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Grew and Malpighi, do indeed, represent them years, he thought he was able to trace the reas occurring often in the root, the former refer- mains of the spiral tubes. The slice was taken ing for examples to the roots of plants in general, from the surface of a longitudinal section passing and the latter to those of the asparagus, poplar, through the centre of the trunk, and clear of diconvolvulus, elm tree, and reed; all of which, vergent layers; and the tubes seemed to appear Keith says, “I have examined with great care, most distinct when the slice was so placed as without being able to discover any spiral tubes. to present their longitudinal dimensions to the Senebier says he found them in the root of the light. They seem to resemble ribands wrapped balsams and thorn-apple; in examining which I spirally round a cylinder, rather than to form sewas equally unsuccessful as in examining the parate vessels, which corresponds very well to former. I cannot, however, doubt the accuracy their appearance, even in the succulent parts of of the observations of the above phytologists, many plants, as described by Knight. Some of and can only set down my own want of success them seemed even separate and entire. And yet, in discovery to the score of some defect, either upon repeated observation, he has not been able in the specimens examined, or in my mode of to satisfy himself entirely on this point; but he examination. Indeed, the only root in which I has stated the case circumstantially, as being the have ever found them, after examining a very probable means of inducing some one to take up considerable number, is that of the common the subject, who may be more felicitous in his ingarden lettuce, know by the name of cos lettuce. vestigations. It cannot be said to be a vain or Having taken the root of a plant that was just fruitless enquiry. For as they are known to putting out its flowers, and stripped it of its have existed at least in the tender shoot, it will bark, I then cut it partly across, about the middle follow that they must exist, in one shape or of its length, and broke the remainder of it other, in the matured wood also. And if their gently asunder. On examining the surface of spiral form is there obliterated, under what other the fracture with the microscope, fragments of aspect do they now appear? It seems certain, spiral tubes were seen projecting from it near the from the observations of Hedwig, that they ascentre. They did not seem very tenacious of sume a different figure in different stages of the their spiral form; and when once uncoiled did plant's growth. In the peduncle of the colchicum not readily resume it.'
autumnale, the rings of the tubes are closer when 151. The spiral threads are to be found also it begins to appear above ground, than at the in the stem nd branch; but not in all parts time of flowering, from which he concludes, that of them; or at least not in all periods of their they are at length entirely obliterated, and the growth. It seems very doubtful, whether tubes converted into woody fibre. But somethey exist at all in the bark. Daubenton pro- times it is difficult to detect them, even in the fesses, indeed, to have seen them in it; but no young shoot; though they are generally to be obone else ever has; so that we are, perhaps, suf- served by breaking it gently asunder, and then ficiently well warranted in entertaining our examining the surface of the fracture with a midoubts. It seems also very doubtful, whether croscope. In this case they appear in small they exist in that part of the stem which consists fragments, projecting from the surface, and someof matured wood, though Daubenton professes to what uncoiled; but if the shoot is split longituhave seen them in the wood of cedrela; in dinally, a portion of them will sometimes be which case he does not altogether stand alone; found extended longitudinally on the surface of as they are represented both by Grew and the fissure in an uncoiled staie. Hedwig, as visible also in the wood. But they 152. In the stem and branches of herbaceous have not been found in the matured wood by plants, they are generally discoverable, without any other vegetable anatomists. Du Hamel never much difficulty, accompanying the longitudinal met with them in any of the woody parts of fibres, and forming part of the bundles. Keith woody plants, except in the young and herba- has found them in the stem and branches of the ceous branches. Mirbel expresses himself to burdock, even in winter, when the fragments of the same effect. And Mr. Knight, who has ex- the mature plant had become quite indurated by amined the subject perhaps still more recently, means of their exposure to the weather. could not detect them in any of the permanent 153. They are also very easily detected in the parts of such plants, except in the annual shoot. foot-stalk, buth of the leaf and Hower, accompakeith's observations on this subject have had nying, or rather seeming almost entirely to comnearly a similar result. Among many subjects pose, the bundles of longitudinal fibres. This of examination he mentions only the elder, wil- may be well exemplified in the leaf-stalk of the low, hawthorn, cherry, and elm tree. In the artichoke, when young and fresh, in the fibres of three former, he found them only in the annual which they are not only remarkably large and shoot, situated immediately without the pith, or distinct, but also remarkably beautiful; sone of rather imbedded in the alburnum; though