Aquatic perennial; culms rather thick, succulent, rooting at the nodes, fre-quently floating, glabrous; sheaths loose, inflated, transversely veined, usually longer than the internodes, glabrous, auriculate, the auricles 1-8 cm. long, fused with the ligule, attenuate to a fine point; blades elongate, acuminate, 1-2.5 cm. wide, gradually narrowed to the thickened base, scabrous and sparsely pilose on both surfaces, the margins hispid-scabrous, almost serrate; staminate panicles 12-15 cm. long, the slender branches ascending to spreading, sparsely pilose, rather densely villous in the axils, the lowest ones subverticillate; spikelets 6 mm. long, the lemma and palea thin, glabrous; pistillate inflorescences partly enclosed, pro-truding sidewise from the inflated sheaths, 5-6 cm. long, about as broad; branches numerous, at first stiffly ascending, finally spreading or reflexed, implicate, glabrous, terminating in a spikelet, the peduncle flat, weak, easily drooping, the panicle turned downward in the water; spikelets at time of flowering 4-5 mm. long, nar-row, acuminate, pale, the lemma and palea thin, but not readily disintegrating, prominently nerved, bulged out at maturity exposing the fruit; caryopsis 2 mm. long, subspherical, minutely striate.
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