13. Stipa arabica Trinius & Ruprecht, Sp. Gram. Stipac. 77. 1842.
图尔盖针茅 tu er gai zhen mao
Stipa arabica subsp. caspia (K. Koch) Tzvelev; S. arabica var. szovitsiana Trinius; S. arabica var. turgaica (Roshevitz) Tzvelev; S. caspia K. Koch; S. szovitsiana (Trinius) Grisebach; S. turgaica Roshevitz.
Perennial, tufted. Culms 40–80 cm tall, gray pubescent, 2–3-noded, nodes often dark-brown. Basal leaves 1/2 length of culms; leaf sheaths shorter than internodes, pubescent or lower part subglabrous; leaf blades filiform, convolute, outer surface glabrous to densely pilose; ligule lanceolate, 5–10 mm. Panicle contracted, 15–35 cm, base enclosed by slightly inflated uppermost leaf sheath. Spikelets pale green or greenish yellow; glumes narrowly lanceolate, 2–3 cm, membranous, apex long-acuminate; callus pungent, ca. 1 mm; lemma 9–12 mm, shortly hairy in longitudinal lines not reaching apex, a ring of hairs at awn articulation; awn 9–20 cm, deciduous, hairy throughout, 2-geniculate, column 1.5–1.8 cm to first bend, hairs ca. 1 mm, ca. 1.5 cm to second bend, bristle 6–7 cm, plumose on second column and bristle, hairs 1–2.5 mm. Fl. and fr. May–Jul.
Rocky slopes, Gobi desert; 500–3100 m. Xinjiang, Xizang [Afghanistan, Kazakhstan, Kyrgyzstan, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan; SW Asia].
This is a widespread and variable species, reaching the eastern limit of its range in W China. It is sometimes subdivided into more narrowly defined species or infraspecific taxa based on variations in leaf indumentum and spikelet size. Chinese material is referable to subsp. caspia, or Stipa caspia at specific rank. Stipa arabica subsp. arabica from SW Asia has lemmas 7–9 mm and awns not exceeding 9 cm. Stipa turgaica is based on a form with densely pilose leaf blades. Stipa arabica is a good forage grass in desert steppe regions.