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.