Plants forming dense clumps. Rhizomes pachymorph, neck 2--12 cm long. Culms to 3 m, to 1.5 cm in diam., nodding to pendulous; internodes to 15 cm, terete, lightly blue-grey waxy at first, becoming yellow or reddened with exposure, smooth, glabrous, wall thick; nodes irregularly swollen, supra-nodal ridge prominent, sheath scar thin; branches initially (3)-5-(7), strong. Culm sheaths deciduous, much shorter than internodes, triangular, tough, smooth, light purple-green, sparsely to densely brown setose, apex narrow, margins distally c. 1mm white-ciliate; auricles absent or very small; oral setae none or few, erect, 2-8mm; ligule to 3 mm, ciliate, tomentose; blade triangular, lightly pubescent, usually erect, reflexed towards base of culm, very persistent, margins ciliate. Leaves 3--8 per ultimate branch; sheath distally lightly tomentose, external margin ciliate, often distally reddened; auricles absent on terminal sheaths to small but distinct on basal sheaths, rounded, often red/purple; oral setae, erect or curved, 3-7 mm, basally stout and often red, scabrous, with slender white tips; ligule convex, to 1 mm, tomentose, ciliate to 1 mm; external ligule prominently white-ciliate to 3 mm; blade lanceolate, to 10 × 1.0 cm, base rounded, glabrous, secondary veins 3-4-paired, margins distally spinescent, transverse veins distinct, petiole glabrous, often red. Synflorescence dense panicles with 1-4 erect branches, supported by persistent sheaths. Name spathiflorus Latin, ‘flowers sheathed’.
This species, from E Nepal, Sikkim, Bhutan and SE Tibet, is characterised by prominent stout leaf sheath oral setae from variable auricles and sparse culm sheath hairs. It can form more open clumps than the other species.
First introduced in the 19th Century, probably from Sikkim. Various more recent introductions have also been made.