Floating aquatic grass; stems stoutish, diffusely branched, rooting at the nodes; branches short, erect, leafy. Leaf-blades flat, ovate-oblong, obtuse; leaf-sheaths inflated, strongly keeled. Panicle shortly exserted from the uppermost leaf-sheath, few-branched, the lowermost branches whorled. Spikelets few, 1-flowered, long-awned; glumes absent; lemma thinly chartaceous, laterally compressed, keeled, strongly 5-nerved, the nerves scabrid and ciliate; palea keeled, 3-nerved, ciliate on the keel; stamens 6; stigmas 2, the styles free and divergent.