Caespitose, tall, stout, bright green perennial with intravaginal branches with slender purpled inflorescences and cleistogenes in leaf-sheaths at the base. Leaf-sheath 10-20 cm, tough, glabrous, purpled below, margins long hairy above, apical tuft of hairs to 2 mm. Ligule c. 1 mm. Leaf-blade to 50 cm × 3 mm, ± rolled, glabrous, becoming very narrow and finely pointed, abaxially ribbed, glabrous, adaxially with many small prickles on ribs; margins with scattered long (1-1.5 mm) straggling hairs and prickle-teeth. Culm erect, to 1 m, nodes swollen, glabrous, internodes glabrous. Inflorescence to 30 cm, narrow, subtended by tufts of hairs, branches to 10 cm in fascicles similarly subtended, compound; rachis ridged, smooth; branches and pedicels short stiff hairy, naked below. Glumes ± equal, 7-8 mm, including lemma, conspicuously 3-nerved, awn tipped (1.3-1.5 mm), keel short stiff hairy, small prickles in internerves, centrally purple, hyaline elsewhere turning brown, margins ciliate below. Lemma 5-5.5 mm, fusiform, 5-nerved, purple towards margins, fading brown, lobes minute or 0, coma 0.5-1.0 mm, margins contiguous, keel and outer margins long (0.5-0.7 mm) hairy, minutely tuberculate elsewhere; awn to 18 mm, 1-geniculate, column 6-9 mm, arista to 10 mm. Palea 4.5-5 mm, lightly purpled, 2-nerved, internerve hairs reaching almost to ciliate apex. Callus to 1 mm, ± blunt, hairs to 1 mm. Lodicules 3, 1.2-2.0 mm, nerved. Anthers 2.5-3 mm in chasmogamous flowers, penicillate. Gynoecium: ovary 0.75-1.0 mm, trigonous; stigma-styles 1.75-2.0 mm, eccentric. Caryopsis 3 mm, obovate, irregularly ribbed, bases of old style eccentric, keeled opposite linear hilum to 2.5 mm, faintly rugose; embryo 1 mm. Chasmogamous in aerial inflorescences; cleistogamous in reduced inflorescences at culm nodes; cleistogenes in basal leaf-sheaths.