Annual or perennial herbs of small to medium size; stems erect or somewhat curved, triangular, polyangular or almost terete, glabrous, scabrid or hairy. Leaves near the base only; blades well-developed, flat or filiform or rarely reduced to sheaths, usually with long flexuose hairs at the opening of the sheaths. Inflorescence a lax anthela, a head of congested spikelets or reduced to a single terminal spikelet; involucral bracts leafy or glume-like, often shorter than the inflorescence. Spikelets with few–numerous spirally arranged glumes, all scales fertile or 1–2 lowermost without flowers. Glumes pale, reddish brown to almost black, often with green midrib, ovate to orbicular with obtuse or acute apex, sometimes the midrib extended into an awn, glabrous or more commonly scabrid or short-hairy. Perianth absent. Stamens 1–3. Style with 2 or (commonly) 3 stigmas. Nutlet obovate to obcordate, obtusely or sharply triangular, rarely biconvex, pale, grey, reddish brown to almost black; surface smooth, transversely wrinkled, papillose, reticulate or longitudinally striate; the style base swollen and often persisting on the mature nutlet as a small knob.