Japan Flora: Dextrorsely twining woody vine more or less pubescent while young and soon glabrous; leaflets 11-19; racemes flowering from the base; flowers purplish, rather smaller than in the following species, the bracts small. May-July. Thickets and woods in hills and mountains.
Honshu, Shikoku, Kyushu; common. Many cultivars are grown in gardens.