Annual or perennials. Culms terete or triangular. Leaves (if present) usually basal. Main inflorescence bract culm-like and appearing as a continuation of the culm beyond the inflorescence. Inflorescence either a dense apparently lateral cluster of spikelets or an anthela of many spikelets. Spikelets with numerous bisexual flowers. Glumes spirally arranged. Perianth bristles present or 0. Stamens usually 3. Ovary with a long style and 2-3 stigmas.

Note that the perianth bristles must not be confused with the 3 filaments arising from the base which may be persistent in fruit. Some of the annual species may produce basal flowers hidden in the lower leaf sheaths.