KOYAMA, Tetsuo, KUOH, Chang-Sheng & LEONG, Wai-Chao
Perennial or annual herbs, grass-like or rush-like, rarely with elongated woody caudices. Culms generally trigonous and solid. Leaves radical and/or cauline; blade linear or lanceolate-elliptic, sheathing at base, occasionally reduced to nearly bladeless sheaths; ligules present or absent; abaxial side of leaf sheaths sometimes projected beyond sheath orifice forming a tongue-like appendage (contraligule). Inflorescences various, mostly corymbose, paniculate, spicate, racemose or heads, subtended by leafy bracts, bearing 1 to numerous spikelets. Spikelets with few to many glumes; glumes imbricate or 2-ranked on a simple axis (rachilla); all or some glumes bearing an axillary flower or at times a bisexual cymule in axil, or rarely rachilla determinate with a single terminal pistillate flower and spikelet bearing 0-few small staminate partial spikelets in axils of some glumes. Flowers hermaphroditic or unisexual, without perianth or perianth of 3-many bristles or scaly segments. Stamens generally 1-3. Pistil bi- or tri-carpellate; styles 2- or 3-(rarely to 8-) fid at apex; ovary unilocular, with a single anatropous ovule; fruit an achene.
A family of more than 5,000 species in 70-120 genera, distributed throughout the world under all ecological conditions, with the highest generic concentration in tropical South America. The family is divided into five tribes: Cariceae, Cypereae, Mapanieae, Rhynchosporeae and Sclerieae.