price! Who would not rather, like the mountain oak, meet the storms of life firmly rooted in virtuous principles, than to be floated along even by the breath of pleasure, without end or aim, forgetful of the past, and careless of the future? To the virtuous, afflictions serve but to strengthen them in goodness; so,

"Yonder oaks! superior to the power

Of all the warring winds of heaven do rise,
And from the stormy promontory tower;

While each assailing blast increase of strength supplies."

We find some roots growing on other plants, and appearing to derive sustenance from their juices. These are called parasites; this term is often applied to persons who are willing to live in dependance upon others; and so despicable does this trait of character ap pear, that we almost conceive it a kind of meanness, even for a plant to live without elaborating its own food. Parasitic plants are common in tropical regions; sometimes many kinds are found upon the same tree, presenting a curious variety of foliage. In our climate, except in the Cryptogamous family, as lichens, mosses, &c. we have but few genera of these plants.* The Dodder and Mistletoe are celebrated parasitic plants.

Some plants grow without roots; these are called air plants: they are furnished with leaves or stems which seem to inhale, but not to exhale fluids; their substance is usually fleshy and juicy; some of them flourish in the most dry and sandy places, exposed to a burning sun; as the Stapelia, sometimes called the vegetable camel. Epidendrum grows and blossoms for years, suspended from the ceiling of a room, and nourished only by air.

The

Many roots, as the rhubarb, wild-turnip, blood-root, &c. possess important medicinal properties. The growth of the root is most rapid in autumn; at this season, the sun being less powerful, and the air more charged with moisture, the juices condense in the lower part of the plant, and nourish it, but as the season becomes cold, vegetation is checked; the winter is the best time to collect roots for medicinal purposes, because their peculiar virtues are then most concentrated

LECTURE VII.

OF THE STEM.

THE stem is the body of a plant, whether it be a tree like the oak, a shrub like the lilac, or an herb like the poppy; its use is to sustain the branches, leaves, and flowers, and to serve as an organ of communication between them and the root, conducting from the latter to the former, the animal and vegetable substances, salts, and earthy matter, which the radicles, by their mouths, suck up for the nourishment of the plant. The influence of light and air is, through the medium of the stem, conveyed from the leaves to the root.

* In the vicinity of Troy, I have seen a very beautiful species of the Pterospora, growing upon a branch of the whortleberry. Its colour was a bright crimson, which contrasted finely with the white flowers and green leaves of the plant on which it grew.

Parasitic plants-Air plants-Proper time to collect roots for medicinal purposesStem, its use.

If a plant be watered by any coloured liquid, the stem will, in time, show that this fluid has ascended into it. There is also in the stem a set of vessels to carry downward the juices, which have passed through peculiar processes in the leaves of the plant.

But of the circulation of fluids in the vegetable substance we shall speak more particularly hereafter. Our present object is, to describe the external appearance of the vegetable organs, and not their internal structure; or, in other words, it is the anatomy and not the physiology of plants, which we are now attempting to explain.

a

The different kinds of stems have been divided into seven classes, as follows—

Caulis, or proper stem, Culm, Scape, Peduncle, Petiole, Frond, and Stipe.

1st. Caulis, or proper stem, is such as is seen in forest trees, in shrubs, and in most annual plants. The caulis is either simple, as in the White lily; or branching, as in the Geranium. The branching is the more common form. You have here (Fig. 24) the representation of a caulis, or proper stem (a ;) Fig. 24. a peduncle, or flower stalk (b;) and a petiole, or leaf stalk (c.)

Fig. 26.

2d. Culm, or straw, (Fig. 25,) is the kind of stem which you see in grasses and rushes. The culm is either without knots, as in the Bulrush, jointed or knotted, as in Indian corn, geniculated, or bent like an elbow, as in some of the grasses. Those culms which are bent, are also knotted, though they may Fig. 25.

be knotted without being bent. The Bamboo, Sugar Cane, and various species of Reeds, have stems of the culm kind; some of them, particularly the Bamboo, are known to attain the height of forty feet.

