Japan Flora: Prominently soft-pubescent, twining perennial; stems slender, with spreading or reflexed pubescence; stipules narrowly ovate-triangular, acute, about 2 mm. long, recurved, pubescent; leaflets rather densely short ascending-pubescent, with reddish brown, sessile, discoid glands beneath, the terminal leaflet rather larger than the lateral ones, depressed-rhombic, abruptly acute with an obtuse tip, 2-3 cm. long and as wide, stipels minute; racemes axillary, short-pedunded, loosely 3- to 8-flowered; flowers solitary on each node of the raceme, 15-18 mm. across, yellow, the pedicels 6-8 mm. long; calyx about 10 mm. long, densely glandular-dotted and short-puberulent, sometimes loosely pilose, the lowest tooth longest, lanceolate, slightly longer than the tube; standard orbicular, short-clawed, with an obtuse tubercle on each side at base of limb, the keel semicircular and curved to the right, not spurred; legumes flat, broadly linear, 3.5-5 cm. long, about 8 mm. wide, short-pubescent, 6- or 7- seeded. Aug.-Sept.
Honshu (Kanto Distr. and westw.), Shikoku, Kyushu. centr. China.