page, be rendered a history of plants, including their uses in the arts and manufactures, and their culture in agriculture and gardening. Such a work is our Encyclopædia of Plants, having, in addition, engravings of one or more species of all the different genera.

CHAP. III.

Taxonomy, or the Classification of Plants.

1636. Without some arrangement, the mind of man would be unequal to the task of acquiring even an imperfect knowledge of the various objects of nature. Accordingly, in every science, attempts have been made to classify the different objects that it embraces, and these attempts have been founded on various principles. Some have adopted artificial characters; others have endeavoured to detect the natural relations of the beings to be arranged, and thus to ascertain a connection by which the whole may be associated. "It was formerly supposed," Lindley observes, "that the organs of fructification were more constant in their character, and less subject to variation, than any other part of the plant; and hence they were exclusively adopted as a means of classification. But modern investigations have shown that characters drawn from the mode in which plants grow, and from certain anatomical peculiarities, are of much higher value; so that the organs of fructification are now chiefly employed for the distinction of genera, or of orders and tribes." (Lind. Introd. p. 308.)

1637. Two kinds of methods have been adopted in arranging vegetables; the natural and the artificial. A natural method is that which, in its distribution, retains all the classes or groups obviously alike; that is, such into which no plants enter that are not connected by numerous relations, or that can be disjoined without doing a manifest violence to nature. An artificial method is that whose classes are not natural, because they collect together several genera of plants which are not connected by numerous relations, although they agree in the characteristic mark or marks assigned to that particular class or assemblage to which they belong. Any artificial method is easier than the natural; as in the latter it is nature, in the former the writer, who prescribes the rules and orders to be observed in distribution. Hence, likewise, as nature is ever uniform, there can be only one natural method: whereas artificial methods may be multiplied almost endlessly according to the several different relations under which bodies are viewed.

1638. The object of both methods is to promote our knowledge of the vegetable kingdom: the natural method, by generalising facts and ideas; and the artificial method, by facilitating the knowledge of plants as individual objects. The merits of the former method consist in the perfection with which plants are grouped together in natural families or orders, and these families grouped among themselves; the merits of the latter consist in the perfection with which plants are arranged according to certain marks by which their names may be discovered. Plants classed according to the natural method may be compared to words arranged according to their roots or derivations; classed according to an artificial method, they may be compared to words in a dictionary. The natural system does not, like the Linnæan, or any other artificial system, depend upon the modifications of any one part of a plant more than another. Its groups are constructed on a careful examination of all the circumstances of the structure of a plant which can be recognised. "Groups formed upon this principle will necessarily consist of species having a greater resemblance to each other than to any thing else;" and, consequently, a knowledge of the structure, habits, qualities, or other important peculiarities, of a single species, gives an accurate general idea of all the others which a group contains. The study of the natural system is an essential part of the education of a young gardener, and one which will require his undivided attention for some time. give a short outline of both systems.

SECT. I. The Linnaan Arrangement.

We shall

1639. The main object of the artificial system of botanical arrangement is to facilitate the discovery of the names of plants. For this purpose some one organ, common to plants in general, is fixed on; and, according to certain conditions in which this organ is found, individual species are referred to their places in the system, as words, by their initial letters, are referred to their places in an alphabetical dictionary. In the progress of artificial systems, different organs have been fixed on by different botanists; but those which have been most extensively employed are the corollas by Tournefort, and the sta mens and pistils by Linnæus. The system of Tournefort has been a good deal employed in France, and may be considered as the artificial system of that country; that of Linnæus has been employed in most other countries, and is justly esteemed by far the most perfect artificial system which has hitherto been produced.

1640. The application of the Linnæan system in practice, Sir J. E. Smith observes, is, above all other systems, easy and intelligible. Even in pursuing the study of the natural affinities of plants, this botanist affirms "that it would be as idle to lay aside the continual use of the Linnæan system, as it would be for philologists and logicians to slight the convenience, and indeed necessity, of the alphabet, and to substitute the Chinese character in its stead." (Introduct. to Bot.) "The student of the Linnæan artificial system," he elsewhere observes, "will soon perceive that it is to be understood merely as a dictionary, to make out any plant that may fall in his way." (Gram. of Bot.) "If we examine," says Decandolle," the artificial systems which have been hitherto devised, we shall find the most celebrated of them, that which was proposed by Linnæus, to possess a decided superiority over all others; not only because it is consistently derived from one simple principle, but also because the author of it, by means of a new nomenclature, has given to his terms the greatest distinctness of meaning." (Elements of the Philos. of Plants, by Decandolle and Sprengel.) Whether or not subsequent advances in science may enable botanists to dispense with the Linnæan system altogether,

it is not for us to affirm.

