Japan Flora: Scandent per­ennial herb, with slender stolons; stems 60-120 cm. long, slightly pubescent; stipules dentate or bifid; leaflets 12-14, membranous, narrowly ovate, 15-30 mm. long, 10-15 mm. wide, obtuse to emarginate, indistinctly ciliate, the lateral nerves ascending and forming a rather acute angle with the midrib; flowers 1 or 2, 15-17 mm. long, violet-purple; calyx 7-8 mm. long, slightly pubescent, the lower tooth slightly elongate, lanceolate, 1/3-2/3 as long as the tube; legumes 3-4 cm. long, 8-9 mm. wide, glabrous. May-July.

Naturalized in Hokkaido and Honshu (Mount Ibuki in Oomt Prov.). Europe.