'w ^i ir W^ e.. ^' S -3 11 ! M B ^///^ .// - / < /^^ ^' / Vv / / \- - W, J, Gage <5^' Cds Educational Series. THE ELEMENTS Structural Botany WITH SPECIAL REFERENCE TO THE STUDY CANADIAN PLANTS TO WHICH IS ADDED A. SELli:CTIO]S" OF KXAjVEI>r^^TIO:X^ P»AF»ERS. H. B. SPOTTON, M.A.,F.L.S., HEAD MASTER OK BARRIE COLLEGIATE INSTITUTE. THIED EDITI02^\ ILLUSTRATED BY THE AUTHOR. W. J. GAGE AND Ct)MPAXY, TORONTO AND WINNIPEG. U^^ -a^^ ^^f -^. Entered according to Act of Parliament of Canada, in the Office of the Minister of Agriculture, by Adam Milllr & Co., in the year 1S79. ^^^^^ Note.— In explanation of the omission of Professor Macoun's name from the title page of the present edition, the Publishers desire to say that the original design of the authors was to prepare jointly a work on the Canadian Flora, Mr. Spotton to write and illustrate an introductory volume, and both parts, for the sake of uniformity, to bear the namis of both authors. 0«-ing to Professor Macoun's engagement with the Dominion Government, the joint scheme was necessarily abandoned, and the whole work (the second part of which is now in the press) will hence- forth be issued under Mr. Spotton's signature only. PREFACE. The work, of which the present Httle volume forms the first part, has been undertaken, at the suggestion of several eminent educationists, to supply a palpabSjfc want. The works on Botany, many of them of great ^^ excellence, which h^ve found their way into this country, have been prepared with reference to climates differing, in some cases, very widely from our own. They consequently contain accounts of many plants which are entirely foreign to Canada, thus obstructing the search for descriptions of those which happen to be common to our own and other countries ; and, on the other hand, many of our Canadian species are not men- tioned at dl in some of the Classifications which have been in use. It is believed that the Classification which is to form the second part of this work will be found to contain all the commonly occurring species of the Provinces whose floras it is designed to illustrate, with- out being burdened with those which are either ex- tremely rare, or which do not occur in Canada at all. ^ The present Part is designed to teach the Elements of Structural Botany in accordance with a method which- is believed to be more rational than that commonly adopted ; and it will be found to supply all that is requisite for passing the examinations for Teachers' Certificates of all grades, as well as any others demand- ing an elementary knowledge of the subject. It contains familiar descriptions of common plants, illus- trating the chief variations in plant-structure, with a view to laying a foundation for the intelhgent study of Systematic Botany with the aid of the second part; then follow a few lessons on Morphology ; and the IV PREFACE. Elements of Vegetable Histology are treated of in as simple and brief a manner as y\a.s thought to be con- sistent with the nature of the subject. The Schedules, the use of which is very strongly Recommended, were devised by the late Professor Hens- low, of Cambridge University, to fix the attention of X3upils upon the salient points of structure. They will be found invaluable to the teacher as tests of the accu- racy of his pupils' knowledge. The cost of striking off a few hundred blanks of each sort would be very trifling, and not worth considering in view of the resulting advantages. The wood-cuts are from drawings from living speci- mens, except in two or three instances where assistance was derived from cuts of well-known excellence in standard works on Botany. It need hardly be said that the engravings are not in any sense intended to take the place of the living plants. They are designed chiefly to assist in the examination of the latter, and whilst it is hoped that they may be of service to those who may desire to read the book in the winter season, it is strongly urged upon teachers and students not to be satisfied with them as long as the plants themselves are available. The works most frequently consulted in the prepar- ation of the text are those of Hooker, Gra}", Bentley and Oliver. Finally, the Authors look for indulgence at the hands of their fellow-teachers, and will be glad to receive sug- gestions tending to increase the usefulness of the work, and to extend a taste for what must ever be regarded as one of the most refining as well as one of the most practically useful of studies. September, 1879, -5>?-**^^^^ ^^f'-C^C^i^l^^-i't^^ // t^t C/ ^.../l2:£; DESCEIPTION OF CUTS. yig- PAge 1. Fibrong root oi Battercap 2 2. Magnified tip of rootlet 3. Stfc;m of Buttercup 4 4. Kadical leaf of same ^ 6 5. B.'.ck view oi one of the flowers of same 5 G. Section of flower of same 7 7. Stamen of same 7 8. Stamea dischargingpollen 7 9. Head of carpels of Buttercup 7 10. A carpel magui'tied, and showing ovule 7 11. Sdgra;i of Buttercup, greatly magnified 8 12. Plan of stamen 8 13. Plan of carpel 9 14. }W.^ Buttercup, Hepatica, Marsla-Marigold.CRowrooT Family. Shepherd's Purse Cress Family. ~''-^^^' Bound-leaved Mallow Mallow Family. ' ^ ^ " Garden Pea Pulse Family. Great Willow-herb Evenixg-Primeose Family. ''*^' ■0 "^^^ Sweet-Brier, Crab-Apple Eose Family. uLt^^t^cf^^^^'^ '/ Water-Parsnip Parsley Family. O/y^^U*. DandeUon Composite Family. C>>m-^ Catnip Mint Family. "-^^^kX Cucumber Gourd Family. i>«-«-i>i^i_^6'<>fec6 Willow Willow Family. A c*^^*^ Dog's-tooth Violet, TrilUum Lily Family. Indian Turnip, Calla Abum Family. ' Showy Orchis Orchis Family. Timothy Grass Family. XI "r-y^i.^'^O / / THE ELEMENTS OF STRUCTURAL BOTANY 1. The study- of Botany is commonly rendered unat- tractive to the beginner by the order in which the parts of the subject are presented to him. His patience be- comes exhausted by the long interval which must neces- sarily elapse before he is in a position to do any j^ractical work for himself. In accordance with the usual plan, some months are spent in committing to memory a mass of terms descriptive of the various modifications which the organs of plants undergo ; and not until the student has mastered these, and perhaps been initiated into the mysteries of the fibro-vascular system, is he permitted to examine a plant as a whole. In this little work, we purpose, following the example of some recent writers, to reverse this order of things, and at the outset to put into the learner's hands some com- mon plants, and to lead him, by his own examination of these, to a knowledge of their various organs — to Z ELEMENTS OF STRUCTURAL BOTANY. cultivate, in short, not merely his memory, but also, and chiefly, his powers of observation. It is desirable that the beginner should provide him- self with a magnifying glass of moderate power for examining the more minute parts of specimens ; a sharp penknife for dissecting ; and a couple of fine needles, which he can himself insert in convenient handles, and which will be found of great service in separating delicate parts, and in impaling fine portions for examination with the aid of the lens. CHAPTER I. EXAillNATION OF A BUTTERCUP. 2. To begin with, there is no plant quite so suitable as our common Buttercup. This plant, which has conspicuous yellow flowers, may be found growing in almost every moist meadow. Having found one, take up the whole plant, loosening the soil a little, so as to obtain as much of the Root as possible. Wash away the earth adher- ing to the latter part, and then • proceed to ex- amine your spec- imen. Begin- ning with the Root, (Fig.l) the \j^g. 1. first uoticeabl 6 thing: is that it is not of the same colour as the rest of E-LZLSl-ESTS OF STRUCTURAL BOTANY. 3 the plant. It is nearly white. Then it is not of the same, form as the part of the plant above ground. It is made up of a number of thread-like parts which spread out in all directions, and if you examine one of these threads through your magnifying glass, you wil] find that from its surface are given off many finer threads, called root efs. These latter are of great im. portance to the plant ; it is largely by means of their tender extremities, and the j)arts adjacent to these, that it imbibes the nutritious fluids contained in the soil. Whilst you are looking at these delicate rootlets, you may perhaps wonder that they should be able to make their way through the soil, but how they do this will be apparent to you if you examine the tip of one of them with a microscope of considerable power. Fig. 2 repre- sents such a tip highly magnified. It is to jjjjjjjl be observed that the growth of the rootlet ffltfffl ^^^^ ^^^ ^^^^ place at the very extremity, ^3 6 ^^^ immediately behind it. The extreme ^^ * tip consists of liarder and firmer matter than Fig. 2. that behind, and is in fact a sort of cap or thimble to protect the growing part underneath. As the rootlet grows, this little thimble is pushed on first through the crevices of the soil, and, as you may sup- pose, is soon worn away on the outside, but it is as rapidly renewed by the rootlet itself on the inside. Another difference between the root and the part above ground you will scarcely have failed to discover : the root has no leaves, nor has it any buds. You may describe the root of the Buttercup asjibrous. BLEMETS OF STRUCTURAL BOTANY. Fig. 3 3. Let us now look at the Stem. (Fig. 3.) Itisuxnight, pretty firm, coloured green, and leaves spring from it at intervals. As there is scarce- ly any appearance of wood in it, we may describe it as herbaceous. At several points along the main stem branches are given off, and you will observe that immediately below the point from which every branch springs there is a leaf on the stem. The angle between the leaf and the stem, on the upper side* is called the aodl of the leaf (axilla, an armpit), and it is a rule to which there are scarcely any exceptions, that branches can only spring from the axils of leaves. The stem and all the branches of our plant termi- nate, at their upper extremi- ties, either in flowers or in flower-buds. 4. Let us now consider the Leaves. A glance will show you that the leaves of this plant are not all alike. Those at the lower end of the stem have long stalks, (Fig. 4) which we shall henceforward speak of q.s -petioles. Those a little higher up liavo pc'iolcs iio, but they are not ELEMENTS OF STEUCTUEAL, BOTANY. quite so long as the lower ones, and the highest leaves have no petioles at all. They appear to he sitting on the stem, and hence are said to he sessile. The lowest leaves oi all, as they seem to sjmng from the root, may be descrihed as radical^ whilst the higher ones may he called canine [caidis, a stem). The hroad part of a leaf is its Hade. In the plant we are now examining, the hlades of the leaves are almost divided into distinct pieces, which are called lobes, and each of these again is more or less deeply cut. Both petioles and hlades of onj- leaves are covered with minute hairs, and so are said to he hairy. Fig. 4. Hold up one of the leaves to the light, and you will observe that the veins run through it in all directions, forming a sort of net-work. The leaves are therefore net-vebied. The points along the stem from which the leaves arise are called nodes, and the portions of stem between the nodes are called iniernodes. 5. Let us next examine the Flowers. Each flower in our plant is at the end cither of the stem or of a branch of the stem. The upper portions of the stem and its branches, upon which the flowers are raised, are called t he peduncles of the flowers. Take now a flower which has just opened. Beginning at the outside, j'ou will find five little spreading leaves, somewhat yellowish in colour. Each of these is called a sepal, . , and the five together form the calyx of the Fig. 5 ^^ -^ b ELEMENTS OF STRUCTURAL BOTANY. flower. If you look at a flower which is a little older, you will probably not find any sepals. They will have fallen off, and for this reason they are said to be decidu- ous. So, in like manner, the leaves of most of our trees are deciduous, because they fall at the approach of winter. You will find that you can pull off the sepals one af a time, without disturbing those that remain. This shows that they are not connected together. They are therefore said to he free, and the calyx is described as poly sepalo lis. Inside the circle of sepals there is another circle oi leaves, usually five in number, bright yellow in colour, and much larger than the sepals." Each of them is called a petal, and the five together form the corolla of the flower. Observe carefully that each petal is not in- serted in front of a sepal, but in front of the space be- tween two sepals. The petals can be removed one at a time hke the sepals. They, too, are free, and the cor- oUa is pohjpetalous. If you compare the' petals with one another, you will see that they are, as nearly as possi- ble, alike in size and shape. The corolla is therefore regular, 6. We have now examined, minutely enough for our present purpose, the calyx and corolla. Though theii- divisions are not coloured green, like the ordinary leaves of the plant, still, from their general form, you will have no difficulty in accepting the statement that the sepals and petals are in reality leaves. It will not be quite so a,pparent that the parts of the flower which still remain are also only modifications of the same structure. But there is good evidence that this is the case. Let us, ELEMENTS OF STRUCTURAL BOTANY. 7 however, examine these parts that re- main. There is first a large number of Httle yellow bodies, each at the top of a little thread-like stalk. Each of these Fig*.' 6. bodies, with its stalk, is called a stamen.. The little body itself is the anther, and the stalk is its filament. Your magnifying glass will show you that each anther consists of two oblong sacs, united length- wise, the filament being a continuation of tlie line of union. (Fig. 7.) ' V\ 'fllV- ^ ^'*^^ ^^^^ ^^ ^ stamen of a flower which f: J ; j Iri lias been open some time, you will find that ^ '^ each anther-cell has split open along its outer edge, and has thus allowed a fine yellowish dust to escape from it. (Fig. 8.) \ 11 This dust IS called pollen. A powerful Fig. 7. Fig 8 magnifier will show this pollen to consist of grains having a distinct form. As the stamens are many in number, and free from each other, they are said to be poljandrous. 7. On remoTing the stamens there is stillleft a little raised mass, (Fig, 9) which with the aid of your needle you will be able to separate into a number of distinct pieces, all exactly alike, and looking something like unripe seeds. Fig. 10 shows one of them very much magnified, and cut through lengthwise. These little bodies, taken separately, are called car}>ds. Taken together, they form the pistil. They are hollow, and Fig 10. each of them contains, as the figure shows, a little grain-like substance attached to the lower end of its cavity. This substance, in its present condition, is the ovule, and later on becomes the seed. ELEMENTS OF STRUCTURAL BOTANY. Fig. n. You will notice that the carpel ends, at the top, in a little bent point, and that the convex edge is more or less rough and moist, so that in flowers whose anthers have burst open, a quan- tity of pollen will be found sticking there. This rough upper part of the carpel is called the stujma. Fig. 11 shows a stigma greatly magnified. In many plants the stigma is raised on a stalk above the ovary. Such a stalk is called a style. In the Buttercup the style is so short as to be almost suppressed. AYhen the style is entirely absent the stigma is said to be sessile. The hollow part of the carpel is the ovary. In our plant the pistil is not connected in any way with the calyx, and is consequently said to be free or superior, and, as the carpels are not united together, the pistil is said to be apocarpous. 8. Remove now all the carpels, and there remains nothing but the swollen top of the peduncle. This swollen top is the receptacle of the flower. To it. in the case of the Buttercup, all four parts, ca-lyx, corolla, stamens, and pistil, are attached. When a flower has all four of these parts it is said to be complete. 9. Let us now return to our statement that the struc- ture of stamens and j)istils is only a modi- fication of leaf- structure generally. The stamen looks less like a leaf than any other part of the flower. Fig. 12 will, however, serve to show you the plan upon which the botanist considers a stamen to be formed. The anther corresponds to the leaf-blade, and the filament to the petiole. The two Fig. 12 cells of the anther correspond to the two EliEMENTS OF STRUCTURAL BOTANY. 9 halves of the leaf, and the cells burst open along wbat answers to the margin of the leaf. 10. In the case of apocarpous pistils, as that of the Buttercup, the botanist considers each carpel to be formed by a leaf- blade doubled lengthwise until the edges meet and unite, thus forming the ovary. Fig. 13 will make this clear. 11. There are many facts which support this theory ao to the nature of the different parts of the flower. Suffice it to mention here, that in the white Water- Lily, in v.hich there are several circles of sepals and petals, it is difficult to say where the sepals end and the petals begin, on account of the gradual change from one set to the other. And Fig. 13. ^o^ o^^y is there a gradual transition from se- pals to petals, but there is likewise a similar transition from petals to stamens, some parts occurring, which are neither altogether petals, nor altogether stamens, but a mixture of both, being, imperfect petals with imperfect anthers at their summits. We can thus trace ordinary leaf-forms, by gradual changes, to stamens. We shall, then, distinguish the leaves of plants as foliar/e-leaves, and Jloiver -leaves, giving the latter name exclusively to the parts which make up the flower, and the former to the ordinary leaves which grow upon the stem and its branches. 12. You are now to try and procure a Buttercup whose flowers, or some of them, have witherecT away, leaving only the head of carpels on the receptacle. The carpels will liave swollen considerably, and will now show themselves much more distinctly than in the 10 ELEMENTS OF STRUCTURAL BOTANY. flower which we have been exam- ^ ^ ining. This is owing to the growth the ovules, which have now become seeds. Remove one of Fig'ii. Fig- 15. the carpels, and carefully cut it through the middle lengthwise. You will find that the seed almost entu'ely fills the cavity. (Figs, l-i and .15.) ^,>^ This seed consists mainly of a hard substance (W ^''if called albumen, enclosed in a thin covering. At \ !3 / the lower end of the albumen is situated a very p. ^g small body, which is the emhryo. It is this which develops into a new plant when the seed germi- nates. 13. "We have seen then that our plant consists of several parts : (1). The Root. This penetrates the soil, avoiding the light. It is nearly white, is made up of fibres, from which numbers of much finer fibres are given oft', and is entirely destitute of buds and leaves. (2). The Stem. This grows upward, is coloured, bears foliage-leaves at intervals, gives ofi* branches from the axils of these, and bears flowers at its upper end. (3). The Leaves. These are of two sorts : FoZw^e- Icaccs aud Floicer -leaves. The former are subdivided into radical and caidine, and the latter make up the flower, the parts of which are four in number, viz. : calyx corolla, stamens, and pistil. It is of great importance that you should make your- selves thoroughly familiar with the different parts of the plant, .as just described, before going further, and to that end it will be desirable for you to review the pre- sent chapter carefully, giving special attention to those ELEMENTS OF STEUCTUBAL, BOTANY. 1] parts which were not perfectly plain to you on your first reading. In the next chapter, we shall give a very brief ac- count of the iises of the different parts of the flower. If found too difficult, the study of it may be deferred until further progress has been made in plant examination. CHAPTER II. FUNCTIONS OF THE ORGANS OF THE FLOWER. 14. The chief use of the calyx and corolla, or Jlora^ ertvelop^^s, as they are collectively called, is to protect the other parts of thejimver. They enclose 'the stamens and pistil in the bud, and they usually wither away and dis- appear shortly after the anthers have shed their pollen, that is, as we shaU presently see, as soon as their ser- vices as protectors are no longer required. 15. The corollas of flowers are usually bright-colour- ed, and frequently sweet-scented. There is little doubt that these qualities serve to attract insects, which, in search of honey, visit blossom after blossom, and, bring- ing their hairy limbs and bodies into contact with the open cells of the anthers, detach and carry away quan- tities of pollen, some of which is sure to be rubbed off upon the stij^as of other flowers of the same kind, subsequently visited. 16. The essential part of the stamen is the anther, and the purpose of this organ is to produce the pollen, which, as you have already learned, consists of minute grains, having: a definite structure. These little grains are usually alike in plants of the same kind. They are 12 ELEMENTS OF STRUCTURAL BOTANY. furnished with two coats, the inner one extremely thin, and the outer one much thicker by comparison. The interior of the jDollen-grain is filled with liquid matter. When a pollen-grain falls upon the moist stigma it begins to groic in a curious manner. (Fig. 17). The inner coat pushes its wa^' through the outer one, at some weak point in the latter, thus forming the beginning of a slender tube. This slowly pene- trates the stigma, and then extends itself down- Fig. 17. wards through the style, until it comes to the cavity of the ovary. The liquid contents of the pollen- grain are carried down through this tulbe, which remains closed at its lower end, and the body of the grain on the stigma withers away. The ovary contains an ovule, which is attached by one end to the wall of the ovary. The ovule consists of a kernel, called the nucleus, which is usually surrounded / \ by two coats, through both of which there is a (;ii* jl minute opening to the nucleu's. This opening \^^ is called the mi^ropyle, and is always to be Fi". 