Leaves: petiole 0-5 mm long; blade 5-30 by 3-15 mm, asymmetric, oblong or obovate, crenate-dentate to lobulate, veins 4-6 on each side, impressed above, prominent beneath, strigose between veins, hairs often with bulbose base on upper, spreading on lower surface. Flowers sub-sessile. Stamens: filaments inserted above middle of corolla, included, longer than the anthers. Ovary glandular-villous; style bifid nearly to the base. Fruit 3-4 mm long, pyramidal, 4-lobed, nutlets beaked, strongly convex by vesicular, corky mesocarp dorsally, sharply angulate ventrally, with one large and one small commissural face.
Africa present, Asia-Temperate: Hainan (Hainan present); Taiwan (Taiwan present), Asia-Tropical: Borneo present; India present; Malaya (Peninsular Malaysia present); Maluku (Maluku present); New Guinea present; Sri Lanka (Sri Lanka present); Thailand (Thailand present), Australasia, Burma present, Flores present, SE Asia present, Timor present, incl. Madura present
India, Sri Lanka, Thailand, Burma, Indochina, Taiwan, New Guinea, China (Hainan); Malesia:Malay Peninsula, Borneo, Java (incl. Madura), Lesser Sunda Islands (Flores, Timor), Moluccas. Widespread in tropical and subtropical SE Asia, Africa, Australia..
A plant of seasonally flooded places, but also able to stand extreme heat and drought. It is a common weed in dry rice-fields. The corky mesocarp may be useful for dispersal in ponds and ditches.