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One variety of the holly has, in addition to a yellow variegation, a beautiful tinge of purple, but this is a rare instance. In the amaranthus tricolor the leaves are naturally adorned with most beautiful and splendid colours, and some in other species of the same genus with more uniform and less vivid tints.

The irritable nature of some leaves is remarkable, not but that all leaves may truly be said to possess irritability with respect to light. The phenomena however to which we now allude are of the most striking kind. The sensitive plant, mimosa pudica, common in hot-houses, when touched by any extraneous body, folds up its leaves one after another, while their foot-stalks droop as if dying. After a while they recover themselves again. Each leaf of the dionæa muscipula, or Venus's fly-trap, is furnished with a pair of toothed lobes, which, when touched near the base, fold themselves together, and imprison any insect that may be in their way. It is presumed that the air evolved by the body of the dead insect may be wholesome to the plant, for leaves are known to purify air impregnated with carbonic acid gas produced from the breathing of animals or the burning of a candle. The sarracenia, of which several species from America are now cultivated in our more curious gardens, bears tubular leaves which retain water in their hollows, and imprison insects, whose putrefying bodies evidently produce a quantity of bad air, and analogy leads us to suppose that air is destined to be serviceable to the constitution of the vegetable. See Dr. Smith's Introduction, page 195.

Many important botanical distinctions are founded upon the situations and forms of leaves. These are explained by the following terms.

Folia radicalia, are radical leaves, as in the primsose.

F. cautina, stem, leaves, and ramea, branched leaves. The situation of the latter is either alternate, opposite, scattered, or clustered. Several leaves standing round a stem or branch are termed verticillata, whorled: such as either ter. nate, quaternate, or quinate, &c.

F. imbricata, imbricated, lie one over the other like tiles upon a house.

F. decussata, cross each other in pairs alternately, as in many plants with opposite leaves.

F. disticha, two-ranked, spread in two directions like the yew.

F. secunda, unilateral, lean all towards
VOL. II.

one side. Some leaves are erect, others reflexed or recurved; but the greater part spread more or less horizontally. A few are obliquely twisted, and still fewer are reversed, resupinata, what should be the upper surface becoming the under, as in the beautiful alstrameria. Curt. Mag. t. 139.

F. petiolata, are such as stand on footstalks; sessilia, sessile leaves, grow immediately from the branch or root without any stalk.

F. peltata, peltate leaves, have the footstalk inserted into their centre, like the handle of a shield, to which the name alludes, witness the common nasturtium trapæolum.

F. amplexicaulia, clasp the stem or branch with their base.

F. decurrentia, run down the same part in the form of a leafy border, as in many thistles.

F. connata are united at their base. F. perfoliata have the stem running through them, as in hair's-ear, bupleurum rotundifolium.

F. vaginantia sheath the stem on each other, as in most grasses.

F. equitantia clasp each other in two opposite rows, being compressed at the base, as in many common species of iris.

The form of leaves is either simple, as in grasses, lilies, &c. or compound, as in parsley, elder, roses, &c. Simple leaves are either integra, undivided, like those just mentioned, or lobed, like the vine, holly-hock, and many others.

The following forms of simple leaves respect their outline only.

Folium orbiculatum, as nearly circular as possible, which is very rare.

Subrotundum, roundish, is much more

common.

Ovatum, ovate, the shape of an egg, very frequent.

Obovatum, obovate, the same figure, with the broad end uppermost.

Ellipticum or ovale, elliptical, or oval, being broadest in the middle.

Oblongum, oblong, several times longer than broad, without any very decided form.

Spatulatum, spatulate, of a roundish figure, tapering into an oblong base. Cuneiforme, wedge-shaped, broad at the summit, tapering down to the base.

Lanceolatum, lanceolate, narrow, and oblong, tapering towards each end, a very common sort of leaf, as in willows.

lineare, linear, narrow, with parallel sides, like most grasses.

Acerosum, needle-shaped, linear, and

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evergreen, generally acute, and rigid, as in the fir, juniper, &c.

