Aesculus comprises 13-19 species of woody trees and shrubs native to the temperate northern hemisphere, with 6 species native to North America and 7-13 species native to Eurasia; there are also several hybrids. Species are deciduous or evergreen. The Eurasian species are known as horse chestnuts while the North American species are called buckeyes.
Aesculus are woody plants from 4 to 36m tall (depending on species), and have stout shoots with resinous, often sticky, buds; opposite, palmately divided leaves, often very large (to 65 cm across in the Japanese Horse Chestnut Aesculus turbinata). Flowers showy, insect-pollinated, with four or five petals fused into a lobed corolla tube, arranged in a panicle inflorescence.
