, as well as 
 acid substances and alkaloids, 
 like strychnine, quinine, etc., 
 dissolved in the cell-sap. 
 
 It is remarkable that such 
 different materials as cellulose, rig. 9. 
 
32 
 
 Easy Lessons in Vegetable Biology. 
 
 chlorophyll, starch, gum, resin, oil, etc., may be pro- 
 duced from similar cells under the influence of the 
 same environment, and equally exposed to heat, 
 moisture, and electricity. (Fig. 10.) 
 
 10. Cells generate 
 by self -multiplication. 
 One will divide into 
 two or more pieces of 
 bioplasm, which w T ill 
 assume the form and 
 function of the orig- 
 inal cell in the sim- 
 pler forms of plants, 
 or may take a dif- 
 ferent shape and use 
 
 Fig. 10.-*, b Cells of a potato, containing fa the p l an t 8 which 
 
 etai-ch. c. Starch -grains apart d, e,f. Wheat- r 
 
 starch in different positions. are CO mpOSed of mi- 
 
 merous cells. If the mother-cell, as it is called, pos- 
 sesses a nucleus, the self -division is preceded by the 
 formation of new nuclei, one for each of the daugh- 
 ter-cells. Sometimes the self -division of the bioplasm 
 is produced by the projection of a sort of bud, which 
 is separated from the parent mass. If the newly- 
 formed cells retain a vital connection with each 
 other, cellular structures, or tissues, of various sorts 
 are produced. The most complete development of 
 this kind occurs in the higher types of plants. 
 
The Cell as a Member of a Group. 
 
 33 
 
 CHAPTER VI. 
 
 THE VEGETABLE CELL AS A MEMBER OP A GROUP. 
 
 1. Only a comparatively small number of plants 
 consist of a single cell. These are the simplest forms 
 of plant life. In the greater number of vegetables 
 the cells are united into groups. Cell-families may 
 originate from a single mother-cell, and remain for a 
 time closely connected, or contiguous, yet each 
 daughter-cell preserves its own individuality, and 
 may originate a new colony. Such cell-families only 
 occur in the lowest classes of plants. In the higher 
 classes the union of cells which forms tissues and or- 
 gans is permanent, and the separate cells are often so 
 closely united as to form a single cavity or vessel; 
 the cell-walls of young contiguous cells fusing into a 
 common mass, or cells originally distinct uniting in 
 those parts of the walls which are in contact. This 
 union is so strong as only to be destroyed by chemical 
 agents which dissolve the cell-wall. Yet sometimes 
 cells which have partially united separate from eacli 
 other, forming a cavity. These spaces also may be 
 grouped together so as to form passages, or air-canals. 
 
 2. The woody fibers of plants, and the cellular 
 tissue which makes the softer, fleshy, and pithy parts, 
 
34 Easy Lessons in Vegetable Biology. 
 
 are made by the union of cells into groups. Obser- 
 vation has shown that in the higher plants new- 
 cells are not produced every-where uniformly, but in 
 particular spots. To places of this kind the terms 
 growing-point and growing, or formative, layer have 
 been applied. Growing-points may be seen in the 
 tips of buds, and formative layers between the wood 
 and bark of trees. The names formative or generat- 
 ing tissue have been given to the tissue which is here 
 formed by the division and union of cells. A tissue 
 in which the cells are not capable of self -division is 
 called a permanent tissue. 
 
 3. In direct contrast to the generating tissues are the 
 healing tissues, or cork tissues. In these the cells 
 lose their cell-sap, and the cellulose of the walls be- 
 comes converted into cork, which is of great im- 
 portance as the true healing tissue of plants. This is 
 formed like a cushion, or callus, over the surface of 
 a wound in a tree. The cuttings of the cochineal 
 cactus would decay at once if set in the ground with 
 the surface of the wounds fresh. They are therefore 
 laid for some time in the sun, in order that a cork 
 tissue may be formed, which closes the wound and 
 prevents decay. Such facts not only prove that the 
 living vegetable is governed by other than invariable 
 mechanical forces, but are also mute prophecies of 
 higher truths revealed to the human intelligence in 
 God's word relative to the healing of the soul. 
 
The Cell as a Member of a Group. 
 
 35 
 
 4. Vessels are made by the union of several cells, the 
 partition-walls disappearing while the union continues 
 at the margin. Such vessels may be dotted, reticula- 
 ted, annular, or spiral, from the deposit on the cell- 
 wall. Chap. V, Sec. 7. (See Fig. 11.) 
 
 ^Bast-tubes, or bast- 
 fibers, are long, point- 
 ed, thick- walled tubes, 
 commonly united into 
 bundles. In hemp, 
 flax, etc., they form 
 textile fibers, and they 
 are sometimes united 
 in the inner layer of 
 bark so as to form a 
 kind of lace, as in the 
 lace-bark of the West Fig. it, 
 
 Indies. Sieve-tubes, or bast-vessels, result from the 
 joining of cells standing one above the other, the 
 partition-walls of which have become perforated. 
 Some have sieve-like perforations through their side 
 walls. 
 
 Other vessels are simple or branched tubes, often 
 making a net-work, and containing a sort of milky 
 fluid called latex. This latter contains different sub- 
 stances in different plants, as gum, resin, opium, in- 
 dia-rubber, etc. 
 
 5. In addition to the groups of cells which form 
 
36 
 
 Easy Lessons in Vegetable Biology. 
 
 tissues and vessels, other smaller groups are found, 
 with receptacles formed by passages between the 
 cells. According to - the nature of the substance 
 secreted these spaces are called oilpassages, resin- 
 passages, camphor-glands, resin-glands, etc. The 
 term nectaries, or honey-glands, is given to any 
 part of a flower which secretes honey or sugary 
 fluid. 
 
 6. The first independent tissue formed in flowering 
 plants by the union of cells is the epidermis or skin. 
 The outer layer of epidermal cells is transformed into 
 a thin, structureless membrane called the cuticle. 
 The form of the cells varies in different plants, but 
 they are usually flat or tubular, but sometimes pro- 
 jecting like little knobs or bladders, which gives a 
 velvety or glistening appearance to the leaf or flower. 
 
 Among the epider- 
 mic cells are found 
 pores, each of which 
 is called a stoma, or 
 mouth. (Plural, sto- 
 mata.) These are in- 
 closed by two or four 
 cells, which are cres- 
 cent-shaped, and dis- 
 tinguished from other 
 epidermal cells by 
 their smaller size and by containing chlorophyll. 
 
 Fig. 12. 
 
The Cell as a Member of a Group. 37 
 
 These cells are thought to regulate evaporation by 
 their expansion. (Fig. 12,) 
 
 Hairs are epidermal structures, composed of one 
 or more cells. Under this general term may be in- 
 cluded prickles, scales, stinging-hairs, and glands. 
 Some secrete volatile oil, and others, as the nettle, an 
 acrid fluid. Fig. 13 exhibits some of their forms. 
 
 Fig. 13. 
 
 7. Next to the epidermis we find the cortex, or 
 bark, often composed of cells containing starch or 
 chlorophyll. Yessels containing latex (Sec. 4) and 
 glands, as well as sap-passages between cells, may also 
 occur in it. In some plants, masses of cork may be 
 found in the bark or beneath it. In such the outer 
 parts die and the bark peels off. 
 
 8. Beneath the bark is the formative layer or 
 
38 
 
 East Lessons in Vegetable Biology. 
 
 cambium, (Sec. 2,) in which thin-walled cells become 
 transformed into vascular or bast-cells, (Sec. 4,) and 
 these are changed into permanent cells. Groups 
 of cells are thus formed which, united into bundles, 
 penetrate the rest of the tissue, forming the fibro- 
 vascular bundles. The development of these bundles 
 is characteristic of different types of plants. The 
 simpler types have no fibro-vascular bundles, and are 
 called Cellular Plants / the rest are termed Vascular 
 Plants. 
 
 9. The fundamental tissue generally consists of 
 thin-walled cells containing starch, although other 
 forms of cells may be present. In plants which have 
 
 no fibro-vascu- 
 lar bundles the 
 whole interior 
 may be regard- 
 ed as funda- 
 mental tissue. 
 In other plants 
 it fills up the 
 spaces between 
 the bundles and 
 within the bark. 
 In the type of 
 Endogens (Ch. 
 IY, Sec. 5) this tissue is most devexoped, while in Ex- 
 ogens it occupies a smaller portion of the structure. 
 
 Fig. 14. 
 
The Cell as a Member of a Group. 
 
 39 
 
 In the latter it generally forms a central pith, con- 
 nected with the bark by more or less developed 
 
 Fig. 14*. 
 
 portions of cellular tissue, 
 called the medullary rays. 
 (Figs. 14 and 14£.) 
 
 10. These various ele- 
 ments of plants, consisting 
 of different forms of cells, 
 tissues, and fibro-vascular bundles, are arranged in 
 each species in a characteristic manner, so that it is 
 often possible to recognize the species from a small 
 fragment of the plant. For this purpose small trans- 
 parent sections of a stem are prepared, cut in three 
 different ways — transversely, longitudinally through 
 the center, and a section parallel to the last. These 
 are mounted on glass slips, three inches long by one 
 wide, saturated with Canada balsam or other preserv- 
 ative fluid, and covered with very thin glass for 
 microscopic examination. 
 
40 Easy Lessons in Vegetable Biology. 
 
 CHAPTEE VII. 
 
 PROTOPHYTES, OR THE SIMPLEST FORMS OF PLANTS. 
 
