functions which each performs. The calyx is the outer covering of the flower-the symmetrical cup in which it rests. It is usually of the same green colour as the leaves, though sometimes, as in the fuchsia and the Indian cress, it is otherwise coloured. The corolla is the blossom or flower, popularly so called. Its parts or leaflets, which are sometimes distinct and sometimes united, are termed petals. These petals are composed of a congeries of minute cells, each containing colouring matter; and as the cells are distinct from one another, the petals may be dark-coloured at one part, and light-coloured at another. No lover of flowers need be told how exquisitely diversified are these colours, and with what masterly skill they are arranged. The remaining organs—the stamens and pistils, on which the production of seed peculiarly depends-occupy the centre of the corolla. The pistil is a hollow tube or shaft, with a spongiole, named the stigma, at one end, and a seed-vessel, or ovary, at the opposite end. The stamens (which commonly surround the pistil) consist each of a stalk or filament, surmounted by a rounded vessel called the anther, which contains a fine fecundating powder, termed pollen.

Now, in order to reproduction, it is necessary that the fecundating pollen, which is produced and ripened in the anther of the stamens, should be conveyed to the stigma of the pistil, and thence sent down to the ovary. Mark how this process is effected. Generally, the stamens and the pistils are found on the same plant, and so arranged that the former overtop the latter. This arrangement enables the pollen, when it bursts from the anther, to fall on the stigma. In order to secure this purpose more effectually, the stigma exudes a slightly glutinous fluid, to which the grains of the pollen adhere; and each grain, moreover, on touching the glutinous matter, elongates itself into a shape which enables it to pass down through the pistil into the ovary, and so to convey to the germ the vivifying powder. Such is the usual arrangement; but it is not the only one. In drooping flowers-such as the fuchsia, where it would be obviously unfit that the stamens should exceed the pistil in length, because in that case the pollen would be scattered

on the ground instead of reaching the stigma-the relation of the parts is inverted, the pistil being longer than the stamens. In the common nettle, the stamens have elastic filaments, which are at first bent down, so as to be obscured by the calyx; but, when the pollen is ripe, these filaments jerk out, and thus scatter the powder on the pistils. In the hazel, again, where the pollen is in one set of flowers, and the pistils on another, the leaves might interfere with the application of the pollen, and therefore they are not produced until it has been scattered. In trees, such as the willow, where the stamen-bearing flowers are on one tree, and the pistil-bearing flowers on another, the process of communication is effected in some cases by the wind, and in other cases by insects-as by the bee, which, while providing food for its young from the flowers, aids, at the same time, in the dispersion of the pollen.

When fecundation is completed, the other parts of the flower decay, while the ovary increases its bulk, till it becomes, under very diversified forms, what is called the fruit; and all these forms would seem to have one object in view, viz., the preservation of the seed. The production of this seed has been the great end of the whole process hitherto described; and, this end accomplished, the flower dies, while the energies of the plant are turned to the nursing of the little embryo which it has left behind.

When the seed, thus matured in the fruit, is deposited in the soil, a process of germination takes place under the influence of heat, air, and moisture. The embryo sends forth a number of fibrous threads, which fix the plant in the ground. The radicle becomes the root. The plumule, on the other side, elongates itself, rising into the air in the form of a stem. Erelong leaves shoot out, and new forms of floral beauty are evolved. And thus the great processes of nutrition and reproduction again proceed in the same varied and beautiful round.

Compiled.

LEAVES.

LEAVES Consist of fibres arranged in a kind of network. They are of various shapes and sizes. Some are so small as to be microscopic objects, and others-those of the Talipot palm, for instance-so large as to measure above 30 feet in circumference. They also fall at different times, and are differently denominated according to the period of their fall; being called caducous, deciduous, persistent, or perennial, according as they fall in summer, in autumn, in spring, or only in the course of years.

