HABIT.—A medium-sized tree 30-50 feet in height, with a trunk not over 2 feet in diameter; usually much smaller; slender, spreading branches, forming a broad, rounded crown; twigs thick.
LEAVES.—Opposite, digitately compound. Leaflets usually 5, rarely 7, 3-6 inches long, 1-1/2-2-1/2 inches broad; ovate or oval, gradually narrowed to the entire base; irregularly and finely serrate; glabrous, yellow-green above, paler beneath, turning yellow in autumn. Petioles 4-6 inches long, slender, enlarged at the base. Foliage ill-smelling when bruised.
FLOWERS.—April-May, after the leaves; polygamo-monoecious; small, yellow-green, in terminal panicles 5-6 inches long and 2-3 inches broad, more or less downy; pedicels 4-6-flowered; calyx campanulate, 5-lobed; petals 4, pale yellow, hairy, clawed; stamens 7, with long, hairy filaments.
FRUIT.—October; a thick, leathery, prickly capsule, about 1 inch in diameter, containing a single large, smooth, lustrous, brown nut. A large pale scar gives the name “Buckeye.”
WINTER-BUDS.—Terminal buds 2/3 inch long, acute, resinous, brownish; inner scales yellow-green, becoming 1-1/2-2 inches long in spring and remaining until the leaves are nearly half grown.
BARK.—Twigs smooth, red-brown, becoming ashy gray; old trunks densely furrowed and broken into thick plates; ill-smelling when bruised.
WOOD.—Light, soft, close-grained, weak, whitish, with thin, light brown sapwood.
NOTES.—A native of the Mississippi River Valley. Occasionally planted in southern Michigan for ornamental purposes, but is less popular than the Horse-chestnut.