THE BLACK LOCUST.
Robinia Pseudacacia, Linn.
The black or yellow locust is a beautiful tree in its youth, with smooth dark rind and slender trunk, holding up a loose roundish head of dark green foliage. Each leaf is eight to fourteen inches long, of nine to nineteen leaflets, silvery when they unfold, and always paler beneath. In late May, the tree-top bursts into bloom that is often so profuse as to whiten the whole mass of the dainty foliage. The nectar-laden, white flowers have the characteristic "butterfly" form, the banner, wings, and keel of the type pease-blossom. (See illustration, page 198). The bees lead the insect host that swarms about them as long as a locust flower remains to offer sweets to the probing tongues. Cross-fertilization is the advantage the tree gains for all it gives. The crop of seeds is sure.
The angled twigs of the black locust break easily in windy weather. The rapid growth of the limbs spreads the narrow head, and its symmetry is soon destroyed, unless the tree grows in a sheltered situation. An old locust is usually an ugly, broken specimen, ragged-looking for three fourths of the year. The twigs look dead, because their winter buds are buried out of sight! The bark is dull, deeply cut into irregular, interlacing furrows, roughened by scales and shreds on the ridges. In winter the pods
chatter querulously, as the wind plays among the tree tops.
The black locust is found from Pennsylvania to Iowa, and south from Georgia to Oklahoma. The lumber is coarse-grained, heavy, hard, and exceptionally durable in contact with the soil or water. This makes it especially adaptable for fence posts and boat bottoms. Crystals, called raphides, in the wood cells, take the edges off tools used in working locust lumber. Yet it is sought by manufacturers of mill cogs and wheel hubs, and railroad companies plant the trees for ties.
The locust-borer has ruined plantations of this tree of late years, and trees in the woods have become infested except in mountainous regions not yet reached by the pest. Trees become distorted with warty excrescences and the lumber is riddled with burrows made by the larvae. Until the entomologist finds a remedy in some natural parasite of the locust-borer, the outlook for locust culture seems dark enough. No insecticide can reach an enemy that hides in the trunk of the tree it destroys.