CYPERACEAE

(Top to bottom) Sedge (Carex vesicaria); umbrella plant (Cyperus alternifolius); the sedge family of monocotyledonous flowering plants, with some 5,000 species of grasslike herbs of wet regions throughout the world. It is one of the 10 largest families of flowering plants. The plants are characterized by the presence of solid stems that are often triangular in cross section; of leaves, when present, with a sheath clasping the stem and the two margins of the sheath coalescent; and of minute flowers in a small spike not enclosed by a leaflike structure (bract). Each flower consists of a single pistil (female part) and two or three stamens (male parts) set in the axil (upper angle) of a small bract. The stems range in height from a few centimetres to 4 m (about 13 feet) or more. Nearly all species are wind-pollinated. Often confused with grasses (family Poaceae), sedges are distinguished by the aforementioned characteristics. Grasses, for example, have round, hollow stems, leaves with noncoalescent sheaths, flowers enclosed by two bracts, and the whole flowering cluster (spikelet) enclosed by two more bracts. Although the Cyperaceae are similar in appearance to grasses and are placed in the same order (Cyperales), there is a growing body of evidence that suggests that the closest relatives of Cyperaceae are the rushes (family Juncaceae, order Juncales). Spikes of sedge (Carex pendula). The largest genera include the sedges (Carex, with about 2,000 species [see photograph]); the galingales (Cyperus, nearly 650 species); the beak rushes (Rhynchospora, about 250 species); and Fimbristylis, Eleocharis, and Scleria (each with about 200 species). Other large genera include Bulbostylis and Schoenus (each with about 100 species) and Mapania (about 80 species). Although the group as a whole is of little economic importance, several species are notable. Among them is the papyrus (Cyperus papyrus), the pith of which was used by the ancient Egyptians for making paper. The papyrus is now often grown ornamentally. Other cultivated genera include Carex, Eleocharis (the spike rushes), Scirpus (bulrushes or club rushes), and Eriophorum. The umbrella plant (Cyperus alternifolius) is a popular potted plant growing to 1.2 m, each stem producing an umbrella-shaped cluster of leaves at its top. The yellow nut sedge (C. esculentus) is considered a grassy weed in many north temperate locations. Its tubers, and those of related Cyperus species, are edible, especially so in C. esculentus sativus, a variety known as chufa, or earth almond, which is rich in stored starch, sugar, and fat. The Chinese water chestnut (Eleocharis dulcis) is one of the edible water chestnuts. Two ornamental bulrushes are frequently grown in bog or water gardens, Scirpus cernuus and S. tabernaemontani. The cotton grasses (Eriophorum species) are also bog-garden favourites. sedge family of monocotyledonous flowering plants, a division of the order Cyperales. The Cyperaceae are grasslike herbaceous plants found especially in wet regions throughout the world. Additional reading L.T. Eiten, Inflorescence Units in the Cyperaceae, Annals of the Missouri Botanical Garden, 63(1):81112 (1976); I. Kukkonen, On the Inflorescence Structure in the Family Cyperaceae, Annales Botanici Fennici, 21(3):257264 (1984); G.C. Tucker, The Genera of Cyperaceae in the Southeastern United States, Journal of the Arnold Arboretum, 68(4):361446 (1987).