in them exhibiting in their natural position the apthe elder some of them seemed to be imbedded pearance of spiral coats, investing interior fibres, even in the pith itself. In the cherry he found rather than that of forming a distinct tube, and also a very few, similarly situated, in the branch seeming when uncoiled to be themselves formed of two years old; but none in wood older than of a sort of net-like membrane. that.' And in the elm tree he has thought he 154. They are discoverable also in the leaf, had discovered them even in the matured wood. though not quite so easily detected as in the leafHaving placed under the microscope a very thin stalk. But if a leaf is taken and gently torn slice, taken from a piece of the trunk of an elm asunder in a transverse direction, fragments of tree, that had been felled at least six or seven the spiral tubes will be seen projecting from the
torn edges, and generally accompanying the internal organisation, so do the latter upou exter
nal peculiarities. 155. They are also to be found both in the calyx 161. Hitherto we have scarcely spoken of the and corolla, but not so generally as in the leaf, flower; that brilliant ornament of plants, which on which account some botanists have decided attracts admiration by the splendor of its colors, rather too hastily with regard to their non-exist- and the delicacy of its texture, by the delicious ence in these parts of the flower. Mirbel says, perfume which it exhales, and by the wonderful no tracheæ are to be found in the calyx nor in mechanism with which it is constructed. Its the corolla, except in the claw. But Keith has base, which acts as an external envelope, is ordifound them most unequivocally in the calyx of arily of a green color, and is called the calyx. scabiosa arvensis; and also in the expansion of The next envelope, which is the most striking, ine corolla of the same plant, as also in the as it is in it that the beauty of the flower resides, calyx, both proper and common, of dipsacus is the corolla. Then succeed the stamens, which sylvestris, and in the corolla of the honey- are generally delicate threads, terminated by a suckle, in which they appear to be placed within dilatation of a particular nature; and the pistilthe nerves, or at least to be closely united to lum, consisting of ovarium and stigma, which them.
in tiine becomes the fruit. These parts generally 156. In the other parts they do not seem to exist all in a single flower, which is then termed occur frequently, or at least it is difficult to detect complete; if a part of the members is absent, them. Malpighi represents them, indeed, as the Aower is termed incomplete. Each organ is occurring in the stamens, but Keith was not for- susceptible of an infinite variety of combinations tunate enough to meet with them in the stamens and modifications in form, in number, in station, of any flower he examined. He looked for them in proportion, or in structure, which give rise to also in the style of many flowers, and found them the smaller divisions of vegetables called genera. in that of the honey-suckle only.
These will be noticed hereafter. The functions 157. According to the observations of Grew only of the organs are to occupy our attention and Malpighi, they are to be met with both in while treating of Vegetable Physiology. fruits and seeds; though Hedwig says, they are 162. The most easy to observe is the corolla ; not to be seen in the cotyledons, except during which is composed of one or more pieces called the process of germination, and that only by petals; in the former state it is monopetalous, in means of their being moistened with some colored the latter polypetalous. The petals are either infusion. But Gærtner says, they are conspicu- equal or unequal in their form or insertion, ous in the thinner cotyledons, even before ger- whence corollas are either regular or irregular. mination takes place; and Reishel is said to have 163. The stamens appear, from their position, detected them even in the plumelet and ra- to bear a direct relation with the corolla ; thus, dicle.
in almost all monopetalous flowers, they origin158. But, in whatever part of the plant they ate from the corolla itself; but in polypetalous are found to exist, they are always endowed with flowers this more rarely happens; then, however, a considerable degree of elasticity, as has been they maintain so many relations with the petals, already noticed. For though they are forcibly being alternate or opposite to them, and equal extended, so as wholly to undo the spires, they or double or multiple in number, that it is imwill again contract, and resume their former possible to doubt of the strict alliance by which figure, when the extending cause is withdrawn; they are connected. The calyx has a yet more and if they are even stretched till they break, the strict analogy with the corolla, the divisions of fragments will again coil themsclves up as be- which are almost always equal in number to fore. It has been said, however, that those of those of the calyx, and alternate in insertion, the butomus umbellatus, if once uncoiled, will especially when the corolla arises immediately eontract again no more. But this is true only from the calyx. It often happens that it arises when they are stretched to a great length. For from a particular place which is called the recepwhen they are stretched gently and moderately, tacle. These three parts, then, have a great they will again contract, as has been proved by analogy with each other; so that one does not experiment.
