Japan Flora: Stems slender, remotely 1- to 3-leaved; leaves orbicular- cordate or ovate-orbicular, 7-20 cm. across, subentire, deeply lobed, the petioles decurrent on the stem, 1-2 cm. long, auriculate，clasping; flowers few, fasciculate, white, about 1.5 cm. across, the pedicels 3-10 cm. long; calyx-lobes broadly lanceolate, subobtuse, 4-6 mm. long; corolla-lobes long-hairy inside; capsules oblong, 4-5 mm. long, not exserted beyond the calyx; style about 2 mm. long; seeds gray-brown, lustrous, nearly globose, smooth, about 0,8 mm. across. July-Sept. Ponds and shallow water in lowlands.

Honshu, Shikoku, Kyu­shu; common. Korea, Formosa, China, se. Asia to Australia, and Africa.