Description from Flora of China
Rhizomes horizontal. Stems green, slender, to 60 cm. Leaves opposite, glabrous adaxially, pale purple-red abaxially; petiole 1.5-3 cm; floating leaves 2.5-3 cm wide, apex obtuse-acute; submersed leaves 3-5 cm X 5-7 mm. Pedicel 1-3 cm, elongated at anthesis. Calyx teeth ca. 2 mm, persistent. Corolla pale red, 1-3 X 2-3.5 cm; lobes rounded. Filaments ca. 1 cm; anthers 2-locular, spreading. Fruit with 3 hooklike appendages to 7 cm and 2 erect spines 0.3-2 cm. Fl. Jun. 2n = 50.
Ponds, lakes; to 300 m. Anhui, Fujian, Guangxi, Hebei, Heilongjiang, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning [Japan, Korea, Russia (Far East)].