Plants loosely cespitose; rhizomes slender, long. Culms 10–90 cm. Leaves: blades 1–3.5 mm wide. Inflorescences 3–12(–22) cm; proximal internodes 10–60(–100) mm; peduncles of proximal spikes to 8 cm; proximal bracts with blades 5–140 mm, sheaths cylindric, 5–25(–35) mm, mouth 0.9–1.5 mm wide. Spikes 3–8; lateral spikes androgynous or pistillate, rarely some entirely staminate, the proximal inclined or pendent, 5–30 × 3–7 mm; terminal spike staminate or androgynous, 10–28 × 1.8–4 mm. Pistillate scales brown to black, oblong-obovate, 3–5.8 × 1.1–2 mm, apex obtuse to acute, sometimes shortly awned. Staminate scales brown or black with hyaline margins, oblong-ovate, 3.1–6.2 × 1–3 mm. Anthers 1.5–3 mm. Perigynia ascending, pale yellow proximally, brown or black distally, 3–9-veined, lanceolate, 3.5–5.5 × 1.1–2.4 mm, margins ciliate-serrulate distally, apex tapered, shortly setose, sometimes setae confined to veins, or subglabrous; beak indistinct, to 0.5(–1) mm. Achenes obovoid, 1.7–2.2 × 1–1.3 mm.
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