Perennial herb, rooted aquatic, colonial from leaf-bearing rhizomes to 2 cm thick, slender.
Leaves alternate leaf stalks very thin, flattened above, blades both floating and submerged, floating leaves 5-10 cm long, elliptic, tip rounded, base lobed, lobes with narrow “V” shaped sinus at least half the length of the blade; submerged leaves kidney-shaped, filmy.
Flowers yellow inside with red center, 1.5-2 cm thick, petals numerous but inconspicuous, sepals 5, to 1.8 cm long, elliptic to widest above middle, becoming fully separated, stamens 0.2-0.3 cm long, shorter than filaments; stigmatic disk red, 0.3-0.6 cm wide, 6-10 rayed; flowers solitary; blooms and fruits June-Oct.
Fruit a capsule 1.5 cm wide, constricted near top.
Wetland status: OBL.
Frequency in NYC: Very infrequent.
Habitat: Sunny ponds. Probably planted in restorations and mitigations also.