FABÀCEAE. The Pea Family.
Trees, shrubs, vines or herbs with alternate leaves, mostly compound; flowers with five petals which are pea-like (papilionaceous); stamens generally 10; fruit a legume.
ROBÍNIA. The Locusts.
Robinia Pseùdo-Acàcia Linnæus. Locust. Black Locust. [Plate 109.] Medium sized trees with deeply furrowed bark; twigs at first green and hairy, becoming at the end of the season glabrous and a light brown, the stipules developing in about a year into a pair of woody spines about 2 cm. long; leaves pinnate, 1.5-3 dm. long; leaflets 7-17 on short stalks, ovate to oblong, 2-6 cm. long, rounded at base, rounded or pointed and with a small indenture at apex, margin entire, pubescent on both sides at first, becoming at maturity glabrous above and remaining more or less pubescent below, especially on the midrib; flowers in loose racemes, white, expanding in May or June; fruit a flat and slightly curved pod about 5-10 cm. long, glabrous; seeds usually 4-8 in each pod, about 4 mm. long and 2.5 mm. wide; wood heavy, very hard, close-grained, takes a good polish, very durable in contact with the soil.
Distribution.—Appalachian Mountains from Pennsylvania south to northern Georgia, and in Arkansas. In Indiana it is found as an escape in all parts and was doubtless native along the Ohio River, at least in the southeastern part of the State. Thomas[59] says: "We had gazed at the majestic beech of this country (near Rising Sun) three feet in diameter; we had seen the honey locust, the black walnut, a buckeye of equal magnitude; and then we saw with surprise, the black locust almost a rival in stature." Drake[60] says: "The flowering locust is abundant in Kentucky. Along the Ohio River it is rarely found more than 30 miles north of the river."
Remarks.—This tree is generally known as the locust tree, but is sometimes called the yellow locust.
Locust wood is somewhat lighter than white oak, but it is 34 percent stiffer and 45 per cent stronger. These remarkable qualities added to its durability in contact with the ground make it one of the most desirable trees for forest planting. The wood has been used principally for posts, ties, tree nails, etc. The locust when grown close together usually grows to 8-12 inches in diameter. There are, however, specimens that have grown in the open that are almost three feet in diameter. The pioneers used it extensively for ornamental planting, and it has escaped from such planting in all parts of the State. It propagates easily by root shoots which is the principal mode of spreading, except where the seed fall on exposed soil.
