Plants perennial, forming dense clumps, not stoloniferous, rhizomatous. Rhizomes usually present, caudexlike, ascending, 1 mm thick, hidden by crowded culms; internodes and scales not evident. Culms sometimes spirally twisted, usually minutely red-spotted at 30X, acutely triangular or sometimes elliptic, 15–70 cm × 0.3–0.5(–1) mm, soft (to firm), often minutely granular at 10X. Leaves: distal leaf sheaths persistent, stramineous to green, often minutely red-spotted, membranous to papery, apex subacute to narrowly acute, often with toothlike callus. Spikelets: basal spikelets absent; never proliferous, ovoid to lanceoloid or ellipsoid, terete, 4–12 × 2–4 mm, apex acute; proximal scale empty, deciduous, clasping 1/2 of culm, similar to floral scales; subproximal scale often empty; floral scales spiraled, 10–25, 5–6 per mm of rachilla, pale orange-brown, midrib regions broadly pale green to colorless, broadly ovate, 2–2.5(–3.5) × 1.5–2 mm, central area and often flanks papery to cartilaginous or sometimes membranous, midrib evident, apex subacute (to rounded). Flowers: perianth bristles 4–6, bright brown, stout, equaling to slightly exceeding tubercle; spinules dense, retrorse, sharply acute; stamens 3; anthers 0.5–0.9 mm; styles 3-fid. Achenes medium brown or yellowish or greenish, obpyriform, obtusely (often obscurely) compressed trigonous, angles evident, 1.2–1.7(–2.4) × 0.9–1.2(–2.2) mm, apex constricted proximal to tubercle, coarsely cancellate at 10X, each face with 8–10 longitudinal rows of distinctly depressed, enlarged cells. Tubercles brown to greenish (or bone-white), pyramidal, trigonous or cross section plano-convex, 0.3–0.7(–1) × 0.3–0.6(–0.9) mm, distinctly shorter or narrower than achene, apex acute, often acuminate.
