Japan Flora: Erect or slighdy twining annual; cotyledons hypogeal; primary leaves simple, long-petioled, cordate; stems 30-80 cm. long, sparsely branched above, sometimes slightly twining above; ordinary leaves petioled, spreading-pilose especially on under side, the terminal leaflets broadly ovate, usually 3-lobed, 6-10 cm. long, 5-8 cm. wide, the stipels lanceolate, acuminate; racemes short-peduncled or subsessile, sometimes long-peduncled, the bracteoles narrowly ovate, few-nerved, acute; flowers 15- 18 mm. across; legumes pendulous, linear, 6-10 cm. long, nearly glabrous, slighdy inflated above the ellipsoidal seeds, the hilum flat. Aug.-Sept.
Widely cultivated in our area.
var. nipponensis (Ohwi) Ohwi. Twining and more slender; terminal leaflets narrowly ovate; racemes pilose; legumes blackish, 4-5 cm. long, the valves thinner. Aug.-Sept. Thickets and grassy places in lowlands; Honshu, Shikoku, Kyushu; rather common.