Procumbent on wet ground or floating on water, rooting at the nodes, the stem hollow. Leaves mostly hastate, the terminal lobe narrowly triangular or lanceolate, the basal lobes smaller and spreading or almost absent, 4-12 cm long, apically acute or obtuse, glabrate. Flowers solitary or in few-flowered cymes. Sepals ovate-oblong, 7 mm long, obtuse or subacute, glabrous. Corolla white or purple, 4-5 cm long. Fruit capsular, ovoid to globose, 8-10 mm long. Seeds densely soft-pilose or glabrous.