A monster genus, which depending upon sources, variable definitions and confusion in identification, can contain 1000-2000 species. The majority come from moist or wet habitats, but many are adaptable to sunny, drier locations. Flowers tend to be visually insignificant, but others such as C. elata can be eye-catching. Foliage colour can be a highlight, with greens, blues, yellow, orange, bold variegation and the coppery-browns. Generally semi or wholly evergreen.
Being wind-pollinated, sedge flowers do not seek to attract insects. However the seeds when ripe do form part of the diet of seed-eating birds and small mammals, especially in wetland areas. The foliage is relatively unpalatable but the structure of the plant, sometimes forming large tussocks, is of major importance providing shelter to all sorts of insects and other invertebrates, many of which are very valuable natural predators.