38. ^ound at that end of the ovule which is not attached to the ovary. (Fig. 18, 777.) About the time the anthers discharge their pollen, a little cavity, called the embryo-sac, appears inside the nucleus, near the micropyle. The pollen-tube, with its liquid contents, enters the ovary, passes through the microjiyle, penetrates the nucleus, and attaches itself to the outer surface of the cmbryo-sa^:^ Presently the tube becomes empty, and then withers away, ard, in the meanwliile, a minute body, which in time developes into the embryo, makes its appeara:;ce in the embryo- sac, and from that time the ovule may i)^*^P®^'^y ^® called a seed. ELEMENTS OF STRUCTURAL BOTANY. 13 17. In order that ovules may become seeds, it is always essential that they should be fertilized in the manner just described. If we prevent pollen from reaching the stigma — by destroying the stamens, for instance — the ovules simply shrivel up and come to nothing. Now it is the business of the flower to produce seed, and we have seen that the production of seed depends mainly upon the stamens and the pistil. These. organs may consequently be called the essential organs of he flower. As the calyx and corolla do not play any direct part in the production of seed, but only protect the essential organs, and perhaps attract insects, we can understand how it is . that they, as a rule, disappear early. Their work is done when fertilization has been accomplished. Having noticed thus briefly ine part played by each set of floral organs, we shall now proceed to the exami- nation of two other plants, with a view to comparing their structure with that of the Buttercup. CHAPTER III. EXAMiNATION OF HEPATICA AND MARSH-MARIGOLD — RESEM- BLANCES BETWEEN THEIR FLOWERS AND THAT OF BUTTERCUP. 18. Hepatica. You may procure specimens of the Hepatica almost anywhere in rich dry woods, but you will not find it in flower except in spring and early summer. It is very desirable that you should have the plant itself, but for those who are unable to obtain 14 ELE.VENTS OF STRUCTURAL BOTANY. specimens, the annexed engravings may serve as a substitute. Beginning then at the root of our new plant, you see that it does not differ in any great measure from that of the Buttercup. It may in hke manner he described Sisjibrous. Fis- IJ- The next point is the stem. You will remember that in the Buttercup the stem is that part of the plant from which the leaves spring. Examining our Hepa- tica in the light of this fact, and following the petioles of the leaves down to their insertion, we find that they and the roots appear to spring from the same place — that there is, apparently, iwjteirii Plants of this kind are therefore called acaulescejitjihdX is, stemless, but it inust be carefully borne in mind that the absence of the ELEMENTS OF STRUCTURAL BOTANY. 15 stem is only apparent. In reality there is a stem, but it is so short as to be almost indistinguishable. The leaves of the Hepatica are of course all radical. They will also be found to be net-veined. 19. The Flowers of the Hepatica are all upon long peduncles, which, like the leaves, appear to spring from the root. Naked peduncles of this kind, rising from the ground or near it, are called scapes. The flower- stalks of the Tuhp and the Dandelion furnish other famihar examples. Let us now proceed to excomine the flower itself. Just beneath the coloured leaves there are three leaf- lets, which you will be almost certain to regard, at first sight, as sepals, forming a calyx. It ^\\ not be diffi- cult, however, to convince you that this conclusion would be incorrect. If, with the aid of your needle, you turn back these leaflets, you will readily discover, between them and the coloured portion of the flower, a very sJfort bit of stem (Fig. 20), the upper end of which is the receptacle. As these leaflets, then, are on the peduncle, heloiv the receptacle, they cannot be sepals, pig. 20. They are simply small foliage leaves, to which, as they are found beside the flower, the name bracts is given. Our flower, then, is apparently without a calyx, and in this respect is different from the Buttercup. The whole four parts of the flower not being present, it is said to be incomplete. 20. It may be explained nere thai there is an under- standing among botanists, that if the calyx and corolla are not both present it is always the corolla which -s wanting, and so it happens that the coloured part of the flower under consideration, though resembling a 16 ELEMENTS OF STRUCTURAL BOTANY. corolla, must be regarded as a calyx, and the flower it- self, therefore, as apetalous. 21. Eemove now these coloured sepals, and what is left of the flower very much resembles what was left of our Buttercup, after the removal of the calyx and cor- olla. The stamens are very numerous, and are inserted on the receptacle. The carpels are '\ also numerous, (Fig. 21) are inserted ^^' >j^ on the receptacle, and are free from W each other [apocarpous). And if you 21. , Fig. 22. examine one of the carpels (Fig. 22) you will find that it contains a single ovule. The flower, in short, so much resembles that of the Butter- cup that you will be prepared to learn that the two be- long to the same Order or Family of plants, and you will do well to observe and remember such resemblances as have just been brought to your notice, when you set out to examine plants for yourselves, because it is only in this way, and by slow steps, that you can acquire a satisfactory knowledge of the reasons which lie at the foundation of the classification of plants. 22. Marsh -Marigold. This plant grows in wet places almost everywhere, and is in flower in early summer. Note the entire aosence of nau's on the surface of ine plant. It is therefore glabrous. The root, like that of the Buttercup anu of ihe He- patica, is fibrous. The stem is hollow and furrowed. The foliage-leaves are of two kinds, as in the Butter- cup. The radical leaves spriug from the base of the stem, whilst the higher ones are cauline. The leaves ELEMENTS OF STRUCTURAL BOTANY. 17 are not lobed, as in the other two plants, but are in- dente.l on the edge. They are also net-veined. 23. Coming to the flower (Fig. 23) we find a circle, or whorl, of bright yellow leaves, looting a good deal hke the petals of the Buttercup, but you will look in vain for the corre- / sponding sepals. In this case there . '^'-~ is no whorl of bracts to mislead you. '^.977^'^^ Are we to say, then, that there is no "'^-^^^^ calyx ? If we adhere to the under- standing mentioned when describing the Hepatica, we must suppose the corolla to be wanting, and then the bright yellow leaves of our plant will Fig. 23. be the sepals^ and wiU together constitute the calyx. As to the number of the sepals, you will find, as in the Hepatica, some variation. Whilst the normal number is five, some flowers will be found to have as many as nine. 24. The stamens are next to be examined, but you should first satisfy yourselves as to whether the calyx is polysepalous or otherwise, and whether it is free from the other floral leaves or not. If your examination be properly made, it will show you that the calyx is free and polysepalous. The stamens are very much like those of the Butter- cup and Hepatica. They are numerous, they have both anthers and filaments, and they shed their pollen througph slits on the outer edges of the anthers. They are all separate from each other (polyandrous) and are all inserted on the receptacle. On this latter account they are said to be hiipogyiwn^. 1 8 ELEMENTS OF STRUCTURAL BOTANY. 25. Remove the stamens, and you have left, as be- fore, a head of carpels (Fig. 24). Examine one : there is the lower broad part, which you recognize as the ovary, the very short style, and the sticky stigma. To all appearance the carpels are pretty much the same as those of the two plants ah'eady examined. It will not do, how- Fig. 24 ever, to trust altogether to appearances in this case. Cut open a carpel and you find that, in- stead of a single ovule at the bottom of the ovary, there are several ovules in a row along that edge of the ovary which is turned towards the centre of the flower. The ovary is, in fact, a pod, and, when the seeds A ripen, splits open along its inner edge. If you Km can find one which has split in this way, you can \lt I hardly fail to be struck with the resemblance p^^ 25^^^ich it bears to a common leaf. (Fig. 25.) On the whole the resemblance between the structure of the Marsh-marigold and that of the Hepatica and Buttercup is sufficiently great to justify us in placing it in the same family with them. 26. Having now made yourselves familiar with the difi'erent parts of these three plants, you are to write out a tabular description of them according to the fol- lowing form ; and, in like mannet, whenever you ex- amine a new plant, do not consider your work done until you have written out such a description of it. In the form the term cohesion relates to the union of like parts ; for example, of sepals with sepals, or petals with petals ; while the term adhesion relates to the union of unlike parts ; for example, of stamens with corolla, or ovary with calyx. Neither cohesion nor ad- hesion takes place in any of the three flowers we have ELEMENTS OF STRUCT [JRAL BOTANY. 19 examined, and accordingly, under these headings in our schedule we write down the terms polysepalous, poly- petalous, &c., to indicate this fact. The symbol X means " indefinite," or " numerous," and may be used when the parts of any organ exceed ten in number. ^ d^\. J BUTTERCUP. J- ■^ ORGAN OB PART OP FLO-WER. XO. • COHESION. ADHESION. KEMvr-.KS. Calyx. Sepals. : Polysepalous. Inferior. i Corolla. :Petals. 5 Polypetalous. Regular. H.vpogynous. i Stamens. j ^ Filaments. Anthers. 1 Polyanclrous. Hypogj-nous. Pistil. Carpels. ^ Ovarrj. 1 1 1 Apocarpous. Superior. 20 . ELEMENTS OF STHUCrj-;V- BJTANl / HEPATIC^ 1 ORGAN. NO. COHESION. ADHESION. KEMAKKS. i Calvs. 1 Sepals. 7-12 Polysepalous. Inferior. Colouredlikea Corolla. i Petals. T/anting. ^ 1 Stame:js. Filaments. Anthers. cc Poiyaudroua,. Elypogynous. < Pistil. Carpels. Ovary. a Apocarpous. Superior. ^ i>*^~r.^^7^^-^" ^ MAP^SH-lilAEIGOLD. ORGAN. NO. COHESION. ADHESION. REMARKS 1 Calyx. ^epals. ry-o Polysepalous. Inferior. Colnurpfllike a Corolla. Corolla . Petals. ! Wa ting. Stamens. Filaments. Anthers. cc Polyandrous. Ii.}-pogynous. Pistil. Carpels. Ovary. OS Apocarpous Superior. Carpels contain severt.1 seeds. ELEMENTS OF STRUCTURAL BOTANY. 21 CHAPTER IV. examination of other common plants with hypogynous sta:mens. shepherd's purse, round-leaved mallow. 27. We shall now proceed to examine some plants, the flowers of which exhibit, in their structure, impor- tant variations from tlie Buttercup, Hepatica. and Marsh-Marigold. 22 iLE.MKNTS OF STRUCTURAL BOTANI. shepherd's Purse. This i)lant, (Fig. 26). is one of the commonest of weeds. As in the Buttercup, the fohage-leaves are of two kinds, radical and cauUne, the former being in a cluster around the base of the stem. The cauline leaves are all sessile, and each of them, at its base, projects backward on- each side of the stem, so that the leaf somewhat resembles the head of an arrow. Such leaves are, in fact, said to be sagittate, or arrow- shaped. The flowers grow in a cluster at the top of the stem, and, as -the season advances, the peduncle gradu- ally elongates, until, at the close of the summer, it f )rms perhaps half of the entire length of the stem. Yon will observe, in this i^lant, that each separate flower is raised on a little stalk of its own. Each of these little stalks is a ■pedicel, and when pedicels are present, the term peduncle is applied to the portion of stem which supports the whole cluster. 28. The flowers, (Fig. 27), are rather small, and so will require more than ordinary care in their examination. The calyx is polysepalou?, and of four sepals. The corolla is polypetalous, Fig. 27. and of four petals. The stamens, (Fig. 28), are six in number, and if you examine them atten- tively, you will see that two of them are shorter than the other four. The stamens are conse- quently said to be tetradynamous. But if there Fig. 28. liad been only/t>?/r stamens, in two sets of two each, they would h-ave been called didynamous. The stamens are inserted on the receptacle (hypogynous). The pistil is separate from the other parts of the flower (superior). 29. To examine the ovary, it will be better to select a ripening pistil from the lower part of the peduncle . ELEMENTS OF STRUCTURAL BOTANY. 23' It is a flat body, shaped something like a heart, (Fig 29) and having the short style in the notch. A ridge divides it lengthwise on each side. Carefully cut or pull away the lobes, and this ridge will remain, presenting now the appearance of a nar- row loop, with a very thin membranous partition stretched across it. Around the edge, on both sides of the partition, seeds are suspended from slender stalks. (Fig. 80). There are, then, two carpels Fig. 29. Fig. so united together, and the pistil is, therefore, syncmyoiis. The pecuhar pistil of this flower should be carefully noticed, as it is the leading character of a whole group of plants. When you nieet with such a pistil, you may be pretty certain that the plant to which it belongs is a member of the Cress or Cruci/er family, so called from the four petals sometimes spreading out like the arms of a cross. We shall find, however, that there are cross- shaped corollas belonging to plants of other groups. SHEPHERD'S PURSE. Of. CAN. I Ko.i Conr,-iox. j ADH^:s:o^•. Rrii.vKKs. Calyx. Senals. i Pulysepalous. Iijfeiior. i' Corolla. Petals. 4 Polypet.alous. Hypogynous. Staraens. Filaments. Anthers. 6 Tetrfidyna- mous. Hypogynous. Pistil. Carj)elo ■ Ovary. 2 Syncarpous. Superior. The t-^vo cells of the ovary se- parated bv a thill partition. 1 24 ELEMENTS OF STRUCTURAL BOTANY. 30. Mallow The round-leaved Mallow (Fig. 31) ^ grows along O \''^M^'yl ^ Jf pt^^ every way side, y^'tXc/^'^^^^^SA^^^^'^ wff~fi<\ ^^^ is a very common weed i n cultivated grounds. Pro- cure, if possible, a plant which has ripened its seeds, as well as one in flower. The root of this plant is of a different kind from those of the three plants first examined. It cons is ts of a stout tapering part, descending deep into the soil, from the surface of which fibres are given off irregularly. A stout root of this kind is called a tap-root. The Carrot is another example. 31. The leaves are long-petioled, net- veined and in- dented on the edges. On each side of the petiole, at its junction with the stem, you will observe a little leaf- like attachment, to which the name stipule is given. The presence or absence of stipules is a point of some importance in plant-structure, and you will do well to notice it in yorur examinations. You have now made yourselves acquainted with all the parts thati any leaf has, viz., blade, petiole and stipules. ELEMENTS OF STRUCTURAL BOTANY. 25 32. Coming to the flower, observe first that the parts of the calyx are not entirely separate, as in the flowers you have already examined. For about half their length they are united together so as to form a cup. The upper half of each sepal, however, is perfectly dis- tinct, and forms a tooth of the calyx ; and the fact that there are five of these teeth shows us unmistakably that the calyx is made up of five sepals. We therefore speak of it as a gamosepalous calyx, to indicate that the parts of it are coherent. As the calyx does not fall away when the other parts of the flower disappear, it is said to be persistent. Fig. 81, a, shows a persistent calyx. 33. At the base of the calyx there are three minute leaf-like teeth, looking almost like an outer calyx. A circle of bracts of this kind is called an involucre. The three bracts under the flower of the Hepatica also con- stitute an involucre. As the bracts in the Mallow grow on the calyx, some botanists speak of them as an ejd- cahjx. The corolla consists of five petals, separate from each other, but united with the stamens at their base. 34. The stamens are numtiou^, and as their fila- ments are united to form a tube they are said to bo monadelplious. This tube springs from the receptacle, and the stamens are therefore hijpoyynous. Fig. 32 will help you to an understanding of the relation between the petals and stamens. Having removed the petals, split the tube of the stamens with the point of your needle. A little care will then enable you to remove the stamens without in- juring the pistil. The latter organ will then be found to consist of a ring of coherent carpels, a rather stout 26 ELEMENTS OF STRUCTURAL BOTANY. style, and numerous long stigmas. (Fig. 33.) If you take the trouble to count the carpels and the stigmas, you will find the nunibers to correspond. As the seeds ]ipen the carpels separate from each other. (Fig. 34.) MALLOW. Organ. No. Cohesion. Adhesion. Kemabks. ■ Calyx. Sepals. 5 Gamosepsa- lous. Inferior. Three bracts grooving on the (Jalvx. i Corolla. Petals. 5 Polypetalous. H3rpogynous. Stamens. Filaments. Anthers. cc Monadelphous United in a ring. One-celled. Hypogynous. Pistil. Carpels. Ovary. 00 Syncarpous. Superior. Carpels as many as the stigmas. CHAPTER V. EXAMINATION OF COMMON PLANTS WITH PEEIGYNOUS STAMENS —GARDEN PEA. GREAT WILLOW-HERB, SWEET-BRIER, 35. Garden Pea. In the flower of this plant, the calyx is constructed on the same plan as in the Mallow. There are five sepals, coherent below, and spreading out into distinct teeth above ''Fig. 35). The calyx is there- fore gamosepalous. Examine next the form of the corolla (Fig. 36), One difference between this corolla and those of tlie* previous plants will strike you at once. In the flawcrs ELEMENTS OF STRUCTURAL BOiANY. 27 of the latter you will re- member that each petal was precisely like its fellows in size and shape, and we there- fore spoke of the corol:; SLsrcf/ular. In the Pea, on tlie other hand, one of the petals is large, broad, and open, whil^t two smaller ones, in Fig. 36, Fig. 38, Fig. 39. Fig. 37. the front of the flower, are united into a kind of hood. We shall speak of this corolla, then, and all others in which the petals are unlike each other in size or shape, as irregular. As the Pea blossom bears some resemblance to a butterfly, it is said to be papilionaceous. 36. Remove now the calyx-teeth and the petals, being very careful not to injure the stamens and the pistil, enveloped by those two which form the hood. Count the stamens, and notice their form (Fig. 37). You will find ten, one by itself, and the other nine with the lower halves of their filaments joined together, or coherent. "When stamens occur in this way, in two distinct groups, they are said .to be diadelpJious ; if in three groups, they would be tHndclphoiis ; if in several groups, pohjadelplious. In the Mallow, you will remem- ber, they are united into one group, and therefore we desciibed them as monadeJphous. You will perhaps be a little puzzled in tryiug to determine to what part ot the flower tlie stamens are attached. If you look closely, however, you will see that llie attachment, or insertion, is not quite the same as in the Buttercup and the other flowers examined. 28 ELEMENTS OF STRUCTURAL BOTANY. In the j^resent instance, they are inserted upon the low^r part of the calyx, and so they are described as yenjynous, a term meaning '* around the pistil." 37. But the pistil (Figs. 38, 39) is not attached to the calyx. It is free, or superior. If you cut the ovary across, you will observe there is but one cell, and if you examine the stigma, you will find that it shows no sign of division. You may therefore be certain that the pistil is ^a single carpel. You are now prepared to fill up the schedule descrip- tive of this flower. GARDEN PEA. Organ. No. ! Cohesion. I Adhesion. ■ Eemaeks. Calyx. Sepals. 1 Gamosepalous. 5 Inferior. - CoroUa. Petals. 5 Polvpetalous. Irregular. Hypogynous. Stamens. Filaments. Anthers. 10 Diadelplious. Perigynous. PistU. Carpels. Ovary. I Apoc:u-pou8. Superior. 38. The beginner will be very Hkely to think, fi'om its appearance, that the largest of the petals is made up of two coherent ones, but the following considera- tions show clearly that this is not the case. In the Buttercup, and other flowers in which the number of "-epals and petals is the same, the petals do not stand ELEMENTS OF STRUCTURAL BOTANY. 29 before the sepals, but before the spaces between them. In the Pea- blossom this rule holds good if the larore petal is considered as one, but not otherwise. Again, the veining of this petal is similar to that of a common leaf, there being a central rib from which the veins spring on each side ; and lastly, there are some flowers of the Pea kind — Cassia, for example — in which this particular petal is of nearly the same size and shape as the other four.^v^.^^^^i^^^^^i^ ':^?^^,«>l*-4^ /^^s^-v^.-^^^ 39. Great Willow-he^. This plant is extremely^ common in low grounds and newly cleared laud, and you may easily recognize it by its tall stem and bright purple flowers. Observe the position of the flowers. In the three plants first examined we found the flowers at the end of the stem. In the Willow-herb, as in the Mallow, they spring from, the sides of the stem, and immedi- ately below the point from which each flower springs you will find a small leaf or bract (Fig. 40.) Flowers which arise from the axils of bracts are said to be axillari/y whilst those which are at the ends of stems are called ter- minal, and you may remember that flowers can only be produced in the axils of leaves and at the ends of stems and branches. Fig. 4o. 40. Coming to the flower itself, direct your attention, first of all, to the position of the ovary. You will find it apparently under the flower, in the form of a tube tinged with pm-ple. It is not in reality under the flower, because its purplish covering is the calyx, o.