Elymus serpentinus (L. B. Cai) S. L. Chen & G. H. Zhu

Culms erect, 40–60 cm tall, 1–2 mm in diam., usually 4-noded, glabrous. Leaf sheath shorter than internode, glabrous; ligule ca. 0.4 mm, membranous, apex truncate; leaf blade flat, 4–15 × 0.3–0.4 cm, abaxial surface glabrous, adaxial surface villous. Spike pendulous, lax, 7–11 cm; rachis flexuose, slender, scabrous on back, margin ciliolate; internodes 7–12 mm. Spikelets 1 per node, green, 13–16 mm excluding awns, with 4–6 florets; rachilla puberulent. Glumes oblong-lanceolate, 4- or 5-veined, scabrous along veins, margin narrowly membranous, apex dentate on one or both sides; proximal glume 5–6 mm, awn 3–4 mm; distal glume 6–7 mm, awn 4–6 mm. Lemma lanceolate, smooth and glabrous abaxially, scabrous along veins; first lemma 9–10 mm; awn distinctly recurved, 14–18 mm. Palea distinctly shorter than lemma, softly ciliolate along keels, puberulent between keels, apex emarginate. Anthers yellow, ca. 3 mm. Ovary puberulent at apex. Fl. and fr. Jul.

Hebei (Yuxian).

* River banks; ca. 2000 m.

Roegneria serpentina L. B. Cai, Acta Phytotax. Sin. 35: 167. 1997.