THE AILANTUS.
The Ailantus is a native of China, where it becomes a very large tree, often attaining the height of seventy feet. It was imported into Great Britain more than a century ago, for the benefit of the silk manufacture. A species of silkworm, which was known to be hardy and capable of forming its cocoons in the English climate, is attached to this tree and feeds upon its leaves. “The Bombyx cynthia,” says Mongredien, “thrives well in the open air (of England) in ordinary seasons, and requires no care after being once placed on the tree. About August it spins its cocoon on one of the leaflets, bending its edges inwards, so as to form a partial envelope. As the tree is deciduous, the leaf would drop and the cocoon with it, were it not that, by an instinct, the insect, before spinning its cocoon, attaches by its strongly adhesive threads the stalk of the leaf to the woody twig that sustains it. Hence the leaves that bear the cocoons are the only ones that do not drop, and there remain persistent through the whole of the winter.”
This experiment with the Ailantus proved a failure; but the tree, being very stately and ornamental, continued to be cultivated in pleasure-grounds. It was introduced into the United States in the early part of this century, and is now very common in almost all the States as a wayside tree. It possesses a great deal of beauty, being surpassed by very few trees in the size and graceful sweep of its large compound leaves, that retain their brightness and their verdure after midsummer, when our native trees have become dull and tarnished.
The leaves of the Ailantus are pinnate, containing from nine to eleven leaflets, each of these being as large as the leaf of the beech-tree. It has a great superficial resemblance to the velvet sumach, both in its foliage and ramification, so that on first sight one might easily be mistaken for the other; for its branches, though more elegant, have the same peculiar twist that gives the spray of the sumach the appearance of a stag’s horn. The flowers are greenish, inconspicuous, and in upright panicles, resembling those of the poison sumach. They emit a very disagreeable odor while the flowers are in perfection, impregnating the air for a week or more.