Annual or perennial herbs, tufted and grass-like, or with sympodial rhizome. Stems usually simple, erect. Leaves mostly clustered at base of stem. glabrous or sparsely hairy, sheathing at base, laminae flat and grass-like, or laterally compressed, or channelled, or terete like stems; or leaves reduced to basal sheaths only. Flowers bisexual, or rarely unisexual and plants dioecious, few to numerous in terminal monochasial cymes, occasionally condensed to a compact head, or flowers rarely solitary. Tepals 6, rarely 4, in 2 whorls, glumaceous, often with membranous margins. Stamens free, in 2 whorls of 3, or with inner whorl missing, or variable 3-6, attached to base of tepals; filaments free, anthers 2-celled, introrse, basifixed. Ovary superior, syncarpous, 1-or ± completely 3-locular; style 1, short, stigmas 3, brush-like. Fruit a 3-valved capsule opening loculicidally. Seeds 3 to numerous, often tailed at one or both ends, or tailless, sometimes mucilaginous. Eight (or nine) genera and c. 400 spp., chiefly in temperate regions, rare in the tropics and then only at high altitudes. Two genera, Juncus and Luzula are cosmopolitan.

Fls bisexual, or rarely unisexual and plants dioec., few or ∞ in terminal monochasial cymes, occ. condensed to a compact head, or fls rarely solitary. Tepals 6, in 2 whorls, glumaceous, often with membr. margins. Stamens free, in 2 whorls of 3, or with the inner whorl missing, or variable 3–6, attached to the base of the tepals; filaments free, anthers 2-celled, introrse, basifixed. Ovary superior, syncarpous, 1- or ± completely 3-locular; style 1, short, stigmas 3, brush-like. Fr. a 3-valved capsule opening loculicidally. Seeds 3 or ∞, often tailed at one or both ends. Annual or perennial herbs, tufted and grasslike, or with creeping sympodial rhizome. Stems us. simple, erect. Lvs mostly clustered at base of stem, glab. or sparsely hairy, sheathing at the base, lamina flat and grasslike, or laterally compressed, or channelled, or terete like the stem; or lvs reduced to scales only. Eight genera and c. 400 spp. chiefly in temperate regions, rare in the tropics and then only at high altitudes. Two genera, and , are cosmopolitan, the other six are confined to the Southern Hemisphere.