Cyperaceae

Abstract

Cyperaceae, known as sedges, graminoid, and resembling rushes, in the order of Cyperales, is a monocotyledonous flowering plant family, consisting of 109 genera with approximately 5500 species, widely distributed mostly in tropical or subtropical regions. They are usually annual or perennial herbaceous, often with rhizomes, and sometimes stoloniferous. Culms or stems are usually trigonous, occasionally rounded or subrounded, robust or slender, often erect or obliquely ascending, solitary to densely fascicled, or dispersed radiately, and rosette-like in outline. Leaves are basal, cauline, usually ranked, and with blades or sheaths. Leaf blades are often linear, grass-like, broad or narrow, usually involute, and concavely shaped. Sheaths are open or closed. Ligules are often present, sometimes on opposite sides to leaf blades. Petioles are absent, or blades are constricted basically to a pseudopetiole. Involucral bracts are one to several, usually leaflike, commonly three, nearly actinomorphic, often with the same shape to the basal ones, and sometimes bracts glumelike. Inflorescences are versatile, spicate, capitate, paniculate, and anthelate. Spikelets are one to numerous glumes. Glumes are spirally or 2-ranked. Flowers are bisexual or unisexual, usually monoecious, and rarely dioecious. Perianth is usually absent or reduced to bristles or scales. Stamens are 1–3. Anthers are basifixed. Ovary is two or three carpellate and unilocular. Ovules 1. Styles usually divided. Stigmas 2 or 3. Fruit is usually a nutlet. Thirty-four species, belonging to 12 genera, are illustrated in the chapter.