Perennials or sometimes annuals, to 150 cm or more. Rhizome often sturdy and long creeping, producing stolons or tillers, sometimes tuberous. Stem trigonous or terete, rarely septate. Leaves from shorter than to much longer than stem; blades sometimes reduced, ligule mostly 0. Inflorescence variable, from a few spikes to a compact head-like structure or compound anthelodium. Bracts of several lowest partial inflorescences foliose. Spikes in ultimate distal partial inflorescences (cluster of spikes) spicately or digitately arranged, supported by glume-like bracts, and with binerved glume-like, often spongy prophylls; glumes from 3 to more than 50, distichous, or (in subg. Micheliani) eventually, spirally arranged; sides of glumes often extending as rachis wings down spike rachis and enclosing flower and nut on opposite side of rachis; glumes or sometimes whole spikes caducous; whole spike axis sometimes swollen, articulated. Flowers bisexual, with 1-3 stamens, stigmas 2 or 3. Nut trigonous or bi-convex, flat side pressed against the spike axis.