Triangulare, quadrangulare,quinquangulare, express the number of angles, without any allusion to their measurement. Daltoides, trowel-shaped, or deltoid, has three angles, of which the terminal one is the most acute.

Rhombeum, rhomboid, nearly square. Reniforme, kidney-shaped, as that of the asarabacca.

Cordatum, heart-shaped, which is extremely common.

Lanalatum, crescent-shaped, whether the points are directed backwards or forwards.

Sagittatum, arrow-shaped, triangular, with the posterior angles much elongated. Hastatum, halbert-shaped, triangular, the lateral lobes spreading horizontally. Panduriforme, fiddle-shaped, as in the fiddle dock.

Runcinatum, runcinate, or lion-toothed, cut into several transverse acute reflexed segments, like the dandelion.

Lyratum, lyrate, or lyre-shaped, cut into several transverse segments, gradually larger towards the extremity of the leaf, which is dilated and rounded.

Fissum, cloven, when the fissures are linear or straight.

Lobatum, lobed, when the segments are rounded.

Sinuatum, sinuated, cut into rounded, dilated openings.

Partitum, deeply divided, almost to the base.

Laciniatum, laciniated, cut into various irregular portions, as if torn.

Incisum, and dissectum, express somewhat of a more regular kind of division.

Palmatum, palmate, cut into several oblong segments, leaving an entire space at

the base.

Pinnatifidum, pinnatifid, cut into several transverse parallel segments.

Bipinnatifidum, doubly pinnatifid. Pectinatum, pectinate, pinnatifid, with remarkably narrow segments, like the teeth of a comb.

Inequale, unequal or oblique, when the two halves of a leaf are unequal, and their bases not parallel.

A leaf in its termination is either truncatum, abrupt; præmorsum, jagged-pointed, having various irregular notches, as if bitten; retusum, ending in a broad shallow notch; emarginatum, with a small acute notch; obtusum, ending in a segment of a circle,; acutum, terminating in an acute angle; acuminatum, having a taper point; obtusum cum acumine, blunt,

with a small point; mucronatum or cuspidatum, tipped with a spine; or cirrosum, tipped with a tendril.

A leaf, with regard to its margin, is either integerrimum, entire, as in the lilac ; for it must be observed, that integrum means an undivided leaf; spinosum, beset with prickles, as in thistles, which is opposed to inerme; ciliatum, fringed with soft hairs; cartilagineum, hard and horny; dentatum, toothed; serratum, serrated, the teeth like those of a saw, pointing forwards, serrulatum, minutely serrated; crenatum and crenulatum, notched with little rounded scollops, as in ground ivy; erosum, jagged; repandum, wavy; glandulosum, glandular; revolutum, having the margin turned or rolled backwards, of which involutum is the reverse; or conduplicatum, having the margins folded together.

A leaf, as to its disk, is either rugosum, rugged; bullatum, blistery; plicatum, plaited like a fan; undulatum, waved obtusely up and down; crispum, elegantly curled and twisted, which is generally a preternatural luxuriance; concavum, hollow in the middle; venosum, veiny; nervosum, ribbed, the principal veins or ribs extending in simple lines from the base to the point; avenium, without veins; enerve, without ribs; trinerve, three-ribbed; triplinerve, triply-ribbed, when the lateral ribs branch off above the base ; basi trinerve, when the base is cut away close to the lateral ribs, as in burdock.

A few other terms relating to leaves in general deserve mention. F. carnosum is a fleshy leaf, such as belongs to those called succulent plants. The internal pulp of these seems to have no share in their peculiar functions as leaves; but to be a reservoir of moisture, and some degree of vitality. F. nudum means a leaf destitute of all clothing or hairiness whatever: the same term applied to a stem, means that it bears no leaves, and to a flower, that it has no calyx. F. tubulosum, is a tubular leaf, as in several species of allium; lobelia dortmanna, has a leaf formed of a double tube; canaliculatum, expresses a leaf with a longitudinal furrow; carrinatum, one with a prominent line like a keel at its back; ensiforme, the sword-shaped, or two-edged leaf of the irises; alcinatum, is used by Dr. Smith, "when the first leaves of a plant give place to others totally different from them, and from the natural habit of the genus, as in many mimosæ of New-Holland;" the first leaves of these are pinnated, the subsequent ones dilatations as it were of

the naked foot-stalks; appendiculatum, is used by the same author for a leaf "furnished with an additional organ for some particular purpose," as in dionæa muscipula above mentioned, and nepenthes destillatoria, the leat of which bears a sort of covered pi cher full of water. We omit to particularize the more common terms which are to be found every where. Compound leaves come principally under the following denominations.