 1. The simplest form of individual plant life is a 
 particle of living matter inclosed in a membrane or 
 cell-wall. Chap. V, Sec. 4. Such plants are called 
 one-celled. Some of these remain entirely distinct 
 from other cells, others form cell-families (Chap. VI, 
 Sec. 1) in a sort of gelatinous investment, while 
 other kinds form a sort of fiber or rod by the adhesion 
 of cells end to end. As each cell in these different 
 kinds is capable of independent life and growth they 
 are all classed as unicellular. 
 
 2. The green slime which grows on stones or 
 boards in damp places contains many of these one- 
 celled plants. 
 One of the 
 simplest forms 
 is shown in 
 Fig. 15. It is 
 often found 
 in rain-water 
 casks, and is 
 called the Pro- 
 
 Fig. is. tococcus — from 
 
Protophytes. 41 
 
 two Greek words : jprotos, first, and coccus, a berry. 
 Each cell is round, and varies in color from bright 
 green to bright red, according to the nature of the 
 coloring matter diffused in the form of granules 
 through the bioplasm. It requires a microscope to 
 see the form and structure of these cells. Each cell 
 is a perfect plant, and like all vegetables which con- 
 tain chlorophyll, (Chap. Y, Sec. 9,) under the influence 
 of sunlight, breaks up the carbonic acid gas which it 
 absorbs from the air, retaining the carbon and giving 
 off the oxygen. In the dark, however, all plants ab- 
 sorb ox}^gen and give off carbonic acid, rendering it 
 unsafe to have many plants in a sleeping-room, since 
 carbonic acid gas is unfit for respiration by men and 
 animals. 
 
 The cell-wall of the protococcus is quite transpar- 
 ent, and if burst will allow the bioplasm and the 
 granules of red or green chlorophyll to escape. The 
 cells multiply by self -division, each one producing 
 two, four, eight, or sixteen cells. These new cells 
 differ from the parent cell in not remaining quiet or 
 still, but having the power of active movement. 
 They swim about like animals by means of two fila^ 
 ments or cilia, (Lat. cilium, an eyelash.) These 
 moving cells may also subdivide into smaller ones 
 which have been called by botanists zoospores, (Gr. 
 zoos, life, and sporon, seed,) or living seeds. Many 
 of the moving cells, however, lose their cilia and 
 
42 Easy Lessons in Vegetable Biology. 
 
 become stationary. In this state the cell-wall may 
 thicken, and the pond where it dwells dry up, but the 
 mass of bioplasm in the cell may retain dormant life 
 for years, and be ready to resume its work as soon as 
 moisture and warmth shall set it free. 
 
 Many of these resting cells, with red chorophyll, 
 are found occasionally in the snow of northern re- 
 gions, or near the tops of high mountains, perhaps 
 
 Fig. 16. 
 
 carried there by winds, and, finding moisture and sun- 
 light, multiply themselves so rapidly as to color the 
 snow by their multitudes. This forms what is known 
 as "Ked Snow." Similar cells may grow rapidly in 
 damp places and form masses which look like coagu- 
 lated blood. In this way we may account for the so- 
 called showers of blood which have sometimes alarmed 
 the superstitious. 
 
 3. Another kind of primitive plants may be found 
 
Photophytes. 43 
 
 as green fibers or threads in almost every running 
 stream. The microscope will show the cells of these 
 fibers applied end to end— the cells at each end mul- 
 tiplying by self-division. In another kind, adjacent 
 cells grow together, and the green chlorophyll and 
 bioplasm mix in one of the cells, forming a sort of 
 spore, or seed, which produces a new filament by cell- 
 division. (Fig. 16.) 
 
 4. The unicellular plants most interesting to those 
 who study with the microscope are called Diatoms, 
 (from two Greek words signifying to cut through,) 
 because of the ease with which a chain of them may 
 be broken up into individual cells. These cells con- 
 tain chlorophyll, generally of a brownish color, and 
 the external membrane, or cell- wall, is hardened by a 
 deposit of flinty matter. There are many kinds of 
 Diatoms, with flinty shells, beautifully marked with 
 lines and dots, often surpassing the most complicate 
 patterns of art. Some are globular in shape, some 
 flat with sides like a pill-box, others square, triangu- 
 lar, boat-shaped, etc. They move about in the water, 
 so that some have thought them to be animals. Many 
 are so minute as to require the very finest micro- 
 scope to make out their details. Each cell consists of 
 two valves, or plates, applied together like the valves 
 in a muscle-shell. Fig. 17 shows a valve of one of 
 the most ornamental diatoms— the Arachnoidiscns 
 EJirenhergii. The first of these words signifies a disk 
 
44 
 
 Easy Lessons in Vegetable Biology. 
 
 built like a spider's web, and is applied to the genus. 
 The second word refers to the name of a distinguished 
 
 Fig. 17. 
 
 naturalist, and names the species — the Arachnoidiscus 
 of Ehrenberg. This example illustrates how the vari- 
 ous kinds of organisms are named. 
 
 In Fig. 18 there are examples of three other kinds 
 of diatoms. 
 
 In the living state diatoms are found abundantly in 
 every pond, rivulet, ocean, and rock-pool. They 
 often make immense deposits by their rapid multi- 
 plication, and in a fossil state they form large strata 
 of rock material. Under the cities of Richmond and 
 
Protophytes. 
 
 45 
 
 Petersburg, in Virginia, is such a stratum 20-40 feet 
 thick. 
 
 5. Each kind, or species, of unicellular plants, like 
 every other organic form, has endowments or in- 
 stincts of its own. One sort remains a rounded cell, 
 
 Fig. 18. 
 
 or changes to a motile one. Another becomes elon- 
 gated, and distributes its coloring matter inside in 
 spiral form. Others appropriate glassy flint from 
 their food, and deposit it in beautiful patterns upon 
 their outer cell-wall. Each cell, however, in this type 
 of Protophytes is capable of independent life apart 
 from the rest, and may be considered as a complete 
 individual. 
 
46 Easy Lessons in Vegetable Biology. 
 
 CHAPTER VIII. 
 
 THALLOGENS, OR DIVISION OF LABOR IN PLANTS. 
 
 1. In the plants which we have been considering 
 each cell is an individual, but in all other kinds the 
 plant, or individual, is made up of many cells, each 
 one of which has a special work to do. Some belong 
 to the root, some to the axis, or stem, and others to 
 the leaves, flowers, or seeds. In the type of Thal- 
 logens there is no very accurate division of root, stem, 
 leaves, and flowers, and the whole plant is called a 
 thallus, a frond, or green expansion. Under this 
 type we find the classes of Algce, or Sea-weeds; 
 Lichens, or the dry, leafy, or mossy patches on trees, 
 stones, etc. ; and Fungi, or mushrooms, molds, and 
 their allies. 
 
 2. The Algce, or Sea-weeds, have been divided 
 into three orders, the Red, the Olive, and the Green 
 sea-weeds. In the more complicate forms we find a > 
 sort of distinction of root, stem, and leaf, which re- 
 minds us of still higher plants, but the distinction is 
 more apparent than real, since the root and stem 
 serve little other use than the mere mechanical at- 
 tachment of the plant. The whole plant is made up 
 of cells, and there are no proper vessels. Chap. VI, 
 
Thallogens. 47 
 
 Sec. 4. These external resemblances seem uncon- 
 scious prophecies of forms which prove that all living 
 things have been formed upon an intelligent plan. 
 
 The cells of algce multiply by self-division, and are 
 of various forms. Some absorb nourishment, or 
 secrete various materials, or serve merely for growth, 
 while others are appropriated to the reproduction of 
 the species, which in some instances has a very com- 
 plicated method. 
 
 3. The class of Fungi contains a large number of 
 different kinds, some quite simple and others complex 
 in structure. These organisms have so many pecul- 
 iarities that some scientists regard them as neither 
 animal nor vegetable, but as forming a sort of third 
 kingdom. They have a similar cellular form to vege- 
 tables, but they have no chlorophyll, as green vegeta- 
 bles have ; light is not necessary to their growth as it is 
 to vegetables ; and, like animals, they need organic sub- 
 stances for food. It has been found that they are the 
 agents of fermentation and putrefaction, and their prin- 
 cipal business seems to be the removal of the waste ma- 
 terial of both animal and vegetable life. They are 
 universal scavengers. The simplest forms of Fungi, 
 or the Molds, resemble Protophytes, except in the ab- 
 sence of chlorophyll. The yeast-plant is one of these 
 forms. It is simply a round or oval cell which mul- 
 tiplies rapidly by putting forth buds and by self -di- 
 vision. It is the cause of fermentation in all sugary 
 
48 Easy Lessons in Vegetable Biology. 
 
 solutions. Bacteria of different kinds are minute 
 fungi, similar to the yeast-plant, but living in solu- 
 tions of animal matter, in which their growth causes 
 putrefaction. Recent studies render it likely that the 
 more simple forms are but imperfectly developed 
 stages in the life-history of other kinds. Fig. 19 
 shows the appearance of bacteria when greatly mag- 
 nified. All fungi are made up of elongated cells, 
 sometimes branching and sometimes membranous or 
 
 riii 11 — \ — r 
 
 At 
 
 ^ 
 
 Fig. 19. 
 
 pulpy, forming a mycelium, or spawn, and rounded 
 cells forming spores, or seeds, which may be supported 
 on filaments or contained in sacs. The common 
 mushroom is one of the larger fungi, and the white 
 or green mold on preserves, cheese, etc., an example 
 of the minuter kinds. 
 
