5. Trisetum debile Chrtek, Folia Geobot. Phytotax. 25: 334. 1990.
柔弱三毛草 rou ruo san mao cao
Perennial. Culms slender, base ascending, ca. 25 cm tall, ca. 0.8 mm in diam., glabrous or appressed-pubescent, densely appressed-pilose with longer spreading hairs below panicle, 3-noded. Leaf blades narrowly linear, ca. 4 cm, 1–1.2 mm wide, both surfaces pubescent with scattered longer hairs, convolute toward acuminate apex; ligule ca. 0.7 mm. Panicle lanceolate in outline, dense, ca. 4 cm, with few spikelets; branches short, densely pubescent with scattered longer spreading hairs; pedicels ca. 2 mm. Spikelets 5–6 mm, florets 2, green or straw-colored; rachilla pilose; glumes lanceolate, unequal, scabrid on keel, apex aristulate, lower glume 3–4 mm, 3-veined, upper glume 4–4.5 mm, 5-veined; lemmas 4–4.5 mm, inconspicuously 5-veined, keel scaberulous, awned from upper 1/3, apex 2-toothed; awn 5–7 mm, geniculate or recurved; palea subequal to lemma, keels densely ciliate. Ovary thinly pilose in upper part. Fl. Aug.
* Habitat unknown; ca. 3400 m. NW Yunnan.
This species is known only from the type gathering, which has not been seen.