Tree 10 - 20 m tall, trunk 30 cm - 0.60 m in diameter Leaves: opposite, palmately compound, stalked, with seven to nine leaflets. Flowers: showy, borne in loosely branched inflorescences (panicle), white with a yellow or red spot near the base, 20 - 30 cm long, 10 - 20 cm wide, each floret with four to five petals, the stamens longer than the petals. Fruit: a capsule enclosing one to three seeds, 5 cm in diameter, rounded, prickly, leathery. The seeds are shiny brown with a pale circular marking, large, and smooth. Bark: dark brown with orangish brown inner bark, shallowly fissured with thin irregular plates. Twigs: stout, reddish brown with tiny, white, corky, raised spots (lenticels). Terminal buds: 2 - 4 cm long, egg-shaped, very sticky, with reddish brown outer scales and yellow inner scales. Leaflets: dark green above, paler beneath, 12 -18 cm long, 3 - 6 cm wide, inversely egg-shaped with a wedge-shaped base and a pointed tip, irregularly toothed. Leaves turn brownish yellow in fall.
Similar species: Aesculus glabra typically has five leaflets, terminal buds 1.5 - 1.8 cm long, fruit 2 - 3 cm in diameter, and releases an unpleasant odor when leaves and twigs are bruised.
Flowering: late May to June
Habitat and ecology: Occasional escapes, usually seedlings, are found near mature cultivated trees. The species also occurs along mesic ravine slopes and slopes of clay ridges.
Occurence in the Chicago region: non-native
Notes: The wood of this species is use in Europe for kitchen utensils, food containers and carving into decorative objects. The seeds are poisonous.
Etymology: Aesculus is the Latin word for a species of oak with edible nuts, but was used by Linnaeus to name this genus. Hippocastanum comes fro the Latin name for horsechestnut.
Tree to 25 m; winter-buds glutinous; lfls commonly 7(9), wedge-obovate, 1-2.5 dm, abruptly acute, irregularly serrate or biserrate, pubescent beneath when young, later glabrous; infls many-fld, ovoid-conic, 2-3 dm; cal 5-7 mm; upper and lateral pet with white rotund blade marked with red or yellow at the cordate base, on slender claws; fifth petal obovate, tapering to a broad claw, or wanting; fr echinate, 5 cm thick; 2n=40. Native of se. Europe and adj. Asia, occasionally escaped from cult. in our range. May.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.