The Orixa (Orixa japonica) belongs to Rutaceae (the Citrus family). It is a small deciduous tree that is distributed from Honshu to Shikoku, Kyushu in Japan, as well as the southern Korean Peninsula and China. This tree grows in mountain dales and can reach 1-5 m in height. The leaves are obovate and alternate. The branches and leaves have characteristic odor. This tree is dioecism. The yellowish green flowers come in the new branches in April to May. The leaves are used for green manure and insecticide. In Chinese, it is called "臭常山" (chou chang shan).