Perennial herbs, dioecious or rarely monoecious, tough and wiry or rush-like, with creeping or tufted rhizomes. Leaves reduced to sheaths which are dark to pale brown, distichous, split on one side and not tubular as in Cyperaceae imbricate at the base of the culm, distant or rarely absent on the upper portion. Flowers small, unisexual, rarely bisexual, each subtended by a glume, arranged in spikelets in lax or dense inflorescences. Perianth segments 6 or fewer, in 2 whorls, glumaceous; female flowers sometimes very few in the spikelet, rarely solitary; male flowers usually with 3 stamens opposite the perianth segments; anthers usually 1-celled. Ovary 3-carpellary, 1-3-locular, superior; styles 3 or 3-fid or simple. Fruit a nut or capsule. 40 gen., temp. to trop., mostly S. hemisphere, particularly S. Africa and Aust.