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.

Fls unisexual, each in the axil of a scale, in a solitary terminal spike, the pistillate below the staminate; bract none; stamens 3; ovary surrounded by a perigynium as in Carex, the style and 3 elongate stigmas persistent on the mature trigonous achene; shortly rhizomatous, the flowering culms bearing at anthesis a few imbricate basal sheaths without blades, the uppermost sheath later splitting and elongating to form a large solitary near-basal lf without midvein or sheath. Monotypic.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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