1641. According to the Linnaan system, all plants are furnished with flowers, either conspicuous or inconspicuous. The plants with conspicuous flowers are arranged according to the number and position of their stamens and pistils; those with inconspicuous flowers are arranged according to the situation of the flowers on the plant, or according to other circumstances in the plant itself.

1642. To discover the name of a plant by the Linnaan system, therefore, all that is necessary for a beginner is to possess a specimen of it in flower, and to be able to know its different parts by the names given them by botanists. To discover the class, order, and genus of a plant, it is only necessary to be able to distinguish and name the different parts of the flower. These parts are as follows:- The calyx or cup (fig. 277. a), which is that leaf, or those leaves, by which the flower is usually enclosed when in bud, and which, when the flower is expanded, appear under it. The

corolla (corona, a crown), which is the coloured leaf, or 278 leaves, of a flower (fig. 277. b). The stamen (or first principle of any thing), which is the thread-like process, or processes, immediately within the leaves of the corolla (fig. 278.). It consists of two parts; the filament or

277

thread (a), and the anther (b): this anther contains what is called the pollen, or fructifying meal (c). The pistil, which is found in the centre of the flower (fig. 279.), and consists of three parts: the germen, or rudiments of the fruit or seed (a); the style (b); and the stigma or summit (c), which crowns the style, and is destined to receive the fructifying pollen.

279

3

1643. The pistil and stamen are the essential parts of a flower. The corolla or the calyx may be wanting, and yet the flower will be termed perfect, because the absence of those parts is no obstacle to reproduction. Even the style and the filament may be absent without preventing the formation or ripening of the fruit; and there are many flowers which have the anther sitting close to the corolla, &c., without a filament, and the stigma to the germen without a style; but the anther, the germen, and the stigma are essential.

1644. The seed is contained in the pericarp, or seed-vessel, which is the germen when grown to maturity. The name of the seed-vessel varies according to its form, substance, &c. ; but the word pericarp (peri, about, karpon, a fruit) is applicable to all its varieties. The receptacle is the base or medium which connects the other parts of the fructification. (Magazine of Natural History, vol. i. p. 233.) The size, figure, form, texture, and condition of the surface of seeds afford characters of considerable service in distinguishing nearly allied species of plants; and characters extensively useful are derivable from their internal structure. Dr. Brown, we believe, was the first to make effective application of this last-mentioned principle of distinction, in characterising the genera of the class Tetradynàmia, in the Hortus Kewensis. The principle has subsequently been adopted by Smith, in his digest of the same class of plants, in the third volume of his English Flora, but more extensively by Decandolle than any one, in his arrangement of the plants of the natural orders Cruciferæ and Leguminòsæ. See an explanation of his terms, in p. 498. and 511. of our Hortus Britannicus.

1645. The following Table, and degree of knowledge conveyed in the preceding observations, will enable a beginner to discover at least the class and order of any plant which he may find in flower.

Ff

Stamens and Pistils

FIRST GRAND DIVISION.- Plants with conspicuous Flowers (Phanerogàmia).

In the same flower,
Male and female organs distinct,
Stamens not united either above or below,
Generally of equal length,

CLASSES.

1. Monandria (monos, one,
aner, a man). Example,
Blitum capitàtum.

2. Diándria (dis, twice, aner,
a man). Verónica Cha-
mæ'drys.

3. Triandria (tris, thrice,
aner, a man). Pòa ánn.

4. Tetrandria (tetra, four,
Cornus
aner, a man).
sanguínea.

5. Pentandria (pente, five,
aner, a man). Lysima-
chia Ephémerum.

6. Hexándria (her, six, aner,
a man). Scilla bifolia.

7. Heptándria (hepta, seven,
aner, a man) 'sculus
Hippocastanum.

S16. Monadelphia

2

(monos,
one, adelphos, brother).
Málva frágrans.

