Perennials. Rhizomes short, creeping. Culms 50-90 cm tall, stout, obtusely 3-angled, smooth. Leaves basally with a brown long sheath, apically bladeless or with a short blade. Involucral bracts 3-5, leaflike, longer than inflorescence. Inflorescence a decompound or compound anthela; rays 5-7, to 5 cm, unequal, each with 3-8 raylets. Spikes broadly ovoid, 1-2 × 1-2 cm, with 4-15 spikelets. Spikelets ± laxly arranged, linear, 8-20 × ca. 1.5 mm, slightly compressed, obliquely spreading, 6-30-flowered; rachilla wings reddish brown, linear-oblong. Glumes reddish brown on both surfaces but middle green, lax, oblong, 2-3 mm, papery, 3-5-veined, not keeled, margin slightly revolute at maturity, apex obtuse to rounded. Stamens 3; anthers linear; connective prominent beyond anther, apex sometimes setiferous. Style of medium length; stigmas 3. Nutlet dark brown, obovoid-oblong, ca. 1/2 as long as subtending glume, 3-sided, densely puncticulate. Fl. and fr. Nov-Jan. 2n = 208.
River margins, water margins, wet places, marshes, stream beds, often found standing in water and in rice fields; at elevations from near sea level to 400 metres in southern China.
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