Culms 10-110 cm. Leaves 3-5 per culm; sheaths tight, inner band hyaline, 3.5-24 cm, apex concave, glabrous; ligules rounded to obtuse, 0.5-3.7 mm; blades plicate, 8-60 cm × 0.4-4(-4.5) mm, widest leaf 0.8-4(-4.5) mm wide. Inflorescences 0.8-5.5 cm; spikes 2-8; lateral spikes pistillate often with a few staminate flowers proximally, 3.1-13.1 mm, sessile, staminate portion 10-flowered, to 6.5 mm, pistillate portion 3-40-flowered, 2.5-12 mm; basal 2 spikes 1.5-18 mm apart; terminal spike gynecandrous, 4.8-23.7 mm, staminate portion 2-21-flowered, 1.8-13.5 × 0.8-1.3 mm, pistillate portion 4-38-flowered, 3-11 × 4.4-7.5 mm. Pistillate scales ovate to ± suborbicular, 1.2-2.4 × 1.2-2 mm, apex obtuse to acute. Staminate scales ovate-lanceolate to ovate, 1.3-3.5 × 0.8-1.4 mm, base clavate, apex acute to obtuse. Anthers 0.6-1.5(-1.8) mm. Perigynia spreading to reflexed, green, 6-13-veined abaxially, (0-)1-12-veined adaxially over achene, broadly ovate to suborbicular, cuneate or concavely tapered from widest point to beak, 1.9-3.8 × (1.3-)2.1-3 mm, 1.1-1.7(-1.9) times as long as wide; beak 0.45-1.25 mm, 0.23-0.5(-0.63) length of body, serrulate, teeth 0.15-0.45 mm. Achenes deltate to rhombic-orbiculate, 1-1.9 × 1-1.7 mm.