deciduous trees or some shrubs of North America; southeastern Europe; eastern Asia

The genus Aesculus comprises 20–25 species of deciduous trees and shrubs native to the temperate northern hemisphere, with 7–10 species native to North America and 13–15 species native in Eurasia; there are also several natural hybrids. They have traditionally been treated in their own monogeneric family Hippocastanaceae, but genetic evidence shows that this family, along with the maples (formerly Aceraceae), are better included in the soapberry family (Sapindaceae).