3d. Scape, (Fig. 26, a, a,) a stalk springing from the root, which bears the flower and fruit, but not the leaves: as the Dandelion, the Cowslip, and the Lily of the Valley. Plants with scapes are sometimes called stemless plants; in this case, the scape would be considered as a peduncle proceeding from the root.

4th. Peduncle, or flower stalk, is but a subdivision of the caulis or stem; (See Fig. 24, b;) it bears the flower and fruit, but not the leaves; when the peduncle is divided, each subdivision is called a pedicel. In determining the species of plants, we often consider the length of the peduncle, compared with the flower; as, whether it is longer or shorter. When there is no peduncle or flower stalk, the flowers are said to be sessile.

This kind of stem is by the French called tige; the i should be sounded like e, the g soft like j, as in teje. The word Calis is from the Greek Kaulos, a stem. Division of stems-Caulis-Culm-Scape.

5th. Petiole, or leaf stalk, is a kind of stem, like a fulcrum, supporting the leaf, as the peduncle supports the flower; it is usually green, and appears to be a part of the leaf itself. The petiole of many plants is somewhat in the form of a cylinder; but the upper surface is rather flattened, the under surface convex. You will find this remark useful, in distinguishing the foot-stalks of compound leaves from young branches, with which they are sometimes confounded. In most cases, the leaves and flowers are supported by distinct foot-stalks, but sometimes the foot-stalk supports both the leaf and flower. The Petiole is often compared with the leaf, as the peduncle is with the flower, as to its relative length, in the different species.

Fig. 27.

6th. Frond. (Fig. 27.) The term frond, belongs entirely to Cryptogamous plants. This term however is applied to the leaf rather than the stem; in this sketch of the fern, the leafy part, b, is the frond; this bears the flower and fruit. Linnæus considered the leaves of palm-trees as fronds; we shall hereafter remark upon the different internal structure of their stems from those of the oak and other plants which are termed cauline, because their stem is a caulis. Plants with fronds are monocotyledonous.

7th. Stipe. The stem of the fern (Fig. 27, a,) is called a stipe. By observations of geologists it is ascertained that stiped plants were created before cauline ones; petrifactions of the former being found in the lower formations of the earth, while no remains of cauline

Fig. 28.

plants are ever found there. The stalk of a fungus or mushroom is called a stipe. The term is also applied to the slender thread, which in many of the compound flowс ers, elevates the hairy crown with which the seeds are furnished, and connects it with the seed. Thus, in a seed a of the Dandelion, which is here represented, the column (Fig. 28, a,) standing on the seed (b,) and elevating the down (c,) is the stipe.

b

Here is a mushroom with the cap (Fig. 29, d,) elevated on its stipe (e.)

Branches. The stem is either simple, or divided into branches. The branches are parts of the plant which proceed immediately from the trunk; the division of these are called branchFig. 29. lets; a diminutive appellation, which means a little branch. These parts resemble, in their formation, the trunk or stem, which furnishes them; the branch may be considered as a tree, implanted upon another tree of the same species. Branches sometimes grow without any apparent order in their arrangement; sometimes they are opposite; sometimes alternate; and sometimes, as in the pine, they form a series of rings around the trunk. Some branches

Peduncle-Petiole-Frond-Which part of the fern is its frond?-Which the stipe? -Difference between stiped and cauline plants-Which first formed?-Different applications of the term stipe-Stipe of a dandelion seed-Stipe of a mushroomBranches-Branchlets-Various appearances of branches.

are erect, as in the poplar, others pendent, as in the willow, and some, as in the oak, form nearly a right angle with the trunk. These various circumstances constitute distinctive characters in plants, a knowledge of which is very necessary to the painter. Of all our forest trees, perhaps none, in the disposition of its branches, presents a more beautiful and graceful aspect than the elm.