vary in the number of its divisions, without 159. Malpighi, in the course of some obser- affecting the two others by the change. They vations on the spiral tubes during the winter are themselves, however, subordinate to the season, fancied he had perceived a sort of vermi- pistillum. cular and spontaneous movement in them. But *163. There is generally only one pistillum in he thought he saw this movement only once, and flowers; occasionally two or more: but these vaas it has never since been seen by any subse- riations in number are independent of the other quent observer, it appears that we must be con- organs. The ovarium has then a more obvious tent to set it down to the score of microscopical relation : it is seated in the centre of the flower, deception, or to the effect of the atmosphere at the bottom of the calyx, to which it is attached upon the tubes when exposed to its action. by its base; sometimes a cohesion takes place
160. We have now run over the differences of between the sides of the calyx and ovarium, which the most important kind, by which the functions latter then appears to support the flower like a of what Darwin not inaptly called the viviparous footstalk. From these two modifications arise system of vegetation, are affected. Let us now those two important distinctions among plants, proceed to consider the nature and destination of ovarium superius, separate from the calyx, of the oviparous system, or of the parts of repro- and ovarium inferius, or adhering to the calyx; duction by seed. As the former depend upon differences which are of extreme importance in characterising many of the most natural of the some cases separated upon the same tree, or systematic combinations of modern botanists. upon different trees, and the agency of the wind
164. In some flowers the corolla disappears, or or of insects, is requisite to enable them to acis not developed, in others the calyx seem to be complish their destiny. wanting. Touching this fact, has arisen a dis- 168. The relation, therefore, of the stamens to quisition, which seems to have no end, as to the pistillum, gives rise to some further conside what name ought to be applied to the envelope rations. When they are united in one flower, of a flower when one envelope only is present. the flower in that case is called hermaphrodite; if By whatever name this single envelope may be they are in separate flowers, it is declinous; it is called, it bears the same relation to the other parts monæcious when the male and female are preas the calyx and corolla when both are present; sent in different flowers of the same individual; it is in some cases itself almost obliterated, and diæcious, if in flowers of different individuals. there are some flowers which consist only of Some plants have male and female flowers mixed stamens without corolla, and which are then called with such as are hermaphrodites; then they are naked.
called polygamous. 165. When both calyx and corolla exist toge- 14. The pistillum offers a multitude of most ther or one of them only, another set of organs important characters. Its ovary is terminated by occasionally disappears, namely the stamens, and one or several styles, and each of the latter has then the pistillum is found alone in the centre; one or more stigmata. The ovarium either conbut in this case it always happens, that, either tains only one rudiment of a seed, called ar upon the same plant or upon a different indivi- ovulum, or several, and is divided internally into dual, flowers exist which contain stamens only, one cell
or many. and no pistillum. Sometimes both organs are 170. The fruit, which is the necessary consedeveloped without covering, and separate from quence of the ovarium, is generally like it in the each other. However these two parts may be number of its parts; the occasional abortion of separated from each other, they always appear at some one of the latter, is the only way in which the same period of time, and, ever since the study the number of parts is smaller in the fruit than of plants has been an object of philosophical re- in the ovarium.' The form, the texture, and the search, no instance has been found of a perfect volume of fruit give rise to an infinity of diffeplant in which both organs did not co-exist. rences. Thus one sees, on the one hand, soft
166. It appears therefore, from this example, pulpy fruit, and, on the other hand, nuts, the and from many others which could be brought shell of which is hard as wood itself. The manforward, that the stamens and the pistil are the ner in which the seeds are attached is also subonly essential parts of a flower; a fact which is ject to variation, for they either proceed from a not surprising as far as the pistil is concerned, central receptacle, or from the paries of the fruit. because we have seen that it contains the rudi- The point from which they proceed is, in all ments of the future progeny. But what manner cases, called the placenta. This organ is of of influence is exercised by the stamens? If we great importance; for it is not only the medium examine them in every flower within our reach, through which the fecundating effluvia of the we shall find that they have a similar structure : pollen is communicated to the ovula, but also we shall see that they consist of two parts, the through which the juices are elaborated, which upper resembling a little bag, generally yel- are required for the development of the embryo. low, and always divided into one or two cells, It may be compared to the placenta of animals. which contain a kind of powder, and the lower • 171. The position of the embryo, with relation resembling a thread-like stalk to the former. to the fruit, is also a point of importance. Thus The former is called the anther, and the latter the axis of the seed may be parallel with the the filament. The powder which it contains, axis of the fruit, and fixed by the basis, which is examined through a microscope, consists of gra- the most natural position; then the seed is callnules, varying in size and form according to their ed erect. It may become horizontal ; or being species, and sometimes so remarkably, that it is affixed to the summit of the cell it may become ofien possible to distinguish genera by the in- inverted; it is in the latter case said to be penspection of the granules only. Thrown into dulous. For various modifications of the posiwater they swell, and eventually burst, emitting tion of the seed, see Seed, under Pure BOTANY. a peculiar fluid which resembles vapor. The 172. Each seed may be considered as an isoname given to the granules is pollen.