- 30 ELEMENTS OF STRUCTURAI, BOTA!^. more accurately the calyx-tube, which adheres to the whole surface of the ovary, and expands above into four long teeth. The ovary therefore is infetior, and the calyx of course superior, in this flower. As the sepals unite below to form the tube the calyx is gam- osepalous. The corolla consists of four petals, free from each other, and is consequently polypetalous. It is also regular, the petals being alike in size and shape. Each petal is narrowed at the base into what is called the daw of the petal, the broad part, as in the ordinary foliage-leaf, being the blade. The stamens are eight iu number (octandrous), four short and four long, and are attached to the calyx (perigynous). 41. The pistil has its three parts, ovary, style, and stigma, very distinctly marked. The stigma consists of four long lobes, which curl outwards after the flower opens. The style is long and slender. The examina- tion of the ovary requires much care. You will get the best idea of its structure by taking one which has , just burst open, and begun to discharge its seeds (Fig. 41). The outside will then be seen to consist of four pieces (valves), whilst the centre is occupied by a slender four-wiaged col- umn, (Fig. 42), in the grooves of which the seeds are compactly arrr.nged. The pistil thus consists Fig. 41. ELEMENTS OF STRUCTURAL BOTAN^ 31 of four carpels united together, and is therefore syncarpous. Every seed is furnished with a tuft of silky hairs, which greatly facilitates its transportation by the wind. 42. The Willow-herb furnishes an excellent example of what is called symmetnj. We have seen that the calyx and corolla are each made up of four parts ; the stamens are in two sets of four each ; the stigma is four-lobed, and the ovary has four seed-cells. A flower is symmetrical when each set of floral leaves contains either the same number of parts or a midtipl.' ci the same number. Observe that the leaves of our plant are c- veined. The schedule will be filled up as follow- : GREAT WTLLOW-HEEB. Organ No. Cohesion. 1 AdhesioiJ. REMARgg. Calyx. Sepals. 4 Gamosepa- lous. Superior. CoroUa. Petals. 4 Polypetaloua. Perigynous. ! Stamens. Filaments. Anthers. 8 Octandrous. 1 i Perigynous. Four short and four long. PistU. Carpels. Ovary. 4 Syncarpous. ; Inferior. Seeds provided with tuits of hair 43. Sweet Brier. As iu the flower just examined, the 32 ELEMENTS OF STRUCTURAL BOTANY. sepals of Sweet- Brier are not en- tirely distinct; their lower halves cohere to form a tube, and the ca- lyx is therefore gamosepalouF. The corolla con- sists of five sepa- rate petals of the same size and shape, and is therefore both regular and poly- Fig. 43. petalous. The stemens are very numerous, and separate from each other. As in the Pea and the Willow-he ih, so in this flower they will be found to be attached to the cal;^Tc. They are, therefore, pe7'igpious. 44. To understand the construction of the p sti], yen must make a vertical section through the roundish green mass which you will find on the under side of the flower. You will then have presented to ^s?-- you some such ajopearance as that in Fig. 44. The green mass, you will observe, is hollow. Its outer covering is simply the con- tinuation of the calyx-tube. The Fig. 44. lining of this calyx-tube is the receptacle of the fioner -, \o it are attached the separate carpels which together ^• I- 1'^ r ELEMENTS OF STRUCTURAL BOTANY ?,^ constitute the pistil (Fig. 45), just as th( c irpels of the Buttercup are attached to the riised receptacle of that flower. We must remind you again that when- evei- the ovary is enclosed in the calyx-tuhe, and the calyx appears to spiiog from the ^^^ "* summit of the ovary, the latter is said to be infoior, and the former superior. /f) ^ SWEET-BRIER. '^S^ OBOAN. NO. COHESION. j ADHESION. REilABKS. , Calyx. Sepals. 5 Gamosepalous Superior. 1 Corolla 1 :PetaU, 5 Polypetalous. Perigynous. Stamens. i ^ Polyandrous. Perigj-nons. Pistil. Carpels. oc Apocarpous. Inferior. The hollow re- coptiv^le liuea the calyx-tube 1 45, Crab-Apple. The flower of the Crab-Apple (Fig. 46), is in most re. spects, like that of Sjveet- Brier. ifee calyx is gam- osepalous, its parts being united below into a tube. The corolla is of five separ- Flg 48. Fig. 47. 34 ELEMENTS OF STRUCTURAL BOTANY. ate petals. The stamens are numerous and are inserted on the calyx. The structure of the pistil (Figs. 47, 48), however, is somewhat different. On making a cross-section through the young apple, five ceils containing the unripe seeds are seen radiating from the centre. These seed-vessels are imbedded in a fleshy mass, the outer limit of which is marked by a circle of green dots, and outside these dots is the flesh which constitutes the eatable part of the apple. The inner mass, which encloses the core, belongs to the re- ceptacle, whilst the outer edible por- tion is the enlarged calyx. At the end opposite the stem will be found the persistent calyx-teeth. We have in this flower, therefore, a syncarpous pistil of five carpels, instead of an as in Sweet-Brier, apocarpous one, CRAB- APPLE. (_J^Ul> ^^tlr.tA>^ ORGAN. NO. coHESIo:^J. ADHESION. EEMABKS. Calyx. Sepals. 5 Gamosepalous Superior. CoroUa. 1 Petals. i 5 Polypetalous. Pengynous. Stainens. oc Polyandrous. Perigynous. PistU. Car2:els. 5 Syncarpous. Inferior. Fruit consists cuirfiy of r. flesLy enlari^e-, mpiit of tiio . Calyx-tube, 1 ELEMENTS OF STRUCTURAL BOTANY. CHAPTEE VI. EXAMINATION OF A PLANT VniB. EPIGYNOUS STAMENS WATER PARSNIP. 46. Water-Parsnip. This is a common swamp plant in Canada ; but if any diffi- culty be experienced in procuring specimens the flower of the com- mon Carrot or Parsnip may be substituted for it, all these plants being closely related, and differ- ing but slightly in the structure of their flowers. Notice first the peculiar ap- pearance of the flower cluster. (Fig. 49.) There are several pedicels, nearly of the same from the end of the peduncle, and from the'^^nd of each pedicel radiate in like manner a number of smaller ones, each with a flower at its extremity. Such a cluster is known as an mnhel. If, as in the present case, there are groups of secondary pedicels, the umbel is comjwund. As the flowers are very small we shall be obliged to use the lens all through the examination. Even with its aid you will have a little difficulty in making out the calyx, the tube of which, in this flower, adheres to the surface of the ovary, as in Willow-herb, and is reduced above to a mere rim or border, of five minute teeth. The petals are five in number, and free from each other. Observe that each of them is incurved at its extremity. (Fig. 60.) They are inserted on a disk which croicns the Fig. 50. Fig. 49. length, jadiatii^ 36 ELEMENTS OP STRUCTUTIAL BOTANY. ovart^, as are also the five stamens, -wLich are hence said to be epigynous. In the centre of the flower are two short styles projecting above the disk, and a vertical section through the ovary (Fig. 51) shows it to be two- celled, with a single seed suspended from the top of each cell. j/^/CiA^iJju^ J-^ ^.^^--t-i/c^ WATBR-PARSNIP. ^ ORGAN. NO. COHESION, ADHESION. 1 EEMABKS. 1 Calyx. ! Sepals. 5 Gamosepalous. ■ Superior. Calyx-teeth al- most obsolete. • Corolla. Petals 5 Polypetalous. Epigj'Ti'ous Petals incurved. Stamens. 5 Pentandrous. Epigynous, [ • Pistil. Carpels. 2 Syncarpous. Inferior. / CHAPTER VII. EXAMINATION OF COMMON PLANTS WITH EPIPETALOUS STAMENS DANDELION CATNIP-^.^ 47. Dandelion. The examination of this flower will be somewhat more difficult than that of any we have yet undertaken. Provide yourselves with specimens in flower and in q/Bed. The root of the plant, like that of the Mallow, is a tap-root. ELEMENTS OF STRUCTURAL BOTANY. 37 The stem is almost suppressed, and, as in the case of the Hepatica, the leaves are all radical They are also net- veined. The flowers are raised on scapes, which are hollow. At first sight the flower appears to have a calyx of many sepals, and a corolla of many petals. Both of these appearances, however, are contrary to facts. With a sharp knife cut the flower through (| '•^'^ the middle from top to bottom. (Fig. Fig. 52. 52.) It will then appear that the flower or rather flower-head, is made up of a large number of distinct pieces. With the point of your needle detach one of these pieces. At the lower end of it you have a small body resembling an un- ripe seed. (Fig. 53.) It is, in fact, an ovary. Just above this there is a shoi-t bit of stalk, sur- mounted by a circle of silky hairs, and above this a yellow tube with one side greatly prolonged. This yellow tube is a coroUa, and a close examina- tion of the extremity of its long side wiU show pjl 53, the existence of five minute points, or teeth, from which we infer that the tube is made up of five coher- ent petals. As the corolla is on the ovary it is said to be Epifiynous. Out of the coi?olla protrudes the long style, divi- ded at its summit into two stigmas. To discern the stamens will require the greatest nicety of observation. Fig. 54 will help you in your task. The stamens are five in number. They are inserted on the tube of the corolla (epipetalous) and their anthers cohere (Fig. 55) and form a ring about the style. When the anthers are united Fig. 54. ill this way, the stamens are said to be syngenesiy- / 88 ELEMENTS OF STRUCTURAL BOTANY. 48. It appears, then, that the Dandelion, instead of being a single flower, is in reality a compound W of a great many flowers upon a common recep- 111 tacle, and what seemed at first to be a calyx is, in Fig. 55. reality, an involucre, made up of many bracts. But have the single flowers, or fiorets, as they are properly called, no calyx ? The theory is that they have one, but that it is adherent to the surface of the ovary, and that the tuft of silky hairs which we noticed is a prolongation of it. Now turn to your specimen having the seeds ready to blow away. The seeds are all single ; the little bit of stalk at the top has grown into a long slender thread, and the tuft of hairs has spread out like the rays of an umbrella (Fig. 5Q). But though the seeds are inva- riably single, it is inferred from the two- lobed stigma that there are two carpels. 49. Flowers constructed on the plan of the Dandelion are called composite flowers. A very large number of our common plants Fig. C6. have flowers of this kind. The May-weed, which abounds in waste places everywhere, the Thi^J^le^ and^ the Ox-Eye Daisy are examples. DANDELION. Organ. No. Cohesion. Adhesion. Remarks. Calyx. j Sepals. 5 Gamosepalous. Superior. The number of Pepals is iiiferred from analogy to be five. Corolla. VetaJs. 5 Gamopfctalou?. tpigynous. Stamens. ' Syngenesious. Epipetalous. PistU. Carpels. 2 Syncarpous. Inferior. Numberof car- 1 els inferred from -u.i:3«r of stigmas. ; ELEMENTS OF STRUCTURAL BOTANY. 39 50, Catnip. Note carefully the appearance of the stem. It is square. The flovv^ers are in axillary clusters. The calyx is a tube (Fig. 57) terminating in five sharp teeth, and you may observe that the tube is a' little longer on the up- per side (that is, the side toivards the stem) than on the lower. The corolla is some- what pecuHar. It has somewhat the ap- pearance of a wide open mouth, and is known as a labiate or two-lipped corolla. The upper lip is erect, and notched at the apex. The lower lip spreads outward, and ng. 57. consists of a large central lobe and two small lateral ones. Altogether, therefore, there are Jive lobes consti.- tuting the gamopetalous corolla. Pull out the corolla, and with the point of your needle split its tube in front. On laying it open, the stamens wiU be found to be in- serted upon it (epipetalous). They are four in number, two of them shorter than the other two. Hence they are described as didynamous. The anthers are peculiar in not having their lobes parallel (Fig. 58), these being wide apart at the base, in consequence of the expansion of the connective, the name given to that part of the anther which unites its two lobes or cells. The pistil consists of a two-lobed stigma, a long st^'le, and an ovary which seems at first as if made up of four distinct carpels (Fig. 59). But the single style and the two-lobed stigma will warn you against this supposition. The ovary really consists of tuo carpels, each of two deep lobes, and, as the seeds ripen, these lobes form four little. nutlets (Fig. 60), each contain- p^^ gg, iug a single seed. ELEMENTS OF STRUCTUKAL BOTANY. 51. The group of plants to which Catnip belongs is easily distinguished by the square stem, irregular corolla, and four stamens. CATNIP. X .'l- ■ -*< ' «y4?>rv^^ OROAK. NO. COHESION. AOHXSION. BEMAKKB, Calyx. 5 GamosepaloQs. Inferior. Coroila. F«tala. 5 Gamopetalous Hypogynous. Two-lipped. Tp- perlip of two. and lower of tlir©« lobea. Staxuenis. 4 I>idyiiamoiis. Epip«talons Lobes of anthexa not parallel. Pistil, * SynoarpoQS. Superior. CHAPTER Ym. EXAitlNATION OF PLANTS WITH MONCEGIOUS AND DICECIOUS PLOWEBS- :UCT.TrIBEii, WILLOW. 52. Cucumber, You can hardly have failed to notice that only a small proportion of the blossoms on a Cucumber rine produce cucumbers. A great many wither away and are apparently of no use. An atten- tive insp>ection will show that some of the blossoms ELEMENTS OF HTUUCTUnA.^ UOTANY. 41 yiu. ci. have oLlong fleHhy j)rotuber-,^ ances boneath them, whilHt if^^:--. otliors are dcbtituto of thcBO attacbmentH. Select a flower of each kind, and examine firyt the one with tlie protuberance (Fig. 01), which latter, from its appearance, you will prob- ably have rightly gucKHed to bo tljo ovary. The Hituation of the ovary here, indeed, is the same as in the Willow-herb. The calyx-tube adhercH to its surface, and is prolonged to some little distance above it, expanding finally into five teeth. The corolla is gamopetalons, and is adlierent to the calyx. Kemove now the calyx and the adherent corolla, and there is left in the centre of the flower a short column, terminating in three stigmas, each two- lobed. 2'here are no stamens. 5y. Now examine the other blossom (Fig. 02). /' Calyx and corolla have almost A^ exactly the same appearance as ^ ' before. Kemove them, and you have left three stamens grow- ing on the calyx-tube, and slightly united by their anthers Fig. 62. (syngenesious). There is no jdstil. You see now why some blossoms produce cucumbers, and others do not. Most of the blossoms have no pistil, and are termed Htaminate or sterile flowers, whilst the others are pisiillntc or fertile. Flowers in whicli 4-2 ELEMENTS OF STRUCTURAL BOTANY. either stamens or pistils are wanting are also called Itpj- perfect. When staminate and pistillate flowers grow on the same plant, as they do in the case of the Cucumber, they are said to be moncecious. 54. In plants of this kind the pollen of one kind of blossom is conveyed to the stigmas of the other kind, chiefly by insects, which visit the flowers indiscrimin- ately, in search of honey. The pollen dust clingfi to their hairy legs and bodies, and is presently rubbed off upon the stigma of some fertile flower. 55. In order to describe monoecious flowers, our schedule will requii*e a slight modification. As given below, the symbol f stands for " staminate flower," and the symbol J for " pistillate flower." J/-';C{r^'lA^ J CUCUMBER. ^ ^ ^-^^ ORGAN. NO. COHESION. ADHESION. REMAEKS. Calyx. Sepals. 5 Gamosepalous Superior. Corolla. Fetals. 5 Gamopetalous Perigynous. \ Stamens. 3 Syngenesious. Perigynous Two anthers are 2— celled, and one 1— celled. + Pistil. Carpels. o X Stamens. o I Pistil. Carpels. 3 Syncarpous. Inferior. ELEMENTS OF STRUCTURAL BOTANY. 48 Fig. 63. 66. Willow. The flowers of most kinds of Willow appear in spring or early summer, before the leaves. They grow from the axils in long close clusters called catkins or aments. Collect a few of these from the same tree or shrub. You will find them to be exactly ahke. If the first one you examine is covered with yellow stamens (Fig. 63), all the rest will likewise consist of sta- mens, and you will search in vain for any appearance of a pistil. If, on the other hand, one of your catkins is evidently destitute of stamens, and consists of oblong pis- .^A.i-A. tils (Fig. 64), then all the others will in like manner be found to be without stamens. Unlike our Cu- cumber plant, the stami nate and pistillate flowers of the WiDow are borne Fig. 64. on different x:)lants. These flowers are therefore said to be dicccious. As a general thing, staminatc and pistil- late catkins will be found upon trees not far apart. Procure one of each kind, and examine first the stami- nate one. You will probably find the stamens in pairs. Follow any pair or filaments down to their insertion, and observe that they spring from the axil of a minute bract (Fig. 65). These bracts are the sccdes of the catkin. There is no appearance of either calyx or corolla, and the flowers are therefore said to be achlamy- deouSf that is, without a covering. Now look Fig. 65 at the fertile catkin. Each pistil will, Hke 44 ELEMENTS OF STRUCTURAL BOTANY. the stamens, be found to spring from the axil of a scale (Fig. GQ). The stigma is two-lobed, and on carefully opening the ovary you observe that though there is but one cell, yet there are tico rous of seeds. We therefore infer that the pistil consists of two carpels. The pistillate flowers, like the staminate, are achlamydeous. In dioecious plants, the process of fertilization is assisted by insects, and also very largely j}y the wind. ^/^i^. /. ^-^ -^"^ ^^^^^^^ HEART-LEAVED WILLOW. ORGAK NO. COHESION. ADHESION. BEMARKS. Calyx. 0 Corolla. 0 f Stamens. 2 Diandrous. 0 + Pistil. 0 ' : Stamens. 0 : Pistil. Carpels. 2 Syncarpous. 0 ELEMENTS OF STRUCTURAL BOTANY. 45 CHAPTEE IX. CHARACTERISTICS POSSESSED IN COMMON BY ALL THE PLANTS PREVIOUSLY EXAMINED. STRUCTURE OF THE SEED IN DICOTYLEDONS. 57. Before proceeding further in our examination of plants, we shall direct your attention to some characters of those already examined, which they all possess in common. The leaves of every one of them are tiet- veined. Some leaves, at least, of each of them have dis- tinct petioles and blades.* The parts of the flowers we found, as a general thing, to be in Jives. In one or two instances they were in /ours, that is, four sepals, four petals, and so on. 58. Now, in addition to these resemblances there are others which do not so immediately strike the eye, but which, nevertheless, are just as constant. One of these is to be found in the structure of the embryo. Take a cucumber or pumpkin seed, and having soaked it for some time in water, remove the outer coat. The body of the seed will then readily split in two, except where the parts are joined at one end. (Figs. 67, 68, 69). The thick Fig. 67. Fig. 68. Fig. 69. lo^cs are Called cotyledons, or seed- leaves, and as there are two, the embryo is dicotyledonous. The pointed end, where the cotyledons are attached, and from which the root is developed, is called the radicle. Between the cotyledons, at the summit of the radicle, you will find a minute upward projection. This is a bud, which is known as the plurmde. It developes into the stem. 59. If you treat a pea or a bean (Figs. 70, 71), in the same manner as the cucumber seed, you will find it to be \l 46 ELEMENTS OF STRUCT LTwAL BOTANY. ^^^* ''^' constructed on the same plan. The em- bryo of the bean is dicotyledonous also. But you will observe that in these cases the embryo occupies the whole of the inte- rior of the seed. In describing the seed of the Buttercup, it was pointed out that the embryo occupies but a very small space in the seed, the bulk of the lat- ter consisting of albumen. Seeds like those of the But- tercup are therefore called albuminous seeds, while thoseof the Bean and Pea are exalbuminous. But, notwithstand- ing this difference in the structure of the seed, the embryo of the Buttercup, when examined under a strong magnifier, is found to be dicotyledonous like the others. In shoit, the dicotyledonous embryo is a character common to all the plants we have examined — common, as a rule, to all i^lants possessing the other characters enumerated above. From the general constancy of all these char- acters, plants possessing them are grouped together in a vast Class, called Dicotyledonous plants, or, shortly, Dicotyledons. 60. Besides the characters just mentioned, there is still another one of great importance, which Dicotyle- dons possesses in common. It is the manner of growth of the stem. In' the Willow, and all our trees and shrubs without exception, there is an outer layer of bark on the stem, and the stem increases in thickness, year by year, by forming a new layer just inside the bark and outside tJie old wood. These stems are therefore called exogenous, that is, outside groicers. Now, in all dicotyledonous plants, whether herbs, shrubs or trees, the stem thickens in this manner, so that Dicotyledons are also Exogens. ELEMENTS OF STRUCTURAL BOTANY. 47 CHAPTER X. EXAIMINATION OF COMINION PLANTS CONTINUED. DOG's-TOOTH VIOLET, TRILLIUM, INDIAN TURNIP, CALLA, ORCHIS, TIMOTHY. 