Aquatic perennial with long spongy culms, often floating in water and rooting at the nodes. Inflorescence a panicle. Spikelets dorsally flattened, lanceolate, falling with the pedicel attached. Lower glume small; upper glume as long as spikelet and with a long awn (> 6 mm). Lower lemma acuminate, separated from the upper floret by a 1.5 mm internode.