Annual large aquatic herb. Submerged leaves are arrowhead or elliptic-reniform, 4-10 cm long, without spines on both sides; petiole without spines; floating leaves are coriaceous, elliptic-reniform to circular, 10-130 cm in diameter, shield-shaped, with or without notched indentations, entire, purple below, with short soft hairs, with sharp spines at the branching points of the leaf veins; petiole and peduncle robust, up to 25 cm long, both with hard spines. Flowers about 5 cm long; sepals lanceolate, 1-1.5 cm long, purple inside, densely covered with slightly curved hard spines on the outside; petals oblong lanceolate or lanceolate, 1.5-2 cm long, purple-red, arranged in several whorls, gradually transitioning to stamens inwardly; no style, stigma red, forming an凹-in stigma disc. Berries are spherical, 3-5 cm in diameter, dirty purple-red, densely covered with hard spines; seeds are spherical, over 10 mm in diameter, black. Flowering period: July to August, fruiting period: August to September.