 Many diseases of plants and animals are associated 
 with the presence of fungi. Mildew and rust in 
 wheat, the potato-blight, the false membrane in diph- 
 theria, and many other evidences of diseased action, 
 
Thallogens. 49 
 
 seem to depend upon the growth of these parasites. 
 
 In many cases, however, it is not fully ascertained 
 
 whether the hacteria, or other fungus, is the cause of 
 
 the diseased condition, or is present, because of the 
 
 disease, to remove the decaying material. 
 4 
 
50 
 
 Easy Lessons in Vegetable Biology. 
 
 CHAPTEE IX. 
 
 ACROGENS, OR PLANTS WHICH G&OW AT THE SUMMIT. 
 
 1. In fresh-water ponds and rivers, growing in 
 tangled masses of a dull green color, we may often 
 
 Fig. 20. 
 
 find plants with stems about as thick as a stout needle, 
 but perhaps three or four feet long, with branchlets 
 (improperly called leaves) arranged in whorls at regu- 
 lar intervals upon the axis. These are the stone-worts, 
 
AcROGENS. 
 
 51 
 
 consisting of two genera, Cham and Nitella. In 
 the latter the stem is a simple tube, but in Chara the 
 central or axial cell is surrounded in a spiral manner 
 by others. In Chara, also, the stem is incrusted by 
 carbonate of lime. Fig. 20 will sufficiently illustrate 
 their forms. The points on the axis, or stem, from 
 which the branchlets spring, are called nodes, and the 
 intervening parts are the internodes. 
 
 These stone-worts illustrate the manner of growth 
 in the type of Acrogens. Each internode is formed 
 by the growth and elongation of single cells. The 
 terminal bud is also formed by a single cell, which 
 subdivides into two. One of the latter forms the in- 
 ternode, while the other subdivides into lateral cells, 
 which by continual division produce the branchlets. 
 After a time the terminal cell in the latter is incapa- 
 ble of further division, but in the stem the process 
 continues indefinitely. (Fig. 21.) 
 
 These stone-worts are 
 also reproduced by cer- ' 
 tain organs which grow 
 at certain parts of the 
 axis. These organs are 
 of two kinds, oval spor- 
 angia, or spore-fruits, 
 and antheridia, or or- 
 gans which contain fila- 
 ments corresponding to __ Fig. 21. 
 
52 Easy Lessons in Vegetable Biology. 
 
 the anthers, or male organs, of flowering plants. The 
 cells of each antheridium contain little swimming 
 bodies called antherozoids, (living anthers.) (Fig. 22.) 
 
 These coiled up anther- 
 ozoids twist and turn about 
 until they escape from the 
 cell and swim in the fluid 
 by means of their two cilia. 
 They find their way to the 
 spore-cases, and by coales- 
 cence form the oospore, (the 
 egg-spore, or embryo,) from 
 which the future plant is 
 Fig. 22. derived. When we consider 
 
 the power of motion in these organs and others simi- 
 lar to them, we are obliged to admit that sharp lines 
 of distinction between plants and animals are impos- 
 sible in these apparently simple forms. The growing 
 spore of the stoneworts gives off two filaments, one 
 of which serves as a temporary root, while a cell in 
 the other produces a group of lateral projections from 
 which the young plant springs. This temporary 
 structure is termed the pro-embryo, and something 
 similar to this is common to all the Acrogens. 
 
 2. Ferns form another family of Acrogens, or sum- 
 mit-growers. Their various species are admired for 
 their beautiful fronds, often improperly called leaves, 
 and books of collectors often grace the parlor table. 
 
ACROGENS. 53 
 
 They vary in size, from the Tree-ferns of the tropics, 
 which may be fifty or sixty feet high, to the delicate 
 Maiden-hair fern of the shady dell. In temperate 
 climes ferns have usually a simple or branched un- 
 der-ground stem, called a rhizome ^ a root-stalk, from 
 which grow root-hairs and fronds. The epidermis of 
 the stem is of brownish hue, and when young and 
 above ground is provided with stomata. Chap. VI, 
 Sec. 6. As in higher plants, the general cellular 
 structure consists of many-sided cells, containing 
 
 Fig. 23. 
 
 chlorophyll and starch granules. There are also ves- 
 sels, (annular, spiral, and scalariform, or ladder-like,) 
 and fibrous or woody tissue, together forming the 
 harder tissues. 
 
 Fig. 23 illustrates the growth of a fern at the 
 summit, together with the metamorphosis of the ter- 
 minal cell into the various tissues. 
 
 In flowering plants the terminal cell of the leaf -bud 
 becomes barren, and the enlargement of the leaf de- 
 pends on the multiplication and growth of cells 
 
54 Easy Lessons in Vegetable Biology. 
 
 nearer the base, but in the fern the frond grows as 
 the stem does, so that the peduncle, or stalk, is first 
 formed, then the embryo frond, then the pinnules, or 
 wings, etc. 
 
 Underneath the frond of a fern we may sometimes 
 see little brown patches. Each patch is called a sorus, 
 (plural, sori.) It is sometimes covered by a mem- 
 brane called an indusium, and the little brown bodies 
 constituting it are spore-cases which have been de- 
 veloped from epidermal cells. An elastic ring sur- 
 rounds each spore-case and assists in opening it. The 
 growth of the minute spores in the spore-cases may be 
 watched from time to time under the microscope. 
 The little spore swells and bursts, and sends out a 
 rootlet into the soil. Then a number of delicate cells 
 are formed from the mother-cell in the spore, making 
 a little green scale, which throws out rootlets on its 
 under side. This jprothallium (as it is called) pro- 
 duces two kinds of cells, one set which contains spiral 
 filaments which escape and, by apparently spontane- 
 ous movements enter the others, or germ-cells, from 
 which the future fern is produced. Fig. 24 gives 
 a good representation of the various parts in the 
 structure and life-history of a fern. 
 
 3. Mosses are also examples of plants which grow 
 at the tip, or summit. They are minute and lowly 
 plants, but are by no means insignificant. They have 
 distinct axes of growth, and their delicate leaves are 
 
AcEOGENS. 
 
 55 
 
 arranged with great regularity. The stem shows some 
 indication of the separation of a bark-like portion 
 from the pith-like, by the intervention of a circle of 
 bundles of elongated cells, from which branches pass 
 into the leaves, so as to afford them a sort of midrib. 
 
 Fie. 24. 
 
 The root-fibers are long, tubular cells, quite trans- 
 parent, within which the circulation of bioplasm may 
 
 be seen. 
 
56 
 
 Easy Lessons in Vegetable Biology. 
 
 The stems of mosses usually terminate in filaments, 
 each supporting an urn-shaped vessel closed by a lid. 
 The urn is covered by a cap, or hood. Under the lid 
 the edge of the urn has a toothed fringe, and within 
 the urn, or spore-capsule, are double-coated spores. 
 (Fig. 25.) 
 
 Fig. 25. 
 
 In producing new plants, the outer coat of the 
 spore bursts and the inner wall protrudes. New cells 
 grow from the extremity, forming a filament, whose 
 cells at certain points multiply by subdivision, so as 
 to form rounded clusters, from each of which an in- 
 dependent plant may arise. 
 
 The minuteness of the spores of mosses and similar 
 plants accounts for their general distribution, even in 
 
ACROGENS. 57 
 
 the most distant and barren places. Bare rocks raised 
 from the bottom of the sea, and lava-flows from the 
 tops of volcanoes, marshes and dry mountain-tops, are 
 soon covered by mosses and their allies. 
 
58 Easy Lessons in Vegetable Biology. 
 
 CHAPTER X. 
 
 ENDOGENS, OR INSIDE-GROWERS. 
 
 1. Grasses, rushes, lilies, and palms, with similar 
 families of plants, are found in the type of Endogens, 
 Chap. IV, Sec. 5. This term was given to them 
 because it was thought that their woody and vascular 
 fibers grew from the inside, and pushed the earlier- 
 formed bundles of fibers toward the circumference 
 of the stem. More exact examinations have shown 
 that the fibro-vascular bundles grow within the cellu- 
 lar or fundamental tissue, turn first inward toward 
 the center or pith, and then bend outward and pass 
 into the leaves. In grasses the cells of the center dis- 
 appear except at the nodes, (Chap. IX, Sec. 1,) leav- 
 ing the stem hollow. 
 
 2. Endogens are often called Monocotyledons, 
 (Greek monos, one, and Tcotyledon, a seed-lobe,) be- 
 cause the young plant has but a single seed-lobe. 
 Exogens have two seed-lobes, as we may see in a 
 sprouting bean or pea, and are called Dicotyledons, 
 (Gr. dis, two.) Acrogens and Thallogens have no 
 seed-lobe at all, but are propagated by cellular spores, 
 and are called Acotyledons, (Gr. a, without.) 
 
 3. In Endogens and Exogens we find a more com- 
 
Endogkns. 
 
 5f> 
 
 plete development of the root, stem, and leaves than 
 in the other types, giving a character to the external 
 form of plants which enables us to recognize them 
 and place them in a natural system of classification. 
 It is therefore appropriate here to consider these 
 structures in as brief and comprehensive manner as 
 possible. 
 
 4. If a pea or bean be soaked in water, and the 
 leathery skin be stripped off, two large fleshy masses 
 will be seen (the cotyledons) inclosing a small cylin- 
 drical body, (the axis,) which bears two minute leaves 
 
 at its extremity. The cotyledons and axis together 
 
 constitute the embryo. 
 
 In the growing plant 
 
 the stem grows from 
 
 the axis upward and 
 
 the root downward, 
 
 and the leaves develop 
 
 only on the ascending 
 
 part of the axis and not 
 
 on the root. 
 
