Carex

Carex (sedges; family Cyperaceae) A genus of perennial herbs that have rhizomes. The stems are characteristically triangular in cross-section, solid, and leafy. The leaves are linear, often inrolled or keeled, with a sheathing leaf base, and a ligule. The inflorescence varies from a branched panicle to a single spike, and is composed of unisexual flowers, usually clearly separated on the inflorescence, the plants being generally monoecious. Each single-flowered spikelet is subtended by a glume. There is no perianth, although the female flowers are surrounded by a triangular or flattened sac with a beak through which the 2 or 3 stigmas project from the triangular or oval ovary. The ovary is superior, with 3 fused carpels and a single locule. The fruit, a small nut, remains within the sac, and contains copious endosperm. The male flowers have 2 or 3 stamens and are generally held at the top of the inflorescence, often in the terminal or upper, later spikes. The female flowers are restricted to the lower branches or the bottom of the spike. Sedges are found throughout the world, often as components of marshy habitats. Each species has very precise ecological requirements. There are about 1000 species, of which a limited number are used locally as food or bedding for animals, and a few are cultivated as ornamentals.