S17. Diadelphia (dis, twice,
adelphos,

a brother).
Ononis arvensis.

18. Polyadelphia (polys, many,
adelphos, brother). Hy-
péricum quadrangulum.

by the anthers or tops, 19. Syngenèsia (ryn, together,

into a cylinder

genesis, origin). Cicho-
rium I'ntybus.
Gynándria (gyne, a wo-
a man).

man, aner,
O'phrys apifera.

21. Monocía (monos, one,
oikos, house). Cucurbita
Pèpo.

22. Dice'cia (dis, twice, oikos,
Cannabis sa-
house).
tiva.

ORDERS.

SECOND GRAND DIVISION.- Plants with inconspicuous Flowers (Cryptogàmia).

9 Filices (filir, fern), Equisetacem (equus, horse, seta, hair), Lycopodinere (lykos, wolf, pous, foot), Marsileace (Corent L. F. Marsigli), Musci (muscus, moss), Hepática (hepar, the liver), Algae (alga, sea weed), Lichènes (Greek name), Pangi (fungus, a mushroom.

SECT. II.

First Grand Division, VASCUwith spiral vessels and cellular)

The Jussieuean, or Natural, System.

First Class, DICOTYLEDO NEE (dis,

Subdivision I. Dichlamydea (dis, calyx and Subclass 1. Thalymiflòræ (thalamus, pistillum) The orders are: cea, Anonacea, Menispermàceæ, peltideæ, &c.

Subclass 2. Calcyciflòræ (calyx and
lastrineæ, Rhámneæ, Bruniàcea,
Aquilaríneæ, Terebinthaceæ, Le-
Subclass 3. Corolliflòræ (corolla
Epacrídeæ, Symplocíneæ, Styra-
Brexièæ, Olèinæ, Jasmíneæ,
Subdivision II. Monochlamydea
and corolla
Plantagineæ, Nyctagínea, Amaran-

Second Class, MONOCOTYLEDONEÆ
one). Cycadeæ, Hydrocharídeæ,
Orchideæ, &c.

Second Grand Division, CELplants with cellular tissue (a priv. and kotyledon; desti

First Class, FOLIA CEE

LA'RES (vas, a vessel; plants tissue), or COTYLEDO'NEÆ.

two, and kotyledon; cotyledons two).

two, and chlamys, a coat or covering; corolla distinct).

a bed, flos, a flower; stamens under Ranunculaceæ, Dilleniàcea, MagnoliaBerberidea, Podophyllàceæ, Hydro

flos; stamens on the calyx). Samýdeæ, Homalínea, Chailletiàcea, guminòsæ, &c.

and flos; stamens on the corolla). cineæ, Myrsineæ, Sapòtea, Ebenaceæ, Strýchneæ, &c.

(monos, one, chlamys, a coat; calyx not distinct).

thacea, Phytolàceæ, Chenopòdeæ, &c.

(monos, one, and kotyledon; cotyledon Alismàceæ. Butòmeæ, Juncagineæ,

LULARES (cellula, a little cell, only), or ACOTYLEDO'NEE tute of a cotyledon).

(foliaceus, leafy; habit).
Lycopodineæ, &c.

priv., phyllon, a leaf; leafless).
chènes, Fúngi.

