Annual or perennial, often grass-like herbs, only the monotypic African genus Microdracoides tree-like; the perennial spp. with short- or long-creeping, mostly sympodial rhizome not rarely emitting stolons. Stems solid, exceptionally hollow, sometimes septate, often trigonous, more rarely 2-sided or terete, or 4-, 5-, or multangular, usually nodeless below the inflorescence. Leaves often 3- ranked, more rarely distichous or polystichous, basal and/or cauline, usually sheathing at the base, the sheaths closed (in Mal.), very rarely open, the blades as a rule sessile, linear (grass-like) or setaceous, rarely lanceolate and petioled, rarely much reduced or even absent; sheath and blade whether or not separated by a rim of short hairs or by a membranous ligule almost completely fused to the upper surface of the blade. Flowers simple, inconspicuous, each subtended by a bract (glume), arranged in small spiciform units (spikelets), in subfam. Caricoideae strictly unisexual, in subfam. Cyperoideae tribe Hypolytreae composed of monandrous lateral ‘flowers’ and a terminal ovary, in tribe Cypereae reduced to bisexual synanthia, a few of which may be functionally male or female by abortion of the other sex. Spikelets often (always?) cymose (‘pseudo-spikelets’), (1-) few- to many-flowered. Inflorescence paniculate, anthelate, capitate, or spicate, with few to many spikelets, rarely reduced to a single spikelet, often subtended by 1-several leafy involucral bracts, Perianth consisting of bristles, hairs, or scales, but often absent. Stamens often 3, not rarely reduced to 2 or 1, very rarely more than 3 to numerous; filaments ligulate, free, only in a few Carex spp. connate, sometimes strongly elongating after anthesis; anthers basifixed, introrse, opening lengthwise by a slit. Ovary solitary, superior, usually 2- or 3-carpellate, unilocular; style not rarely thickened at the base, the thickened part whether or not articulated with the ovary; stigmas 2 or 3 (rarely more), only in a few spp. style unbranched; ovule solitary, erect from the base of the ovary, anatropous. Fruit indehiscent, a nut (often termed achene), sessile, or seated on a disk, free, or surrounded by a modified prophyll (perigynium, utricle). Seed erect, with thin testa not adhering to the pericarp; embryo small, at least partly surrounded by abundant mealy or fleshy endosperm. Dist ribution. About 70-80 genera with probably some 4000 spp., throughout the world.