Japan Flora: Rhizomes stout and fleshy; leaves long-petioled, ovate-orbicular to ovate-elliptic, 5-12 cm. long, 8-15 cm. wide, basifixed, entire, rounded, deeply cordate-sagittate; lobes of leaves shorter than the length from the attachment of petiole to apex, the inner margin often overlapping; petals usually 8, white; sepals green, broadly lanceolate to narrowly ovate, 3-3.5 cm. long, 10-15 mm. wide, subacute; outer filaments broadly oblanceolate, the inner ones nearly linear, 3-5 mm. long, the connective not produced above; fruit ovoid-globose, covered by the persistent calyx. ——July-Oct. Ponds and shallow lakes;

Hokkaido, Honshu, Shikoku, Kyushu. e. Siberia, Manchuria, China, Korea, India, and N. America.

Var. angusta Casp. Lobes of leaves longer than the length from the attachment of petiole to apex, with more or less distant inner margin; petals usually 12-15. Ponds and lakes at low elevations; Honshu, Shikoku, Kyushu.