ブナ科コナラ属の落葉高木で、学名は Quercus dentata。英名は Japanese emperor oak。
The Japanese emperor oak (Quercus dentata) belongs to Fagaceae (the Beech family). It is a tall deciduous tree that is distributed all over Japan, as well as Taiwan, the Korean Peninsula and China. This tree grows in mountains and can reach 10-15 m in height. The barks are blackish brown and furrowed longitudially. The leaves are ovate with wavy serrated edges, and arranged in dense alternate at the terminal branches. The female flowers bloom in axils and the male clusters are drooping from May to June. The fruit is ovate-round nut and covered with cupules at its lower part. The cupules are covered with dense involucal bracts. The leaves are used to wrap Kashiwa Mochi. It is called "槲樹" in Taiwanese Chinese, and "柞櫟" (hu shu) in Chinese.