Plants perennial; rhizomatous, rhizomes short, usually more than 1 cm thick. Culms 2-10 m tall, 1-3.5 cm thick, usually erect, occasionally pendant from cliffs; nodes glabrous; internodes hollow. Leaves cauline, conspicuously distichous, glabrous; sheaths open, longer than the internodes; ligules membranous, shortly ciliate; blades flat or folded, margins scabrous. Panicles terminal, plumose, silvery to purplish. Spikelets laterally compressed, with 1-several florets; rachilla internodes glabrous; disarticulation above the glumes and between the florets. Glumes longer than the florets, 3-5-veined; lemmaspilose, hairs not papillose-based, 3-7-veined, apices entire or minutely awned; paleas shorter than the lemmas, 2-veined; anthers 3. x = 12. Name from the Latin arundo, reed.