61. Dog's-tooth Vi let. This plant (Fig. 72)wliich tlowers in Spring, may be pretty easily recognised by Fig. 72. its peculiar blotched leaves. It may be found in rich 48 ELEMENTS OF STRUCTURAL BOTANY. moist pasture lands and low copses. The name "Violet" is somewhat unfortunate, because the plant is not in any way related to the true Violets. To obtain a com- plete specimen requires some trouble, owing to the fact that the root is commonly six inches or so below the surface of the ground'; you must therefore insert a spade or strong trowel sufficiently deep to avoid cutting or breaking the tender stem. Having cleared away the adhering earth, you will find that the roots proceed from what appears to be the swollen end ol the stem. This swollen mass is coated on the outside with thin scales. A section across the middle shows it to be more or less solid, -with the stem growing up through it from its base. It'is, in fact, not easy^to say how much of this stem-like growth is, in reality, stem, because it merges gradually into the scape, which bears the flower, and the petioles of the leaves, which sheathe the scape. The swollen mass is called a bulb. 62. The leaves are two in number, gradually narrow- ing at the base into sheaths. If you hold one of them up to the light, you will observe that the veins do not, as in the leaves of the Dicotyledonous plants, form a network, but run only in one direction, namely, from end to end of the leaves. Such leaves are consequently called straight -veined. 63. In the flower there is no appearance of a green calyx. There are six yellow leaves, nearly aUke, ar- ranged in two sets, an outer and an inner, of three each. In such cases, we shall speak of the colored leaves collectively as the perianth. If the leaves are free from each other, we shall speak of the perianth as poly- phyllous, but if they cohere we shall describe it as cfatfw- ELEMENTS OF STRUCTURAL BOTANY. 49 Fig. 73. phijllom. Stripping off the leaves of the perianth we find six stamens, with long upright anthers which open along their outer edges. If the anthers be pulled off, the filaments will be found to terminate in long sharp points. The pistil (Fig. 73) has its three parts, ovary, style, and stigma, well marked. The stigma is evidently formed by the union of three into one. The ovary, when cut across. Fig. 74. is seen to be three-celled (Fig. 74), and is therefore syncarpous. X ^^ ^^ DOG'S-TOO'BH VIOLET. ORGAN. NO. COHESION. ADHESION. BEMAEK8. Perianth. Leaves. 6 Polyphyllous. Inferior. Btamens. 6 HexandrouB. Hypogynous. Filaments ter- minating in sharp points. PiBtU. CarpeU. 3 Syncarpous. Superior. 64. Trillium. This plant (Fig. 7o) may be found in flower about the same time as the one just described. The perianth of Trillium consists of six pieces in two sets, but in this case the three outer leaves are green, like a common calyx. The stamens are six in num- ber. There are three styles, curving outwards, the whole of the inner side of each being stigmatic^ 50 ELEMENTS OF STRUCTUKAL BOTANY. The ovary (Fig. 76) is six- angled, and on being cut across is seen to be three- celled. 65. Comparing this flower with that of Dog's-tooth Vio- let, we find the two to exhi- bit a striking resemblance in structure. But in one respect the plants are strikingly un- like : the leaves of the Trillium are net-veined (Fig. 77), as in the Exogens. From this cir- cumstance we learn that we cannot altogether rely on the veining of the leaves as a con- stant characteristic of plants whose parts are not in fi^ves Fig. 75. LIUM. . ^ OEGAN. NO. COHESION. ADHESION. REMAEKS. Perianth. Sepals. Petals. 3 3 Polyphyllous. Inferior Sepals persist- ent. Stamens. 6 Hexandrous. Hypogynous. Pist'l. Carpels. 3 Syncarpous. Superior. The inner facf of eac style stigmatic. Leaves net-veined. ELEMENTS OF STRUCTURAL BOTA^•Y. 51 \ 66. Indian Turnip. This plant may be easily met with in our woods in early summer. If you are not familiar with its appearance, the annexed cut (Fig. 78) Fig. 78. will help you to recognise it. Procure several speci- mens ; these will probably at first seem to you to be ahke in every respect, but out of a number, some are pretty sure to differ from the rest. Notice the bulb from which the stem springs. It diffeis from that of the Dog's-tooth Violet, and Lilies generally, in being a solid mass. It is called a corm. Between tlie pair of 52" ELEMENTS OF STRUCTURAL BOTANY. Fig. 79. leaves j^ou ooserve a curious strip- ed sheath, having an arching, hood-hke top, and enclosing an up- right stalk, the top of which almost touches the hood (Fig. 79). Can this be a flower ? It is certainly ijijl the only thing about the plant ' ml which at all resembles a flower, ''"' and yet how different it is from any we have hitherto examined ! Care- fully cut away the sheaths from all your specimens. Most, and per- haps all, of them will then present an appearance like that in Fig. 80. If none of them be hke Fig. 81, it will be well to gather a few more plants. We shall sup- pose, however, that you have been fortunate in obtain- ing both kinds, and will proceed with our examination. Take first a specimen cor- responding with Fig. 80. Around the base of the column are compa<;tly arrang- ed many spherical green bodies, e^ch tipped with a little point. Separate one of these from the rest, and cut it across. It will be found to contain several ovulee, and is, in fact, an ovary, the point at the top being a stigma. In the autumn, a great change will have taken place in the appearance of plants like the one we are now examining. The arched hood will have disappear- ed, as also the long naked top of the column, whilst the part below, upon which we are now engaged, will have Fig. 80. Fig. 81 NTS OP STRUCTURAL BOTANY. '63 vastly increased in size, and become a compact ball of red berries. There can be no doubt, then, that we have here a structure analo'gous to that found in the Cucum- ber and the Willow, the fertile, or pistillate, flowers being clustered together separately. But in the Cucum- ber all the flowers were observed to be furnished with calyx and corolla, and in the Willow catkins, though floral envelopes were absent, each pair of stamens and each pistil was subtended by a bract. In the present plant there are no floral envelopes, nor does each pistil arise from a separate bract. 67. But, you will now ask, what is this sheathing hood which we find wrapped about our column of pistils ? There is no doubt that we must look upon it as a bract, because from its base the flower-cluster springs. So that, whilst the flowers of Indian-Turnip are, like those of Willow, imperfect and dioecious, the clusters differ in having but a single bract instead of a bract under each flower. 68. We must now examine one of the other speci- mens ; and we shall have no difficulty in determining the nature of the bodies which, in this case, cover the base of the column. They are evidently stamens, and your magnifying- glass will show you that they consist mostly of anthers, the filaments being extremely short, and that some of the anthers are two-celled, and some four-celled, all discharging their pollen through little holes at the top of the cells. 69. The column upon which, in plants like Indian- Turnip, the flowers are crowded, is known as a spadix, and the surrounding bract as a spathe. You will observe that the leaves of this plant are net- veined, as we found them in the Trillium. 64 ELEMENTS OF STRUCTUKAI. BOTA.NV. INDIAN-TUR^sIP L liOTA.NV. ,- , OB3AN. NO. COHESION. ADHESION. + Stamens. \ 1 1 ! Monandrous. i 0 1 i tP.stil. Car^oU. i 1 Apocarpous. 0 ■i 1 Flowers crowded o i a spadix, and surrounded by a spathe. Laaves net- veined. ^ 70. Marsh Calla. This plant must be looked for in low marshy grounds, where it will be found in flower generally in the month of June. With the knowledge which you have of the structure of Indian-Turnip, you will hardly doubt that the Calla is closely related to it. You will easily recognize the spadix and the spathe (Fig. 82), though in the present instance the sTDadix Fig ^ Pig. S3. ELEMENTS OF STRUCTURAL BOTANY. 55 bears flowers to the ^op, ana aie spatbe is open instead of enclosing the column. Observe, however, that the veining of the leaf (Fig. 83) is different, that of Calla being straight, like the Dog's-tooth Violet. There is also a difference in the flowers. Those of Indian-Tur- nip were found to be dioecious, but the spadix, in the present case, bears both stamens and pistils, and the lower flowers, if not all, are perfect ; some- times the upper ones consist of stamens only. Fig. 84 shows one of the perfect i'| flowers much enlarged. The stamens, it will be observed, have two-celled anthers, opening lengthwise. MARSH CALLA. Fig. 84. iy/L^^? the name glumes is ajipUed. They are present i'l all ELEMENTS OF STRUCTURAL BOTANY. 59 plants of the Grass Family, and are often found enclos- ing several flowers instead of one as in Timothy. Inside the glumes will be found a second pair of minute chaff-like bracts, which are known as palets ov pales. These enclose the flower proper. 76. The stamens are three in number, with the antliers fixed by the middle to the long slender filament. The anthers are therefore versatile. The styles are two in number, bearing long feathery stigmas. The ovary contains a single ovule, and when ripe forms a seed- like ^rca"^, technically known as a canjopsis. A^1^a[^<^^ rt i/^^ Jg^THY. \ ORGAN. i ^°- /pbHESION. ADHESION. Glumes. 2 1 1 i Palets. 2 1 - Stamens. i 3 1 Triandrous. Hypogynous. PistU. 1 Carpel". ! 1 Apocarpous. Superior. CHAPTER XI. COMMON CHARACTERISTICS OF THE PLANTS JUST EXAMINED. STRUCTURE OF THE SEED IN MONOCOTYLEDONS. 77. It is now to be pointed out that the six plants last examined, viz., Dog's-tooth Violet, Trillium, Indian Turnip, Calla, Orchis, and Timothy, though differing in various particulars, yet have some char*'- 60 ELEMENTS OF STRUCTUR.\L BOTANY. ters common to all of them, just as the group endmg with Willow was found to be marked by characters possessed by all its members. The flowers of Dicoty- ledons were found to have their parts, as a rule, in fours or fives ; those of our second group have them in threes or sixes, never in fives. 78. Again, the leaves of these plants are straight- veined, except in TriUium and Indian-Turnip, which must be regarded as exceptional, and they do not as a rule exhibit the division into petiole and blade which was found to characterize the Exogens. 79. We shall now compare the structure of a grain of Indian Corn with that of the Cucumber or Pumpkin seed which we have already examined (page 45). It will facilitate our task if we select a grain from an car which has been boiled. And first of all, let us observe that the grain consists of something more than the seed. The grain is very much like the achene of the Buttercup, but differs in this respect, that the outer covering of the former is completely united with the seed-coat underneath it, whilst in the latter the true seed easily separates from its covering. Remove the coats of the grain, and what is left is a whitish starchy- looking substance, having a yellowish body inserted in a hollow (Fig. 90) in the middle of one side. This latter body is the embryo, and may be easily removed. All the rest is albumen. Fig. 91 is a front view of the .^'■~~^ ^ embryo, and Fig. 92 shows a vertical fc\ / /m K ^^^^^^^ ^^ *^® same. The greater part Vj / tj' ) h of the embryo consists of a simjte cotijle- ^ ^)J don. The radicle is seen near the base, Kj.90. rig. 91 Pic. 92. and the plumule above. 80. Comparing the result of our observations with ELEMENTS OF STBUCTURAIi BOTANY. 61 what we have already learned about the Cucumber seed, we find that whilst in the latter there are avo cotyledons, in the present case there is but ?ne, and this peculiarity is common to all the plants just exam- ined, and to a vast number of others besides, which are consequently designated Monoc tyledonous plants, or shortly Monocotyledons, The seeds of this great Class may differ as to the presence or absence of albu- men, just as the seeds of Dicotyledons do, but in the number of their cotyledons they are all alike. The Orchids, however, are very peculiar from having no cotyledons at all. 81. In addition to the points just mentioned, viz : the number of floral leaves, the veining of the foliage leaves, the usual absence of distinct petioles, and the single cotyledon, which characterize our second great Class, there is still another, as constant as any of these, and that is, the mode of growtli of the stem, which is quite at variance with that exhibited in Dicotyledonous plants. In the present group the increase ia the thickness of the stem is accomplished not by the deposition of circle after circle of new wood outside the old, but by the production of new wood-fibres through the interior of the stem generally, and the consequent swelling of the stem as a whole. These stems are therefore said to be endogenous, and the plants com- posing the group are called Endogens, as well as Monocotyledons. We shall explain more fully the structure of exogen- ous and endogenous stems, wl.en we come to speak of the minute structure of plants in a subsequent chapter. 62 ELEMENTS OF STRUCTURAL BOTAJJY CHAPTER XII. MORPHOLOGY OF ROOTS, STEMS, AND FOLIAGE -LEAVES. 82. From what has gone before, you should now be tolerably familiar with the names of the different organs of plants, and you have also had your attention directed to some modifications of those organs as they occur in different plants. In all these cases, the adjective terms, which botanists use to distinguish the variations in the form of the organs, have been placed before you, and if you have committed these carefully to memory, you will have laid a good foundation for the lessons which foUow on Morphology, the name given to the study of the various forms assumed by the same organ in different plants, or in different parts of the same plant. In some instances, the terms employed, being derived from Latin and Greek, and specially devised for botanical purposes, may seem difficult to learn. We believe, however, that this difficulty will be found to be more apparent than real. You will be surprised at the ease with which the terms will occur to your mind if you learn them with the help of plants which are every- where within your reach — if you be not satisfied with being mere book-botanists With a good tnany terms you will find no difficulty whatever, since they will be found to have the same meaning in their botanical applications as they have in their everyday use. ELEMENTS OF STRUCTURAL E' TANY. 63 83. The Root. This organ is called the descending axis of the plant, from its tendency to grow downward into the soil from the very commencement af its devel- opement. Its chief use is to imbibfe liquid nourishment, and transmit it to the stem. You will remember that in our examination of some common seeds, such as those of the Pumpkin and Bean (Figs. 67-71), we found at the junction of tlie cotyledons a small pointed pro- jection called the radicle. Now, when such a seed is put into the ground, under favourable circumstances oi warmth and moisture, it begins to grow, or germinate, and the radicle, which in reahty is a minute stem, not only lengthens, in most cases, so as to push the cotyle- dons upwards, but developes a root from its lower ex- tremity. All seeds, in short, when they germinate, l)roduce roots from the extremity of the radicle, an4 loots so j)roduced are called primnrij roots. 84. There are two well-marked ways in which a pn mary root may develop^ itself. It may, by the down' ward elongation of the radicle, assume the form of » distinct central axis, from the sides of which branches or fibres are given off, or root-fibres may spring in a cluster from the end of the radicle at the very l/^ commencement of growth. If the root grow iy in the first way, it will be a tap-root (Fig. 93), /" ,( examples of which are furnished by the Car- rot, the Mallow, and the Bean ; if in the sec- ond way, it will be a fibrous root, examples of which are furnished by the Buttercup (Fig. 1) . and by the entire class of Mouocotyledcnous ' or Endogenous plants. 86. Tap-roots receive different names, ac- 64 f.LEMENTS OF STRUCTURAL BOTANY. Fig. W. cording to the particular shape they hap- pen to assume. Thus, the Carrot (Fig. 94) is conical, because from a broad top it tapers gradually and regularly to a point. The Eadish, being somewhat thicker at the middle than at either end, is spindle-shaped. The Turnip, and roots of similar shape, are napi. form {napus, a turnip). These fleshy tap-roots belong, as a rule, to bi- ennial plants, and are designed as storehouses of food for the plant's use during its second year'sgrowth. Occasion- ally fibrous roots also thicken in the same manner, as in the Peony, and then they are said to he fascicled or clustered. (Fig 95) 86. But you must have observed that plants somg^- times put foith roots m addition to those develop- ed from the end of the radicle. The Y.rb:na of Pi, 93 of our gardecs, for ex- Fig. 9ft. / ent as it were at second-hand. These are jmrasitic plants. The Dodder, Indian-Pipe, and Beech-drops, of Canadian woods, are well-known examples. 88. The Stem. As the root is developed from the lower end of the radicle of the embryo, so the stem is developed from the upper end, but with this important difference, that a bud always precedes the formation of the stem, or any part of it or its branches. Between the cotyledons of the Bean (Fig. 71), at the top of the radicle, we found a minute bud called the jAumule. Out of this bud the first bit of stem is developed, and duricg the subsequent growth of the plant, wherever a branch is to be formed, or a main stem to bo prolonged, there a bud will invariably be found. The branch buds are always in the axils of leaves, and so are called axillary. Adientitious buds, however, are sometimes produced in plants like the Willow, particularly if the 66 elfmEnts cf structural botany. Etem has been wounded. The bud from which the main stem is developed, or a branch continued, is of course at the end of the stem or branch, and so is ^enr.inal. 89. If you examine a few stems of plants at random, you will probably find some of them quite soft and easily compressible, while others will be firm, and will resist compression. The stem of a Beech or a Currant IS an instance of the latter kind, and any weed will serve to illustrate the former. The Beech and the Currant have woody stems, while the weeds are herde ceous. Between the Beech and the Currant the chief difference is in size. The Beech is a tree, the Currant a shruh. But you are not to suppose that there is a hard, and fast line between shrubs and trees, or between herbs and shrubs. A series of plants could be constructed, commencing with an unquestionable herb, and end- ing with an unquestionable tree, but embracing plants exhibiting such a gradual transition from herbs to shrubs, a id from shrubs to trees, that you could not say at what precise point in the series the changes occurred. 90. The forms assumed by stems above ground ai-e numerous, and they are described mostly by terms in common use. For instance, if a stem ■ is weak, and trails along the ground, it is trailing, or prostrate ; and if, as in the run- ners of the Straw- berry, it takes root on the loweiv side, then it is creeping. Many weak stems raise Fig. 97. ELEMENTS OF STRUCTURAL BOTANY. 67 themselves by clinging to any suppoil that may happen to be within their reaili. In some instances tlie stem itself winds round the support, assummg a spiral form, as in the Morning- Glory, the Hop, and the Bean, and is therefore distinguished as tinning. In other cases the stem puts forth thre-ad-Uke leafless branches callpd tendrils (Fig. 97), wJiich grasp the support, as in the Virginia Creeper, the Grape, and the Pea (Fig. 98), or sometimes the leaf-stalks serve the same purpose, as in the Clematis or Virgin's Bower. In these cases the stems are said to climb. The stems of wheat and grasses generally are known as cubns. They are jointed, and usually hollow except at the joints. • Fig. 98. 91. Besides the stems which grow above ground, there rig. 99. are varieties to be found below the surface. Pull up a ELEMENTS OF STRUCTURAL BOTANY. Potato plant, and examine the underground portion (Fig dd). It is not improbable that you will regard the whole as a mass of roots, but a very httle trouble wih undeceive you. Many of the fibres are unaues- ticnably roots, but an inspection of those having pota- toes at the ends of them will show you that they are quite different from those which have not. The former wil; be found to be furnished with little scales, answer- ing to leaves, each with a minute bui in the axil ; and the potatoes them- selves exhibit buds of the same kind. The potato, in short, is only Hit swollen end of en itriderfjround .ueni Such swollen ex- tremities are known as tubers, whilst the Fig. ICO. underground stem is called a rootstock, or rhizome, and may always be distinguished from a true root by the presence oi buds. The Solomon's Seal and Tcothwort of Canadian woods, and the Canada Thistle, are com- mon instances of plants producing these stems. Fig. 100 shows a rhizome. 92. Take now an Onion, and compare it with a Potato. Yon will not find any such outside appear- ances upon the f 3i*mer as are presented by the latter. The Onion is smooth, and has no buds upon its surface. From the under side there spring roots, and this cir- cumstance will probably suggest that the Onion must be a stem of some sort. Cut the Onion through from top to bottom (Fig. 101). It will then be seen to be r ELEMENTS OF STEUCTUEAL BOTANY. 69 F:g L maae up of a number of coats. Strip off one or two, and observe that whilst they are somewhat fleshy where the onion is broadest they gradually become thinner to- wards the top. The long green tubes, which project from the top of the Onion during its growth, are, in fact, the prolongations of these coats. But the tubes are the leaves of the plant. The mass of our Onion,* therefore, con- sists of the flesh]) bases of the leaves. But you will observe that at the bottom there is a rather flat solid part upon which these coats or leaves are inserted, and which must consequent- ly be a stem. Such a stem as this, with its fleshy leaves, is called a hu^'}. If the leaves form coats, as in the Onion, the bulb is coated or tunicated ; if they do not, as in the lilies (Fig. 102), it is scaly. 