The "Ara-kashi" (Quercus glauca) belongs to Fagaceae (the Beech family). It is a tall evergreen tree that is distributed from Miyagi-Ishikawa Prefecture of Honshu south to Shikoku and Kyushu in Japan, as well as Taiwan, Jeju Island of Korea, central and southern China and the Indo-China Peninsula. This tree grows in scrublands of mountains and fields, and up to a height of about 20 m. The leaves are obovate-oblong with large toothed edges at upper-half of leaf blades. The male clusters are descending at lower-half of new branches and the female clusters stand upright at the top, from April to May. The cupules have 6-7 circular layers. This timber is hard and used for making handles of farm implement. It is called "青剛櫟" in Taiwanese Chinese and "青岡" (qing gang) in Chinese.