Aquatic perennial, mostly 1-2 m tall; culms +/- stout, rooting at nodes. Sheaths mostly shorter than internodes, glabrous, sometimes ciliate; blades 15-35 cm long, 1.5-3 cm wide, cordate-clasping at base, glabrous, scabrid on margins and ciliate near the base. Inflorescence a dense, spikelike panicle 8-30 (50) cm long, 1-1.5 cm thick; spikelets 3-4 mm long, acuminate; first glume one-fourth to one-half as long as spikelet with scabrous keel; second glume and sterile lemma covering fruit, scabrous on veins, the sterile lemma narrowly acuminate. Fruits oblong-elliptic, +/- flattened, dull, light greenish. Croat 7197. Infrequent, usually growing in shallow water at the edge of the lake. Flowers throughout the year, especially in the late rainy and early dry seasons. The spikelets are probably dispersed in part by water, but the sharply pointed sterile lemma could easily be caught and carried in bird feathers.