Tall robust tussock forming perennial, commonly of river beds. Prophyll 2.5 cm or more, keels antrorsely prickle-toothed and with mixed short hairs. Branching intravaginal and extravaginal when shortly rhizomatous. Leaf-sheath 5-20 cm, striate, finely scabrid or smooth becoming scabrid near ligule. Ligule 0.5-1-3 mm, firm. Auricles clasping 0.7-1.5 mm, hairs c. 0.3 mm. Leaf-blade 10-100 cm × 5-10 mm wide, many-ribbed, midrib prominent, finely antrorsely scabrid below becoming very scabrid above, margins finely prickle-toothed. Culm to 1.5 m, stout, nodes conspicuous, dark, constricted, internodes glabrous. Panicle to 40 cm, erect or nodding, with 10 or more nodes of many spikelets; basal branches to 20 cm, binate, one long, naked below, other shorter with spikelets to base, other nodes with similar binate branches becoming shorter and eventually solitary near apex or solitary throughout and spikelets to base of branches; rachis smooth below becoming scabrid above pedicels and branches with prominent prickle-teeth. Spikelets 10-15 mm, narrow, of 4-7 florets. Glumes unequal, shortly awned, keel scabrid above otherwise smooth, margins membranous; lower 3-8 mm, 1-nerved, upper 4-9 mm, 3-nerved. Lemma 7-10 mm, 5-nerved, rounded, fine prickle-teeth on central and lateral nerves, margins membranous shortly toothed throughout broadly membranous above terminating in small (0.3-0.6 mm) hyaline prickled lobes; awn 1-2.5 mm, visible through apical lobes. Palea ≥ lemma, 7-10 × 1.5 mm wide, apex bifid ciliate, keels toothed ± to base, interkeel glabrous. Callus 0.25 mm, margin hairs 0 or few; articulation flat. Rachilla 1.5 -1.75 mm, stiff hairs scattered throughout. Lodicules 0.75-1.6 mm, > ovary, deeply to ± irregularly lobed, glabrous. Anthers 3-4 mm, caudate. Gynoecium: ovary 0.6-1.0 mm, apex glabrous; stigma-styles subterminal, 1.8-3.0 mm, hairs almost to base. Caryopsis 3 mm, obovate, adherent to palea; embryo 1 mm; hilum 2 mm.