Plants perennial, cespitose or solitary, to 70 cm; rhizomes slender, scaly, to 2 mm thick. Culms erect, slender, leafy-based, trigonous, several-ribbed. Leaves spreading to erect, overtopped by culm; blades narrowly linear, proximally flattened, 0.5–3 mm wide, apex tapering, trigonous. Inflorescences terminal, solitary, headlike, dense, white, leafy-involucrate; involucral bracts several, flaring to recurved, white from broadened base nearly to median, then green to tapered tip, longer bracts 13 cm × 2–7 mm. Spikelets white, ovoid, 5–7 mm, apex acute; fertile scales many, boatshaped, sharply curvedkeeled, 3–4(–5) mm, apex acute or blunt. Flowers: perianth absent. Fruits several per spikelet, 1.5–1.7(–2) mm; body yellow to mahogany, broadly pyriformobovoid, tumidly lenticular, 1 × 0.5–0.7 mm, widest at apex, margins thickened, interrupted at base of tubercle; surfaces transversely undulaterugose, ridges contiguous, of shortlinear papillae; tubercle broadly triangular, 0.5–0.6 mm, graycrustaceous, apex short acuminate. 2n = 12.
