Japan Flora: Glabrous perennial with short rhizomes; stems 10-50 cm. long, 1-leaved, usually few together; leaves orbicular-cordate, sometimes broadly ovate, 15-35 mm. long and nearly as wide, rounded to obtuse, sometimes subacute, the radical leaves long-petiolate> the cauline sessile and clasp­ing; flowers 2-2.5 cm. across, white; petals broadly ovate to elliptic, scarcely clawed at base, rounded at apex; anthers broadly ovoid, 2-3 mm. long, the staminodes 12- to 22-cleft; capsules 10-12 mm. long, broadly ovoid. Aug.-Oct. Wet places.

Hokkaido, Honshu, Shikoku, Kyushu. Temperate and northern regions of the N. Hemisphere.

var. tenuis Wahlenb. Small alpine phase with 9- to 1 l-cleft staminodia. Alpine regions of Hokkaido and Honshu (centr. distr.). Cold regions and high mountains of the Old World.