Monoclinous. Stems short, rhizomatous. Leaves basal, long-petiolate, floating; blade ovate to oblong, apex rounded, base rounded. Inflorescence scapose, obscurely paniculate, verticillate. Flowers long-pedicellate; sepals persistent; petals much longer than sepals, broad-obovate, delicate, white to pinkish; stamens 6, grouped in pairs opposite petals; carpels 6-9(-10). Achenes ovate, nearly terete, sulcate; seeds not or weakly sculptured. 2n = 42.