Aquatic herb with tuberous rhizome. Leaves 8–35 x 7.5–42 cm., chartaceous, with long petioles, glabrous or densely pubescent, orbicular or subelliptic, incised-cordate, peltate, lobes slightly divergent or somewhat overlapping, acute or caudate, margin ± irregularly sinuate-lobulate or entire towards the apex, upper surface smooth, under surface with conspicuously raised nerves, green or rarely reddish or reddish-purple, primary lateral nerves 8–11 on each side of the midrib, forming elongated closed areas stretching to more than 2/3 of the way to the margin, 6–8 pairs of secondary nerves arising from the midrib. Flowers blue or pinkish, 8–12 cm. in diam. Sepals 4, 4–10 x 1.5–3.5 cm., green or purple at the margins. Petals 14–20, outermost as long as the sepals, oblong, obtuse or subacute. Stamens very numerous, 100–200 or more, densely congested, the outermost with long appendages. Carpels 14–24; style very short. Fruit 2.2 x 3.2 cm. (in the specimens seen), depressed-globose. Seeds 1.2 mm. long, ellipsoid.
