The Chinese Chestnut (Castanea mollissima), a member of the family Fagaceae, is a species of chestnut native to China, in the provinces of Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xizang, Yunnan, and Zhejiang, and also to Taiwan and Korea. It grows close to sea level in the north of its range, and at altitudes of up to 2,800 m in the south of the range. The species prefers full sun and acidic, loamy soil, and has a medium growth rate.
It is a deciduous tree growing to 20 m tall with a broad crown. The leaves are alternate, simple, 10-22 cm long and 4.5-8 cm broad, with a toothed margin. The flowers are produced in catkins 4-20 cm long, with the female flowers at the base of the catkin and males on the rest. The fruit is a densely spiny cupule 4-8 cm diameter, containing two or three glossy brown nuts; these are 2-3 cm diameter on wild trees. The scientific name mollissima derives from the softly downy shoots and young leaves.
In Vietnam, Chinese chestnut (Vietnamese language: hạt dẻ, Tày language: mác lịch) which are grown in Trùng Khánh district, Cao Bằng province (Castanea mollissima Bl.) have highest quality with 3,3-5,4% glucose, 43,36- 46,47% glucid, 1,16 – 2% lipid, 3,12 – 3,62% protein analyzed by Vietnam National Vegetable and Fruit Researching Institution in 1999.
When cultivated in close proximity to other species of chestnut (including Japanese Chestnut C. crenata, American Chestnut C. dentata, and Sweet Chestnut C. sativa), Chinese Chestnut readily cross-pollinates with them to form hybrids.
Chinese Chestnuts have evolved over a long period of time in coexistence with the bark fungal disease chestnut blight (Cryphonectria parasitica, formerly Endothia parasitica), and have evolved a very successful resistance to the blight, probably more so than any other species of chestnut, so that, although it is not immune, it typically sustains no more than minor damage when infected. This is in stark contrast to the American Chestnut, which had no resistance to the blight, and was nearly wiped out by it after its introduction from Asia to North America. An active program has been pursued in North America to cross-breed Chinese and American Chestnut to try to maximize the traits of the American Chestnut, such as larger stature, larger leaf size, larger nut size, and greater nut sweetness, while also isolating and carrying the blight resistance from the Chinese Chestnut.