F digitatum is when several leaflets, or partial leaves, stand on the summit of a common foot-stalk. Such are either two,

three, or more. F. pinnatum, a pinnate leaf, is composed of leaflets ranged laterally on the foot-stalk; when it has no terminal leaflet, it is said to be abruptly pinnate; sometimes a tendril takes place of the odd leaflet, as in the pea and vetch. The leaflets are either opposite or alternate; sometimes they are interrupted by an intermediate series of smaller ones, as in spirea filipendula, dropwort. F. lyratopinnatum resembles a lyrate leaf, as in the turnip. F. auriculatum is a simple leaf, with a pair of auricles or leaflets at its base. F. pedatum has three primary leaflets, of which the lateral ones are lobed in their fore part, as in helleborus fœtidus. The different degrees in which leaves are compounded are thus expressed F.compositum is simply compound; decompositum doubly compound: supra decomposi

tum, thrice compound, or more; of all which the umbelliferous tribe afford examples; begeminatum and tergeminatum are twice and thrice paired; ternatum consists of three leaflets: biternatum is twice ternate, and triternatum thrice ternate. In

the same manner, pipinnatum is doubly pinnate, and tripinnatum triply pinnate.

OF THE FULCRA, OR APPENDAGES OF
PLANTS.

There are various appendages to the herbage of plants, all of which are comprehended by Linnæus under the term of fulcrum, a prop or support, which term in its literal sense, however, applies but

to a few of these organs.

1. Stipula. This is a leafy appendage

to the true leaves, or to their stalks, for

the most part in pairs, more or less constant even in the same genus or species: in roses they are invariable; in willows very much the contrary. Some species of Cistus have stipulas, others none. The peculiar stipula of grasses is a membrane, crowning the sheaths of their leaves and embracing their stem, but it is not found in all the species. Plate 1. fig. 18.

2. Bractea, is a leafy appendage to the flower or its stalk, conspicuous in the lime-tree, beautifully coloured in the purple or pink-topped clary, and very much diversified in different plants. Fig. 19.

3. Spina, a thorn, proceeds from the wood itself, as in the wild pear-tree, which loses its thorns by cultivation. This is fcifully expressed by Linnæus, who cals such garden plants tamed, or deprived of their natural arms.

4. Aculeus, a prickle, proceeds from the bark only, having no connection with the wood, as in the rose, bramble, &c. It might be expected that this should be less permanent than the foregoing, but the reverse is the case, for prickles are. not effaced by culture. They rather abound most upon the most luxuriant stems. Plate II. fig. 21.

5. Cirrus, a tendril or clasper, is really intended as a support for weak stems, by which they are enabled to climb rocks, or the trunks of lofty trees. These organs are either simple or branched, straight in the first instance, but soon becoming spiral, and thus are rendered capable of taking hold of any thing that comes in their way; especially as many of them are so constructed, that, after having made a certain number of turns, they perform as many in a contrary direction. Some attach themselves by a dilatation of their

extremities to the smoothest and hardest stone.

Thus, the vine, the passion-flower, and the family of vetches, are elevated to a considerable height above the ground. Such tendrils differ essentially from roots, in never imbibing nourishment, any more The than the short fibres of the ivy. gloriosa, or superb lily, has a spiral tendril at the end of each leaf, and in some few plants the flower stalks produce tendrils. Plate I. fig. 22.

6. Glandula, a gland, is a small tumour secreting a sweet, resinous, or fragrant liquor, as on the calyx of the moss-rose, the foot-stalks of passion-flowers whose glands are like little cups, and the leaf of salix pentendra: which last being sion of an elegant row of yellow dots. pressed between paper,leaves the impresFig 23.

