Japan Flora: Soft, puberulous to glabrous green perennial with thick roots and rather thick woody rhizomes; stems 20-35 cm. long, erect, usually simple, green, terete, rather thick; leaves thin, few, mostly toward the top of the stems, obovate-oblong to oblong, 8-17 cm. long, 3-7 cm. wide, abruptly acute to abruptly acuminate, acute or gradually narrowed at base, short-petio- late, thin, soft, green, slightly paler beneath; racemes solitary, terminal, about 10-flowered, 2-5 cm. long, erect; flowers short- pedicelled, yellow, about 2 cm. long, the 2 lateral sepals larger, broadly oblanceolate, obtuse, as long as the petals, the 2 smaller sepals oblong, obtuse to rounded, ciliate, the upper one rather longer, bowed out on the back, about 7 mm. long; petals 3, connate, about 2 cm. long, the lowest with a fimbriate appendage at apex; fruit depressed-orbicular, glabrous, about 10 mm. wide, longitudinally ribbed; seeds about 4 mm. long, reddish brown. Woods in hills and low mountains.
Honshu (Tokaido and Kinki Distr.); rather common.
f. angusti£olia (Makino) Ohwi. Leaves narrow, lanceolate.