Chinquapinsare at least large shrubs but some species grow into sizeable trees. Their leaves are usually tough and much sclerotized and have a well-developed cuticula. Their flowers are unisexual, and the male ones are borne in erect catkins. The epigynous female flowers produce a single seed each but are congregated in small clusters. The fruit is a calybium, the kind of encased nut typical of Fagaceae. The calybium (nut) resembles a pointed acorn; the cupule (casing) is hard like that of beechnuts and spiny like that of chestnuts. The genus contains about 120 species, which are today restricted to tropical and subtropical eastern Asia.