Tussocky perennial; roots stout, aromatic. Culms robust, 1–2.5 m tall, ca. 5 mm in diam. Leaf sheaths glabrous, lower sharply keeled and imbricate in fanlike clusters; leaf blades linear, pale green, stiff, 30–90 × 0.5–1 cm, pilose on adaxial surface toward base, otherwise glabrous; ligule a scarious rim. Panicle oblong in outline, 20–30 cm, usually contracted, purplish; branches numerous, lowermost 5–20 cm, bare at base, smooth or slightly scaberulous; racemes slender, with 5–13 spikelet pairs and a terminal triad; internodes and pedicels slightly scabrid. Sessile spikelet linear-lanceolate to almost linear, 4–5 mm; callus rounded, subglabrous; lower glume muricate, 3–5-veined, veins spinulosely aculeate, apex acute; upper glume spinulosely aculeate on keel, not awned; upper lemma slightly 2-toothed, awnless or mucronate; mucro 0–2 mm, not exserted. Pedicelled spikelet staminate, sparingly aculeolate or almost smooth. Fl. and fr. Aug–Oct. 2n = 20.
Perennial up to 200 cm high or more; culms erect, the nodes all concealed within the leaf sheaths; ligule a scarious rim; leaf laminas up to 90 cm × 4–20 mm, linear.
Panicle up to 30 cm long or more, oblong, contracted; main axis smooth and glabrous; whorls 6–10 each with up to 20 racemes; racemes very slender; rhachis internodes as long as or slightly longer than the spikelets, glabrous; pedicels shorter than the sessile spikelets, glabrous.
Pedicelled spikelet sparingly aculeolate or almost smooth, male; inferior lemma as for the sessile spikelet; superior lemma acute, entire; anthers c. 2.5 mm long.
Sessile spikelet linear-lanceolate, variable in colour (yellowish, olive, violet-brown, purplish); callus up to 1 mm long, obtuse, glabrous; inferior glume muricate on the back; superior glume spinulose on the keel; inferior lemma as long as the glumes, acute, retrorsely ciliate; superior floret bisexual, the lemma up to 3 mm long, narrow, oblong-lanceolate, mucronate, glabrous; anthers 2–3 mm long.