yellow locust, white locust

Robinia pseudoacacia Linnaeus

Black locust is not a native of the state, but was a great favorite with early settlers as a dooryard tree from where it has escaped to form dense thickets along the roadside in many sections of the state. In favorable locations, its spread by means of root suckers is very rapid. It grows with exceptional rapidity on well-drained fertile soils, and in such locations seems better able to survive attacks of the locust borer which in some sections has rendered the tree worthless. The wood is very strong, heavy, hard, and extremely durable in contact with the soil. As a post wood it has no equals and is also used for ties and fuelwood, and was used for insulator pins on pole lines.

Bark - rough even on young trunks, yellowish brown in color, becoming deeply furrowed into distinct, thick, rounded ridges, which are not scaly.

Twigs - slender, brittle, reddish to greenish brown in color; generally bearing short stiff spines 1/4 to 1/2 inch long, in pairs at base (node) of leaves.

Winter buds - terminal bud absent; lateral buds very small, in a cavity below leaf scars, rusty brown in color, covered with down.

Leaves - alternate, compound, 8 to 14 inches long, with 7 to 19 entire leaflets arranged along a central stem; leaflets usually odd in number, short-stalked, oval in shape, 1 1/2 to 2 inches long.

Fruit - a pod, flat, smooth, brown in color, 2 to 4 inches long, containing 4 to 8 small brown or black seeds, ripening in September. Pods hang on into the winter and are finally torn off by the wind in halves with seeds attached, the dried pod acting as a sail to carry the seed considerable distances.

Distinguishing features - compound leaves with oval leaflets; small, downy buds depressed in bark; short stiff spines; papery pods.

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