Plants colonial from long-creeping rhizomes. Culms solitary or few together, somewhat trigonous, (20–)30–70(–80) cm, stout, to 1.5(–4) mm diam. basally; basal sheaths persistent, brown to purplish brown, septate-nodulose. Leaves: blades filiform, trigonous-channeled, (2–)3–10 cm × 1–2 mm; distal 1–2 leaf sheaths bladeless, inflated. Inflorescences: involucral bracts absent. Spikelets solitary, erect, globose in fruit, 1.5–2(–4) cm; scales blackish to purplish brown; proximal empty scales not more than 7, obovate or trigonous-obovate, 4–20 mm, margins white or paler, as wide as dark portion, apex blunt; distal scales obovate to ovate-lanceolate, margins hyaline, 1 mm wide or wider. Flowers: perianth bristles 10 or more, red-brown to white, 20–40 mm, smooth; anthers (0.6–)1.5–3 mm. Achenes oblong-obovoid, 2–2.7 mm, as wide as long, apex apiculate (0.3–0.5 mm).