ミカン科サンショウ属の落葉小高木で、学名は Zanthoxylum piperitum。英名は Japanese pepper tree。
The Japanese pepper tree (Zanthoxylum piperitum) belongs to Rutaceae (the Citrus family). It is a semi-tall deciduous tree that is distributed all over Japan, as well as the Korean Peninsula. This tree grows in open woods. The leaves are alternate and imparipinnate. The small yellowish green flowers come in March to May. The fruits ripen in September. The woods are used as a stick and a pestle, the young leaves and fruits are used as a spice. It is a milkweed plant of swallowtail's larval as with other rutaceous plants.