Herbs, perennial, forming slender to massive tussocks. Roots stout. Rhizomes woody. Culms erect, usually tall and robust, terete, several noded. Leaves linear, deeply many channeled, narrowly crescent-shaped, twisted lengthwise through 180°, involute on drying; ligule present, usually truncate, papery. Inflorescences plumose-paniculate, usually decompound, consisting of several fascicles per node. Spikelets brown or black, numerous, solitary or 2-4 together. Flowers 1 or 2, apical one bisexual, usually with a second more basal one male. Glumes black or dark brown, spirally arranged, papery; basal 3-8 glumes empty, lanceolate, keeled, abaxial surface and margin scabrous, apex acute; apical 2 or 3 glumes smaller than remaining ones, thin at anthesis but becoming thick in fruit, apex obtuse; apicalmost glume bearing a bisexual flower. Perianth bristles absent. Stamens (2 or)3[or 6]; filaments elongating markedly after anthesis, persistent on nutlet and entangled in glumes thereby suspending fruit. Stigmas 3[or 4]. Nutlet ovoid, ellipsoid, obovoid-fusiform, or globose, terete or 3-sided; endocarp blackish, thick, bony.