ミツバウツギ科ミツバウツギ属の落葉低木で、学名は Staphylea bumalda。英名は Japanese bladdernut。
The Japanese bladdernut (Staphylea bumalda) belongs to the family Staphyleaceae. It is a small deciduous tree that is distributed throughout Japan, the Korean Peninsula and China. This tree grows along mountain streams and collapsed areas, and can reach 3-5 m in height. The leaves are trifoliate and opposite, an with oblong to ovate leaflets. The leaf edges have short awn-shaped serrations. The small white flowers come on the panicles at the tips of the branches from April to May. The fruits are nock-shaped capsules. It is called "省沽油" (sheng gu you) in Chinese.