Himalayacalamus asper Stapleton, Edinburgh J. Bot. 51(3): 310. 1994.

Synonym: Drepanostachyum merretii Demoly

Rhizome neck 4-6 cm. Culms 2-6 m, 0.5-2 cm in diam.; internodes 10-30 cm, cylindrical, glabrous, initially distally prominently white-waxy, very smooth, initially mid green, without stripes; wall 0.5-3 mm thick; nodes slightly raised; sheath scar thick, becoming nearly white, initially with basal ring of short white hairs; branches initially 7-20, more later, central dominant. Culm sheaths deciduous, tough, shorter than internodes, initially green, purple at base, becoming uniform light brown, outer surface densely scabrous and very rough, apically rounded; margins distally with sparse clear ca. 0.5 mm cilia; auricles absent, oral setae absent or very short; ligule broad, to 6 mm tall, asymmetrically truncate or erose, serrate; blade curved linear-lanceolate, long, to ca. 7 cm, reflexed, deciduous. Leaves 2-6 per ultimate branch; sheaths green, glabrous, external margin distally ciliate; auricles small to prominent and falcate, deciduous; oral setae erect to spreading, weak; ligule ca. 1 mm, rounded, tomentose; external ligule shortly cilate; blade broadly linear-lanceolate, delicate, matt bright green at first, 4-17×0.5-2.5 cm, abaxial initially densely pilose, adaxial initially sparsely pilose, base cuneate to rounded, secondary veins 3-4-paired, transverse veins not visible. Spikelets scabrous.

Name from Latin asper ‘rough’ referring to the short spines on the culm sheaths.

This bamboo from C & W Nepal is distinguished by its very rough culm sheaths, the small falcate auricles with oral setae on many of its leaf sheaths, and its broad, pubescent leaf blades. 

When H. asper was published, a somewhat similar bamboo from the Langtang Valley in C Nepal, previously distinguished as ‘H. aequatus’, was conservatively included because their flowers were not known. The latter species was then found, quite remarkably, to be already in cultivation in Europe and the US under the name Neomicrocalamus microphyllus. When it flowered it was separated again as a distinct species, H. planatus, having hairy rather than scabrous culm sheaths, no auricles or oral setae on the leaf sheaths, glabrous leaves and glabrous spikelets. H. planatus is a little hardier and is much more widely grown than H. asper, and is still frequently referred to as H. asper.

 Himalayacalamus asper was first reported in 1983 after a herbarium collection was made in a pheasant reserve below Machhapuchhre in W Nepal, above the village of Karuwa in the Seti Khola Valley. Muriel Crouzet introduced it to France from near Gorapani, further west towards the Kali Gandaki in 1992. Jean Merret introduced it in 1994 from the Marsyangdi Valley, further to the east, and that collection was described as new species Drepanostachyum merretii Demoly in 2006. All 3 collections appear to represent the same species. It is known in Nepal as ghunre nigalo, and is considered inferior to other species such as H. cupreus for weaving and for edible shoot consumption.