Grasslike or rushlike herbs, perennial with rhizomes or annual with fibrous roots. Culms solid or rarely hollow, terete to variously angled. Lvs. mainly basal, alternate, commonly 3-ranked, the blades narrow and sheaths closed. Infl. commonly subtended by 1 or more involucral lvs. and consisting of a terminal spikelet or a cluster of spikelets. Each spikelet of a series of scales (bracts) subtending individual fls. Scales spirally imbricated or 2-ranked, persistent or deciduous. Flowers perfect or unisexual. Perianth represented by several bristles or by an inner hyaline member, or absent. Stamens 1-3. Pistil 1, the ovary superior, 1-loculed, with 1 ovule and a single 2- or 3-fid style. Fruit a triangular or lenticular ak. Embryo minute. Endosperm mealy. A large cosmopolitan family of about 60 genera and 2600 species. (Munz, Flora So. Calif. 883).