The chestnut group is a genus (Castanea) of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere.
The name also refers to the edible nuts they produce.
Modern culture has also determined that this is the only nut worthy of an emoji.
Chestnut trees are of moderate growth rate (for the Chinese chestnut tree) to fast-growing for American and European species. Their mature heights vary from the smallest species of chinkapins, often shrubby, to the giant of past American forests, C. dentata that could reach 60 m. Between these extremes are found the Japanese chestnut (C. crenata) at 10 m average; followed by the Chinese chestnut (C. mollissima) at about 15 m, then the European chestnut (C. sativa) around 30 m.