变绿异燕麦 bian lü yi yan mai

Avena junghuhnii Buse in Miquel, Pl. Jungh., Gramineae, preprint, 15. 1854; A. aspera Munro ex Thwaites var. roylei J. D. Hooker; Helictotrichon virescens (Nees ex Steudel) Henrard; Trisetum virescens Nees ex Steudel.

Perennial. Culms loosely tufted, erect, 60–120 cm tall, 3–5-noded. Leaf sheaths usually longer than internodes, basal sheaths densely pubescent, upper sheaths glabrous; leaf blades flat or margins involute, 10–25 cm, 3–5 mm wide, scabrid or adaxial surface thinly pubescent, apex acuminate; ligule truncate, 1–2 mm. Panicle loose, up to 20 cm, erect or nodding; branches 2–4 per node, ascending or spreading, lower 5–12 cm, slender, scabrid, bare in lower part, with up to 9 spikelets. Spikelets 1–1.4 cm, greenish or purplish, florets 2–5; rachilla hairs 1–2 mm; glumes hyaline at margins and apex, lower glume 4–9 mm, 1–3-veined, upper glume 7–10 mm, 3–5-veined; lemmas subleathery with hyaline apex, lowest 9–11 mm, 5–7-veined, scabrid at least toward apex, apex 2-lobed, lobes acuminate or shortly awn-pointed; awn 1–2 cm, weakly geniculate, column loosely twisted, terete; palea keels minutely ciliolate to ciliate with 0.1–0.2 mm hairs. Anthers 2–3.5 mm. Fl. and fr. Jun–Aug.

Grassy mountain slopes, forests, damp places; 2000–3900 m. Guizhou, Henan, Qinghai, Shaanxi, Sichuan, E Xizang, Yunnan [Bhutan, India, Indonesia, Myanmar, Nepal, Pakistan].

The publication of the name Avena junghuhnii in Buse's preprint in February 1854 shortly predates the publication of Trisetum virescens by Steudel in April 1854.

This taxon lies at the center of a polymorphic complex extending from Pakistan and India to China and mountains in SE Asia. Variation within the complex is poorly understood and requires further investigation. Variable characters include lemma scabridity and apex, length and quantity of rachilla hairs, length of the cilia on the palea keels, and anther length. The midline of the lemma above the awn insertion is very fragile, frequently splitting into acuminate lobes, but sometimes remaining almost entire, even within the same panicle.

The name Helictotrichon polyneurum (J. D. Hooker) Henrard has been misapplied in China to specimens of H. junghuhnii. This member of the H. junghuhnii complex is known only from the Nilgiri Hills of S India. It is distinguished by its open, ovate panicle with smooth, widely spreading panicle branches and large, brownish spikelets with many prominent veins.