93. Tubers and bulbs, then, consist chiefly of masses of nourishing matter ; but there is this difference, that, in the latter, the nourishment is contained in the fleshy leaves themselves, whilst, in the former, it forms a mass more or less distinct from the buds. 94. The thickened mass at the base of the stem of our lu^ian Turnip (Fig. 78) is more like a tuber than Pj bulb in its construction. It is called a conn, or solid bulb. The Crocus and Gladiolus of the gardens are other examples. 95. In the axils of the leaves of the Tiger Lily are produced small, black, rounded bodies, which, on exami. nation, prove to be of bulbous structure. They arc, in -g. If 2 70 ELEMENTS Of bTKUCTL KAL BUTAA'\% fact, hulblets, aud new plants may be grown from them. 96. Oar Hawthorn is rendered formidable by the presence of stout spines (Fig. 103) along the stem and branches. These spines invariably proceed from the axik of leaves, and are, in fact, branches, whose growth has been arrested. They are appendages of the wood, and will remain attached to the stem, ' ^ig. i03. even after the bark is stripped off. They must not be confounded with the lyrickles (Fig. 104) of the Rose and Brier, which belong strictly to the bark, and come off with it. 97. Foliage-Leaves. These organs arc usually more or less flat, and of a green colour. In some plants, however, they are extremely thick and succulent ; and in the case of para- sites, such as Indian-Pipe and Beech-drops, ig. 104. ^j^gy ^^g usually either white or brown, or of some colour other than green. The scaly leaves of underground stems are also, of course, destitute of colour. 98. As a general thing, leaves are extended horizon- tally from the stem or branch, and turn one side towards the sky and the other towards the ground. But some leaves are vertical, and in the case of the common Iris each leaf is doubled lengthwise at the base, and sits astride the next one within. Such leaves are accordingly called equitant. 90. As to their arrangement on the stem, loaves are alternate when only one arises from each node (I'ig. 3). If two are formed at each node, they are sure to be ELEMENTS OF STRUCTURAl. BOTAN\ 71 on opposite sides of the stem, and so are described as opposite. Sometimes thero cxe several leaves at the same node, in which case they are wlwrled or ve^ticilkac (Fig. 105). 100. Forms of Foliage-Ler.veSc Leaves present an almost endloss va- riety in their forms, and accuracy in Fig. 105. describing any given leaf depends a good deal upon the ingenuity of the student in selecting ani combining terms. The chief terms in use will be given here. Compare a leaf of the Round-leaved MalloT,- vzith one of Red Clover (Figs. 106, 107). Each of them iz fur- Fig. IOC. Fig. 107. nisbed with a long petiole and a pair of stipules. In the blades, however, there is a difference. The blada oi the i-ormer consists of a sinr/le piece ; that ol the latter- la in three separate pieces, each of which is called a Iccficl- bul all Ox which, taken collectively, constitute the blaJc ^2 ELEMENTS OF STRUCTURAX, BOTANY. of the leaf. The leaf of the Mallow is simple ; that of ths Clover is compound. Between the simple and the compound form there xs every possible shade of iradation. In the Mallow ieaf the lobes are not very clearly defined. In the Maple (Fig. 108) they are well-marked. In other cases, again, the lobes are so nearly separate, that the leaves appear at first sight to be really compound. 101. You will remember that in our examinations of dicotyledonous plants, we found the leaves to be in- variably net-veined. But, though they have this gener- al character iu common, they difier considerably in the details of their veiniug, or venation, as it is called. The two leaves employed as illustrations in the last section will serve to illustrate our meaning here. In the Mallow, there are several ribs of about the same size, radiating from the end of the petiole, something like the s^Dread-out fingers of a hand. The veining in this case is therefore described as digitate, or radiate, or palmate. The leaflet of the clover, on the other hand, is divided exactly in the middle by a single rib (the midiib), and from this the veins are given off on each side, so that the veining, on the whole, presents the appeai'ance of a feather, and is therefore described as pinnate [penna, a feather). 102. Both simple and compound leaves exhibit these two modes of venation. Of simple pinnately-veined J)^^ ELEMENTS OF STRUCTURAL BOTANY. 73 leaves, the Beech, Mullein, and "Willow supply familiar instances. The Mallow, Maple, Grape, Currant, and Gooseberry have simple radiate-veined leaves. Sweet-Brier (Fig. 43), Mountain Ash, and Rose have compound pinnate leaves, whilst those of Virginia-Creeper (Fig. 109), ig. 109. Horse-Chestnut, and Ilemp are compound digitate. As has already been pointed out, the leaves oi Mon" cotyledonous plants are almost invariably straigi. veined. 103. In addition to the venation, the description )f a simple leaf includes particulars concerning. (Ij the general outline, (2) the edge or margin, (3^ the point or apex, (4) the base 104. Outline. As to outline, it will be convenient to consider first the forms assumed by leaves without lobes, and whose margins are therefore more or less continuous. Such leaves are of three sorts, viz : those in which both ends of the leaf are alike, those in which the apex is narrower than the base, and those in which the apex is broader than the base. 105. In the first of these three classes, it is evident that any variation in the outline will depend altogether on the relation between the length and the breadth of the leaf. When the leaf is extremely narrow in com- parison wilh its length, as in the Pine, it is azirSLar or needle-shaped (Fig. 110). As the width increases, we pass through the forms known as linear^ ohhvg, cval, and finally orbicular ^ in which the width and length are nearly, or quite equal (Fig. 111). 74 ELEMENTS OF STRUCTURAL BOTANY. Fig. 110 Fig. 111. 106. In the second class the different forms aiise jTom the varying width of the base of the leaf, and we thus have subulate or aul-shaped (Fig. 112), lanceolate, ovatej and deltoid leaves (Fig. 113). Lanceolatf Ovate I - DeltoU Fig. 112. Fig. 113. 107. In the third class, as the apex expands, wehav Fie. U7. F-ig. 118. Fifz. 114. Fig. 115. Fig. 116. ELEMENTS OF STRUCTURAL BOTANY. 7o the forms spathulate (Fig. 114), ohlanceolate (that is, the reverse of lanceolate) (Fig. 115), emd obovate {Fig. 116). 108. lu leaves of the second kind we frequently find the base indented, and then the leaf is cordate, or heart-shaped (Fig. 117;, The reverse of this, that is, when the indentation is at the apex, is obcor- date (Fig. 118). The hastate, or spear- shaped (Fig. 119), sagittate, or arrow- shaped (Fig. 120), and renifonn, ox Licney-shaped (Fig. 121), forms are Fig. 119. modifications of the second class, Fig. 120. Fig. 121. Fig. 122. and will be readily understood from the annexed figures. If the petiole is attached to any part of the under surface of the leaf, instead of to the edge, the leaf is peltate (shield- shaped) (Fig. 123). 109. Leaves which are lo^ed are usually described by stating whether Fig. 123. they are palmately or pinnately veined, and, if the former, the number of lobes is gentJiaUy 76 ELEMENTS OF STRUCTURAL BOTANT. given. K the leaves are very deeply cut, they are said to be palmatijid or pinnati/id according to the veining (Fig. 124) . If the leaf is palmately lobed, and the lobes at the base are themselves lobed, the leaf is pedate (Fig. 125), be- cause it looks something like a bird's foot. If the lobes of a pinnatifid leaf are themselves lobed, the leaf is hijnmia- tifid. If the leaf is cut up into fine segments, as in Dicentra, it is said to be multifid. 110. Apex. The principal forms of the apex are the mucronate (Fig. 122), when the leaf is tipped with a sharp Fig. 124. point, as though the midrib were projecting beyond the blade ; cuspidate, when the leaf ends abruptly in a very short, but distinctly tapering, point (Fig. 126) ; acute, or sharp; and obtuse, or blunt. 111. It may happen that the point of any kind. If Fig. 125. apex does not end in it looks as though the end had been cut off / square, it is truncate. If the end is slightly f notched, but not sufficiently so to warrant the description obcordate, it is emaryinate. Fig. 126. 112. Margin. If the margin is not indented in any way, it is said to be entire. If it has sharp teeth, jjoint- ing in the direction cf the apex, it is serrate, and will be coarsely or finely serrate, according to the size of the ELEMENTS OF STRUCTURAL BOTANY. 77 Fig. 127. Fig. 128 teeth. Sometimes the edges of Icjrge teeth are themselves finely serrated, and in that case the leaf is doubly sen-ate (Fig. 127). If the teeth point outicards, that is, if the two edges of each tooth are of the same length, the leaf is dentate, but if the teeth, instead of being sharp, are rounded^ the leaf is crenate (Fig. 1 28) . The term wavy explains itself. 113. Base. There are two or three peculiar modifications of the bases of simple sessile leaves which are of considerable importance in distinguishing plants. Sometimes a pair of lobes project backwards and cohere on the other side of the stem, so that the stem appears to pass through the leaf. This is the case in our common Bellwort, the leaves of which are accordingly described as perfoliate (Fig. 129). Sometimes two opposite sessile leaves grow together at the base, and clasp the stem, as in the upper leaves of Honeysuckle, in the Triosteum, and in one of our species of Eupatorium. Such leaves are said to be connate or con- nate-perfoliate (Fig. 130). In one of our Everlastings the margin of the leaf is con- tinued on each side below the Fig. 120. Fig. 130. Fig. 13L point of insertion, and thp lobes grow fast to the sides 78 «l-:i3Sn^c of stuuctur^vl. botany. oT llie stem, giving rise to what is called the decurrent form (Fig. 131). The terms by which simple leaves are described are applicable also to the leaflets of compound leaves, to the copals and petals of flowers, and, in short, to any flat forms. Fig. 132. 114. We have already explained that compound leaves aie of two forms, pinnate and iDolmate. In the former, the leaflets are arranged on each £,ide o the midrib. There may be a leaflet at the end, in which case the leaf is odd-pinnate, or the terminal leaflet may be wanting, and then the leaf is '' -'ifpthj pinnate. In the Pea, the ic pinnate and terminates in a ■j.idril (Fig. 98). Very frequently the primary divisions of a pinnate leaf are themselves pinnate, and the whole leaf is then tiv ice-pinnate (Fi^o 132). If the subdivision is continued through another stage, '^:^^^ the leaf is t-lirice- pinnate, and so on. Sometimes, as in the leaves of the Tomato, very small leaflets are found between the Ic^rger ones, and this form is described as inierriipt- '^dhj pinnate (Fig. 183V Fig. 133, ELEMENTS OF '^TRUCTXIR.'lL BOTANY. 7D In the palmate or digitate forms, the leaflets spread out from the end of the petiole, and, in desciibing them, it is usual to mention the number of divisions. If there are three, the leaf is tri-foUolate ; if there are five, it is qidnquefoliolate. 115. In the examination of the Mallow, we found a couple of small leaf-like attachments on the petiole of each leaf, just at the junction with the stem. To these the name stipules was given. Leaves which have not these appendages are exstipulatc, 116. Besides the characters of leaves mentioned above, there remain a few others to be noticed. With regard to theii' surface, leaves present every gradation from perfect smoothness, as in Wintergreen, to extreme roughness or woolliness, as in the Mullein. If hairs are entirely absent, the leaf is glahruus ; if present, the degree of hairiness is described by an appropriate ad- verb ; if the leaf is completely covered, it is villous or villose ; and if the hairs are on the margin onlv, as in )ur Clintonia, it is ciliate. Some leaves, like those of Cabbage, have a kind of bloom on the surface, which may be rubber otf with the fingers ; this condition is described as glaucous. 117. A few plants have anoma- lous leaves. Those of the Onion are filiform. The Pitcher ll::jit of our Northern swamps has very curious leaves (Fig. 134), appar- ently formed by the turning in and cohesion of the outer edges of r^n ordinary leaf, so as to form a tube, closoc. except at the top, and armed 80 ele: ENTS OF ^TRUCTURAI. BOTANY. on the inner surface with bristles pointing towards the base of the leaf. 118. Finally, as leaves present an almost infinite variety in their forms, it will often be necessary, in de- scribing them, to combine the terms explained above. For instance, a leaf may not be exactly linec^r, nor ex- actly lance-shaped, but may approximate to both forms. In such a case the leaf is described as lance-linear^ and so with other forms. The following form of schedule may be used with advantage in writing out descriptions of leaves. Two leaves — one of Maple and one of Sweet-Brier — are described by way of illustration. If a leaf is compound, the particulars as to outhnc, margin, apex, base, and surface will have reference to the leaflets. LEAF SCHEDULE. LiEA"^ or .. .. Maple. Sweet-Beiee. 1. rosition. Cau'.inc. Cauline. 2. Arranscracnt. Opposite. Alternate. 3. Insertion. Petiolate. Petiolate. 4. Gtipulation. Exstipulate. Stipulate. 5. Division. Simple. Odd pinnate, 7 leaflctfe. 6. Venation, Palmate. 7. Outline. Poundish or oval. 8. Margin. Deeply lobed. Doubly serrate. ELEMENTS OF STRUCTURAL BOTANY. 81 9. Apes. Pointed. i Acute. 10. Ease. Cordate. Hardly indented, ^ f 11. Curface. i Glabrous above ; whitish Downy nbovc ; covered avIlIi glunds bcneixtii. CHAPTER XIII. MORPHOLOGY OF FLOWER-LEAVES. THE CALYX. THE CO- ROLLA. THE STAI.IEKS. THE PISTIL. THE FRUIT. THE SEED. GERMINATION. 119. From an examination of the various forms pre- sented by foliage leaves, we proceed now to those of the floral ones, and we shall first consider the chief modifications in the arrangement of fiowers as a ulwle, to which the term inflorescence is apphed. 120. It is found that inflorescence proceeds upon two yrell-define;! plans. To understand these, let us recur to our specimens of Shepherd's- L^urse and Buttercup. You will remember that, in the former, the peduncle continues to lengthen as long as the summer lasts, and" new flowers continue to be produced at the upper end. Observe, however, that every one of the flowers is produced in the axil of a hract, that as the stem lengthens new bracts appear, and that there is no flower on the end of the stem. You will easily understand then, that the production of flovv'ers in such a plant is only hmited by the close of the season or by the exhaus- tion of the plant. Such inflorescence is therefore called indefinite or indeterminate, or axill:^ry. It is sometimes also called centripetal, because if the flowers happen to be in a close cluster, as are the upper d2 ELEMENTS OF STKUCTURAL BOTANY. oneo in Shepherd's-Pnrse, the order of developement is from the outside towards the centre. 121. If you now look at your Buttercup, you will be at once struck with the difference of plan exhibited. The main axis or stem has a flower on the end of it, and its further growth is therefore checked. And so in like manner, from the top downwards, the growth of the branches is checked by the production of flowers at their extremities. The mode of inflorescence here displayed is definite, or determinate, or terminal. It is also called centrifugal, because the developement of the flowers is the reverse of that exhibited in the first mode. The upper, or, in the case of close clusters, the central flowers open first. In either mode, if there is but one flower in each axil, or but one flower at the end of each branch, the flowers are said to be solitary. 122. Of indeterminate inflorescence there are several varieties. In Shepherd' s-Purse we have an instance of the race^ne, which may be described ac ' cluster in which each flower springs from an axil, anc. IS supported on a pedicel of its own. If the pedicels are absent, and the flowers consequently sessile in the axils, the cluster becomes a spike, of which the common Plantain and the Mullein fiirnish good examples. The catkins of the Willow (Figs. 63, 64) and Birch, and the spadix of the Indian Turnip (Figs. 80, 81) are also spikes, the former having scaly bracts and the latter a fleshy axis. If you suppose the internodes of a spike to be suppressed, so that the flowers are densely crowded, you will have a head, of which Clover and Button-bush supply instances. If the lower pedicels of a raceme are considerably longer than the upper ones, so that all the blossoms are nearly on the same ELEMENTS OF STRUCTURAL BOTANY. 83 P ^ D Fig. 1S5. 1 i_ 1:g. level, the cluster is a corymb (Fig. 135). If the flowers in a head were elevated on separate pedicels of the same length, radiating like the ribs of an umbrella, we should have an umbel, of which the flowers of Geranium and Parsnip (Fig. 49) are examples. A raceme will be compound (Fig. 136) if, instead of a solitary flower, there is a raceme in each axil, and a similar remark will apply in the case of the spike, the corymb, and the umbel. 123. The inflorescence of most Grasses is what is called a panicle. This is a compound form, and is usually a £Tiid ot raceme having its primary divisions branched in some irregular manner. If the panicle is 84 ELEMENTS OF STRUCTURAL BOTANY. isompact, as in the Grape and Lilac, it is what is called a iJnjrse. 124. Of determinate inflorescence the chief modification is the ctjme. This is a rather flat-topped cluster, having something the appearance of a com- pound corymh, but easily distinguished by this pecuU- arity, that the central blossom opens first, then those at the ends of the first set of branches of the cluster, then those on the secondary branches, and so on until the outer buds are reached. The Elder, Dogwood, and St. John's "Wort furnish good examples of the cymose Fig. 137. structure. Fig. 137 shows a loose open cyme. 125. It has aheady been pointed out that cauline leaves tend to diminish in size towards the upper part of the stem, where the flowers are found. Such re- duced leaves, containing flowers in their axils, are called bracts. In the case of compound flower-clusters, this term is limited to the leaves on the peduncle, or main stem, the term hractlet being then applied to those oc- curring on the pedicels or subordinate stems. In the ELEaiENTS OF STRUCTURAL. BOTANY. 86 case of the umbel and the head, it generally happens that a circle of bracts surrounds the base of the cluster. They are then called, collectively, an involucre, and in tho case of compound clusters a circle of bractlets is called aniiivohicel. Bracts are often so minute as to be reduced to mere scales. From our definition, it will be evident that the spatlie surrounding the spadix in Indian Turnip is merely a bract. 126. It has already been stated that the parts of the flower, equally with the foliage-leaves, must be regarded as modifications of the same structure, and some proofs of this similarity of structure were given. We shall now pi-QCGcd to consider in detail the variations iu form assumed by these organs. 127. The Calyx. As you are now well aware, this term is applied to the outer circle of floral leaves. These are usually green, but not necessarily so ; in some Ex- ogens, and in nearly all Endogeus, they are of some other colour. Each division of a calyx is called a sepal, and if the sepals are entnely distinct from each other, the calyx is pohjsepalous ; if they are united in any de- gree, it is fjamosepalous. A calyx is re'ooi'efZ appearance is the face, the opposite side being the bach. The filament is invariably attached to the connective, and may adhere through the entire length of the latter, in which case the anther is adnate I 1 . Fig. 144. Fig. 145. Fig. 146. (Fig. 144), or the base of the connective may rest on the end of the fila:-:ient, a condition described as innate (Fig. 145), or the extremity of the filament may be attached to the middle of the back of the connective, so that the anther swings about ; it is then said to be 'versatile (Fig. 146). In all these cases, if the face of ELEMENTS OF STRUCTURAL BOTANY. ^9 the anohcr is turned towards the centre of the flowerj it ^jj said to be introroc; if turned outwards, extrorcc, 133. The cells of anthers commonlj open along their outer edges to dis- charge their pollen (Fig. 147). In most of the Heaths, however, the pol- \ ien is disch^^rged through a, minute aperture at the top of each cell (S^ig. i!^..-7.n:.-^.fig.-:3. 1^3^^ ^^^ ^.^ ^^^ 3^^^^ Cohosh each ceil :j& pz^o.'i.lcd with a lid or valve near the top, wLic!: opens n a iiind of liinQ-e (Fig. .40). 134. Btrjncnc mr.y bo either entirely distinct from cac!: oihor, in which case they are described ac. dian- drouCf pe-u^indrjus, octandrouc, cjc, according- to tl^c^ number (or, if 'Jiore than tvonty, cs indefinite), or they ma;- be united in variouc wcys. Ii their anthers ere unitec- i:: z circle, "hile the filaments ai-e separate (Fig. w-)- Lhey are said bo bo syncjenecious , but it the filaments anitetoform :. tube, while the anthers remain diotinct, they are said to be rjionadelphouc (Figc 32) ; if they are in two groups they arc diadelphous (Fig. 87) • if in three ; tnadelpJious ; if in more than three, polya- ddphoiLS. lGi>. As to insertion, when stamens ere inserted on the receptacle, they arc kypofiynous ; when borne on the calyx, perigyiwus ; when borne on the ovary, epirjy- nous; zxid. if inserted on the corolla, epipetalouo. They may, however, be borne even on the style, ac in Crchic. and then they cxc described qs gynandrous. 