Japan Flora: Leaves peltate, long-petioled, orbicular, lustrous above, purplish and short-pubescent beneath, 30-120 cm. across, flat, subentire, slightly
emarginate at base; calyx-lobes 15-20 nun. long, narrowly deltoid, subacute to obtuse, persistent, erect in fruit; petals broadly lanceolate or oblanceolate, 6-10 mm. long, obtuse; anthers 3-3.5 mm. long, the filaments unequal in length; fruit ellipsoidal or subglobose, 5-7 cm. long, beaked; seeds subglobose, about 1 cm. across, with a fleshy aril. Aug.-Oct. Ponds and lakes in lowlands;

Honshu, Kyushu. India, China, and Formosa.