9. Saccharum arundinaceum Retzius, Observ. Bot. 4: 14. 1786.
斑茅 ban mao
Perennial, forming large clumps. Culms robust, (0.7–)1–6 m tall, 1–2 cm in diam., glabrous. Leaf sheaths glabrous or pubescent, ciliate at mouth and margins; leaf blades (60–)100–200 × 1–2 cm, abaxial surface glabrous, adaxial surface velvety with long soft hairs on broad lower midvein, margins serrate, base narrow, apex long attenuate; ligule 1–2 mm. Panicle (25–) 30–80 cm, much branched, axis glabrous; racemes 3–5.5 cm; rachis internodes 3–5 mm, pilose with long silky hairs. Spikelets 3–4 mm, straw-colored tinged purple upward; callus hairs ca. 1 mm, shorter than spikelet; lower glume thinly cartilaginous, back pilose with silky hairs twice length of spikelet, keels scabrid, apex acuminate; upper glume usually glabrous in sessile spikelet, rarely thinly pilose, clearly pilose in pedicelled spikelet; lower lemma subequal to glumes; upper lemma lanceolate, apex mucronate or with awn to 3 mm. Lodicules glabrous. Anthers 1.8–2 mm. Fl. and fr. Aug–Dec. 2n = 30, 40, 50, 60.
Hill slopes, riversides, dry stream beds, often on sandy soils. S Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Henan, Hubei, Jiangxi, Shaanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, India, Indonesia, Laos, Malaysia, Myanmar, Sri Lanka, Thailand, Vietnam].
It is necessary to look carefully, preferably using a disarticulated spikelet, in order to distinguish the basal, short callus hairs from the long, silky hairs of the rachis internodes, pedicels, and glumes.
This species is used for forage in China.
Saccharum arundinaceum is similar to S. bengalense Retzius, from N India and Pakistan. The latter species is distinguished mainly by its rather narrow panicle and much narrower leaf blades, which are channeled and consist mostly of midrib.