Rhizomatous perennial, culms to 1.5 m high, plants often forming swards in or near water and rooting from submerged nodes. Leaf-blades flat, to 20 cm long and 10(–15) mm wide, prominently veined, glabrous but distinctly scabrous on upper surface; ligules firm, 1.5–3 mm long. Inflorescence narrow to somewhat spreading, to 15 cm long, at least initially enclosed at base by upper leaf-sheath, branchlets weakly or barely flexuose. Spikelets 3–4.5 mm long, shortly pedicellate; lemma 5-nerved (3 obvious, 2 submarginal), scabrous-ciliate along keel, scabrous on lateral and submarginal nerves, internerves smooth or sparsely scabrous; palea 3-nerved, keeled, loosely clasped by narrowly incurved lemma margin, hispid along keel; anthers 6, c. 2 mm long. Flowers Feb.–May.
GipP. Presently known only from the verges of an ornamental pond and associated drainage line at La Trobe University, Bundoora, where presumed naturalised. Otherwise regarded as native in tropical and sub-tropical Australia. Occurs widely through tropical regions of the world.
