Infl. a simple terminal spike with unisexual fls, ♂ at top, ♀ lower, in 1-fld spikelets each subtended by a glume; ♂ with 3 stamens; ♀ surrounded by a plano-convex to trigonous, us. glab., occ. hispid, closed sac or utricle; style-branches 3, protruding from mouth of utricle; nut trigonous; axis of spikelet, the rhachilla, produced beyond mouth of utricle and terminating in a rigid glume which is sharply reflexed to form a hook. Perennial herbs, tufted or shortly rhizomatous. Culms ± trigonous, occ. terete, with bract-like sheaths at base. Lvs grass-like, linear, us. Shallowly channelled, almost flat towards the base, flanged-channelled towards the tip, occ. involute, rarely plano-convex, margins ± scabrid, tip us. trigonous, lf-base sheathing. Between 40 and 50 spp., mainly in the S. Hemisphere but not found in S. Africa. Most N.Z. spp. are endemic but 2 are recorded from elsewhere in the Pacific.