 In the growing stem 
 
 the terminal cells (#, 
 
 Fig. 26, A) multiply 
 
 and enlarge. They fur- 
 nish new cells to the 
 
 cambium layer, or that 
 
 between the bark and 
 
 FJg.2C. 
 
60 Easy Lessons in Vegetable Biology. 
 
 wood of Exogens. Chap. VI. Sec. 8. In the root, 
 the multiplying cells are not quite at the extremity. 
 A sort of cap is formed, which receives additions to 
 its interior and pushes out the layers external to 
 them. Thus the new-formed tissue is protected from 
 the rough soil. (Fig. 26, B, C.) Sometimes the ab- 
 sorbing activity of the points of the root-hairs is so 
 great that particles of soil actually unite with them, 
 to be afterward dissolved by the cell-sap. 
 
 5. The primary root is that which is formed by 
 the downward elongation of the axis. It is in a line 
 with the stem. It is called a tap-root when it is 
 thicker than the branches which spring from it, and 
 may be fusiform or spindle-shaped like the carrot, 
 napiform or turnip-shaped as the radish or turnip, 
 filiform or threadlike, or cylindrical. Secondary or 
 lateral roots are those which spring laterally from the 
 stem or primary root, as the clasping roots of ivy. 
 Sometimes the primary root is undeveloped, or dies, 
 and is replaced by secondary roots. In grasses these 
 are filiform, and are called fibrous roots. Sometimes 
 secondary roots become tuberous or fasciculated, 
 (swollen in the middle, or at intervals,) as in the 
 dahlia, etc. All roots are more or less branched, and 
 are covered with delicate root-hairs. If the branches 
 of the root run near the surface of the ground, they 
 are called creeping roots. 
 
 6. The stem is that part of the plant which bears 
 
Endogens. 01 
 
 the leaves, flowers, and fruit. Some plants are ap- 
 parently stemless, from this part remaining very 
 short and undeveloped in proportion to the roots and 
 leaves, as in the primrose. The woody stem or trunk 
 characterizes trees and shrubs. A simple unbranched 
 trunk, as the palm, is called a candex. The scape is 
 a leafless stem bearing only flowers, and belonging to 
 a so-called stemless plant. It may bear only a single 
 flower, as the tulip, or several, as the hyacinth and 
 lily of the valley. Sometimes stems send out run- 
 ners or branches which run above the ground, and 
 send out adventitious roots from their nodes or ex- 
 tremities which develop perfect plants, as the straw- 
 berry. The rhizome is an under-ground stem, send- 
 ing up branches into the air. The tuber is a thick- 
 ened, fleshy under-ground stem, as the potato, in which 
 we may find buds or eyes concealed in depressions. 
 The lull is also fleshy, but has scales surrounding the 
 solid base or •dish of the stem, or attached to its apex. 
 "When the disk is large and surrounded by only a few 
 leaves, as in the crocus, it is called a corm. Bulbs 
 may be squamose or scaly, tunicated as in the onion, 
 fibrous, etc. 
 
 The length of life of the stem and roots may be 
 only a single year, or annual; two years, or liennial; 
 or a number of years, or perennial. 
 
 The trunk or woody stem of Exogens, or outside- 
 growers, shows on a transverse section a number of 
 
62 Easy Lessons in Vegetable Biology. 
 
 circles of fibro- vascular bundles, with cellular rays 
 passing from the pith to the bark. Chap. VI, Sees. 
 9, 10. These circles are supposed to indicate the layers 
 of annual growth, but this is quite uncertain. Some- 
 times two or more circles are formed in a year. The 
 diameter and height attained by some E^xogens may 
 be very great. The Big-Tree Grove, in Calaveras 
 County, California, contains trees from 350 to 400 
 feet high, and 33 feet in diameter. 
 
 The stems of Endogens, or inside-growers, exhibit 
 in their sections no distinct pith, no concentric circles, 
 no medullary rays, and no separable bark. 
 
 7. Stems produce buds, which may be regarded as 
 shortened axes, capable of elongation. According to 
 the organs which result from their development, they 
 are termed stem-buds, leaf -buds, and Jtoicer-buds. 
 They are terminal if produced at the extremity of 
 the primary axis, and lateral if at the sides of the 
 axis. In palms and tree-ferns the bufls are termi- 
 nal, and if the top of the stem is cut off the 
 plants perish. Buds are often protected by coarse 
 leaves or scales, which may be covered with hairs, 
 or with gummy or resinous matter for additional pro- 
 tection. 
 
 Buds often lie dormant, and do not appear as 
 branches unless stimulated by some local injury to the 
 plant ; others are altered into thorns. Thorns are 
 undeveloped branches, and many plants which are 
 
Endogens. 63 
 
 thorny when wild are not so nnder cultivation. 
 Thorns differ from prickles, which are hardened 
 hairs. 
 
 8. Lewes are constituted of cells, with cavities, 
 fibro-vascular bundles, and epidermis. (Fig. 27.) 
 
 Fig. 27. 
 
 The veins in a leaf are the vascular parts, and their 
 distribution differs in the types of Endogens and 
 Exogens, so as to afford a ready means of discrimina- 
 tion. The veins in the leaves of Endogens are gen- 
 erally parallel or straight, and do not form a network 
 as in Exogens. (Fig. 28.) 
 
 When two leaves are at the same level, one on each 
 side of the stem, they are called opposite; when a 
 circle of leaves is thus produced it is called a whorl. 
 When there is only one leaf on the same level the 
 
G4 Easy Lessons in Vegetable Biology. 
 
 leaves are alternate or scattered. Irregular as the 
 latter mode may appear in different plants, observa- 
 tion shows that it is tolerably uniform in each species. 
 If a spiral line (or thread) is drawn round 
 the stem connecting the points of attach- 
 ment of the leaves, and these are marked 
 on the spiral, it is found that in any par- 
 ticular species there is a definite number 
 of leaves on any given number of turns 
 made by the spiral round the stem. In 
 the peach and plum the cycle made by 
 the leaves directly above each other em- 
 braces five leaves, and the spiral goes 
 twice round the branch. This is expressed 
 by the formula £, In the alder three 
 leaves form the cycle, and the spiral has 
 but a single turn on the stem. This is 
 represented by the fraction £. 
 
 Covering-leaves are so called because 
 they cover or protect other parts, as the 
 scales of buds, and bracts, or leaves in 
 axils of which flowers are placed. The 
 leaf-stalk is called a petiole. When it is 
 absent the leaf is said to be sessile. At 
 the base of the petiole flat leaf-like ap- 
 pendages are often found, called stipules. 
 
 Leaves are said to be sinvple when the blade is 
 composed of one piece, however irregular may be its 
 
 Fig. 28. 
 
Endogens. 65 
 
 shape, and compound when divided into distinctly 
 separate parts, or leaflets, connected with the petiole 
 by secondary petioles. 
 
 Leaves may be lanceolate, or narrow and tapering; 
 oblong, or narrow and not tapering ; cordate, or heart- 
 shaped; sagittate, or arrow-shaped; ovate, or egg- 
 shaped, etc. A compound leaf having leaflets placed 
 laterally is called pinnate. If the leaflets are them- 
 selves divided, it is bipinnate, and a further division 
 of the leaflets is tripinnate. Sometimes a compound 
 leaf is triple, or ternate, etc. When a ternate leaf 
 divides twice it is biternate ; when thrice, triter- 
 nate. 
 
 It is not uncommon to find on the same plant leaves 
 of different forms. The radical leaves, or those 
 which grow from the lower part of the stem, are often 
 different from the upper ones. 
 
 The function, or use, of leaves is to expose the 
 juices of the plant to light and air, and thus aid in 
 forming the woody matter of the stem and the vari- 
 ous secretions. If the leaves are excluded from air 
 and light, as is the case in crowded plantations, the 
 wood is not properly formed. The same may be said 
 of all the substances formed by the plant. Thus, 
 potatoes grown in the shade, which impedes the ac- 
 tion of the leaves, become watery, and produce little 
 starch in their tubers. 
 
 Leaves also exhale watery fluid, and by decompos- 
 5 
 
66 Easy Lessons in Vegetable Biology. 
 
 ing carbonic acid gas are able to appropriate the car- 
 bon as food, and return the oxygen to the air. Chap. 
 V, Sec. 9. 
 
 The length of life of leaves varies greatly. In 
 temperate climates the majority of leaves fall off in 
 the autumn, or are deciduous. In the so-called ever- 
 green trees and shrubs they persist through the win- 
 ter, and may even remain several years. 
 
 9. The root, stem, and leaves of a plant constitute 
 its organs of nutrition. Fluid matters are taken up 
 from the soil by the cells of the roots, these are con- 
 veyed to the leaves, and under the influence of air and 
 light are fitted for the purposes of plant life, and for 
 the production of various materials, as starch, gum, 
 sugar, woody matter, gluten, oils, and resins. Chap. 
 V, Sec. 9. 
 
 10. The flower is the organ, or assemblage of or- 
 gans, for the production of the seed. In Endogens 
 and Exogens this structure is conspicuous, and they 
 are hence called flowering plants, to distinguish them 
 from other types. 
 
 Fig. 29 illustrates the general structure and ar- 
 rangement of parts in a flower. The poet Goethe 
 taught that all the various parts of a plant are modi- 
 fications of leaves. Not that they w r ere originally 
 leaves and were transformed, but that they are formed 
 of the same elements, arranged upon the same plan, 
 and follow the same general laws as leaves. The 
 
Endogens. 
 
