Annuals. Rhizomes short, subwoody. Culms 30-60 cm tall, slender, 3-angled, glabrous. Leaves cauline; sheath 3-angled, not winged, glabrous; contraligule semicircular; leaf blade narrowly linear, 2.5-3.5(-5.5) mm wide, papery, slightly shiny, glabrous, margin scabrous, apex acute. Involucral bracts leaflike, sheathing; bractlets small, narrow, sheathless. Inflorescences paniculate; branches single or binate, (0.5-)1-2 cm, distant. Spikelets mostly unisexual, narrowly ovoid, ca. 5 mm, lax, with ca. 9 flowers, with 11 or 12 glumes. Bisexual spikelets with 1 or 2 empty basal glumes, middle glumes with a female flower, apicalmost glume empty or with a reduced flower. Glumes pale brown, ovate to ovate-lanceolate but apical ones lanceolate, membranous, keel abaxially green, apex acute. Perianth lobes rounded at apex. Male flowers: stamens 2 or 3. Female flowers: style slender; stigmas 2, almost as long as style. Disk not well developed. Nutlet white, subovoid-spherical, 2-2.5 mm (excluding stalk), obscurely reticulate, glabrous, base truncate, apex subrounded and without a tip. Fl. and fr. Jul-Oct.