Herbs, perennial, rhizomatous. Culms trigonous, (30-)45-80 cm × (0.8-)1.2-2.2 mm, glabrous. Leaves flat to V-shaped, becoming trigonous apically, 15-30 cm × 0.5-3.2 mm. Inflorescences: spikes oblong-cylindric, densely spicate, ± truncate at base, (9-)12-22 × (4-)6-12 mm; rays 2-4(-5), (1.5-)2.5-6 cm; bracts 4-6, longest erect or nearly so, larger ones flat or V-shaped, smaller capillary, trigonous, 3-24 cm × 0.4-3.6 mm; rachilla ± deciduous, wings 0.2-0.4 mm wide. Spikelets (10-)20-60, oblong to linear-lanceoloid, compressed-quadrangular, 3-9 × 2-3.4 mm; floral scales deciduous, 2-4(-8), spreading, medially green, laterally stramineous, dull whitish or pale reddish brown, often red-dotted laterally, (3-)7-9-ribbed, ovate-lanceolate, (2-)2.2-2.8(-3) × (1-)1.2-1.8 mm, apex acute, weakly 3-dentate, mucro 0.2-0.6 mm, with apical tuft of crystalline prickles. Flowers: anthers 0.4-0.9 mm; styles 1-1.4 mm; stigmas 1-1.6 mm. Achenes brown, ± stipitate, broadly ellipsoid, 1.4-1.5(-1.6) × 0.8-0.9 mm, 0.1 × 0.1-0.2 mm, apex ± truncate, apiculate, surfaces papillose. Fruiting late summer. Seepage slopes in montane forests; 1000-1500 m; Ariz., N.Mex.; Mexico.