 67 
 
 parts of a flower are lience called floral leaves. These 
 are usually arranged in four whorls. The outer whorl 
 
 Fig. 29. 
 
 is the calyx, the next the coroUa, the third the sta- 
 mens, and the innermost the pistil. 
 
G8 Easy Lessons in Vegetable Biology. 
 
 The flowers of Exogens exhibit two Or five parts, 
 or multiples of these numbers, in their whorls, while 
 Endogens have three, or a multiple of three, in their 
 whorls. In Exogens, also, the calyx is usually green 
 and the corolla colored, but in Endogens both are often 
 colored. The term perianth is generally applied to 
 the floral envelopes of Endogens. 
 
 The parts of the calyx, when separate, are called 
 sepals, and the leaves of the corolla petals. Stamens 
 have two parts, the filament, or stalk, and the anther, 
 or broader portion, corresponding to a folded leaf, and 
 containing fertilizing grains called pollen. The pistil 
 is also made up of two parts, the ovary, containing 
 ovules, or young seeds, and the stigma for the recep- 
 tion of the pollen-grains. This latter is sometimes 
 sessile, or resting on the ovary, and sometimes ele- 
 vated on a stalk, or style. 
 
 Some flowers have no stamens, and are called fe- 
 male flowers; others have no pistils, and are male 
 flowers. But these organs are always present, either 
 on the same plant or on different plants. If the co- 
 rolla is absent the flower is called incomplete, and if 
 corolla and calyx are both absent it is naked. The 
 position of the stamens in relation to the ovary is of 
 botanical importance. Sometimes they are attached 
 to the receptacle, or upper part of the flower-stalk. 
 They are then below the ovary and free from it, as 
 well as from the calyx, and are said to be hypogynous. 
 
Endogens. 69 
 
 or under the ovary. Sometimes they are attached to 
 the calyx, but free from the ovary, and are called 
 perigynous, or around the ovary. In other cases the 
 stamens appear above the ovary, and are epigynous, or 
 upon the ovary. In such instances the calyx is also 
 epigynous. The grains of pollen when discharged 
 from the anther are applied to the stigma, and in a 
 short time send forth tube-like prolongations to the 
 ovule in the ovary, by which means the embryo plant 
 is formed. Many curious and beautiful arrangements 
 are made to ensure the proper application of pollen 
 to the upper part of the pistil. In some flowers the 
 stamens have elastic filaments which are at first bent 
 down and held by the calyx, but when the pollen is 
 ripe the filaments jerk out and scatter the powder on 
 the pistil. The agency of winds and of insects is 
 made use of in some cases. In the hazel, where the 
 pollen is in one set of flowers, the leaves might inter- 
 fere with the application of pollen, hence they are 
 not produced until it has been scattered. 
 
 11. The term fruit is applied, in botanical lan- 
 guage, to the mature perfect pistil, whether dry or 
 succulent. Fruits are formed in different ways. 
 Some, as the pea and bean, consist solely of the 
 slightly altered pistil ; others, as the grape, peach, and 
 plum, have the pistil so changed as to be succulent. 
 The gooseberry, currant, apple, and pear are formed 
 by both pistil and calyx, a portion of the latter 
 
70 Easy Lessons in Vegetable Biology. 
 
 remaining at the top of these fruits in the form of 
 brownish scales. The hazel-fruit consists of the pis- 
 til developed into the nut, with a covering of bracts 
 called the husk. The cup of the acorn is also formed 
 by bracts. In the strawberry, the succulent part is 
 the enlarged receptacle, containing numerous small 
 carpels, or fruits, often called seeds. The mulberry, 
 pine-apple, bread-fruit, pine-cone, and fig are made 
 up of numerous pistils formed by separate flowers 
 and combined into a common mass. 
 
 12. The seed is usually contained in the seed-vessel 
 or fruit. If there is no seed-vessel, as in the fir, the 
 seed is said to be naked. In order that the seed may 
 be complete, it must contain the rudiment of the 
 young plant, or em~bryo. 
 
 "When the seed is placed in favorable circumstances 
 the little plant begins to germinate. Sec. 4. The 
 phenomena of sprouting seed are well seen in the 
 malting of barley. The grain is exposed to moisture, 
 heat, air, and is kept in comparative darkness. These 
 are favorable circumstances analogous to prepared 
 soil. A change takes place in the contents of the 
 grain. The starch, which is insoluble in water, and 
 unfit for the nourishment of the plant, is converted 
 into sugar, which is soluble, and easily absorbed by 
 the bioplasm of the cells as food. The young roots 
 are first protruded, and then the stem, surrounded by 
 a leaf called a cotyledon, or seed-leaf. If the barley 
 
Endogens. 
 
 71 
 
 were allowed to grow, the wliole of the sugar would 
 be used by the plant. But man wishes to get the 
 sugar, and lie therefore stops the growth of the plant 
 by drying it, and thus makes malt. 
 
 13. Grasses and Sedges are families of Endogens 
 whose flowers have imbricated bracts, or scales, called 
 glumes, instead of a colored perianth. (Fig. 30.) 
 
 Among the grasses are classed 
 the nutritious grains, as Wheat, 
 Barley, Oats, Rye, Rice, and 
 Indian Corn. 
 
 14. The families of Palms 
 and Bananas are also noted 
 members of the type of En- 
 dogens. (Fig. 31.) 
 
 Linnaeus, the father of botan- 
 ical science, called Grasses the 
 
 Fig. 30. 
 
 plebeians, and Palms the princes, 
 of the vegetable world. The latter are certainly 
 beautiful, and often gigantic, plants. As to utility it 
 would be difficult to make a comparison. Various 
 species of Palms are used for supplying food and for 
 forming habitations. The fruit of some is edible. 
 Many supply oil, wax, starchy matter, and sugar. 
 Their fibers make ropes, and various utensils are 
 formed from their wood or fruit. 
 
 15. The Orchid family has numerous species, re- 
 markable for the variety of forms and brilliant colors 
 
Fig. 31 
 
 Fig. 32. 
 
Endogens. 73 
 
 in their flowers, which often resemble insects, birds, 
 and lizards. The visits of insects are often needed 
 for their fertilization. 
 
 16. The Lily family, including many garden flow- 
 ers, as Tulips, and Lilies, (Fig. 32,) as well as such 
 plants as the Onion, Squill, Aloes, and Asparagus, is 
 a beautiful representative of the type of Endogens. 
 Other families, as that of the Bulrushes, have in- 
 complete flowers. 
 
74 Easy Lessons in Vegetable Biology. 
 
 CHAPTER XL 
 
 EXOGENS, OR OUTSIDE GROWERS. 
 
 1. Plants which produce woody and vascular layers 
 near the circumference of the stem are very numer- 
 ous, including about 70,000 different species. 
 
 Between the woody layers, or rings, and the bark 
 of such plants is a semi-fluid mucilaginous matter 
 containing the new or growing cells. This layer is 
 called the cambium layer. At the apex of the 
 stem, and at that of the root, this layer is continuous 
 
 with the cells of bioplasm 
 which multiply by self-di- 
 vision in these localities so 
 as to supply the elements of 
 the new tissues. (Fig. 33.) 
 2. Incomplete Exog ens 2ccq 
 those whose flowers have no 
 corolla. Sometimes, but not 
 always, they have a calyx, 
 or simple perianth. They 
 are of two kinds : 1) Those 
 whose seeds are naked, as 
 Fig. 33. in the Cone-hearing family, 
 
 consisting of the Fir and Spruce tribe, the Cypress 
 
EXOGENS. 
 
 tribe, and similar plants. These conifers are gener- 
 ally large trees or evergreen shrubs, and furnish 
 much valuable timber, 
 pitch, turpentine, and 
 resin. (Fig. 34.) 
 
 2. Those whose seeds 
 are contained in an ova- 
 ry, as the Amaranth, 
 Buckwheat, Laurel, Net- 
 tle, Fig, and the Catkin- 
 hearing family. This 
 latter family is the most 
 important of this order, 
 since it contains the most 
 important timber - trees, 
 as the Alder, Birch, Wil- 
 low, Poplar, Oak, Chest- 
 nut, etc. Their flowers, 
 either male or female, 
 are arranged on a com- 
 mon axis, without sepa- 
 rate stalks, and are with- 
 out either calyx or corol- 
 la, but furnished only 
 with scaly bracts. Such 
 clusters, or catkins, at- 
 tract attention in early spring to the willow, alder, or 
 poplar trees. This family, with the Conifers, gives 
 
 Fig. 34. 
 
76 
 
 Easy Lessons m Vegetable Biology. 
 
 character to the woodland scenery of temperate climes. 
 (Fig. 35.) 
 
 3. In the next subdivision of the type of Exogens 
 we find plants whose flowers have both calyx and 
 corolla. The petals of the corolla are also united, and 
 
 Fig. 35. 
 
 bear the stamens, as the Honeysuckle, Teazel, Lobelia, 
 Convolvulus, Primrose, Labiate and Composite fam- 
 ilies, etc. 
 
 The Labiate family contains many fragrant and 
 aromatic plants, as Mint, Lavender, Sage, Balm, etc. 
 It is characterized by two long and two short stamens, 
 
Exogens. 77 
 
 four little nuts, or naked seeds, and irregular corollas. 
 The Composite family is very extensive. It includes 
 all such plants as the Thistle, Sunflower, Daisy, Aster, 
 and Chrysanthemum. There are about twelve thou- 
 sand species in this family, distributed all over the 
 globe. They are generally herbaceous plants, and 
 often contain a milky fluid, or latex. The flowers are 
 placed on a common expanded receptacle, crowded to- 
 gether into a capitulum, or head, and surrounded by 
 a general involucre of densely crowded bracts. The 
 florets of the central part of the capitulum are often 
 of a different structure and color from those of the 
 margin, and the two kinds are distinguished as florets 
 of the disk and florets of the ray. 
 