1646. The difficulties connected with the adoption of the Natural System are these,- that the characters of many of the orders are at present imperfectly known, and that they all depend upon a consideration of many points of structure which are not to be determined without much labour and a considerable degree of practical skill in the use of the microscope and the dissecting knife. But the facilities which the habit of viewing natural bodies with reference to the relations they bear to other bodies, and not as insulated indi viduals merely possessing certain peculiarities by which they may be referred to some station in an artificial system, ultimately gives to the investigations of the naturalist, are so great, that difficulties of the nature just alluded to should not be suffered to influence the botanist in determining which line of study he will follow, whether that pointed out by Linnæus, or that traced by the hand of nature. By the artificial system of Linnæus, indeed, no great difficulty exists in determining the number of stamens or styles possessed by a given plant, or the nature of their combination, and from the knowledge so obtained, in referring them to their class and order in the Linnæan system. But when this step has been gained, what more has been acquired than the bare knowledge that the plant in question possesses a certain number of stamens and styles? No possible notion can be formed of the relation it bears to other plants of the same nature, of the qualities it probably possesses, or of the structure of those parts not under examination-the fruit, for example; and, finally, if it were wished to convey an idea of the plant to a stranger, no means would be in the possession of the Linnæan botanist of doing so, except by stating that the plant belonged to Pentándria Monogynia for example, which is stating nothing. But what would be the condition of the student of the natural affinities of plants in a similar case? It is true he would be obliged to consult more characters than the two uninfluential ones of Linnæus: it would be necessary to ascertain if his subject was Vas cular or Cellular; if Vascular, whether it was Monocotyledonous or Dicotyledonous; if Dicotyledonous, whether the leaves were opposite or alternate, stipulate or exstipulate,

whether the flowers were monopetalous, polypetalous, or apetalous, the nature and station of the stamens, the condition of the ovarium, and so on. But when he has ascertained thus much, only let it be remembered, for a moment, how much he has gained indirectly as well as directly. Perhaps he has discovered that his plant belongs to Rubiacea; he will then have learned that all vegetables with opposite entire stipulate leaves, and a monopetalous superior corolla, are also Rubiaceous. If a fragment of the leaves and stem only of such a plant were afterwards submitted to him for examination, he would recognise its affinities, and remember that it was Rubiaceous; and, being aware of that fact, he would be able safely to infer that its calyx and corolla would be of a particular nature; that if the roots afforded any colour for dyeing, it would be red; that the medicinal properties of the bark, if any, would be tonic, astringent, and febrifugal; and that its seeds would be of the same nature as those of coffee; and, finally, its geographical position would be tolerably certain to him. The most complete introduction to the natural system which has yet been published, either in this country, or on the Continent, is that by Professor Lindley.

1647. Plants considered with reference to their general structure are separated into two grand divisions, called CELLULARES and VASCULA`RES. The Cellulares answer to the Linnæan Cryptogàmia, and are also called Acotyledoneae; the Vasculàres answer to the rest of the Linnæan system, which is sometimes called Phanerogàmia and Cotyledonea. 1648. Cellulares, Cryptogamous, or Acotyledonous, plants, are all, therefore, different terms denoting the same combination of vegetables. The first term is here adopted in preference to the others, as expressing the most obvious character upon which the division depends, namely, the cellular, not vascular, structure of the plants composing it. Cellular plants are formed entirely of cellular tissue (fig. 280.), without spiral vessels; or in more

familiar terms by having no veins in their leaves if foliaceous, and not forming wood; they also are destitute of perfect flowers. The lower tribes, such as Fúngi and A'lgæ, are destitute of leaves, and in some points approach the animal kingdom so nearly as to be scarcely distinguishable. In the highest tribe, Ferns, apparent veins are formed in the leaves; but as they are not supplied with spiral vessels, they cannot be considered more than analogous to the veins of other plants. Ferns, however, hold the intermediate station between Cellulàres and Vasculàres, and are chiefly retained among the former on account of their perfect accordance in other respects. In the whole of Acotyledons, it is unnecessary to examine the seed for the purpose of determining whether it has one cotyledon, several cotyledons, or none, the structure of the perfect plant giving the most obvious and satisfactory evidence.

1649. Vasculares, Phænogamous, or Cotyledonous, plants, are also separated into two great classes called Endogenes or Monocotyledons, and Exogenes or Dicotyledons, both which are distinguished as accurately by their obvious physical structure as they are by the minute and obscure peculiarities of the seed. They are all formed with cellular tissue, woody fibre, and spiral vessels (fig. 281.), and their leaves are traversed by veins; the last character is sufficient for practical purposes, if it is remembered that they also bear perfect flowers (that is, flowers furnished either with stamina, or pistillum, or both), which will always prevent their being confounded with the highest tribes of Cellulares. The probability of a third division, intermediate between the monocotyledonous and the dicotyledonous plants, may be inferred from the very peculiar structure of Aristolochia, Trichopòdium, Bragántia, Trimerìza, and, perhaps, some other genera; but this idea, sug