Japan Flora: Rhizomes creeping; stems elongate, re­motely leaved; leaves floating, ratlier thick and soft, ovate to orbicular, 5-10 cm. across, deeply cordate with overlapping lobes or sometimes slightly peltate, undulately toothed, the petioles elongate, dilated and sheathing at base, the pedicels 2-12 cm. long; calyx 8-15 mm. long, the lobes broadly lan­ceolate, obtuse, rather thick; corolla yellow, 3-4 cm. across, long-ciliate; capsules narrowly ovoid, slightly longer than the calyx, narrowed at apex; style about 3 mm. long; seeds flat, obovate, about 3 mm. long, tubercled on margin, minutely scabrous on both sides. June-Aug. Ponds and shallow lakes in lowlands.

Honshu, Shikoku, Kyushu; common. Korea, Formosa, China, and generally in the temperate regions of the N. Hemisphere.