136. If the stamens ere four in numbci', end in two pdrc of different lengths, they are eciid to be didyna- mous (Fig. :;G) ; if cix in number, four long and twc sliort, they rjrc tctrad7mamous (Fig. C3), end, ansAy. 90 ELEMENTS OF STRUCTURAL BOTANY. if the stamens are hidden in the tube of a gamopetalous corolla, they are said to he included, hut if they protrude beyond the tube they are exserted (Fig. 139). 137. The Pistil. This is the name given to the central organ of the flower. It is sometimes also called the gi/)ioecium. As in the case of the stamens, the structure of the^ pistil must be regarded as a modifica- tion of the structure of leaves generally. The pistil may be formed by the. folding of a single carpellary leaf as in the Bean (Fig. 159), in which case it is simple ; or it may consist of a number of carpels, either ■entirely separate from each other, or united together in various ways, in which case it is compound. If the car- pels are entirely distinct, as in Buttercup, the .pistil is apocmyous ; if they are united in any degi-ee, it ic synca}pous. 13o. In our examination of the Marsh Marigold (Figs. 24, 25) we found an apocarpous pistil of several carpels. We found also that each carpel contained a number of seeds, and that, in every case, the seeds were attached to that edge of the carpel which icas turned towards the centre of the flower, and that, as the carpels ripened, they invariably split open along that edge, but not along the other, so that the carpel when, opened out presented the appearance of a leaf with seeds attached to the margins. The inner edge of a simple carpel, to which the seeds are thus attached, is called the ventral suture, the opposite edge, corresponding to the mid-rib of a leaf, being the dorsal suture. i30o If we suppose a number of simple carjDels to approach each other, and unite in the centre of a flower, Jt is evident that the pistil so formed would contain as mar."? cehs as there were carpels, the cells being separ^ ELEMENTS OF STRUlIURAL BOTANY. 91 ated from each other by a double wall, and that the seeds would be found arranged about the qeutre or axis of the pistil ; aLd this is the actual state of things in the Tulip, whose pistil is formed by the union of three carpels. When the pistil ripens, the double walls sepa- rating the cells split asunder. To these separating walls the name dissepiment or partition is given. 140. But it often happens that though several car- pels unite to form a compound pistil, there is but one cell in the ovary. This is because the separate carp lary leaves have not been folded before uniting, ^'.ave been joined edge to edge, or rather with their edges slightly turned inwards. In these cases the seeds cannot, of course, be dn the centre of the ovary, but will be found ^^" ^ " ^s- ^ • on the walls, at the junction oi the carpels (Figs. 150j 151). In some plants the ovary is one-ceiled, and the seeds are arranged round a column which rises from the bottom A of the cell (Figs. 152, 153). This cr.se is Figs, i i53. explained by the early obliteration of the partitions, which must at first have met in the centre of the cell. 141. In all cases the line or projection to which tl e seeds are attached is called the placenta^ and the term placentation has reference to the manner in which the placentas are arranged. In the simple pistil the placentation is marginal or sutural. In the syncarpous pistil, if the dissepiments meet in the centre of the ovary, thuz dividing it into separate cells, the placenta- tion is central or axile ; if tho ovary i.: one-celled ^ " bears the seeds on its wails, the i^lacentation isparieto^.- 92 ELEMENTS OF STRUCTURAL BOTANY. and if the seeds are attached to a central column, it is free central. 142. Besides the union of the ovaries there may also be a union of the styles, and even of the stigmas. 143. A very exceptional pistil is found in plants of the Pine Family. Here the ovules, in- stead cf being enclosed in an ovary, are usually simply attached to the inner sur- face of an open carpellary the scales forming what is ('.Q^^ (% cone (Figs. 154, 155, 156). ^^^ ^ The plants of this family are hence called Figs. 155, i5«. gymnoxperraous^ or naked-seeded. 144. The Fruit. In coming to the consideration of the Fruit, you must for the present lay aside any popu- lar ideas you may have acquired as to the meaning of this term. You will find that, in a strict botanical sense, many things are fruits which, :n the language of common life, are not so designated. For instance, we hardly speak of a pumpkin or a cucumber as fruit, and yet they are clearly so, according to the botanist's defi- nition of that term. A fruit may be defined to be the ripened pistil together with any other organ, such as the calyx or receptacle, which may he adherent to it. This definition will perhaps be more clearly understood after a few specimens have been attentively examined. 145. For an example of the simplest kind of fruit let us revert to our Buttercup. As the. carpels ripen, the style and stigma are reduced to a mere point. On cutting open one of these carpels when fully ripe, we find it contains a single seel, not quite filling the cavity, but attached at one point to the wall of the latter. What you have to guard against, in this ELEMENTS OF STRUCTURAL BOTANY. VO instance, is the mistake of considering the entire carpel to be merely a seed. It ,i3 a seed envel- oped in an outer covering which we called the ovary in the early stages of the flower, but which, now that it is ripe, we shall call the ^^er/crtrj?. This pericarp, with the seed which it contains, is the fruit. The prin- cipal difference between the fruit of Marsh-Marigold and that of Buttercup is, that, in the former, the peri- carp envelopes several seeds, and, when ripe, splits open doicn one side. The fruit of Buttercup does not thus split open. In the Pea, again, the pericarp encloses several seeds, but splits opm along both margins. The fruits just mentioned all result from the ripening of apocarpous pistils, and they are consequently spoken cf as apocarjwus fruits. 140. In Willow-herb, you will recollect that the calyx tube adheres to the whole surface of the ovary. The fruit in this case, then, must include the calyx. When the ovary ripens, it splits longitudmally into four pieces (Fig. 41), and, as the pistil was syncarpous, so also is the fruif. 147. In the Peach, Plum, Cherry, and stone-fruits or drupes generally, the seed is enclosed in a hard shell called a putamen. Outside the putamen is a thick layer of pulp, and outside this, enclosing the whole, is a skin-like covering. In these fruits all outside the seeds is the pericarp. In one respect these ^tone-fruits resemble the fruit of the Buttercup : they do not split open in order to discharge their seeds. All fruits having this peculiarity are said to be indehiscent, whilst those in which the pericarp opens, or separates into pieces (called valves)^ are de- hiscent. 94 ELEMENTS OF STKUCTURAL BOTANY 148. In the Apple (Fig. 48) and Pear, the seeds are contained in five cells in the middle of the fruit, and these cells are surrounded by a firm fleshy mass which is an enlargement of the calyx. In fact, the remains of the five calyx-teeth may be readily detected at the end of the apple opposite the stem. As in Willow-herb, the calyx is adherent to the ovary, and therefore calyx and ovary together constitute the pericarp. These ileshy-fruits, or i^omes, as they are sometimes called, are of course indehiscent. 149. In the Currant, as in the Apple, you will find the remains of a calyx at the top, so that this fruit, too, is inferior, but tbe seeds, instead of being separated from the mass of the li'uit by tough cartilaginous cell- walls, as in the Apple, lie imbedded in the soft juicy pulp. Such a fruit as this is a berry. The Gooseberiy and the Grape are other examples. The Pumpkin and other gourds are similar in structure to tlie berry, but besides the soft inner pulp they have also a firm outer layer and a hard rind. The name pepo is generally given to fruits of this sort. 1 50. A Easpberry or Blackberry (Fig. 157) proves, on examination, to be made up of a large number of juicy little drupes, aggre- gated upon a central axis. It cannot, therefore, be a true berry, but may be called Fig. 157. an aggregated fruit. 151. A Strawberry (Fig. 158) is a fruit-, consisting chiefly of a mass of pulp, liav- ing its surface dotted over with little carpels (achenes) similar to those of the Buttercup. The flesh of the StrawbeiTy '■ Fig. lie. ELE^IENTS OF STRUCTURAL BOTANY. 96 !S simply an enlarged receptacle ; so that this fruit, also, is not a true berry. 152. The fruit of Sweet-Brier (Fig. ^IS) consists of a red fleshy calyx, lined with a hollow receptacle which bears a number of achenes. This fruit is therefore aualogous to that of the Strawberry. In the latter tlie achenes are on the outer surface of a raised receptacle, while, in the former, they are on the inner surface of a hollow receptacle. 153. The Cone of the Pine (Fig. 154) is a fruit which diflers in an important respect from all those yet men- tioned, inasmuch as it is the product, not of a single flower, but of as many, flowers as there are scales. It may therefore be called a cAlective or multiple fruit. The' Pine- Apple is another instance of the samo thing. 154. Of dehiscent fruits there are some varieties which receive special names. The fruit of Uie Pea, or Bean (Fig. 159), whoso pericarp splits opo::^ along both margins, is called a legume ; thct ai Mcrsh-Marigold (Fig. Fig. i£^. 25), which opens down one side only, is a Jollicle. Both of these are apocar- pous. 155. Any syncarpous fruit, having a dry dehiscent pericarp, is cdled a capsule, A long and alondcr cap- sule, having two cells scpr.rated by u, membranous partition ber.ring the seed, and from vliicli, when ripe, the valve 3 fall r^way on each side, ie called r. silique 06 ELEMENTL OF STRUCTURAL BOTANY. 160). If, as in Shepherd's Purse (Fig. the capsule is short and broad, it is called a silide. If the capsule opens horizontally, so that the top comes off like a lid, as in Purslane (Fig. 161), it is Sb pyxis. Any dry, one-seeded, indehiscent fruit is called an achene, of which the fruit of Buttercup (Fig. 14) is an example. In Wheat the fruit differs from that of Butter^ ^ig. leo. cup in having a closely fitting and adherent pericarp. Such a fruit is called a caryopsis or grain. A nut is usually syncarpous, with a hard, dry peri- carp. A winged fruit, such as that of the Maple (Fig. 162), is called a Fig. 162. samara or key. 157. The Seed. The seed has already been de- scribed as the fertilized ovule. It consists of a nucleus, enveloped, as a rule, in two coats. The outer one, which is the most important, is known as the testa. Occasionally an additional outer coat, called an aril, is found. In the Euonymus of Canadian woods, the aril is particularly prominent in autumn, owing to its bright scarle 8 colour. The stalk, by which the seed is attached to the placenta, is i\iQ funiculus, and the scar, formed on the testa where it separates from the seed-stalk, is called the kilum. In the Pea and the Bean this scar is very distinct. 158. Germination of the Seed. Whenaseedis lightly covered with earth, and supplied with warmth and moisture, it soon begins to swell and soften, owing to the absorption of water, and presently bursts its ELEMENTS OF STRUCTURAL BOTANY. 97 coats, either to such a degree as to liberate the cotyle- dons completely, or so as to permit- the escape of the radicle and the plumule. The former immediately takes a downward direction, developing a root frem its lower end, and either elongates through its whole length, in which case the cotyledons are pushed above the surface, as in the Bean, or remains stationary, in which event the cotyledons remain altogether under ground, as in the Pea and in Indian Corn. Before the root is developed, and the little plantlet is thereby enabled to imbibe food from the Eoil, it has to depend for its growth upon a store of nourishment supplied by the parent plant before the seed was cast adrift. The relation of this nourishment to the embryo is different in different seeds. In the Bean and the Pumpkin, for exam2Dle,it is contained in the cotyledons of the embryo itself. But in Indian Corn, as we have already seen, it constitutes the bulk of the seed, the embryo merely occupying a hollow in one side of it. In such cases as the latter, it will be remembered that the term albumen is applied to the nourishing matter, as distinguished from the embryo. 159. As to the number of cotyledons, it may be re- peated that, as a rule, seeds are either dicotyledonous or monocotyledonous. Some plants of the Pine Fam- ily, however, exhibit a modification of the dicotyledo- nous structure, having several cotyledons, and being consequently distinguished Si,s jjolycotyledonous. 98 ELEMENTS OP STRUCTURAL BOTANY. CHAPTER XV. ON THE MINUTE STRUCTU*RE OF PLANTS EXOGENOUS AND ENDOGENOUS STEMS FOOD OF PLANTS. 160. Up to this point we have been engaged in observing such particulars of structure in plaints as are manifest to the naked eye. It is now time to enquire a little more closely, and find out what. we can about the elementary structure of the different organs. We have all observed how tender and delicate is a little plantlet of any kind just sprouting from the seed; but as time elapses, and the plant develop^s itself and acquires strength, its substance will, as we know, assume a texture varying with the nature of the plant, either becoming hard and firm and woody, if it is to be a tree or a shrub; or continuing to be soft and compressible as long as it lives, if it is to be an herb. Then, as a rule, the leaves of plants are of quite a different consis- tency from the stems, and the ribs and veins and petioles of foliage leaves are of a firmer texture than the remaining part of them. In all plants, also, the newest portions, both of stem and root, are extremely soft compared with the older parts. It will be our object in this chapter to ascertain, as far as we can, the reason of such differences as these ; and to accomphsh this, we shall have to call in the aid of a microscope of much higher power than that which has hitherto served our purpose. 161. Il a small bit, taken from a soft stem, be boiled for a while so as to reduce it to a pulp, and a little of this pulp be examined under the microscope, it will be foi::iu to be entirely composed of more or less rounded ELEMENTS OF STRTCTURAL BOTANY. 99 or oval bodies, which are either loosely thrown together (Fig. 163), or are pressed into a more or less compact ilfZ. 16:-!. Fi<,'. 164. Fig. IGi {a,. mass. In the latter case, owing to mutual pressure they assume a somewhat angular form. These bodies are called cells. They are hollow, and their walls are usually thin and transparent. The entire fabric of every plant, without any exception whatever, is made up of cells ; but as we proceed in our investigation, we shall find that these cells are not all precisely ahke, that as they become older they tend, as a rule, to thicken their walls and undergo changes in form, which, to a great extent, determine the texture of the j^lant's .'^ub.=}tance. \()'l. A fabric made up of cells is called a tissue. A collection of such cells as we found constituting our pulp, and as we should find constituting the mass of all the soft and new parts of plants, as well as of some hard parts, is called cellular tissue. The cells com- posing cellular tissue vary a great deal in size in different plants, being, as a rule, largest in aquatics, in which they may sometimes be observed with the naked eye. Ordinarily, however, they are so minute that milUons of them find room in a cubic inch of tissue. 163. When young, the walls of the cells are quite unbroken. Each cell is lined with an extremely thin membrane, and a portion of its cavity is occupied by a > 100 ELEMENTS OF STRUCTURAL BOTANY. / ' soft body called the nucleus. The space between the nucleus and the lining of the cell is filled with a thick- ish liquid called i^rotoiAasm., and the microscope re- veals to us the fact that, as long as the cells are living cells, a circulation or current is constantly kept up in the protoplasm of each. To this curious movement the term cijclosis has been applied. As the cells become older, the nature of their contents is altered by the introduction of watery sap, in which other substances are found, notably starch, sugar, chlorophyll (to which leaves owe their green colour), and crystals (raphides) of various salts of lime. The substance of which the cell-wall is composed is called cellulose, and is a chemical compound of carbon, hydrogen, and oxygen. in the protoplasm nitrogen is found in addition to the xjhree elements just mentioned. 164. llie growth of a plant consists in the multiplication 9/ its cells. Every plant legins its existence with a single cell, and by the repeated division of this, and the growth of the successive sections, the whole fabric of the plant, whether herb, shru j, or tree, is built up. The division of a cell is accomplished by the formation of a partition across the middle of it, the nucleus having previously separated into two pieces. The partition is formed oat of the lining of the cell. Each half of the cell then enlarges, and, when its full size is attained, divides again, and so on, as long as the cells are living cells. 165. But in order to increase their size, food of some kind is essential. Growing plants supply this to their cells mainly in the form of sap, which is taken in by the root-fibres, and m^de suitable, or elaborated, or assimilated, by chemical action in the plant itself. B;; ELEMENTS OF STRUCTUE.\I. BOTANY, 4 a very curious process, the liquids absorbed by the root pass from cell to cell, though each is quite enclosed, until they reach the leaves, where the elaboration is performed. The process is carried on under the law, that if two liquids of different density be separated by a thin or porous diaphragm, they will permeate the diaphragm, and change places with greater or less rapidity according to circumstances, the liquid of less density penetrating the diaphragm more rapidly than the other. The cells of plants, as we have said, contain dense liquid matter. The moisture present in the soil, and in contact with the tender root-hairs (which are made up of cells, you will remember), being of less den- sity than the contents of the cells, flows into them, and is then passed on from cell to cell on the same princi- y\Q. The supply of assimilated matter is thus renewed as fast as it is appropriated by the newly divided and growing cells. 1G6. If a plant, during its existence, sirnxDly multiplies its cells in this way, it can of course only be a mass of cellular tissue as long as it Uves. But we see every- where about us plants, such as trees and shrubs, whose stems are extremely firm and enduring. How do these stems differ from -those of tender herbs? How d^ they differ from the soft parts of the plants to which they themselves belong ? A moment's consideration will make it evident that, as every plant begins with a single cell, and increases by successive multiplications of it, every part of the plant must at some time have bee. composed c^ cellular tissue, just as the newer portion9*^ are at present. The ceils of those parts which are no 102 ELEMENTS OF STRUCTURAL BOTANY. / — — ^ longer soft must, then, have undergone a chauge of some kind. Let us try to understand the nature Oi this change. It has been stated that the walls of new cells are extremely thin ; as they become older, however, they, as a rule, increase in thickness, owiug to deposits of cellulose upon their inner smface. It sometimes happens, indeed, that the deposits are so copious as to almost completely fill up the cavity of the cell. The idea will naturally suggest itself, "that this thickening of , the walls must impede the passage of the sap, but it is found that the thickening is not uniform, that there are, in fact, regular intervals which remain thin, and that the thin spot in one cell is directly opposite a cor- responding thin spot in the wall of its neighbour. Eventually, however, these altered cells cease to convey sap. 167. The hard pai'ts of plants, then, differ from the soft parts in the different consistency of their cell-ualls. But they differ also in the form of the cells themselves. In those parts where toughness and strength will be required, as, for ex- ample, in the inner bark, in the stem, and in the frame-work of the leaves, the cells become elongated and their extremities as- sume a tapering form, so that they overlap each other, instead of standing end to end as in ordinai-y cellular tissue (Fig. 165). To this drawing-out process, combined with the Fig. 155. hardening of the walls, is due the fii-mness of wood generally, and the tissue formed by these modi- fied cells is known as woody tissue. On account of the gi-eat relative length of the cells found in the inner SLEIEEKTS OF STBUCTUBAL. BOTaST. lOS bosk, and the conseqnent tonghness conferred npon thcit part, the tissue formed by them is specially dis- tinguisiied as bast tissue. Associfi'.^ed with the "wood- cells are commonly foxmd others, differing frori them chiefly iu being larger in diameter, and farmed out of rows of short cells, standing end to end, by the disap- pearance of the partitions which separated them. These enlarged cells, produced in this way, are called res&th or ducts, and a combinatiun of them is known as vascular tissue. Ducts in- variably show markings of some sort on their walls. The one figured in the margin (Fig. 166) is a dotted duct,, the dots being spaces which have not been thickened by deposits of cellulose. Other ducts are spimJbj marked on Ifil their inner suiface, but in this case the mark- f= = =j ing3 are themselves the thickened part of the pig. im. cell-walL It is convenient to speak of the mixture of woody and vascular tissue as \he Jibro-vascular sijstenu The name parcmhjma is con^monly apphed to ordi- nary cellular tissue, whilst tissue formed of long cells IS csMed. prosenchyma. It will be understood, then, that all cells of every description, found entering into the composition of a plant, are only modifications of one original form, the particular form ultimately assumed by the cells depend- ing mainly on the functions to be discharged by that portion of the plant in which the cells occur. ESOGEXOUS A^-X) ENTX>GEXOUS STEMS. 