岩生草沙蚕 yan sheng cao sha can

Culms 10–35 cm tall. Basal leaf sheaths papery becoming slightly fibrous; leaf blades 4–12 × 0.08–0.12 cm, adaxial surface scabrid, sparsely pilose with long scattered hairs, abaxial surface glabrous. Racemes 5–20 cm, flexuose, spikelets loosely appressed to the slender rachis, spaced their own length apart or only slightly imbricate. Spikelets 4.3–8 mm, tinged brownish purple; florets 4–7, tightly to loosely imbricate; lower glume narrowly lanceolate, asymmetrical, broadened into a prominent lateral tooth on one side, 2.2–3 mm, acuminate; upper glume narrowly lanceolate-oblong, 3.2–5 mm, apex emarginate and mucronate; lemmas elliptic-lanceolate, 2.4–3 mm to sinus, 3-awned with 2 teeth between the awns, central awn 5–9 mm, flexuose, often recurving, teeth variable, obtuse to acuminate, lateral veins extended into (1.5–)2–3.5 mm awns; palea keels winged, shortly ciliate. Anthers 3, 0.5–0.9 mm. Fl. and fr. Aug.

Damp rocks, often among moss; 2300–3000 m. Xizang, Yunnan [N India, Nepal].

This small species, forming delicate tufts with dark, flexuose racemes, was formerly usually identified as Tripogon filiformis. Tripogon rupestris has a looser raceme of spaced spikelets with widely spreading awns. Identification can be confirmed by inspecting the number of anthers.