lated individual; for nature has prepared them 167. From the combination of these observa- for separation from their parent without incontions, we come to an important discovery; we venience. Their interior consists of a substance perceive that the petals, with the brilliant tints of of various degrees of texture, which is called the every color of the rainbow, are in fact the cur- albumen, and of the fleshy body already mentains of the nuptial bed of Flora, within the pro- tioned as the seminal embryo. The albumen may tection of which the mysteries of generation are be absent, the embryo must be present. The accomplished. We have, therefore, sexes in coat of the seed consists of two layers, the inplants; these, indeed, appear almost indispensa- terior of which is much more membranous than ble. In most animals they are separated; but in the exterior. vermes we see them confounded, and at length 173. But now arises a problem in vegetation disappear entirely. The want of the power of which it is very important to resolve. Whence motion in vegetables renders their union in one is the origin of the flower ? Linnæus has offered individnal of great importance. But, as if the an explanation, which he considered capable of resources of nature were illimitable, they are in of meeting every difficulty, and which he bor
rowed from Cæsalpinus, whose knowledge ran 177. The pistillum, which is the terminating far beyond that of his age. According to these point of the line of vegetation, is now ascertained two authors the flower is only a manifestation of to be, not, as was formerly supposed, an anomathe interior of a plant. The epidermis and lous organ, which was referable to none of the cuticle give rise to the calyx, the fibre to the co- simple types upon which the other parts of rolla, the woody fibre to the stamen, and the pith fructification are modelled, but a leaf or leaves to the pistillum; this last part is the most esseu- also in a state of greater affinity to their type than tial, and the centre of vegetation; the others are any other organ. The style is an alteration of only accessory;
the middle nerve, the stigma a secreting surface 174. But this ingenious notion, like many proceeding from the tip of the same part, the other brilliant hypotheses, will not bear a strict sides of the ovarium the two halves of the leaf, scrutiny. The nature of the pith is now better and the placenta the edge of the leaf. This is undersiood, and instead of being a creating organ, tolerably obvious in a strictly simple unilocular it is itself, in fact, a body in a state of disorgani- ovarium, such as one segment of a Pæony fruit. sation. A single fact has overthrown the whole But in a many-celled pistil it is not so apparent. theory: this is the more intimate knowledge of Mr. Robert Brown, however, has demonstrated, the interior of palms, and other monocotyledo- that all multilocular compound ovaria are merely
According to the arrangement of an aggregation of a number of simple ovaria their interior, and the mixture of the pith and round a common axis; that the cells are woody fibre, it would happen, if Linnæus's theory occasioned by the interposition and cohesion of were true, that the flowers of the palm would have the sides of simple ovaria, which in that slate are quite another arrangement from that of other called dissepiments. plants, and that the parts would neither be 178. Besides the plants which are furnished arranged round a centre, nor be placed in the with a flower, there are others in which no same relation to each other.