163. It has already been hinted that the two great classes of plants, Dicotyledons and Monocotyledons, differ in the mode oi growth of their steixi^ We shall 104 ELEMENTS OF STRUCTURAL BOTANY. now explain somewhat more in detail the nature of this difference. Bearing in mind the fact stated in the pre- ceding part of the chapter, that old and new parts differ mainly in the shape of their component cells and the texture of the cell- walls, it will he found that the dis- tmction between Exogenous aud Endogenous growth depends mostly upon the relative situation of the new cells and the old cues — of the parenchyma and the prosenchyma, 169. Let us begin with the stem of a Dicotyledon. Y'\". 167 shows a section of a young shoot. The whole of the white part is cellular tissue, the central portion being the pitJi. The dark wedge-shaped portions are fibro-vascular bundles, consist- ing mainly of woody tissue, a few vessels, easily recognised by their larger openings, being interspersed. Fig. 167. ^g ^j^g shoot becomes older, these bundles enlarge, and others are formed between them, so that the radiating channels of cellular tissue which separate them are in the eud re- ^^ — ---.^^ duced to much smaller compass ^^^^^ than in the earUer stages of growth ^^" - "" ' ^^^, (Fig. 168). The narrow channels , ^_:i '-'J^ are the medullary rays. The \ i cells of which they are composed ' . / - ^^ are flattened by compression. Eventually, a ring of wood is Fig. ics. formed, the medullary rays intersecting it in fine lines, a-s the sawed end of almost any log will show. Outside the zone of wood is the bark, which at first consists altogether of cellular tissue. As the season advances, ELEMENTS OF STRUCTURAL BOTANY. 105 however, long bast cells are formed 'in the iymer part, next the wood, which part. is thereafter specially desig- nated the liber. The outer ring of all, enclosing the whole stem, is the epidermis or skin. 170. It is now to be observed that, year after year, the rings of wood are increased in thickness hy Jic 'riidt:pii- cation of their outer cells. There is, consequently, always a layer of soft cells between the wood and the bark. This is known as the cambium layer, and it is here that the whole growth of an exogenous stem takes place. The soft cells on its inner side are gradu- ally transformed into woody tissue and vessels, whilst those on its outer side become the bast cells of jhe liber, and others form the extension of the medullary rays. Bear in mind, then, that the exogenous stem is char- acterized (1) by the formation of its wood in rings, (2) by the presence of the continuous cambium-layer, and (3) by the presence of a true bark. 171. Let us now consider the structure of an endo- genous stem. Fig. 169 represents a section of one. Here, again, the white portion is cellular tissue, whilst the dark parts are the fibro-vascular bundles. This stem is at once distinguished from the other by the isolation of these bundles. They never co- alesce to form a ring. That por- tion of each bundle, which is nearest the centre of the stem, corresponds to the wood of the exogen, whilst the outer portion of each consists of cells which resemble the exogenous bast-cells, but there X ICj ELEITENTS OF STRUCTUEAL BOTANY. is no camhium-layer, and consequently no arrangement for the indefinite continuance of the gro"wth of tae bundles. Once formed, therefore, they remain un- changed, and the growth of the stem consists in the production of new ones. These (which oiigmate at the bases of new leaves) being introduced amongst the older ones, act as wedges, and swell the stem as a whole. THE FOOD OF PLANTS. 172. A word or two is necessary on this subject in addition to what has alreadj been said. The nature of a plant's food may be determined by making a chemical analysic of the plant's substance. A:: already stated, the chemical elemcuuC found in plants are chiefly four. carbon, oxygen, hydrogen aucx nitrogen, th3 latter ele- ment occurring in th: protoplas: . of active cells. What, then, are the sources from which the plan! obtains these materidk of its growlii ? In the atmosphere there is always prcsen, a gac known as carbon dioxide, or car- bonic acid. This gas, which is 2. compound of carbon and oxygon, i: produced largely in the lung: of animalC; ancl by them exhaled. Zt is readily soluble in water, ::^ thc". rain-dr j^).: in their passage through the au- dissolve io auc carry i: with them into the soil. Again, wherever &nraia. or vegetable matter is decaying thet-e is nro- duced a gas called ammonia, a compound of nitrogen and hydrogen, and. liks carbonic acid, readily soluble, so that thi- also is present in rain-water. Anl when it is considered that ^ verj- large proportion of the air con- sists of froo nitrogen, soluble to some extent in water, and that r.ic elements c. water itself arc oxygen and hydro- gen i: wiL- be cAqj^ii'^ that the moisture iz the eai'feh contaiBS a supply of eve-- one of the elements i BLEilENTS OF STRUCTURAL BOTANY. 107 chiefly required by the plant. No\r it is a matter of common experience that, with rare exceptions, a plant will wither and die unless supplied with adequate mois- ture. We therefore come to the conclusion, that at any rate the greater part of the nourishment of plants is imbibed in liquid form through the roots. The law of endosmose, in accordance with which this imbibing goes on, has already been explained. The sap, as it is called, ascends through the newer tissues, and is at- tracted to ths leaves by the constant evaporcticn going on there, and the consequent thickening of the contents of the cells in those organs. 173. And this leads to the question — How does the water-vapour make its escape from the leaves ? The microscope solves this difficulty for us. A leaf almost always presents one surface towards the sky and the other towards the ground. It is protected on both sides oy an epidermis or skin, consisting of very closely packed cells. The side exposed to the sun is almost J unbroken, but the lower side is seen, under \\jr\ji the microscope, to be perforated by iunu- ' ^,J ^\ merable Httle openings, which lead into the Wj)} l| body of the leat. These openings, to which inil ^^^® name stomata, or stomates (Fig. 170) // Ui I ^^^ ^^^^ ^'iveu, have the power of expanding !/}-■[ ^^^^^ moistened by damp air, and contract- X' ing when dry. By this wonderful contriv- Fig.170. pQgg^ ^j^g j.^^g of evaporation is regulated, and a proper balance maintained between the supply at the root and the loss from the leaves. The stomates, it may be noticed, serve also as means whereby carbonic acid may be directly absorbed from the air. In those plants whose leaves float on water the stomates are 108 ELEMENTS OF STEUCTUKAL iiOTAXY. found on the upper surface, and in vertical leaves they occur pretty equally on both surfaces. Immersed lei^ves are without stomates. 174. The crude sap, then, which ascends into the leaves is concentrated by the evaporation of its super- fluous water. When so concentrated, the action of sun- light, in connection with the green colouring matter . existing in the cells of the leaves, and known as chloro- phyll, decomposes the carbonic acid, contained in the sap, into its carbon and oxygen. The latter gas issuf^c from the leaves into the air, whilst the carbon is retained and combined with the r-^maining elements to form elaborated sap, out oi which the substance of new colls is constructed. 175. It thus appears that the chemical action which goes on in the leaves of plants is precisely the reverse of what takes place in the lungs of animals. The latter inhale oxygen, combine it with the carbon of the blood, and exhale the resulting carbonic acid. The former take in carbonic acid, decompose it in the leaves and other gi-een parts, and exhale the oxygen. Plants may there- fore be regarded as purifiers of the air. 17G. It remains to be added, that besides the four substances, carbon, oxygen, hydrogen, and nitrogen, which are called the orcfanic elements, many others are found in the fabric of plants. When a piece of wood is bumu away, the organic elements disappear, but a quantity of ash remains behind. This contains the various mineral substances which the water absorb- ed by the plant has previously dissolved out of the soil, but which it is not necessary to our present pm'pose to cniimei-ate hero. ELEMENTS OF STRUCTURAL BOTANY. 109 CHAPTER X^^. CLASSIFICATION OF PLANTS ACCORDING TO THE NATURAL SYSTEM. 177. Hitherto, our examination of plants has been confined to a few selected specimens, and we have examined these chiefly in order to become acquainted with some variations in the details of growth, as exem- plified by them. Thus, we have found plants which agree in exhibiting two cotyledons in the embryo, and others, again, which are monocotyledonous. Some members of the former group were found to exhibit two sets of floral envelopes, other only one, and others, again, were entirely without these organs. And 80 on through the various details. We now set out with the vegetable world before us — a world populated by forms almost infinite in number and variety. If, therefore, our study of these forms is to be carried on to advantage, we shall have to resolve upon some definite plan or system upon which to proceed ; otherwise we ehalt merely dissipate our energies, and our results will be without meaning. Just as, in our study of language, we find it convenient to classify words into what we call pa-.ts of speech, and to divide and subdivide these again, in order to draw finer distinctions, so, in cur study of plants, it will be necessary to arrange them 110 ELEMENTS OP S TJG TLT.AL BOTANY. first of all into comprehensive groups, on the ground of some characteristic possessed by every member of each group. Just as, in Latin, every noun whose genitive case is found to end in ce is classed with nouns of the first declension, so in Botany, every i)lant presenting certain peculiarities will be placed in a group along with all the other plants presenting the same peculiar- ities. 170. Some hints have already been given you as to the kind of resemblances upon which classification is based. For instance, an immense number of plants arc found to produce seeds with a dicotyledonous embryo, while an immense number of others have monocotyledonous embryos. This distinction, there- fore, is so pronounced, that it forms the basis of a divis- ion into two very large groups. Again, a very large number of dicotyledonous plants have their corollas in separate petals ; many others have them united, whilst others again have no petals at all. Here, then, is an opportunity to subdivide the Dicotyledons into poly- petalous, gamopetalous, and apetalous groups. And so we go on, always on the plan that the more widely spread a peculiarity is found to be, the more compre- hensive must be the group based on that peculiarity ; and so it happens, that the smallest groups of all come to depend upon distinctions which are, in many cases, by no means evident, and upon which botanists often find themselves unable to agree. 179. As our divisions and subdivisions will neces- sarily be somewhat numerous, we shall have to devise a special name for each kind of group, in order to avoid confusion of ideas. We shall, then, to begin witli, draw a broad line of distinction between those plants ELE3IEin:G C? BTRTJCTUBAL CCTAITY. Ill Trhich prod 7ice J! ower 8 of some kindj aiid those which cf-^ nctj and to each of these great groups "we shall give th9 name Series. We thus h .y. the P'^lo'/ering, or, ty use the Greek term, Phan^rogaT-Cus, Series, and tha Flowerless, or Cryptcg.mou::, oeries ; or we may spoai of th:,m briefly as Phanercf>ins and Crypto- •;;-".nis. Then, leaving the Cryptogams aside foi tne moment, we may break up the Phanerogams into two great Classes, Exogens (or Dlsctyledons) and Endoger_2 (or Monocotyledon^)- for reasons al- ready explained. By far tie greater number oi Exogens produce seeds which are enclosed in a pericarp oi some kind ; but there is a remarkable group of plants .[repre- sented in Canada only by the Pines and their imme- diate relatives) which dispense with the pericarp alto- gether, and whose seeds are consequently naked. So that we canmake two aub-Classes of th: I^xogens, on the basis of tbis difference, and these we r:hdl call the Angiospermous Sub-Class, and the Gymiccpcr- mous (naked-seeded) Sub-Class. The first of these may be grouped in three Divisions, the Pol>jpetalous, Gamopetalous, and Apetalous, and the Endogens also ill three, the SpadkeouSy the Peialoid'ous, and the (xiumaceoud, types of which we have already examined i:-" the Marsh Calla (spadiceous), Trillium (pctaloideous)^ and Timothy (glumaceous), and the distinctions between wiiich are sufficiently obvious. Lhe Cryptogams are divided into three great Classes, viz.: Aeroguns, embracing Ferns, Horse- tails and Ciub-mosses; Anophytcs, embracing Mosses and Liverworts; and*i'hallopliytes,cmbraciBgLichens, Seaweeds, and Musiirooms. 112 ELEMENTS OF STKUCTURAL 30TANY. So far, then, our classification is ac follows f f Sub-class 1— ADgicsperoa FolypetaloiLS Division. s Class I .— Exogens .- Gamopetalous c o Series I. Phanero- gams Apetalous 2 ^^Sub-clas8 2-Gymr:osi Drra3 ^ Spadiceotts Division. fn ^ Class II.— Endogens- Petaloideous Division. » n I Glujuaceous Division. > Series II. - Cryptogams. Xiass III. -Acrogens. Class rV.-Anophytes. .Class v.— Thallophytes. Each of the Divisions ic sub-uiviJed into r. number of Families or Orders ; each Order into a number of Genera ; and each Genus into Species. A species is the sniLi cJ all the individual plants Y.-hose resemblances m all essential respects are so great as to warrant the belief that they have sprung from one common stock. De Candolle has this statement : " Wo unit 3 under ',he designation ^I'^ s/?^ciV6" all those individuals that mutu- ally bear to each other so close a resemblance as to allow of our supposing that they may have proceeded originally from a single being or a single pair/' We may also speak of each one of these individual plants a glossary. Essential organs, 17. Evergreen : retaining foliage during winter. Exalbuminous, 59. Excurreut :^ said of main stems which are distinct, and well- marked to the top, as in the Pine and Fir ; the reverse of deliquescent. Exhalation, 175, 173. Exogen, 60. Exogenous growth, 169. Exserted protruding, 13G. Exsti^Dulatc, 115. Extrorse. 132. Fascicle : a close bundle, either of leaves or flowcrn. Fascicled roots, 85. Feather-veined : same as pinnately-veined, 101. Fertile flower. 53. Fertilization, 17. Fibrous thread-like, 2. Fibro-vascular system, 167. Filament, 6. Filiform, 117. Fimbriate : fringed. Fleshy fruits, 148. Flora : a description of the plants of a district ; a collective name for the whole of the species of a district. Floral envelopes, 14. Floret, 48. riower : the part of a phanerogamous plant in which the stamens and pistil are situated. Flower-leaves, 11. Flowering plants, 179. Flowerless jDlants, 170. Toliaceous : iike a leaf in appearance, roliolatc : having leaflets. Follicle, 154. Free, 5. Fruit, 144. Fugacious : falling away early. Funiculus, 157. Funnel-shaped, Fig. 140. Furcate: forked. Fusiform : same as spindle-shaped, 85. Gr.lea : an archiug petal or sepal, as the two upper ones in CatrcT, :.:- 57. Camop. ilous, C3. C.-.mopetalous, 120. Ccimosepalous, 127. dtdej: and glossary. 12)2 Genera : plural Ox genns. Genus, 179. Germ : same as embryo. Germination, 153. Gibbous : swollen on ono Bide. Glabrous, 116. Gladiate : Bword-shaped. Glands : applied generally *o cells or hairs on the surfaces of plants, in which resinous or oily matters are secreted ; but the term is also used to describe any projection, the use of which is not clear. Glandular : bearing glands. Glaucous, 116. Globose : like a globe or sphere. Glumaceous : bearing or resembling glumes. Glumes, 75. Gourd, U9. Grain, 156. Granules : particles. Gymnospermous, 143. Gymnosperms, 179. Gynoecium, 1S7. Gynandrous, 135. Habitat : a term applied to the region most tavourabie to tha growth of a plant : the place where it grows natm-ally. Hairs, 116. Hairy, 4. Halberd-sheped, Fig. 119. Hastate- Fi^ 119. Head, 122. Heart-shaped, 108. Heptandrous : with seven distinct stamens. Herb, 69. Heibaceous, 89. Herbarium : a botanist's collection of dried plants. Hexandrous : with six distinct stamens. Hilum, 157. Hirsute : rough with hairs. Hispid : covered witli stiff hairs. Hoary : densely covered with fine grayish hairs Hortus siccus : same as herbarium. Hybrids : plants resulting from the crossing o- nearly related species. Hypogynous. 135. Imbricate : overlapping like shingles on a roof. Immersed : wholly under water. Imperfect, 53. 126 INDEX AND GLOSSARY Included, 136. Incomplete, 19. Incurved (petals) Fig. 50, Indefinite, 26, 134. Indefinite inflorescence, 120. Indebiscent, 147. Indeterminate inflorescence, 120. Indigenous : naturally growing in a country. Inferior : underneath ; farthest from the axis ; the ovary is inferior when the calyx adheres to it throughout ; the calyx is inferior when free from the ovary. Inflorescence, 119. Innate, 132. Inserted : attached to. Insertion : the point, or manner, of attachment. Internodcs, 4 Interruptedly pinnate, Fig. 138. Introrse, 132. Involucel, 125. Involucre, 125. Involute : rolled inwards from both edges. Irregular, 35. Isomerous : having the parts equal in number. .Joints : a name pometimes given to the nodes of a stem. Keel, see Carina. Kernel, 16. Key-fruit, 156. Kidney-shaped, Fig. 121. Labellnm (or lip), 71. Labiate. 50. Lanceolate, Fig. 113. Leaf, 97. Leaf-arrangement, 99. Leaf-green, see Chlorophyll. Leaflet, 100. Leafstalk, 4. Legume, 154. Leguminous : producing or relating to legumes. Liber, 169. Ijigneous : woodv. Ligulate, 131. Ligule : a strap-shaped corolla n Grasses, a scale-iil^o projec- tion between the blade of a leaf and the sheath. Limb, 1-29, 130. Lip, see Labellum. Linear, Fig. 111. INDEX. AND GLOSSARY. 127 Lobe, 4, 100. Loculicidal (dehiscence) : Bplitting midway between the partitions. Loment : a jointed legume. Lyrate : pinnately-lobed, with the terminal lobe much larger than the others. Marcescent : withering persistent. Marginal : relating to the margin. Markings (on cells), 167. Medullary rays, 169. Membranous : thin, like a membrane. Mesocarp : see Endocarp. Micropyle, 16. Midrib, 101. Monadelphous, 134 Monandrous: with a single stamen, 72. Monochlamydeous : with only one set of floral envelopes. Monocotyledonous, 80. Monocotyledons, 81. Moncecious, 63. Morphology, 82. Mucronate, 110. Multifid, 109. Multiple fruits, 153. Naked flowers . those which are destitute of calyx and corolla. Naked seeds . those not enclosed in an ovary, 143. Napiform, 85. Natural system of classification, 177, (fee. Naturalized : introduced from other countries, but growing spon- taneously from seed. Neck, Bee Collum. Nectary : that in which nectar i.s secreted. Needle-shaped, Fig. 110. Net-veined, 4. Neutral flowers : those having neither stamens nor pistil. Nodding : hanging with the top downwards, hke the flower in Fig. 72. Node, 4, Normal: regular; according to rule. Nucleus (of an ovule), 16, 157 ; (of a cell), 163. Nut, 156. Nutlet : a small nut, or nut-like body, 50. Obcordate, 108. Oblanceolate, 107. Oblique : having the sides unequal. Obliteration (of partitioi5s), 140. Oblong, 105. 128 INDEX AND GLOSSAKY. Obovate, 107. Obtuse, 110. Cchrea : a tube formed by the union of both edges of a pair of ctipules. Ociireate : having ochreffi. Octandrous : having eight separate stamens. Ofiset: a short, prostrate branch, rooting at the end. Opposite, 99. Orbicular, 105. Orders, 179. Organic elements, 176. Organs : the parts or members of a living body. Organs Oi Reproduction : the parts of the flower. Organs oi' Vegetation : root, stem, and leaves. Orthotropous : applied to ovules when straight, so that the micro« pyle is as far as possible from the ^oint of attachment. Oval, "lOo, Ovary, 7. Ovate, 106. Ovoid: egg-shaped. Ovule, 7. Palate, 131. Palet, 75. Palmate, 101. Palmatelv-lobed, 109. Palmatifid, 109. Panicle, 123. Papilionaceous, 35 Pappo:e, 128. Pappus : a circle of bristles or hairs representing the limb of th? calyx in flowers of the Composite Family, 48. Parallel-veined : same as straight-veined, 62. Parasites, 87. Parenchyma, 167. Parietal : on the walls, 141. Parted : almost completely cut through. Pectinate: pinnatifid with lobes like the teeth of a comb. Pedatc, Fig. 125. Pedicel, 27. Peduncle, 5. Peltate, Fig. 123. Pentandrous : with five distinct stamens. Pepo, 149. Perennial : a jDlant which continues to grow year after yea?. Per:'"ect : having both stamens and pistil. Perfoliate, 113. Perianth, 63. Pericarp, 145. INDEX AND GLOSSABT 1559 Porigynous, 86. Persistent, 32. i^ersonate, 131. Petal, 5. Petiolate : having petioles. Petiole, 4. Phanerogamous or Phsenogtimous, 179. Pilose : having long soft hairs. Pinna : a primary division of a pinnately compound leaf. Pinnate, 101. Pinnately-lobed, 109. Pinnatifid, 109. Pinnule . a secondary division of a pinnately compound leaf. Pistil, 137, 7. Piotillate : having a pistil, 53. Pitcher- shaped (leaf). Fig. 134. Pith, 169. Placenta, 141. Placentation, 141. Plumose : feathery. Plumule, 58. Pod : a dehiscent fruit. Pollen, 6. PolUn-tube, 16. PoUinia : pollen-masses, Fig. 87. Polyadelphous, 134. Polyandrous : with numerous distinct stamens. Polycotyledonous, 159. Polygamous: having perfect as well as imperfect flowers, Polypetalous : having separate petals. Polysepalous : having separate sepals. Pome, 148. Posterior : next the axis. Prasfl'^rati'^n, see ^Estivation. Prcfoliation : the disposition of leaves in th« b^d. Prickles, 96. Procumbent : lying on the ground. Prosenchyma, 167. Prostrate, 90. Protoplasm, 163. Pn'^-^-cent : covered with fine dowii. Punctate : having transparent dots, like the le..ves of fat. John'a Wort. .'