The function of leaves in elaborating the sap has been already pointed out. But their property of absorbing and perspiring moisture is also worthy of attention. A leafy branch, after being gathered, speedily withers in a dry atmosphere; but in a damp situation it retains its verdure for a time. Haymakers are quite familiar with the fact, that, in moist weather, it is next to impossible to get their hay-harvest lodged in safety; and every one has observed the effects of a hot day in causing plants to droop, and of a moist one in causing them to flourish. The great annual sunflower is said, in a hot dry day, to perspire in twelve hours, not less than 1 lb. 14 oz.; and the cornelian-cherry is a still more remarkable instance, for it evaporates moisture equivalent to twice the weight of the whole shrub in twentyfour hours.

The effect of light upon leaves is also worthy of notice. If not the actual cause of their green colour, it has at least some influence in making and keeping them green. Leaves raised in the dark are invariably of a sickly white colour; and the blanching of celery, it is well known, is effected by covering up the plant from the light. It is singular also, that light, whilst it benefits the upper, injures the under sides of leaves; and none can have attended to fruit-trees without remarking, that they invariably turn their leaves towards the light. If leaves are disturbed, they will turn again to their former position, and quicker, too, in proportion to the intensity of light. A field of clover follows the course of

the sun as regularly as the sunflower, the marigold, and the daisy. We ought not to omit quoting, en passant, the striking remark of Sir J. E. Smith in reference to the flowers just mentioned, that Nature, in their forms, seems to have imitated the radiant luminary to which they are apparently dedicated. Compiled.

THE SEED.

THERE is no part of a plant which affords so many striking proofs of admirable contrivance as the seed. The care which Nature has bestowed upon it is astonishing. Independently of the numerous and admirable provisions for producing and perfecting it, the mode in which this organ is preserved after it is matured, evinces consummate care and wisdom. Sometimes it is packed up in a capsule, a vessel composed of tough and strong coats; sometimes, as in stone-fruits, it is enclosed in a shell, which again is enclosed in a pulp; sometimes, as in grapes, it is plunged overhead in a glutinous syrup contained within a skin or bladder; at other times, as in apples, it is embedded in the heart of a firm fleshy substance; or, as in strawberries, pricked into the surface of a soft pulp. These, and many other contrivances for preserving it, are found in what are called fruits. In pulse, grain, grasses, and ordinary trees and shrubs, the variety of the seed-vessels is incomputable. We have the seeds, as in the pea-tribe, regularly disposed in parchment pods, which completely exclude the wet; the pod itself also, being not seldom, as in the bean, lined with a fine down, distended like a blown bladder. We have the seed enveloped in wool, as in the cotton plant; lodged, as in pines, between the hard and compact scales of a cone; barricaded, as in the artichoke and thistle, with spikes and prickles; in mushrooms, placed under a penthouse; or we find it covered by a strong close tunicle, and attached to the stem, as in several kinds of grain and of grasses.

Equally numerous and admirable are the contrivances for dispersing seeds. Who has not listened, in a calm and sunny day, to the crackling of furze-bushes, caused by the explosion of their little elastic pods; or watched the down of innumerable seeds floating on the summer breeze, till they are overtaken by a shower, which, moistening their wings, stops their further flight, and at the same time accomplishes its final purpose by immediately promoting the germination of each seed in the moist earth! How little are children aware, as they blow away the seeds of the dandelion, or stick burs in sport on each other's clothes, that they are fulfilling one of the great ends of Nature! The awns of grasses answer the same purpose. Pulpy fruits serve quadrupeds and birds as food, while their seeds, often small, hard, and indigestible, pass uninjured through the intestines, and are deposited, far from their original place of growth, in a condition peculiarly fit for vegetation. Even such seeds as are themselves eaten, like the various sorts of nuts, are hoarded up in the ground, and occasionally forgotten, or carried to a distance, and in part only devoured. The ocean itself serves to waft the larger kind of seeds from their native soil to far-distant shores. Compiled.

GERMINATION.

LET us endeavour to illustrate the subject of Germination, by taking a view of what happens to a common bean after it has been committed to the earth.

A novice in the study will be surprised to find how nearly a bean resembles the egg which is daily placed before him at breakfast. In taste or flavour, indeed, the two entirely differ; but between the arrangements within the cover of the bean and those within the eggshell, there is a close similarity.

The rudiment of the future chick is so placed as to occupy the upper central part of the yolk or red part of the egg. All around this, and enclosed within suitable membranes, is