7. Pilus, a hair. Fig. 24. Under this are included all the various kinds of pubescence; bristles, wool, &c some of which are curious objects for the microscope. Some few of these bristles discharge a poison, as in the nettle, causing great irritation, whenever they are touched in such a manner as for their points to

wound the skin. Hence arose the fol- and wall-flower. The yarrow and mounlowing lines:

"Tender handed touch a nettle,

And it stings you for your pains; Grasp it like a man of mettle, And it soft as silk remains."

OF THE DIFFERENT KINDS OF INFLORESCENCE, OR MODES OF FLOWERING.

The various modes in which flowers are situated upon or connected with a plant, are of great botanical importance, not only for specific distinctions,but as leading the way to the knowledge of natural families or orders. Yet Linnæus does not allow them to enter into the generic characters of plants, which he founds solely on the seven parts of fructification to be hereafter described. This is one of those classical maxims of the Linnæan school, which rival botanists are continually attempting to undermine and depreciate, conscious of their own deficiency in that technical skill for which Linnæus was pre-eminent. We shall take occasion to mention an instance in which he himself went counter to this law.

The following are the several kinds of inflorescence.

1. Verticillus, a whorl, in which the flowers surround the stem in a garland or ring, though perhaps merely inserted on its two opposite sides, as in the natural order to which the mints, the dead nettle, Lamium, and many others, belong. Fig. 25.

2 Racemus, a cluster or raceme, bears several flowers,each in its own stalk, loosely ranged along one common stalk, like a bunch of currants, and this common stalk may be either simple or branched. A racemus is generally drooping or pendulous, and the flowers are all nearly in perfection at once. Fig. 26.

3. Spica, a spike, is composed of numerous crowded flowers, ranged along an upright common stalk, expanding progressively and properly, destitute of any partial stalks; but this last circumstance cannot be rigidly observed. Wheat and barley are good examples of a genuine spike. Some lavenders have a compound spike. Spicula, a spikelet, is a term used only for grasses, and expresses that assemblage of florets in a common calyx which constitutes their flowers. Fig. 27.

4 Corymbus, a corymb, fig. 28, may be called a flat-topped spike, the long stalks of whose lowermost flowers raise them to a level with the uppermost, or nearly so; this is exemplified in the cabbage

tain-ash bear a kind of compound and irregular corymbus, to which is nearly allied,

5. Fasciculus, a fascicle, expressive of a close bundle of flowers, on little stalks, variously connected and level at the top, as in the sweet-william. Fig. 29.

6. Capitulum, a head or tuft, is composed of numerous sessile flowers, collected into a globular form, as the globe amaranthus and thrift. Fig. 30.

7. Umbella, an umbel or rundle, consists of several stalks, called rays, spreading from one common centre, like an umbrella. Each stalk is either simple and singleflowered, or, as most commonly occurs, subdivided into an umbellula, or partial umbel. This inflorescence belongs to a natural order, thence called Umbellate, to which the parsley, carrot, hemlock, and many others belong. Fig. 31.

8. Cyma, a cyme, consists of stalks springing from one common centre, but which are afterwards irregularly subdivided, as in the laurustinus and alder, fig. 32. Linnæus was led by some considerations to reckon these two last forms of inflorescence as aggregate flowers, but it is found more correct to esteem them modes of inflorescence, though by so doing we lose the advantage of taking parts properly belonging to the umbel into the generic character. By a contrary mode of proceeding we presume to think Linnæus swerved from his own rule of founding his genera on the actual parts of fructification.

9. Panicula, a panicle, Plate III. fig. 33. is a loose subdivided bunch of flowers, arranged without order, as in the oat. It is either close or spreading. When its branches lean all towards one side, it is called Panicula secunda.

10. Thyrsus, a bunch, is a very dense panicle, inclining to an ovate figure, of which Linnæus cites the lilac and the butter-bur as instances. Dr. Smith adds to these a bunch of grapes, which appears to him to have been inaccurately reckon. ed a racemus. Fig. 34.

OF THE FRUCTIFICATION OF PLANTS.