apparent flowers exist, which are constructed 175. It appears certain, that, notwithstanding differently from either monocotyledonous or dicothe striking differences which all parts of a tyledonous plants, and whose methods of reproflower exhibit, they have all the same origin; duction are quite of another nature. These plants which is indicated by the propensity they all are called cryptogamous, and consist of ferns, have, under certain circumstances, of changing mosses, hepaticæ, lichens, algæ, and fungi. They into each other from circumference to centre, or are all supposed to be destitute of cotyledons, of reverting to one common appearance; which whence they are also named acotyledonous. is that of the leaf. . Upon this subject Mr. Lind- 179. In ferns, which are by some authors ley remarks,' that it is well understood that the referred to monocotyledons, the mode of growth universal principle upon which perfect vegeta- resembles in some measure such plants. The bles are formed, is by the continual addition of grain from which they are reproduced, and parts one above the other, round a common axis, which is called a sporule, in germination dilates which is produced by their accretion. This law into a very small leaf of a particular kind, which is not confined to the production of foliage, or successively gives rise to others, which finally branches only, but must be considered to extend acquire the stature and the form of adult leaves. to the ultimate point of vegetable development in A species of trunk or stipes, similar to that of the ovarium; and seems to indicate that the pro- the palm, creeps along the surface of the earth, gress of nature is continually onwards. Unless, or elevates itself above it. Its internal structure therefore, it should be shown that the order of separates it as far from monocotyledons as from alteration in the structure of organs so produced dicotyledons. It has, however, at the first sight, is in monstrous formations reversed, it would be the grcatest resemblance to the former ; a section a reasonable inference that nature follows her of it offers, as in mon
onocotyledons, certain scatusual course in transformation, as well as in tered points, among a mass of parenchyma. original production; and that the changes which These points, which vary in almost every differparticular portions of a flower may undergo, ent species, are a section of a peculiar substance, always have the character of that series which is which is divided at the base, and united at the placed next them in the inside, and not of that summit, and which may be compared in texture on the outside. The consequence of the preva- to the liber of dicotyledons. It is surrounded lence of such a law would therefore be this, with by a fur, which is more or less apparent, and respect to the formation of double flowers, that more or less deeply colored, and which seems bracteæ, if present, would change into calyx, analogous to the woody texture, especially as in calyx into petals, petals into stamens, and sta- arborescent ferns it is it which forms the solid mens into ovaries; and that the reverse of that substance. Both these substances are distribuorder could vot take place.'
ted among the nerves of the leaves, which are 176. It may thence be concluded that a flower simple, ramified, or verticillated, according to the is a leaf-bud in a particular state of alteration; species. In the opinion of a celebrated modern that the calycine lobes, the petals, the stamens, physiologist, a fern may be considered as a plant the pistillum, are all leaves in an altered form, iurned inside out. and that they have all a tendency, which may 180. The remaining classes of cryptogamia now and then manifest itself, of assuming their consist entirely of cellular tissue, amassed in primitive habit and structure. Whence they different proportions, and under various forms. arise, or in what way this extraordinary meta. They are destitute of woody vessels or of tracheæ, morphosis takes place, we are as yet unable to and have no distinction between bark, wood, determine.
and epidermis; they may perhaps be considered to consist wholly of the latter and former con- smooth that it reflects the rays of light, and has a founded.
shining or glancing appearance, as in the leaves
of the holly, Ilex aquifolium. IV.-PURE BOTANY.
2. Dull (opacus), when the surface does not 181. We have thus considered botany with reflect the rays, and is entirely void of lustre. respect to its analogies, its history, and its 3. Even (lævis), without striæ, furrows, or physiology. It now remains for us to explain its raised dots. It is the opposite of Nos. 6, 7, 23, practical details, as applied to what is called 24, 25, 28, and 29. Systematic Botany, or the science of arranging 4. Smooth (glaber), when there are no visible the natural objects of which it consists.
hairs, bristles or thorns. It is the opposite of 182. The materials of this branch of the science Nos. 8, 22, 26 and 27. are the modifications of parts; from a just appli- 5. Dotted (punctatus), where small fine dots cation of these materials result classifications. are perceived by the eye but not by the touch. We shall first attend to modifications.
