Annual, 25-50 cm, forms small tufts. Stem 1.5-2 mm diam.,trigonous, smooth. Leaves basal or subbasal, equalling or longer than stem; sheaths up to 10 cm, lowermost blade-less, yellow-brown, often reddish, upper grey-yellow, mouth margin straight; blades up to 45 cm, 3-6 mm wide, flexuous, flat, yellowish green, margins scabrous towards apex, which long, acute, scabrous. Inflorescence an irregular, spreading anthelodium; primary branches up to 30 mm; lowest 3-5 bracts foliose, up to 30 cm; branches ending with tight cluster of spikes of c. 50 spreading spikes. Spikes 7-9 x 2.5-3 mm, compressed, with 8-14 flowers; rachis laterally compressed, 4-angled, internode c. 1.3 mm, winged; glumes 2-2.5 mm, cymbiform, mid-nerve area green, scabrously mucronate, sides with 2-3 conspicuous, yellow nerves, more or less reddish brown, margins scarious. Nut c. 1.3 mm, obovoid, triangular, apiculate, with a short stipe, minutely papillose, black-brown or greyish black.