Under the term fructification are comprehended, not only all the parts of the fruit, but also those of the flower, which last are indispensable for the perfecting of the former. All these organs are, therefore, essential to a vegetable, which may be deficient in any of those that we have previously described, but can never be

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The parts which constitute these essential organs are seven. 1. Calyx, fig. 55, the flower cup, or external covering of the flower. This also is of seven kinds. 1. Perianthium, or calyx, properly so called when it is contiguous to and makes a part of the flower, as the five green leaves which encompass a rose, including their urn-shaped base 2. Involucrum, which is remote from the flower, as in the umbelliferous tribe; but if the idea of these plants, as above expressed, be just, the part in question ought rather to be considered as a bractea. 3. Amentum, a catkin, is formed of numerous scales attached to one cylindrical receptacle, and falling off with it: in catkins which bear seed the scales are often enlarged, and hardened into a cone, as in the fir. 4. Spatha, a sheath, bursts longitudinally, and is more or less remote from the flower, as in the snow-drop, narcissus, and arum. 5. Gluma, a husk, is the peculiar chaffy calyx of grasses and their allies: to it belongs the arista or awn, which however is not constant in the same species of grass or corn: an elegant feathery awn is seen in the stipa pennata, feather-grass. 6. Perichatium, a scaly sheath, investing the fruit-stalk in some mosses, as hyp7. Volva, the wrapper of the Fungus tribe, is either of a membranous kind, sheltering their fructification, as in the common mushroom, or more coriaceous, investing the base of their stalk, as in many fungi.

num.

2. Corolla, fig. 36, the delicate, generally coloured, leaves of a flower are always situated within the calyx, when both are present. This term comprehends both the petal, petalum, and the nectary, nectarium. A Ĥower consists of one petal, or of several, the former, denominated monopetalous, is either campanulate, funnel-shaped, salver-shaped, wheel shaped, ringent like the mouth of an animal, or personate, closed by a palate. Its parts are the tube and the limb. A polypetalous corolla is either cruciform, as in a wall-flower, rosaceous, papilionaceous, as in the pea-kind, or incomplete, when some parts found in analogous

flowers are wanting. The parts of a polypetalous corolla are the claw and the border. The great point to be considered with respect to the corolla in general is, whether it be regular or irregular: in some flowers, however, it varies in the same species from one shape to the other, witness the genera antirrhinum and bignonia.

Neither the calyx nor corolla is indispensably necessary to a flower. Both are wanting in hippuris, and one or other is deficient in many genera. Hence botanists are led into a perplexity, how, in some cases, to denominate the part which is present. When its green colour and thick texture agree with the generality of flower cups, we do not hesitate to esteem it such; but a calyx is often beautifully coloured, and there is some doubt whether the splendid leaves of tulips and lilies be not a true calyx; at least they answer to the Linnæan definition, that their parts are opposite to the stamens, whereas those of a corolla should be alternate with the latter. The Linnæan hypothesis, however, though sanctioned by Jussieu, of the corolla proceeding from the inner bark, and the calyx from the outer, is entirely subverted by recent and more correct observations on vegetable physiology. The functions of these two parts are, logous. Those of the calyx probably reperhaps, though similar, not exactly anasemble what are performed by the leaves, and this part is presumed by Dr. Smith even to secrete woody matter, for rolla, indeed, seems destined to answer strengthening the fruit-stalk. The cosome exclusive purpose to the essential organs of impregnation with regard to air is altogether of temporary duration, and light. It fades when they wither, and

quently a part of, or an appendage to, the Nectarium, the nectary, fig. 37, is frecorolla; sometimes the petal itself secretes honey: sometimes a set of glands perform this function; and in other cases there is a peculiar petal-like apparatus for preparing or holding the nectarious juice. Linnæus has remarked that plants, whose nectary is distinct from the petals, are commonly poisonous, which in general holds good with those of the more elaborate nectaries. A German writer, named Sprengel, has proved the corolla to be in many instances an attraction, as well as accommodation, for insects in their search after honey: he remarks certain spots, called by him maculæ indicantes, which he conceives are designed to direct these little animals to their prey. The scent of flowers may perhaps con

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