The Wood sorrel (Oxalis acetosella) belongs to Oxalidaceae (the Wood sorrel family). It is a perennial herb that is distributed throughout Japan, and as well as widely to the Northern Hemisphere. This herb grows in mountain conifer woodlands and can reach 10-15 cm in height. The leaves are three-lobed compound with long petioles. The white or pale rose pink flowers bloom from April to July. In Chinese, it is called "白花酸漿草" (bai hua cu jiang cao).