 4. Another class of Exogens also have calyx and 
 corolla, but the corolla has distinct petals, and the 
 stamens are attached to the calyx. 
 
 The Umbelliferous family is found in this division, 
 and contains culinary plants, such as Carrot, Celery, 
 Parsley, and Parsnip ; medicinal herbs, as Caraway, 
 Fennel, Coriander, and Assaf cetida ; and some poison- 
 ous plants, as Hemlock and Fool's Parsley. This 
 family is named from the mode of its inflorescence. 
 An umlel, like the capitulum, has the stem terminat- 
 ing in a number of flowers, but each separate flower 
 is stalked. The umbel is simple when the main stem 
 or peduncle ends in a number of separate stalked 
 flowers, as in the Cherry, compound when it branches 
 
78 Easy Lessors in Vegetable Biology. 
 
 into a number of secondary umbels, as in the major- 
 ity of genera in the family of Umbelliferce. 
 
 The Zeguminose family, characterized by the ovary 
 developing into a pod, (or legume,) is also very ex- 
 tensive. It includes many forms of herbs, shrubs, 
 and trees. Some have flowers resembling a butterfly, 
 and hence called papilionaceous, as Clover, Lupins, 
 Peas, and Beans. Others have irregular flowers which 
 are not papilionaceous, as the Tamarind-tree and 
 various species of Senna, or Cassia. In other 
 cases the flowers are regular, the scales of the calyx 
 in the bud are vallate, or touch only at the edges, 
 and the stamens are sometimes very numerous, as in 
 different species of Acacia, and the Mimosa, or Sen- 
 sitive-plant. The Hose family is also a very large 
 one, and includes not only the roses of our gardens? 
 but Raspberries, Strawberries, Plums, Apples, Pears, 
 Cherries, Peaches, Apricots, and Almonds. 
 
 The Cactus family is also found in this division. 
 It contains many succulent plants, generally destitute 
 of leaves whose place is supplied by fleshy stems of 
 grotesque figures. Some are angular, others are 
 roundish and covered with stiff spines. They vary 
 in height from a few inches to twenty or thirty feet. 
 The flowers are often very showy, varying from pure 
 white to rich scarlet or purple. In Mexico and 
 Southern California there are numerous species, some 
 of gigantic size. (Fig. 36.) 
 
ExOGENS. Jm 
 
 5. In the highest class, or most perfect Exogens, 
 the calyx and corolla are present, the petals are disl 
 
 Fig. 36. 
 
 tinct and inserted into the receptacle, and the stamens 
 grow from beneath the ovary. 
 
 The Crowfoot family, having distinct carpels above 
 numerous stamens, and embracing the Hanunculus, or 
 Buttercup, the Larkspur, Aconite, and Peony ; the 
 Poppy family, having the carpels united into an un- 
 divided ovary ; the Cruciferous family, readily known 
 by their four cruciate petals, and including many 
 flowers and vegetables, as "Wallflower, Cabbage, Tur- 
 nip, Eadish, and Mustard; the Flax family; the Tea 
 family, containing the Camellias and the Tea-plants ; 
 the Orange family; the Maple family; and many 
 others, are found in this group. 
 
 >^?*^vvy 
 
80 Easy Lessons ts Vegetable Biology. 
 
 CHAPTER XII. 
 
 THE VEGETABLE CLOTHING OF THE WORLD. 
 
 1. The beautiful forms of vegetable life, and the 
 peculiarities of different species, give character to the 
 landscape scenery of the world, and the comparison 
 of the different floras (or groups of plants) on the 
 earth's surface will aid us greatly in our biological 
 generalizations. 
 
 2. The study of the distribution of plants over the 
 earth is sometimes termed Botanical Geography. It 
 has been greatly promoted by the travels of Hum- 
 boldt. Standing a few hundred feet below the sum- 
 mit of Chimborazo, he saw an epitome of the vegeta- 
 tion of the globe — a picture of all climates from the 
 tropics to the poles, with their zones or belts of vege- 
 tation. Just above him rose the inaccessible summit 
 of snow — a beautiful image of purity set in the cloud- 
 less blue of a tropical sky. The only vegetation present 
 was the Red Snow, or a few Thallogens. The vol- 
 canic rocks around him were draped with Lichens, a 
 few Mosses, and Alpine flowers. Beneath, the grass- 
 green slopes, with varied flowers and willowy shrubs, 
 were succeeded by forest belts, and these latter by the 
 tropical luxuriance at the base of the mountain. 
 
The Vegetable Clothing of the World. 81 
 
 3. Each species of plant has its center of distribu- 
 tion at the spot from which it originally sprang. It 
 is not easy, however, to determine these centers, be- 
 cause of plant migration. All plants are not 
 equally capable of migration, or the strongest would 
 have replaced the rest and occupied all the ground. 
 Migration is also hindered by seas, deserts, mountain- 
 chains, and climate, as well as by the existence of 
 other plants and animals. 
 
 4. The transitions from one species to another met 
 with in gradually ascending mountain regions are 
 not such as Darwin's theory of natural selection might 
 lead us to expect, nor do they favor any theory of 
 transmutation of one kind into another. Such a 
 mountain-side is the most appropriate place in the 
 world for practically testing such theories. If any 
 transitional forms ever existed between species we 
 may reasonably expect to find them here. But the 
 Alpine species make their appearance, and those of 
 the plains disappear suddenly at particular elevations, 
 and we find no transitional varieties. 
 
 5. Climate has much to do with the similarity in 
 the floras of different regions. This holds good in 
 widely separated regions, as seen in the resemblances 
 of the beeches of Japan and the Straits of Magellan, 
 and of the heaths of the Cape of Good Hope and of 
 Western Europe. 
 
 6. Griesbach divides the surface of the earth into 
 
 6 
 
82 Easy Lessons in Vege table Biology. 
 
 twenty-four regions of vegetation or natural floras. 
 Each of these is subdivided into zones, and the char- 
 acter of each zone is determined by its elevation 
 above sea-level. A succession of zones is thus ob- 
 tained until the line of perpetual snow sets a limit to 
 vegetable life. We do not find in nature such defi- 
 niteness as our classifications and theories imply, yet 
 there is a general similarity between the flora of any 
 part of the earth and that of a mountain-zone of cor- 
 responding temperature. Thus, similar and often 
 identical plants occur in the lower zones of the mount- 
 ain and in the districts (north or south) having an 
 increase of latitude, and this principle continues until 
 the floras of the snow-line and of the arctic regions 
 generally correspond. Yet, notwithstanding simi- 
 larities, the floras of mountain and of arctic regions 
 show considerable differences. 
 
 7. The base of the mountains near the equator, 
 from the sea-level to about 2,000 feet high, forms the 
 zone of palms and bananas. Erom this to the height 
 of 4,500 feet is the zone of tree-ferns and figs. In 
 India these are covered by many kinds of peppers, 
 and orchids. In the islands of the Southern Ocean 
 the figs are replaced by tree-like Urticacece, and 
 the valuable cinchona-trees characterize the South 
 American region. The zone of myrtles and laurels 
 comes next, extending to 6,000 feet. The predomi- 
 nant trees are those with thick, shining leaves, as 
 
The Vegetable Clothing of the Woeld. 83 
 
 myrtles, camellias, and magnolias. Acacias and 
 heaths attain here their highest development, and 
 evergreen oaks abound. The laurels occur 
 mainly near the upper limit of this zone, and are 
 found also in the next, the zone of evergreen trees, 
 which reaches the height of 9,000 feet. Next is the 
 zone of trees with deciduous foliage, which extends 
 to the height of 10,000 feet. In the tropics this is 
 only seen on elevated plains. From this to 12,500 
 feet is the zone of conifers, and thence to 15,000 feet 
 is the zone of rhododendrons. Here lofty trees dis- 
 appear, and are replaced by luxuriant meadows and 
 herbs with thick, shining leaves and magnificent flow- 
 ers, as the rhododendrons and azaleas. The last zone 
 is that of Alpine herbs, extending to the snow-line. 
 The plants are chiefly perennial, with woody roots, a 
 small amount of foliage, and brightly colored flowers. 
 Nearly all contain resinous and bitter substances. 
 
 The Alps and other mountains of temperate climes 
 have but five or six zones. The zone of fruit trees 
 rises to about 2,000 feet. The apple and grape ascend 
 thus high, but the walnut may be found up to 3,000 
 feet. The woods here consist chiefly of beeches, 
 alders, pines, and oak. The zone of beeches may 
 reach to 5,000 feet. The birch, sycamore, hazel, wild 
 cherry, and many herbs, as the plantain, dandelion, 
 and chrysanthemum, attain their upper limit here, and 
 disappear with the beech. At the same time, we 
 
84 Easy Lessons in Vegetable Biology. 
 
 reach the lower limit of the rhododendron, gentian, 
 primrose, etc. The zone of pines comes next, to 
 6,000 feet. The zone of Alpine herbs extends to the 
 limit of perpetual snow, 9,000 or 10,000 feet. The 
 dwarf willow, a few rhododendrons, the mountain- 
 heath, and a single azalea are all the woody plants 
 of this zone in the Alps. The zone of cryptogams, 
 or the snow region, has only mosses and lichens, and 
 occasionally the " red-snow plant." 
 
