Herbs usually with solid or (rarely) ± hollow stiff culms. When perennial the rhizomes often produce short stolons covered with short sheathing scales. Leaves chiefly basal, usually with closed sheaths, or leaves reduced to sheathing scales. Flowers bi- or unisexual, in spikelets, subtended by scale-like bracts (glumes) which are distichous or spirally imbricate; lower glumes often sterile. Spikelets either solitary or clustered in terminal or apparently lateral simple or compound spikes panicles or umbels. Compound inflorescence and its branches subtended by bracts the lower of which often closely resemble cauline leaves; the upper bracts increasingly glumaceous. Perianth absent or present as bristles or scales. Stamens 1–3, rarely more; filaments free, filiform or slightly flattened; anthers usually exserted from the spikelets, attached by their bases, oblong or linear, with 2 parallel cells opening by slits. Ovary 1-locular, with 1 erect ovule; style terminal, filiform or thickened at the base, 2–3(4)-fid. Fruit a small nut, flattened when style is 2-fid, ± 3-angular when style is 3-fid. c. 98 gen., cosmop.