Thymus vulgaris. 183. All perfect plants consist, as has been 6. Scabrous (scaber), where small raised dots already seen, of the following organs. 1. The are felt but not seen; as in Carex acuta. Root; 2. the STEM; 3. the FOLIAGE; 4. the 7. Rough (asper), when these dots are both INFLORESCENCE; 5. the FLOWER; 6. the FRUIT. felt and seen. Pulmonaria officinalis. Each of these organs must be considered sepa- 8. Hispid (hispidus), beset with very short rately. But, before entering upon an explana- stiff hairs. Myosotis arvensis. tion of the peculiarities of each of them, it will be 9. Hirsute (hirtus), where the hairs are modeproper to notice the terms used in speaking of rately long but very stiff. Echium vulgare. their size, surface, and color; these terms being 10. Hairy (pilosus), beset with long single applicable to each of the six parts into which a bairs, somewhat bent. Hieracium pilosella. plant is divisible.
11. Villous (villosus), where the hairs are 184. There are eleven terms which are em- long, soft, and white. Stachys Germanica. ployed to designate the size or measurement of a 12. Pubescent (pubescens), overgrown with plant or its parts, viz. :
short fine white hairs. Oenothera mollissima. 1. A hair breadth (capillus), the measure of 13. Silky (sericeus), when the surface is white a hair, or the twelfth part of a line.
and shining, by means of thick and almost in2. A line (linea)," the length of the white visible hairs. Potentilla anserina. crescent at the root of the nail of the middle 14. Woolly (lanatus), when the surface is beset finger, or the twelfth part of an inch.
with long thick white hairs, easily distinguished. 3. A nail length (unguis), the length of the Stachys lanata. nail of the middle finger, or half an inch.
15. Tomentose (tomentosus), when fine hairs 4. An inch (pollex, uncia), the length of the are so matted together that the particular hairs first joint of the thumb, the twelfth part of a cannot be distinguished. In this case the surfoot.
face generally appears white, as in Verbascum; 5. A hand breadth (palmus), the breadth of or of a rust color, as in Ledum. the four fingers of the hand, or three inches. 16. Bearded (barbatus), when the hairs are in
6. A span (dodrans), as far as one can span tufts. Mesembryanthemum barbatum. with the thumb and the little finger, or nine 17. Strigose (strigosus), when the surface is inches.
armed with small, close-lying bristles, which are 7. A small span (spithama), as far as one can thickest below. Lithospermum officinale. span with the thumb and fore finger, or seven 18. Stinging (urens), when a painful burning itaches.
sensation is caused by small hairs. Urtica. Such 8. A foot (pes), the length from the elbow to hairs are called stimuli. the wrist, or twelve inches.
19. Fringed (ciliatus), when on the margin of 9. A cubit (cubitus), from the elbow to the a leaf, or the surface of a stalk, there is a row of point of the middle finger, or seventeen inches. hairs of equal length.
10. An ell (ulna, brachium), the length of the 20. Warty (papillosus), when small fleshy whole arm, or four and twenty inches.
warts appear. Aloe margaritifera. 11. A fathom or toise (orgya), the length of 21. Pustular (papulosus), when there are small the arms stretched out from the tip of one middle hollow bladders. Mesembryanthemum hispidum. finger to that of the other, or six feet.
22. Muricated (muricatus), armed with small for these the following have been substituted short herbaceous spines. Asperugo procumbens. by some French botanists :
23. Scaly (lepidotus), when the surface is The millimètre 1 of a line.
covered with small scales closely placed, by The centimètre = 4 lines
which means the color is changed, as in Elæagnus The decimètre = 3 inches 8 lines to
angustifolia. The mètre = 3 feet 11 lines from
24. Mealy (farinosus), when the surface is 185. The surface of plants is of great import- thickly covered with a white powder, as in Priance in distinguishing the species and varieties of mula farinosa. plants, but is not of value in generic discrimina- 25. Hoary (pruinosus), when the surface is tion. The terms which follow are, or ought to strewed with a very fine white dust, like the fruit be, used precisely in the sense here ascribed to of some plumbs. Prunus domestica. them; they are extremely well defined by Will- 26. Glutinous (glutinosus), when the surface denow, who limits them thus :
is covered with an adhesive matter, which is 1. Shining (nitidus), when the surface is so soluble in water. Primula glutinosa.