GLOSSARY AND INDEX. 
 
 A'cid products of plants, 31. 
 
 Acotyle'dons, 58 : plants without seed-lobes. 
 
 Ac'rogens, 26, 50 : plants which grow at the summit. 
 
 Albu'men, 12: in animals, white of egg and similar material; in 
 
 vegetables, the nourishing matter in seeds, etc. 
 Adventitious, 61: accidental or additional. 
 Al'gse, 46 : water-plants belonging to the type of Thallogens. 
 Alkaloids, 31: active principles (not acids) of certain plants; as 
 
 morphia, quinia, etc. 
 Alternate, 64 : by turns. 
 An'iher, 52: the part of the stamen in a flower which contains 
 
 pollen. 
 Antherid'ia, 51: the organ in mosses, etc., corresponding to the 
 
 anther in flowering plants. 
 Antherozo'id, 52 : the moving male element in plants without flowers. 
 An'nuals, 61 : yearly plants. 
 An'nular, 35: ring-like. 
 Amce'boid, 18: resembling the Amoeba, one of the most primitive 
 
 animals. 
 Arachnoidis'cus, 43 : a genus of Diatoms, named for its net-like 
 
 markings on the disk. 
 Ax/is, 46 : the central column of a plant, round which the other parts 
 
 are arranged. 
 
 Bacteria, 48 : a minute organism, of globular or rod-like form, gener- 
 ally regarded as one of the Fungi. 
 Bast-fibers, 35: the vessels or fibers of inner bark. 
 Bi/oplasm, 13, 15 : living germinal or formative matter. 
 Bienmial, 61, pertaining to two years. 
 Biol'ogy, 1 : the science of living beings. 
 
86 Easy Lessons in Vegetable Biology. 
 
 Bipin'nate, 65 : twice pinnate, or having two series of leaflets. 
 
 Bot'any, 8: the science of plants. 
 
 Bracts, 64 : a small leaf, or scale, from the axil of which a flower or 
 
 its pedicle proceeds. 
 Bnlbs, 61 : a fleshy roundish body consisting of scales or imperfectly 
 
 developed leaves, producing a stem and roots. 
 Buds, 62: a small protuberance containing the rudiments of future 
 
 leaves, flowers, or stem. 
 Bulrushes, 73: a large kind of rush, growing in water. 
 
 Cac'tus, 78: a family of succulent, prickly plants. 
 
 Cap'sule, 9 : a sort of cup, or seed-pod. 
 
 Cam'bium, 38, 59: the glutinous layer between the bark and wood, 
 from which new tissue is made. 
 
 Cam'phor-glands, 36: groups of cells secreting camphor. 
 
 Carbon'ic acid gas, 31: a gas imbibed by plants for nutrition, the 
 carbon being retained and oxygen given out. 
 
 Carpels, 70: the leaves forming the pistil, sometimes separate and 
 sometimes united into a single ovary. 
 
 Cat'kins, 75 : a mode of inflorescence so called from its resemblance 
 to a cat's tail. 
 
 Capit'ulum, 77 : a thick head or cluster of flowers, as a clover-top 
 or dandelion. 
 
 Ca/lyx, 68 : the outer leaves of a flower, generally green. 
 
 Can'dex, 61 : the stem of a palm. 
 
 Cell, 13 : a mass of living matter. 
 
 Cell- wall, 27: the outer layer, or membrane, of vegetable cells. 
 
 Cel'lulose, 28: the starchy material of which the cell- wall is com- 
 posed. 
 
 Cell-contents, 31 : materials within cells. 
 
 Cel/lular-plants, 38 : a term given to those plants which are destitute 
 of vessels. 
 
 Cell-families, 33 : clusters proceeding from a single cell. 
 
 Centers of plant distribution, 80 : the original place of plant growth. 
 
 Cha'ra, 51 : a genus of Stoneworts. 
 
 Chemical elements of bioplasm, 14. 
 
 Chemical products of bioplasm, 16. 
 
 Chlo'rophyll, 31: the green coloring matter in plants, which some- 
 times becomes red, brown, etc. 
 
Glossary and Index. 87 
 
 Classification, 23 : arrangement. 
 
 Class'es, 25 : primary modifications of types. 
 
 Cil'ia, 41 : hair-like projections from cells. 
 
 Circulation in cells, 28: movements of the living matter within 
 
 Climate, 80 : its effects. 
 
 Coales'cence, 52 : union of parts. 
 
 Cork, 34 : the healing tissue of plants. " 
 
 Cor'tex, 37 : bark. 
 
 Corolla, 6*7 : the inner covering of a flower, generally colored, sur- 
 rounding the stamens and pistil. 
 
 Corm, 61 : a solid bulb. 
 
 Cor'date, 65 : heart-shaped. 
 
 Co'nifers, 75 : trees bearing cones, like the Pines and Firs. 
 
 Composite plants, 77: having flowers gathered in a capitulum or 
 head. 
 
 Cotyle'dons, 58: seed-lobes. 
 
 Cruciate, 79: like a cross. 
 
 Cru'cifers, 79: plants having cruciform flowers. 
 
 Crow-foot family, 79 : a family of plants, containing buttercups, etc. 
 
 Cu'ticle, 36 : external skin. 
 
 Crystals, 31 : small chemical accumulations found in cells. 
 
 Cy'cle, 64: a round, or set. 
 
 Daugh'ter-cells, 32: the progeny of a single cell. 
 
 Decid'uous, 66 : falling off. 
 
 Deposits on cell-walls, 29 : hard material left on the external mem- 
 brane, in shape of dots or signs. 
 
 Diatoms, 29, 43 : a kind of unicellular plants with flinty deposit on 
 the surlace. 
 
 Dicotyledons, 58: having two seed-lobes. 
 
 Differences in bioplasm, 17, 23. 
 
 Diphthe'ria, 48 : a diseased condition connected with the presence of 
 Fungi. 
 
 Distribution of plants, 81. 
 
 Em'bryo, 54, 59: the rudimental or undeveloped condition of the 
 
 organism. 
 En'dogens, 26, 58, 62: plants whose vessels and fibers grow inside 
 
 the cellular tissue of the stem. 
 
88 Easy Lessons in Vegetable Biology. 
 
 En'dosmose, 15 : passage of liquid inward through a membrane or 
 
 porous partition. 
 Environment, 29 : surrounding circumstances. 
 Epidermis, 36: outer skin. 
 Epig'ynous, 69 : upon the ovary, or pistil. 
 Ex'ogens, 26: plants whose vessels and fibers grow outside, or 
 
 between the bark and wood. 
 Ex'osmose, 15 : passage of fluid outward through a membrane. 
 Evolu'tion, 21 : a theory of development of things from simple to 
 
 complex, by a power within themselves. 
 External forms of plants, 59. 
 
 Family, 25 : a group within an order in classification. 
 
 Fascic'ulated, 60 : growing in bunches or bundles. 
 
 Fermentation, 47 : a chemical change produced by the growth of 
 
 a fungus, the yeast- plant. 
 Ferns, 52 : a class of Acrogens, generally having spores on the back 
 
 of the fronds or leaves. 
 Fi'bro-vas'cular, 38, 58: pertaining to vessels and fibers. 
 Fil'iform, 60: threadlike. 
 Filament, 43, 50, 54: the part of a stamen supporting the anther. 
 
 A thread. 
 Flo'rets, 77 : small flowers. 
 
 Flo'ra, 80 : a group of flowers belonging to a district or country. 
 Flow'er- structure, 66, 67. 
 Forms of cells, 30, 31. 
 Formed material. 15 : material or shapes produced by bioplasm, or 
 
 living matter. 
 Form'ative layer, 34 : the cambium, or layer where new cells grow. 
 Frond, 57, 46: the leaves of Ferns. 
 Fun'gi, 46: a class of Thallogens, embracing the mushrooms and 
 
 molds. 
 Fundamental tissue, 38 : the cellular parts of plants. 
 Functions of leaves, 65 : the uses served by them. 
 Fu'siform, 60: spindle-shaped. 
 
 Geolog'ic history, 9. 
 
 Ge'nus, 25 : a group within an order in classification. 
 
 Germ-cell, 54 : a cell answering to the ovary in flowering plants. 
 
Glossary and Index. 
 
 80 
 
 Gen'erating-tissue, 34: the cells which form new tissues. 
 
 Germination of seeds, 70. 
 
 Glumes, 71: husks, or scales, as in the flowers of grasses and 
 
 grain. 
 Grass'es, 58, 11 : a large family of plants with simple leaves and 
 
 jointed stems, as wheat, rye, oats, etc. 
 Grow'ing-point, 34 : the place of growth in Acrogens. 
 Growth at summit, 52. 
 Growth of Ferns, 52. 
 Growth of Ex'ogens, 74. 
 Groups of cells, 33. 
 
 Hairs, 31 : epidermic appendages. 
 Heal'ing-tis'sues, 34. 
 Heat, effects of, 16. 
 Hypog'ynous, 68 : uuder the ovary. 
 
 Identity of bioplasm, 22. 
 
 Iner'tia, 11 : the tendency of matter to remain in a state of rest or 
 motion. 
 
 Individuals, 25 : persons or things which cannot be divided without 
 loss of identity. 
 
 Incomplete Ex'ogens, 68, 74: those whose flowers have no co- 
 rolla. 
 
 Indu'sium, 54: a membranous covering to the fruit-spot of some 
 Ferns. 
 
