Chinese cork oak

Description

Quercus variabilis, the Chinese cork oak, is a species of oak in the section Quercus sect. Cerris, native to a wide area of eastern Asia in southern, central, and eastern China, Taiwan, Japan, and Korea. Quercus variabilis is a medium-sized to large deciduous tree growing to 25–30 metres (82–98 ft) tall with a rather open crown, and thick corky bark with deep fissures and marked by sinuous ridges. The leaves are simple, acuminate, variable in size, 8–20 centimetres (3.1–7.9 in) long and 2–8 centimetres (0.79–3.15 in) broad, with a serrated margin with each vein ending in a distinctive fine hair-like tooth; they are green above and silvery below with dense short pubescence. The flowers are wind-pollinated catkins produced in mid spring, maturing about 18 months after pollination; the fruit is a globose acorn, 1.5–2 centimetres (0.59–0.79 in) diameter, two-thirds enclosed in the acorn cup, which is densely covered in soft 4–8 millimetres (0.16–0.31 in) long 'mossy' bristles. Evergreen and deciduous forests; below 3,000 metres (9,800 ft). Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang, Japan and Korea. It is cultivated in China to a small extent for cork production, though its yield is lower than that of the related cork oak. It is also occasionally grown as an ornamental tree. For pharmaceutical grade production of Ganoderma lucidum, known in China as ‘the mushroom of immortality,’ the dead wood logs of Q. variabilis are used. An oak is a tree or shrub in the genus Quercus (""oak tree"") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name ""oak"" also appears in the names of species in related genera, notably Lithocarpus (stone oaks), as well as in those of unrelated species such as Grevillea robusta (silky oaks) and the Casuarinaceae (she-oaks). The genus Quercus is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in the Americas, Asia, Europe, and North Africa. North America has the largest number of oak species, with approximately 160 species in Mexico of which 109 are endemic and about 90 in the United States. The second greatest area of oak diversity is China, with approximately 100 species.