The chestnuts are the deciduous trees and shrubs in the genus Castanea, in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere.
The name also refers to the edible nuts they produce.The unrelated horse chestnuts (genus Aesculus) are not true chestnuts, but are named for producing nuts of similar appearance that are mildly poisonous to humans. True chestnuts should also not be confused with water chestnuts, which are tubers of an aquatic herbaceous plant in the sedge family Cyperaceae.
Other species commonly mistaken for chestnut trees are the chestnut oak (Quercus prinus) and the American beech (Fagus grandifolia), both of which are also in the Fagaceae family.
Brazil nuts, called "Brasil chestnuts" (castañas de Brasil in Spanish) or "chestnuts from Pará" (castanha-do-Pará in Portuguese) are also unrelated.
