Annuals. Roots fibrous. Rhizomes absent. Culms nearly tufted, 30-40 cm tall, slender, 3-angled, glabrous. Leaves cauline; sheath tubular, 3-angled, barely winged, glabrous, apex of basal ones with triangular teeth; contraligule semicircular, pubescent; leaf blade linear, 2.5-5.5 mm wide but apically attenuate, papery, smooth, glabrous, margins scabrous, apex slightly obtuse. Involucral bracts leaflike, basal one to 15 cm, sheathing, opening of sheath with brown pubescence; bractlets setaceous, sheathless, much longer than spikelet. Inflorescences paniculate, with 2 or 3 branches; branches 1.5-2.5 cm, with many spikelets; lateral branches distant. Spikelets 1 or 2 in a cluster, narrowly ovoid, 3.5-4 mm, mostly unisexual; female spikelets with 4 or 5 glumes and 1 female flower; male spikelets with 7-9 or more glumes. Glumes ovate to lanceolate, apically attenuate, keel green to same color as glume, apex acute and apiculate. Male flowers: stamens 2 or 3. Female flowers: ovary obovoid, finely reticulate, densely pubescent. Disk ca. 1/2 height of nutlet, 3-lobed; lobes ovoid-triangular, slightly shiny. Nutlet white or yellowish, subspherical, ca. 2 mm in diam., reticulate, apex with a purple tip. Fl. and fr. Aug-Sep.