About 15 deciduous species of trees or shrubs. Leaves opposite, palmately compound, 5-11 leaflets, the middle leaflet often largest. Flowers white, yellow, pink or red in erect terminal clusters, calyx 5-lobed, 4-5 petals. Fruit smooth, scaly, or spiny, with 1-6 seeds, seed light or dark brown with a conspicuous lighter circular patch.
Aesculus: the classical Latin name for an oak with edible acorns, applied to this genus by Linnaeus.
Taxonomy: The horsechestnuts and buckeyes (family Hippocastanaceae) and maples (family Aceraceae) have long been known to be closely related to the family Sapindaceae. Several taxonomists (including the Angiosperm Phylogeny Group) now include these two families in Sapindaceae.