LEGUMINOSAE 
Locust. Black Locust 
Robinia pseudo-acacia L. 
HABIT.—A tree 50-75 feet high, with a trunk diameter of 
2-3 feet; forming a narrow, oblong crown of irregular, more or 
less contorted branches. 
LEAVES.—Alternate, compound, 8-14 inches long. Leaflets 
7-21, short-petiolate, 1-2 inches long, about one-half as broad; 
ovate to oblong-oval; entire; very thin; dull dark green above, 
paler beneath, glabrous both sides. Petioles slender, pubescent. 
FLOWERS.—May-June, after the leaves; perfect; showy 
and abundant; very fragrant; borne on slender pedicels in loose, 
drooping racemes 4-5 inches long; about 1 inch long; calyx short, 
bell-shaped, 5-lobed, hairy; corolla papilionaceous, white, 5- 
petaled; stamens Io. 
FRUIT.—Late autumn, but persistent on the tree through 
the winter; a smooth, dark brown, flat pod 3-4 inches long, con- 
taining 4-8 small, flattish, brown seeds. 
WINTER-BUDS.—Terminal bud absent; lateral buds min- 
ute, 3-4 superposed, partially sunken within the leaf-scar, rusty- 
hairy. : 
BARK.—Twigs smooth, green, more or less rough-dotted 
at first, becoming red-brown and armed with prickles; dark 
red-brown and thick on old trunks, deeply furrowed into firm, 
sinuous ridges. 
WOOD.—Heavy, very strong and hard, close-grained, very 
durable in contact with the soil, brown, with very thin, pale 
yellow sapwood. 
NOTES.—Native to the Appalachian Mountains, but much 
planted in Michigan for ornamental and economic uses. Very 
rapid of growth in youth. Short-lived. Seriously attacked by 
borers. Spreads by underground shoots. 
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