Japan Flora: Slender annual, thinly retrorse-pilose on stems, petioles, and racemes; stems slender, twining; stipules narrowly ovate, rather obtuse, 3-4 mm. long, nerved, persistent, the terminal leaflets ovate or broadly so, 3-6 cm. long, 2.5-4 cm. wide, obtuse to acute, appressed-pilose on upper side, paler or whitish with as­cending pubescence beneath, the midrib beneath with spread­ing hairs; racemes axillary, short-peduncled, several-flowered; flowers pale purple, 15-20 mm. long; calyx with ascending pubescence, the teeth shorter than the tube; legumes flat, slightly curved, 2.5-3 cm. long, 7-8 mm. wide, glabrous but with appressed hairs on both margins.  Sept.-Nov. Woods and shaded places in lowlands.

Honshu (Kanto Distr. and westw.), Shikoku, Kyushu; common.

var. trisperma (Miq.) Ohwi. Plant uniformly appressed-pilose, with thinner leaves promi­nently whitish beneath; terminal leaflets slightly attenuate; flowers deeper purple.  Frequent in Hokkaido and n. Hon­shu, rare in Kyushu. The typical phase and other variants occur from Korea, Manchuria, and Ussuri to the Himalayas.