The chestnut (Castanea) is native to temperate regions of the Northern Hemisphere. They belong to the Fagaceae family of beeches. This family includes eight species of deciduous trees and shrubs that include oaks and beeches. The four main species are commonly referred to as European, Chinese, Japanese, and American chestnuts.
All Castanea species readily hybridize with each other. Their flowers are not self-compatible, so more than one tree is necessary for pollination.
The fruit is covered by a spiny cupule between 5–10 cm in diameter. These so-called ‘burrs’ are found in clusters and contain up to seven nuts depending on the species.