 Inherent mo'tion, 18: movement originating from within. 
 
 In'stinct, 45 : an inward impulse, or tendency. 
 
 In'ternodes, 51: the space between the nodes, or places whence the 
 leaves arise. 
 
 Inflorescence, 11: mode of flowering. 
 
 Involu'cre, 11 : a whorl or set of bracts around a flower, umbel, or 
 head. 
 
 La'biate, 76: plants whose flowers have leaf-like projections 
 
 Landscape scen'ery, 81. 
 
 La'tex, 35: fluid,' generally milky, contained in special vessels and 
 
 holding peculiar substances in solution. 
 Lan'ceolate, 65 : oblong and tapering. 
 
90 Easy Lessons in Vegetable Biology. 
 
 Legu'minose, 18 : plants having legumes, or pods. 
 
 Leaves, 63. 
 
 Lich'ens, 46: a class of Thallogens, often improperly called rock- 
 moss, or tree-moss. 
 
 Life, 9 : the power by which organized beings live, or the state of 
 animate existence. 
 
 Life his'tories, 8. 
 
 Living matter, 1 2 : bioplasm. 
 
 LiHes, 73: a large family of flowering plants, including lilies, tu- 
 lips, etc. 
 
 Materialism, 10: the dogma that all things consist of matter alone. 
 Med'ullary rays, 39 : rays of cellular tissue or pith, passing from the 
 
 center to the bark. 
 Metamor'phosis, 53 : transformation, or change of form or shape. 
 Microscopic sections, 39. 
 Mo'tions of bioplasm, 18. 
 Mo'tile, 45 : having power of self-motion. 
 Monocotyle'dons, 58: plants with single seed-lobe. 
 Moth'er-cells, 32 : the cell from which others originate. 
 Moss'es, 54: a class of Acrogens, with plants of small size, and 
 
 stems with narrow, simple leaves. 
 Mountain- vegetation, 83. 
 Molds, 47 : minute fungous plants. 
 Multiplication of cells, 32. 
 Myce'lium, 48 : the filaments, or spawn, from which a fungus grows. 
 
 Names of species, 25. 
 Na'ked, 68 : without calyx or corolla. 
 Na'piform, 60 : turnip shaped. 
 Neb'ulous, 8 : cloudy or misty. 
 
 Neb'ular hypothesis, 8 : theory of development of worlds from primi- 
 tive fire-mist. 
 Nec'taries, 36 : groups of cells which secrete honey. 
 Nu'cleus. 28: a concentration of vital power in a cell. 
 Nucleolus, 28: a secondary nucleus. 
 
 Nodes, 51 : points on the stem from which the leaves proceed. 
 Nutrition, 20 : the process of nourishment; 
 
Glossary and Index. 91 
 
 O'ospore, 52: the embryo of Acrogens, etc. 
 
 Or'chids, 11: a group of plants with very peculiar flowers. 
 
 Or'ders, 25 : subdivisions of classes. 
 
 Organ/ic forms, 45 : forms of animals or vegetables. 
 
 Organiza'tion, 9, 27 : the arrangement of organs or parts. 
 
 Or'gans of nutrition, 66. 
 
 Oil-pas'sages, 36 : cavities conveying oil. 
 
 O'vary, 68 : the lower part of the pistil. 
 
 O'vate, 65 : egg-shaped. 
 
 O'vule, 68 : a young seed. 
 
 Pab'ulum, 15 : food. 
 
 Palms, 71 : a group of conspicuous tropical plants. 
 
 Pedun'cle, 77 : the stalk of the flower or fruit. 
 
 Perianth, 68 : the envelope of the flower when caylx and corolla are 
 indistinguishable. 
 
 Perig'ynous, 69 : around the ovary. 
 
 Permanent tis'sue, 34 : bells in a plant incapable of further growth. 
 
 Peren'nial, 61: plants which live more than two years. 
 
 Petiole, 64 : the foot-stalk of a leaf. 
 
 Pet'al, 68 : the leaf of the corolla. 
 
 Pin'nate, 65 : a compound leaf, with leaflets along a common pe- 
 tiole. 
 
 Pis'til, 67 : the central organ of a flower. 
 
 Papiliona'ceous, 78: butterfly -like. 
 
 Pin'nule, 54 : a branchlet of a pinnate frond or leaf. 
 
 Pol'len, 69 : the fecundating dust in the anther of a flower. 
 
 Pop'pies, 79 : a genus of flowering plants. 
 
 Physical forces in bioplasm, 15. 
 
 Pith, 39 : the central cells in the stem of plants. 
 
 Primordial u'tricle, 28 : the mucilaginous layer within the cell-wall 
 of a cell. 
 
 Pro'tococcus, 40 : a genus of primitive plants. 
 
 Pro'tophytes, 26 : the simplest type of plants. 
 
 Plant migration, 81. 
 
 Pro-em'bryo, 52 : a temporary structure in the early life-history of 
 Acrogens. etc. 
 
 Pro'toplasm, 13: the physical basis of life, or rather, of living 
 matter. 
 
92 Easy Lessons in Vegetable Biology. 
 
 Prothallium, 54: a structure in Ferns similar to the pro-embryo in 
 
 Stone-worts. 
 Putrefaction, 47 : decay of albuminoid matter, produced by the action 
 
 of Fungi. 
 Radical, 65 : belonging to the root. 
 Receptacle, 68 : the tip of the flower-stalk, sometimes dilated, which 
 
 supports the organs or florets. 
 Retic'ulated, 35 : like a net- work. 
 Red snow, 42 : one of the type of Protophytes. 
 Re'gions of vegeta'tion, 82. 
 
 Reproduction, 20 : the multiplication of cells or individuals. 
 Resem'blances of bi/oplasm, 14. 
 Rhizome', 53 : an under-ground stem. 
 Roots, 59. 
 
 Ros'es, 78 : a family of flowering plants. 
 Run'ners, 61 : branches of stems which give off roots from their 
 
 nodes. 
 Rust in wheat, 48: a species of fungus. 
 
 Sea-weeds, 46. 
 
 Scales, 62 : undeveloped leaves protecting buds, etc. 
 
 Scape, 61 : a flower-stem without leaves. 
 
 Sagittate, 65 : arrow-shaped. 
 
 Seeds, 70: the part containing the embryo in flowering plauts. 
 
 Sedg / es, 71 : a family of plants similar to rushes. 
 
 Se'pals, 68 : the leaves of the calyx. 
 
 Sieve-tubes, 35 : cells forming tubes by sieve-like perforations through 
 
 adjacent ends. 
 Ses'sile, 64, 68 : without footstalk. 
 Scalarfform, 53: ladder-like. 
 Show'ers of blood, 42. 
 Shapes of leaves, 65. 
 Soul and life, 10. 
 
 Sorus, 54 : the fruit-spot on a fern. 
 
 Spores, 52: parts analogous to the seeds of flowering plants. 
 Spore'-cases, 52 : the vessels containing the spores in Ferns, etc. 
 Sporan'gia, 51 : spore-cases. 
 Spe'cies, 25 : a group of individuals which may have descended from 
 
 a single pair. 
 
Glossary and Index. 93 
 
 Spontaneous genera/tiou, 21. 
 
 Spi'ral arrangement of leaves, 64. 
 
 Sta'mens, 67 : the male organs in flowers. 
 
 Stems, 60 : the stalk, or part which bears the leaves, flowers, and 
 fruit. 
 
 Starch, 31. 
 
 Stig'ma, 68 : the upper part of the pistil. 
 
 Stip'ule, 64 : leaf-like appeudages to the petiole. 
 
 Sto'ma, 36: the opening between the cells of epidermis for evapora- 
 tion, etc. 
 
 Stone' worts, 50 : an order of Acrogens. 
 
 Squamose, 61 : scaly as the cone of a pine. 
 
 Style, 68 : the pillar or filament, supporting the stigma of the pistiL 
 
 Suc'culent, 69 : juicy, fleshy. 
 
 Tei/nate, 65 : an arrangement of three leaflets on a petiole. 
 
 Thallogens, 26: a type of plants. 
 
 The'oriesoflife, 10. 
 
 Transitional forms unknown, 80. 
 
 Tu'ber, 61 : a fleshy rounded stem or root, as the potato. 
 
 Tu'berous, 60 : containing tubers. 
 
 Tu'nicated, 61 : covered with layers, as the onion. 
 
 Tripin'nate, 65 : bipinnate leaves on each side of a petiole. 
 
 Types, 25, 26: general plans of structure. 
 
 Unicellular, 40 : having a single cell. 
 
 Un'ion of cells, 33. 
 
 Unorganized, 27 : matter which has not lived. 
 
 Um'bel, 77 : a flower cluster in which the stalks spread from a com- 
 
 mon point. 
 Umbelliferous, 77: bearing umbels. 
 
 Varieties, 25 : races or breeds among species. 
 Yas'cular, 38 : belonging to vessels. 
 Yalv'ate, 78 : meeting at the edges without overlapping. 
 Vessels, 35 : tubes or canals among the cells. 
 
 Wa'ter in bioplasm, 14. 
 White blood-cells, 13, 20. 
 
94 Easy Lessons m Vegetable Biology. 
 
 Whorls, 50 : an arrangement of leaves, or organs, around the stem in 
 the same plane. 
 
 Yeast-plant, 47 : a fungus which is the cause of fermentation. 
 
 Zool/ogy, 7 : science of animal life. 
 
 Zoospores, 41 : spores having spontaneous movements. 
 
 Zones of vegetation, 83. 
 
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 THE END. 
 
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