?ajamcn, 147- Pyxis, 1.55. Quinqnefoliolate : having five leaflets. Baceme, 122. 130 INDEX AND GLOSSAEY. Racemose : like a raceme. Racliis: an axis. Radiate, 101. Radical : pertaining to the root. Radical leaves, 4. Radicle, 58. Raphides, 163. Ray : the marginal florets of a ouuiposite flower, as distinguished from the disk. Receptac'e, 8. Recurved : curved backwards. Reflexed : bent backwards. Regular : with parts of the same size and shape. Reniform, Fig. 121. Reticulated: netted. Retuse : slightly notched at the apex. Revolute : rolled back. Rhizome, 91. Pibs, 101 Ringent, 131. Root, 2, 83. Root-hairs, 165. Rootlet, 2. Rootstock, 91. Rotate, 130. Rotation in cells, 163. Rudimentary : imperfectly developed. Rugose : wrinkled. Runcinate : with teeth pointing backwards, as in the leaf DandeUon. Runner, 90. Sagittate, Fig. 120. Salver-shaped, Fig. 14] Samara. Fig. 162. Sap, 172, 174. Sarcocarp : the flesh of a drupe. Scabrous : rough. Scandent : climbing. Scape, 19. Scar, 157 Scion : a voung shooi. Seed, 17,' 157, 158. Seed-vessel, see Ovary. Sepal, 5. Septicidal (dehiscence) : splitting open along th partitions.e Septum : a partition. Series, 179. Serrate. 112 INDEX AND GLOSSARY. 131 C'essile, 4. Cetaceous : like a bristle. Sheath : "^ tube surrounding a stem, 62. Sheathing : surrounding like a sheath. Shield-shaped, see Peltate. Shoot : a newly formed branch. Shrub, 89. Silicle, 155. Silique, 155. Simple (leaves), 100; (pistil), 137. Sinuate : wavy on the margin. Solitary, 121. Spadiceous, 179. Spadix, 69. Spathe, 69. Spathulate, 107. Species, 179. Spike, il-2. Spikelet, a secondary spike. Spindle-shaped, 85. Spine, 96. Spiral markings, 167. Spores : the reproductive bodies in Cryptogams which correspond to the seeds of Phanerogams. Spur, 131. Stamen, 6, 132. Staminate (flower) : having no pistil, but only stamens. Standard : the broad upper petal of a papilionaceous corolla. Stem, 3, 88. Stemless, 18. Sterile (flower) : having no pistil. Stigma, 7. Stigmatic : bearing the stigma. Stipulate : having stipules, 115. Stipule, 31, 115. Stolon : ■:. short branch which droops to the ground and takea root. ntomate, 173, Stone, see Putamen. Stone-fruit, see Drope. Strap-shaped, see Ligulate. Striate : marked lengthwise with lines or furrows. Strobile : same as Cone. Style, T. Bub-class, 179. Subulate, Fig. 112. Succulent : juicy ; fleshy. Sucker : an underground branch, at length emerging and form- ing a stem. 183 INDEX AND GLOSSARY. Superior, 7, 37, 44. Suppressiou : absence of parts. Suspended : liuug from above. Suture, 138. Symmetrical, 42. Syncarpous, 29. Syngenesious, 47 Tap-root, 84. Te th (of calyx), 32. Tendril, 90. Terete : cylindrical. Terminal: at tie end of a stem or branch. Ternate : in threes. Testa, 157. Tetradyuamous, 28, 136. Tetrandrons : having four distinct stamens. Thalamiflorous : having the stamens inserted on the receptacle. Thalamus : the receptacle. Thread-shaped, see Filiform. Throat (of clyx), 128. Thorn, see Spine. Thyrse, 123. Tissue, 162. Tomentose : woolly. Toothed, see Dentate, 112. Torus : same as receptacic Tree, 89. Triadelphous, 134. Triandrous : having three distinct stamsns. Tiiennial: lasting three years. Trifoliolate : having three leaflets. Truncate, 111. Trunk : the main stem. Tube, 34, 128, Tuber, 91. Tuberous : like a tuber. igJM Tunicated, 92. Twining, 90. Two lipped, see Labiate, 60. Umbel, 122. Umbellet : a secondary umbel. Unguiculate : having a claw. Valvate : edge to edge, but not overlapping. Valve, 41, 133, 147. Valved : having valves. Varieties, 179. INDEX AND GLOSSARY. 133 Vascular tissne, 167. Veins : the finer parts of the framework of a leaf. Venation, 101. Ventral suture, 138. Vernation, same as Praefoli^tiou. Versatile, 132. /' ^ ^. , ' J Vertical leaves. 98. ^^^^- ^ ^ Verticillate, 99. Vessels, 167. Villose, 116. Wavy : with alternate rounded hollows and projections, 112. Wedge-shapt'd : like a wedge, the broad uart being the a^ex. Wheel-shappd, see Rotate. Whorl : a circle of three or more leaves at the same node. Woody tissue, 1G7. ^ r V / > //•/ / / / APPENDIX. ^zintionB from g^amination ^ap^rs UNIVEKSITY OF TORONTO. 1. Define suckers, stolons, offsets, runners, tendrils, thorns, and prickles, describing their respective origins and uses, and giving examples of plants in which they occur 2. "What are the functions of leaves ? Describe the lifferent kinds of compound leaves. 8. What is meant by inflorescence ? Describe the different kinds of flower-clusters, giving an example of each. 4. Mention and explain the terms applied to the various modes of insertion of stamens. 5. How are fruits classified ? What are multiple or collective fruits ? Give examples. 6. Relate the differences in structure between endo- genous and exogenous stems. Describe their respective modes of growth. 7. What is the food of plants ? how do they obtain it ? and how do they make use of it ? 8. Describe the component parts of a simple flower. How is reproduction effected ? 9. Describe the anatomical structure of a leaf, and the formation and office of leaf-stomata. 10. Explain the consequences of flowering upon the health of a plant, and shew how these effects are reme- died in different climates. What practical bearing has this upon horticulture ? 11. Trace tho development of a carpel from a leaf. Describe the different forms assumed by placenta in APPENDIX. 135 compound ovaries, and explain the origin of these variations. 12. Mention the principal modes in which pollen gains access to the stigma. What are hybrid plants, and how are they perpetuated ? 13. Describe the anatomy of a leaf. What are stomata ? 14. What is the placenta in a seed vessel ? Describe the different modes of placentation. Shew how the varieties! of placentation agree with the " altered-leaf theory " of the pistil. 15. Give the characters of the Compositas. How is the order subdivided ? Describe the composite flower, and mention some of the common Canadian examples of this order. 16. Give the peculiarities of Endogens in seed-leaf, leaf, and stem. Subdivide the class. Describe shortly the orders Araceae and Gramineae. 17. Describe the wall of a seed-vessel, and notice its varieties of form. 18. What is meant by the dehiscence of a capsule ? Shew the different modes in which pods dehisce, and give examples of each. 19. Give the characters and orders of Gymnosper- mous Exogens. , 20. Give the charaoters of Kanunculaceae. Describe shortly some of the principal plants of the order. 21. Give some account of the special forms which the leaves of plants assume. 22. What are stipules ? What their size and shape ? 23. Wliat is meant by Imperfect, Incomplete, and Un. symmetrical flowers respectively ? 24. Describe Papilionaceous and Labiate corollas. 25. Write notes on Abortive Organs, Gymnosper- mous Pistil, and Pollen Granule. 26. Distinguish between the essential and non-essen- tial materials found in plants, and notice the non-es- sential. 27. What is vegetable growth ? Illustrate by a ref- 136 APPExNDIX. erence to the pollen granule in its fertilization of the ovary. 28. What is an axil ? What is the pappus ? 29. What are the cotyledons ? What is their func- tion, and what their value in systematic Botany ? 30. Distinguish between Epiphytes and Parasites ; Describe their respective modes of growth, and give ex- amples of each. 31. What is the difference between roots and subter- ranean branches ? Define rhizoma, tuber, corm, and bulb, giving examples of each. How does a potato differ botanically from a sweet-potato ? 32. Describe the calyx and corolla ; what modifica- tions of parts take place in double flowers ? 33. What IS a fruit in Botany ? Explain the struct- ure of an apple, grape, almond, strawberry, fig, and pineapple. 31. What organs appear in the more perfect plants ? In what two divisions are they comprised ? 35. Weak climbing stems distinguished according to the mode in which they support themselves, the direc- tion of their growth, the nature of their clasping organs. 36. Structure and parts of a leaf : What is most im- portant in their study ? Give the leading divisions, and mention what secondary distinctions are required in specific description ? 37. Function of the flower : its origin : its essential and accessory parts : names of the circles and their component organs : circumstances which explain the differences among flowers. 38. Parts of the fully formed ovule and distinctions founded on their relative position. 39. Sub- kingdoms and classes of the vegetable king- dom. SECOND CLASS TEACHERS' CEETIFICATES, PEOYINCE OF ONTAEIO. 1. Name the parts of the pistil and stamens of a flower and give their uses APPENDIX. 137 2. What are Perennial plants ? Describe their mode of life. 3. " There are two great classes of stems, which differ in the way the woody part is arranged in the cellular tissue." Fully explain this. 4. Describe the functions of.leaves. How are leaves classified as to their veinimi! 5. Name and describe the organic constituents of plants. 6. Name the organs of reproduction in plants, and describe their functions. 7. Give, and fully describe, the principal parts of the flower. 8. What are the different narts of a plant ? Describe the functions of each part. 9. State all the ways by which an Exogenous stem may be distinguished from an Endogenous. 10. Describe the functions of leaves. What is the cause of their fall in autumn ? Draw and describe a maple leaf. 11. Name the different parts of a flower, and describe the use of each part. Draw a diagram showing a sta- men and a pistil and the parts of each. 12. What is the fruit? Why do some fruits fall from the stem more easily than others ? 13. Of what does the food of plants consist ? In what forms and by what organs is it taken up, and how is it asssimilated ? Name the substances inhaled and those exhaled by plants, and the uses of each in the economy of nature. 14. Describe fully (1) the plant in Vegetation ; (2) the plant in Reproduction. 15. Describe Fibrous roots, Fleshy roots, and differ- ent kinds of Tap-root. 16. Describe the structure and veining of leaves. /17. "The nourishment which the mother plant pro- vides in the seed is not always stored up in the embryo." Explain and illustrate. ^8. Describe the various modes in which Perennials 138 APPENDED. •'provide a stock of nourishment to begin the new growth.'' 19. Describe fully the organs of reproduction in a plant. Describe the process of germination. ^ 20. What are the parts of a flower ? Give illustra-' tions by diagram, with a full description. 21. Name and describe the principal sorts of flowers. 22. What elementary substances should the soil con- tain for the nourishment of plants ? 23. How are plants nourished before and after appearing above ground ? 24. Tell what you know about the various forms of the calyx and the corolla. 25. Explain the terms Cotyledon, Pinnate, Root- stock, Filament, and Radicle. 26. Explain the terms Papilionaceous, Cruciferous, Silique, and Syngenesious ; and in each case name a jamiiy in the description of which the term under con- sideration may be properly applied. 27. Give the characters of the Rose family. 28. Describe the various modes in which biennials store up nourishment during their first season. 29. Explain the meaning of the terms Sepal, Bract, Raceme, and Stipule. Describe minutely the Stamen and the Pistil, and give the names applied to their parts. '30. Are the portions of the onion, the potato, and the turnip which are capable of preservation through the winter, equally entitled to the name of roots ? Give reasons for vour answer. FIRST CLASS CERTIFICATES. 1. What are the cotyledons? Describe their func- tions, &c. State their value in systematic botany. 2. Describe the difference in structure and modes ol growth of exogenous and endogenous stems. 3. Describe the circulation in plants. *' In the aci of making vegetable matter, plants purify the air foi animals." Explain this fully. APPENDIX. 139 4. What are Phoenogamous plants ? Define Raceme, Corymb, Head, Panicle, Ament. 5. Give the characters of (a) The classes Exogena and Endogens ; (h) The Mint and Lily famihes. 6. To what family do the. Cedar, Clover. Mustard, and Dandelion respectively belong ? 7. Why does a botanist consider the tuber of the po- tato an underground stem ? 8. Give the philosophical explanation of the nature of a flower considered as to the origin and correspond- ences of its different parts. 9. Draw a spathuiate, an obcordate, a truncate, a palmately- divided and an odd pinnate leaf. 10. Explain the constitution of a pome or apple- fruit. 11. What organs appear in the more perfect plants, and in what divisions are they comprised ? 12. Give the function of the flower, its origin, and its essential and accessory parts. 13. Describe the nature and chief varieties of roots, and distinguish between them and underground stems. 14. " As to the Apex or Point leaves are Pointed, Acute, Obtuse, Truncate, Retuse, Emarginate, Obcor- date, Cuspidate, Mucronate." Sketch these different forms. 15. " There is no separate set of vessels, and no open tubes for the sap to rise through in an unbroken stream, in the way people generally suppose." Comment on this passage. 16. The great series of Flowering Plants is divided into two classes. Describe these classes. 17. Give the chief characteristics of the order cruci- fercc (^Cress Family j, and name some common exam- ples of this order. 18. State the difference between definite and indefin- ite inflorescence, and give examples of the latter. 19. Of what does the food of plants consist ? in what form is it found in the soil ? How is it introduced into the plant ? What inference may be drawn respecting the culture of the plant ? 140 APPENDIX. 20. Distinguish weak climbing stems according to the mode in which they support themselves, the direc- tion of their growth, and the nature of their clasping organs, 21. Name the three classes of Flowerless Plants, and give an example oi each. 2i. Explain the terms Spore, Capsule, Bract, Stip- ule, Albumen, and Epiphyte. 28. What are tendrils, and of what organs are they supposed to be modifications ? 24. Give the characters of the Cress Family, and name as many plants belonging to it as you can. 25. Tell what you know about the minute structure and the chemical composition of vegetable tissue. 26. Describe the origin of the different kinds of pla- centas ; and of the different parts of the fruit of the plum, the oak, and the maple. 27. Describe fully the procass by which it is sup- posed that water is carried up from the roots of plants. 28. Give the meaning of the terms stomate, indehis- ceitt, thyrse, glume, pyxis. Distinguish epiphytes from parasites. 29. Describe any plant you have examined ; if you can, tabulate your description. 30. Name all the families of monopetalous dicotyle- dons which you remember, and give the characters of any one of them. McGILL UNIYEESITY. 1. Describe the germination of a plant. 2. Explain the differences in the structure of the embryo. 3. Explain the functions of the itoot. 4. Describe the structures in a leaf, ana expiain their action on the air. 5. Mention the several parts of the stamen and the pistil, and explain their uses. 6. Describe an Achene, a Samara, a Drupe and a Silique. - APPENDIX. 141 7. Describe the differences in the stems of Exogens and Endogens, and the relations of these to the other parts of the plant and to classification. 8. Explain the terms Genera, Species, Order. 9. What is an excuiTent stem, an axillary bud, bud scales ? 10. Explain the terms primoraial utricle, parenchyma, protoplas77i, as used in Botany. 11. What are the functions of the nucleus in a living cell? 12. Explain the movements of the sap in plants. 13. Describe the appearance under the microscope of raphides, spiral vessels, and disc-bearing wood -cells. 14. Describe the structure of the bark of an Exogen. 15. Describe freeh the anatomy of a leaf. 16. Describe shortly the parts and structures denoted by the following terms, spine, aerial root, phyllodium^ cambium, stipmle, rhizcnna. 17. Give examples of phce-nogams, cryptogams, exogens and endogetis, properly arranged. 18. Describe the principal forms of indeterminate inflorescence. 19. In what natural families do we find siliques, didi/U'c/iious sf aniens, labiate corollas, or papjms-bearing achenes. Describe these structures. 20. State the characters of any Canadian Exogenous Order, with examples. 21. Describe the cell- walls in a Uving parenchymatous cell. 22. Describe the fibro-vascular tissues in an Exogen- ous stem. 23. Describe the appearance of stomata and glan- dulai- heirs under the microscope. 24. DefiiiQ pn'seiichymc, corm, cyclosis, thallus. 25. Explain the souices of the Carbon and Nitrogen of the plant, and the mode of their assimilation. 26. Describe the pericarp, stating its normal struc- ture, and naming some of its modifications. 27. Explain the natural system in Botany, and state the gradation of groups from the species upward, with examples. 142 APPENDIX. ONTAEIO COLLEGE OF PHAEMACY. 1. What do plants feed upon ? 2. What do you understand by the terms Acaulescent, Apetalous, Suffrutescent, Culm ? 8. Name some of the different forms of Primary, Secondary, and Aerial Roots, giving examples. 4. Explain the followiug terms descriptive of forms of leaves, giving sketch: — Ovate, Peltate, Crenate, Serrate, Cleft, Entire, Cuspidate, Perfoliate. 5. Explain difference between Determinate and In- determinate inflorescence, giving three examples of each. 6. What organs are deficient in a sterile and a fertile flower ? 7. Give the parts of a perfect flower, with their rela- tive position. 8. Give the difference between simple and compound Pistil, with example of each. 9. Name the principal sorts of buds, and explain how the position of these affects the arrangement of branches. 10. Give description of multiple and primary roots, with two examples of same ; also explain the difference between these and secondary roots. 11. Name the iDrincipal kinds of subterranean stems and branches, and explain how you would distinguish between these and mots. 12. In the classification of plants explain difference between classes and orders : genus and species. 13. Name three principal kinds of simple fruit. 14. When roots stop growing does the absorption of moisture increase or decrease ? Give_reason for it. 15. Upon what do plants live ? Indicate how you would prove your answer correct. 16. In what part of the plant, and when, is the work of assimilation carried on ? . 17. Name three prmcipal kinds of determinate, and some of indeterminate inflorescenc ) ; name the essenti?.; organs of a flo\^er. APPENDIX. 143 18. In -^hat respects do plants differ from inorganic matter ? And from animals ? 19. Describe a Rhizome, Tuber, Bulb ; and say if they belong to the root or stem ; which are Rheum, Jalapa, Sweet Potato, Onion ? 20. Define the difference between natural and special forms of leaves ; between simple and compound leaves. Give example of each. Sketch a counate-perfoliato leaf. 21. Mention the parts of an embryo. Of a leaf. Of a pistil. Of a stamen. Of a seed. 22. What is meant by an albuminous seed ? By dioecious flowers ? By a comj^ound ovary ? 23. What is the difference between determinate and indeterminate inflorescence ? How do they influence growth of the stem ? Give three principal kinds of each. 24. Name the parts of a flower. What ofiice is performed by the ovule ? Name two kinds. 25. Name the parts of a vegetable cell. What are spiral ducts ? 26. In what parts of the plant is the work of absorp- tion carried on ? In what part the work of assimila- tion ? How do plants purify the air for animals ? 27. Explain the natural system of classification in Botany ? Name and characterize the classes of plants. 28. Explain the structure and functions of the Leaf, Bud, Root. 29. Give some of the terms used in describing the shape of a simple leaf as concei'ns (a) its general con- tour, (b) its base, {c) its margin, (d) its apex. 30. Name the organs in a perfect flower ; describe fully the structure of the anther and pollen. What is coalescence and adnation ot tue parts of a flower ? 31. Explain the terms Raceme, Pappus, Coma, Rhi- zome, Pentastichous. 32. State the distinction between Exogens and Endo- gens. 33. What are cellular structures as distinguished from vascular ? What is chlorophyll ? 144 APPENDIX, 34. Mention the organs of fructification, and explain the i^rocess of fertilization in a flowering plant. 35. Explain the structure of a seed, and describe in a few words the process of germination. 36. Djfine what is meant by the following terms : — Morphology, Polycotyledonous, Epiphyte, Peduncle, Stipules. 37. Describe briefly the root stem, leaf, and flower of the common dandelion, giving the functions or office of each. 38. Name some of the most common forms of leaves, giving a few rough outlines. 39. Of what part of the flower does the fruit nomin- ally consist ? What additional parts are in some inp stances present ? 40. Define the terms Drupe, Pollen, Gynandrous, Pome, Adnate. 41. Explain the process of fertilization in flowering plants, and mention the different ways in which it is brought about. 49. Enumerate the different varieties of tissue recog- nized by botaijists, and give their situation in an Endo- genous stem. THE END. i;--^CAxA^ yi.'^t^ :ldi- fj ^//V../// • ^- (Cl^^fi^U c^ /-^ # "11 II «i I J