Plants densely cespitose, often forming tussocks, short-rhizomatous. Culms to 20(–30) cm. Leaf blades 2–(–10) cm × 0.5–1.5 mm, dead leaf remains often circinnate. Spikes: staminate 2–8 × 0.7–2 mm; pistillate 2–9 × 1–3 mm. Pistillate scales reddish black with hyaline margins, subcircular, 1.4–2.5 × 1.2–2 mm, apex obtuse to subacute, shorter than to as long as perigynium body. Staminate scales reddish black or dark brown, midvein paler, obovate, 2–3 × 0.8–1.4 mm, apex obtuse to acute. Perigynia reddish black to dark brown distally, 1.5–2.5 × 0.9–1.2 mm; beak 0.3–0.5 mm. Achenes obovoid, 1.75 × 0.8 mm. 2n = 34.