The branches of trees, as they grow older, usually form a more open angle with the trunk than at first. We often see branches form a very acute angle, but as the tree advances in age, the angles enlarge more and more, until the branch becomes pendent.

Some stems are remarkable for bearing little bulbs, called bulbilles, in the axils of their leaves. These, like the bulbous root, contain within them the germ of a new plant. The LILIUM bulbiferum, or tiger-lily, is of this description. (Fig. 30.) The bulbs are of a redbrown colour, about the size of a large gooseberry. They begin, soon after they are formed, to detach themselves from the plant, and falling upon the ground, shoot out fibres and take root. This splendid flower may thus be rapidly increased.

A remarkable phenomenon is described by travellers, as being exhibited by the stems of the Banyan tree of India, Ficus Indicus; these stems throw out fibres, which descend and take root in the earth. In process of time, they become large trees; and thus from one primitive root, is formed a little forest. This Fig. 30. tree is called by various names; as the Indian-Godtree, the arched-Fig-tree, &c. The Hindoos plant it near their temples, and in many cases, the tree itself serves them for a temple. Milton speaks of this tree, as the one from which Adam and Eve obtained leaves to form themselves garments; he says it was not the fig-tree renowned for fruit, but

now considered, may be included under two divisions; 1st, such as grow externally, having their wood arranged in concentric layers; Branches alter in their angles as they grow older-Bulb-bearing stems-Rooting

stems.

the oldest being in the centre of the trunk, and the newest forming the outer layer. This kind of stem may be seen in the oak and other forest trees in our climate, and also in most of our common herbaceous plants; these spring from seeds with two cotyledons, and are called dicotyledonous.

2d. Stems which grow internally, as palms and grasses: here the wood, instead of circling around the first formed substance, is pushed outwards by the development of new fibres in the centre; this kind of stem belongs to plants whose seeds have but one cotyledon, and are therefore called monocotyledonous.*

LECTURE VIII.

OF BUDS.

MOST leaves and flowers proceed from scaly coverings called buds. The scales envelop each other closely; the exterior ones being dry and hard, the interior moist, and covered with down; they are also furnished with a kind of resin or balsam, which prevents the embryo from being injured by too much moisture. Buds have been known to lie for years in water, without injury to the germ within.

The sap is the great fountain of vegetable life; by its agency new buds are yearly formed to replace the leaves and flowers destroyed by the severity of winter. Branches also originate from buds. Linnæus supposed that buds spring from the pith, this being found necessary to their formation and growth. The bud is a protuberance formed by the swelling of the germ; and as, for this purpose, the agency of an additional quantity of sap is needed, we see the bud appearing at the axils of leaves, or the extremities of branches and stems, where there is an accumulation of this fluid. If you plant a slip of Geranium, you will observe that it either sprouts from the axil of a leaf, or from knots in the stem, which answer the same purpose as the leaf, by slightly interrupting the circulation of the juices, and thus affording an accumulation of sap necessary for the production of a new shoot.

Some botanists distinguish the different periods of the bud as follows: first, the point in the plant which gives rise to the bud, is called the eye; when this begins to swell and become apparent, it is termed the button; and when it begins to unfold, the bud.†

Herbs and shrubs have buds, but these usually grow and unfold themselves in the same season, and are destitute of scales; while the buds of trees are not perfected in less than two seasons, and, in some cases, they require years for their full development. You have, no doubt, observed in the spring, the rapid growth of the leaves and branches of trees; and perhaps, have also noticed, that as summer advances, the progress of vegetation seems almost suspended. But nature, instead of resting in her operations, is now busy in providing for the next year; she is turning the vital energies of the plants to

*These two kinds of stem have by some French botanists been called exogenous and endogenous: these words are derived from the Greek; the first signifying to grow externally, the second, to grow internally.

†These terms in French, are l'ail, the eye, bouton, the button, and bourgeons, the bud.

Dicotyledonous stems-Monocotyledonous stems-Description of buds-Agency of sap-The eye, button, and bud-Herbs and shrubs destitute of scaly buds.