Perennials, with or without rhizomes. Leaf-blades flat or convolute. Inflorescence a spike. Spikelets 3-10-flowered, pectinate or imbricate, strongly laterally compressed, solitary at the nodes of the tough rhachis; rhachilla disarticulating above the glumes and between the florets; glumes narrowly lanceolate to ovate-lanceolate, prominently keeled, with 1-2 inconspicuous lateral nerves, covering the backs of the lower florets; lemmas membranous, 5-nerved, keeled, awnless or shortly awned; palea 2-keeled, coarsely ciliate along the keels.