纤瘦披碱草 xian shou pi jian cao

Roegneria gracilis L. B. Cai, Acta Phytotax. Sin. 34: 328. 1996, not Elymus gracilis Philippi (1864).

Plants with short rhizome. Culms erect, ca. 70 cm tall, 1.2–2 mm in diam., 3- or 4-noded. Leaf sheath usually shorter than internode, glabrous; ligule very short, apex truncate; leaf blade flat or margin involute, 2–6 × 0.2–0.3 cm, abaxial surface often glabrous, adaxial surface scabrous or also sparsely pubescent. Spike slightly nodding, lax, 10–12 cm; rachis slender, margin spinose; internodes 5–12 mm. Spikelets purplish, 12–16 mm excluding awns, with 3 or 4 florets; rachilla puberulent; internodes 2–2.5 mm. Glumes lanceolate, 3-veined, scabrous along veins, apex acuminate; proximal glume 2–3 mm; distal glume 4–5 mm. Lemma narrowly lanceolate, usually spinose above middle and near margin; first lemma 8–10 mm; awn 6–8 mm. Palea slightly shorter than or equaling lemma, spinose along keels, glabrous between keels, apex truncate or obtuse. Anthers yellow, ca. 1 mm. Ovary obovate, apex pubescent. Fl. and fr. autumn. 2n = 28*.

* Stream banks; ca. 4000 m. Xizang (Gongbo'gyamda).