10. Pennisetum longissimum S. L. Chen & Y. X. Jin, Bull. Bot. Res., Harbin. 4: 65. 1984.
长序狼尾草 chang xu lang wei cao
Pennisetum baojiense W. X. Tong.
Perennial forming loose tussocks. Culms decumbent, rooting at base, up to 1.8 m tall, 8–14-noded. Leaf sheaths usually longer than internodes, glabrous or papillose-pilose; leaf blades linear, 50–90 × 0.5–2 cm; ligule 2.5–3 mm. Inflorescence up to 30 cm, usually pendulous; axis densely hispidulous with angular ribs, peduncle stumps crowded, very short with a tuft of spiculae; involucre enclosing 1(–3) spikelets, basal stipe ca. 0.5 mm; bristles glaucous or purple, stiff, glabrous, unequal, one conspicuously longer and stouter, up to 4 cm. Spikelets lanceolate, 6–8 mm; lower glume ovate, ca. 1/4 as long as spikelet, 0–1-veined, obtuse, acute or erose; upper glume 1/3–1/2 as long as spikelet, 1–3(–5)-veined, acuminate; lower floret usually neuter, lemma as long as spikelet, 5–7-veined, scaberulous, acuminate-rostrate; upper lemma similar but usually slightly shorter; anthers without hairs at tip. Fl. and fr. Jul–Oct.
* Open hill slopes; 500–2000 m. Gansu, Guizhou, Shaanxi, Sichuan, Yunnan.
This species is very similar to Pennisetum shaanxiense, but is rather more vigorous. The involucral bristles appear to be always glabrous.