Plants densely cespitose. Culms 50-110 cm; vegetative culms with numerous leaves spaced evenly along distal 1/2. Leaves: sheaths adaxially green-veined nearly to collar, with ± triangular white-hyaline area to 3-8 mm proximal to collar, somewhat loose, expanded near summits, ± wing-angled, adaxially firm, summits U-shaped, somewhat thickened, slightly prolonged beyond collar; distal ligules 4-8(-12) mm; blades 4-10 per fertile culm, 15-40 cm × (2-)3-7 mm. Inflorescences erect, dense distally, brown, 2-5(-8) cm × 10-20 mm; proximal internode 2-20 mm; 2d internode 2-13 mm; proximal bracts bristlelike, 1(-8) cm. Spikes 6-15, overlapping or distinct, ovoid-oblong to globose, 6-12(-16) × 4-8 mm, base rounded to tapered, apex rounded. Pistillate scales white-hyaline or pale silvery brown with green midstripe, lanceolate, (1.9-)2.5-3 mm, 1/2 length of and narrower than perigynia, apex acute to acuminate. Perigynia more than (30-)40 per spike, appressed-ascending to ascending, pale green to pale brown, 3-6-veined abaxially, conspicuously or, occasionally, faintly, 2-4-veined adaxially, often somewhat asymmetric, ovate-lanceolate to ovate-elliptic, plano-convex, 3-5.4 × 1.1-1.7 mm, 0.3-0.5 mm thick, margin flat, including wing 0.1-0.5 mm wide; beak tip flat, ciliate-serrulate, abaxial suture with golden to dark brown hyaline margin, distance from beak tip to achene 1.4-2 mm. Achenes oblong-ovate, 1-1.8 × 0.6-0.9 mm, 0.3-0.5 mm thick. 2n = 70. See note under 146. Carex longii.