"Matsukaze-so" (Boenninghausenia japonica) belongs to the Rutaceae (the Citrus family). It is a perennial that is distributed southward from Miyagi prefecture of Honshu to Shikoku and Kyushu, and also Taiwan. This herb grows in forest edges and landslide scars, and can reach 50-80 cm in height. The leaves are triternate pinnately compound with obovate leaflets. They have glandular dots and a characteristic odor. The cymes are borne on the terminal branches, and the small, four-petaled flowers bloom from August to October.