Any of about 13 trees and shrubs of the genus Aesculus (family Hippocastanaceae), native to North America, southeastern Europe, and eastern Asia.
The name refers to the resemblance of the nut, which has a pale patch on a shiny red ground, to the eye of a deer. Buckeyes are valued as ornamental trees for their handsome candelabra-like flower clusters. Both the young foliage and the nuts are poisonous. Among the most notable is the Ohio buckeye ( A. glabra ), also called fetid buckeye and American horse chestnut, with twigs and leaves that yield an unpleasant odour when crushed. The sweet, or yellow, buckeye ( A. flava , or A. octandra ) is the largest buckeye, up to 89 ft (27 m) tall, and is naturally abundant in Great Smoky Mountains National Park, U.S.