in N. L. Britton and A. Brown, Ill. Fl. N. U.S. ed. 2, 1: 441. 1913.
Herbs, perennial, cespitose, evergreen. Culms compressed or terete. Leaves basal, bladeless; proximal sheaths 4–6, whitish to straw colored, disintegrating at maturity, distal 1 (–2, rarely), blade flat, formed from open, elongated sheath, without ligule or evident midvein, usually 2–5 cm wide. Inflorescences terminal, single spike; bracts spirally arranged, each subtending flower, scalelike. Spikelets 1-flowered; scales 0–1. Flowers unisexual; staminate flowers without scales; pistillate flowers with 1 scale enclosing flower (perigynium), open only at apex; perianth absent; stamens 3; styles deciduous, linear, 3-fid. Achenes sharply trigonous.
e North America