VEGETABLE AND INSECT LIFE.

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have been devoured, and, thus in spite of the large number and voracity of its enemies, the foliage is generally able to resist all their efforts.

Week after week the pastures are cropped by numerous herds, or mowed by the husbandman, and yet the grass never ceases to flourish, and after countless caterpillars and beetles have feasted upon the plenty of the forest, it still bears a luxuriant crown, until finally the winter scatters its foliage to the winds. This indomitable energy of vegetation, which not only supports itself, but a whole world of animals, and sets the ravages of centuries at defiance, is indeed one of the great wonders of creation!

In all climates we find a harmonious balance between insect and vegetable life. Towards the north, where the growth of plants is confined to a few months or even weeks, they have but few enemies to encounter; in the temperate zones hostility increases with the increase of vegetation, until finally, in the damp tropical lowlands, the herbivorous insects take the field in countless legions. But here, where the plantain raises its colossal shaft in eight or ten months to a height of twenty feet, where the bamboo grows at the rate of eighteen inches in twenty-four hours, and the same field yields three harvests in the course of the year, an amazing power of vegetation resists all these devastations; and here, also, the defences of the plants increase with their increasing dangers; for nowhere are the leaves better protected with hairs and spines, and nowhere do they elaborate more pungent juices or exhale more penetrating odours.

Thus harmony is everywhere maintained between the two great divisions of organic life, and thus firmly established on the laws of an All-wise Power, an eternal order reigns supreme amidst the conflicting interests of all created beings.

Where we see so much care bestowed upon the leaves, which are but simple individual organs, we may well expect to find still greater precautions taken for the protection of the buds, in which the foliaceous rudiments of a whole branch, or even of a whole plant, are contained.

A bud is seldom naked; generally it is invested with a panoply of thick scales of a coriaceous or fibrous consistence, and, moreover, frequently covered with hairs or impregnated with

resin. Under this comfortable mantle, which from its being a bad conductor of heat opposes an effectual resistance to the cutting winds or nipping night-frosts of early spring, the first tender leaflets are developed by the influence of the warming sun, as safely and securely as a brood of chickens under the fostering care of a hen. Slowly they swell within the little dungeon in which they are so providently inclosed; but as soon as they have burst their fetters, they expand with an astonishing rapidity, and in a few days the tree appears in the full beauty of its youthful verdure.

CHAPTER XI.

BLOSSOMS.

Their Functions.-Their Accessory and Essential Parts.-The Calyx.-The Corolla. -The Pistils.-The Anthers.-The Pollen.-Insects as Means of Fructification. -The Vallisneria Spiralis.

NOTHING can equal the immense variety of flowers, their charming colours, or their delicious fragrance. How differently formed are the radiate aster and the hooded wolf's-bane, the bell-shaped campanula and the papilionaceous lupin, and yet it would be difficult to say which of them most pleases the eye.

The colours with which the flowers are adorned baffle description. The snowy whiteness of our fruit-trees adds new beauties to spring, and the purple heath invests the bleak and barren Highlands of the north with a magnificence equal to the warm tints of Italy or Spain. The humble daisy, the golden buttercup enamel our verdant meads, and every hue of the rainbow is reflected in the gay parterres of our gardens, or in the conservatories where Flora assembles her favourites from all parts of the world.

The foliage of many plants exhales an agreeable odour, but no leaf produces a balsam which can in any way equal the aroma of the violet or the rose, of the pink or of the lily of the valley. Without the flowers, the variety of perfumes which regale our sense of smell would be but small; without them its faculties of enjoyment would not have harmonised with the outer world.

But the corolla on which Nature has thus lavished all that can gratify the senses, plays after all but an accessory part in the economy of the vegetable kingdom, as, conjointly with the calyx, it merely serves as a protecting cover, or as an ornamental envelope to the pistil and to the stamina, which, though generally of a more humble appearance, are the essential organs

of fructification in all the higher plants. Thus, both the corolla and the calyx may be wanting, as for instance in the vast family of the grasses, which spreads in thousands of species over the face of the globe.

The pistil or pistils-for they vary in number from one to twelve, and sometimes more-commonly appear in the centre of the corolla, from which they rise like so many green columns. A pistil consists of three parts-the stigma at its upper extremity, which is sometimes globular, sometimes cleft, sometimes crossshaped; the style or hollow pillar which supports the stigma; and the germen, or seed-bud, which forms its pedestal or base, and in which the germs or ovula are contained.

The stamens, which resemble threads, or pillars, usually stand between the corolla and the pistil, but are extremely various in their arrangement and number-a circumstance on which Linnæus founded his method of classifying plants. Some have but one stamen, others two, three, and so on up to ten, twelve, twenty, or even several hundreds. In some flowers we find the stamina standing apart from each other, in others united by their filaments into one or several sets; here they are all of equal length, there of unequal dimensions; sometimes they are attached to the inside of the calyx, sometimes to the corolla, to the receptacle, or to the pistil. They invariably consist of two parts, the anther and the filament. The anther is the summit of the stamen, and contains the mealy or powdery substance called pollen, which, brought into contact with the stigma, serves to fecundate the ovula contained within the germ. When come to maturity, the anthers open in various ways -longitudinally or transversely, or through the raising of a lid, or through numerous apertures, so that the pollen contained in its interior becomes free and

Pollen-Grains of

a, althæa rosea; b, cobæa scandens; c, passiflora coerulea; d, ipomoea purpurea.

covers its surface with a fine generally yellow-coloured powder.

If these golden cushions carried on pillars of ivory afford an agreeable spectacle to the naked eye, our admiration increases when we come to view the pollen-grains under a magnifyingglass-for every genus of plants has its own characteristic form of this fructifying dust, the surface of which is often most curiously marked. Its roughening by spines or knobby protuberances is a very common feature, and answers the purpose of enabling it to adhere more readily to the stigma.

These elegant little globes are so small that they generally attain a diameter of only 1-1,200th or 1-3,000th of an inch; while they are so numerous that frequently many thousands are brought forth by one single flower, and thus the seed we tread under foot produces with a boundless prodigality objects so exquisitely formed and modelled that the most skilful pencil can hardly do justice to their beauty.

Even the pollen-grain which the vernal wind carries in countless billions through the air, and which man scarce ever deigns to notice, is the work of a consummate master, a wonderful monument of Almighty power!

Although both the pistils and the stamina are essential organs of fructification, and seed can only be formed by their mutual co-operation, yet they are not always united in the same blossom. Sometimes, as in the birch, we find flowers of different kinds on the same plant, some bearing pistils and others stamens only; or, as in the willow and poplar, stamens on one plant and pistils on another; or, even as in the common ash, the same tree will bear flowers of three different kinds.

In most plants, however, the pistils and anthers are united within the same corolla, an arrangement which greatly facilitates the admission of the pollen to the stigma; and for the same purpose the stamina of most plants surround the pistilla, an arrangement which gives the pollen an opportunity of falling upon the stigma at every breeze of wind. In those flowers which stand upright, the stamina are higher than the top of the pistil, so that, as the pollen is specifically heavier than air, some of it must almost inevitably fall upon the stigma as soon as it detaches itself from the anther, while in those flowers which hang down or incline to one side, the pistil is longer than the stamina.

The flowers of most plants expand by the heat of the sun,

G