Stems leafy, floating or creeping, rooting at nodes. Basal leaves: blade ovate-reniform or cordate, largest 1-2.5 × 1-5 cm, margins nearly entire. Inflorescences 2-6-flowered. Flowers 8-13 mm diam.; sepals white or pinkish, 4-7(-8) mm. Follicles 20-55, widely spreading, sessile, oblong; bodies 3.2-6.5 × 1-2.5 mm; style and stigma curved, 0.1-0.4 mm. Seeds broadly elliptic, 0.5-0.8 mm. 2 n =16, 32.

Flowering late spring-summer (Jun-Aug). Floating or on moist mud, ponds, lakes, slow-moving rivers and streams; 25-1500 m; Alta., B.C., Man., N.W.T., Ont., Sask., Yukon; Alaska, Minn., Wis.; Eurasia.

Unlike the other species of Caltha in North America, C . natans is relatively invariable morphologically and has not been divided into segregate taxa.