Japan Flora: Nearly glabrous herb; leaves long-petioled, the petiole 3-6 cm. long, the sheath usually truncate at apex, ciliate, 1-2 cm. long, the blade 5-8 cm. long, 3-5 cm. wide, abruptly long-acuminate, deeply cordate at base, minutely ciliate on margin, sometimes with long hairs above; flowers 2 or 3, white, 5-6 mm. across; sepals 1- to 3-nerved, obtuse, about 4 mm. long; filaments curled-pubescent; capsule 8-11 mm. long including the terminal beak, glabrous. Aug.-Oct.