Herbs, perennial, cespitose to mat-forming, 2--5 dm. Rhizomes short, nearly erect, branching. Culms 1(--2). Cataphylls 2--4. Leaves basal, 3--6; auricles 0.2--0.4 mm, membranous to scarious; blade arcuate, spreading, grayish green, channeled, 7--30 cm x 1--2 mm, nearly leathery, margins entire. Inflorescences terminal, 7--40-flowered, somewhat loose, 3--10 x 1--2 cm; primary bract usually shorter than inflorescence. Flowers: pedicels 0.5--2 mm; bracteoles 2; tepals brown to blackish, 4--5.5 mm; outer and inner series nearly equal, apex obtuse to nearly acute; stamens 6, filaments 0.5 mm, anthers 1.5--2 mm; style 0.2 mm. Capsules brownish, 3-locular, ovoid to ellipsoid, 4--5 x 2.3--3 mm, nearly equal to perianth. Seeds brownish, ellipsoid, 0.6--0.9 mm, not tailed. 2n = 42.

Flowering and fruiting late spring--summer. Moist, open sites and bogs, occasionally disturbed areas; 20--200 m; introduced; Greenland; Wis.; native, Europe.