See what a beautiful creeping spray of ivy—dark green, with russet veins—from the ground beneath the copse here! How close it keeps to the earth! how exquisitely the leaves fit in with one another, like a living mosaic! That is why the ivy-leaf is shaped as we know it, with re-entrant angles, very abrupt and deep-lobed. The plant, as a whole, crawls snake-like over the ground in shady spots, or climbs up the face of stony cliffs, or mantles walls and ruins, or clambers boldly over the trunks of trees—which last, though its most conspicuous, is not by any means its commonest or most natural situation. It is a haunter of the shade; therefore it wants to utilize to the uttermost every inch of space and every ray of sunlight. So it clings close to the soil or to its upright support, and lays its leaves out flat, each occupying its own chosen spot of earth without encroaching on its neighbour’s demesne, and none ever standing in the light of another. That shows one at once the secret reason for the angular foliage: it is exactly adapted to the ivy’s habitat. All plants which grow in the same way, half trailing, half climbing, have leaves of similar shape. Three well-known examples, each bearing witness to the resemblance in their very names, are the ivy-leaved veronica, the ivy-leaved campanula, and the ivy-leaved toad-flax. Or look once more at the pretty climbing ivy-leaved geranium or pelargonium, so commonly grown in windows. Contrast all these angular leaves of prostrate creepers with the heart-shaped or arrow-headed foliage of the upright twining or tendril-making climbers, such as convolvulus, black bindweed, black bryony, and bittersweet, and you will recognize at once how different modes of life almost necessarily beget different types of leaf-arrangement.

Nay, more. If you watch the ivy itself in its various stages, you will see how the self-same plant adapts its different parts from time to time to every variation in the surrounding conditions. Here in the copse, left to itself, as nature made it, it spreads vaguely along the ground at first with its lower branches, developing small leaves as it goes, narrow-lobed and angular, which are pressed flat against the soil in such a way as to utilize all possible air and sunshine. They cover the ground without mutual interference. And they are evergreen, too, so as to make the best of the scanty light that struggles through the trees in early spring and late autumn, while the oaks and ashes are all bare and leafless. But the main stem, prying about, soon finds out for itself some upright bank or trunk, up which it climbs, adhering to its host by the aid of its innumerable short root-like excrescences. Here its foliage assumes still the same type as on the ground, but is not quite so closely appressed to the support, nor yet so sharply angular. The mode of the mosaic, too, has altered a little to ............