1. Deschampsia flexuosa (Linnaeus) Trinius, Mém. Acad. Imp. Sci. Saint-Pétersbourg, Sér. 6, Sci. Math., Seconde Pt. Sci. Nat. 4, 2(1): 9. 1836.
曲芒发草 qu mang fa cao
Aira flexuosa Linnaeus, Sp. Pl. 1: 65. 1753; A. kawakamii Hayata; Avenella flexuosa (Linnaeus) Drejer; Deschampsia kawakamii (Hayata) Honda; Lerchenfeldia flexuosa (Linnaeus) Schur.
Perennial, tufted, sometimes rhizomatous; old basal sheaths tightly overlapping. Culms slender, erect, 15–60 cm tall, 2- or 3-noded. Leaf sheaths longer than internodes, smooth or scaberulous upward; leaf blades setaceous, rather stiff, 3–15 cm, 0.3–0.5 mm wide, abaxial (outer) surface smooth; ligule lanceolate, 2–4 mm. Panicle open, ovate in outline, 5–10 cm, silvery with purple or brown tinge; branches usually paired, capillary, flexuous, bearing spikelets on distal part. Spikelets 4–6(–8) mm, florets 2, rachilla internode short; glumes thinly membranous, 1-veined, lower shorter than upper, apex acute; callus hairs ca. 1 mm; lemmas 3.5–5(–6) mm, asperulous, awned from near base, apex denticulate or erose; awn 5–8 mm, exserted from spikelet, geniculate in middle, column dark brown, twisted. Anthers 1.5–2.5 mm. Fl. and fr. Jul–Sep. 2n = 28.
Exposed mountain peaks, on stony soil and rocky slopes. Taiwan [Japan, Philippines (Luzon), Russia; Africa (high mountains), SW Asia (Caucasus), Europe, North America, South America (S Argentina, S Chile)].
A variant of this widespread species found on Yu Shan (Mt. Morrison) in Taiwan has larger spikelets than usual (6–8 mm), since the glumes are drawn out into long caudate tips, with the upper glume 1–2 mm longer than the lower. This variant is the basis of Deschampsia kawakamii. Typical D. flexuosa also occurs in Taiwan.