肠须草 chang xu cao

Chloris dolichostachya Lagasca, Gen. Sp. Pl. 5. 1816.

Perennial. Culms erect or geniculately ascending, sometimes rooting at lower nodes, (0.5–)1–1.5(–2) m tall. Leaf sheaths glabrous or tuberculate-hispid, especially on margin, pilose at mouth; leaf blades linear, flat or rolled, 15–45 cm, 4–15 mm wide, scabrous, often tuberculate-hispid near ligule, apex setaceous; ligule ca. 0.4 mm. Racemes digitate, 3–10, ascending at first, later divaricate or drooping, 10–20 cm; rachis triquetrous, scabrous. Spikelets with 2 florets, 5–7 mm; lower glume linear-lanceolate, 2–3 mm; upper glume lanceolate, 3–5 mm, awn-pointed; lemma of fertile floret oblong-lanceolate, 3.5–5 mm, glabrous, scabrous along either side of midvein and toward apex; awn 8–16 mm; palea linear-lanceolate, narrower than lemma, keels scabrous; upper floret reduced to an oblong 0.8–1.8 mm lemma with 2–5 mm awn, appressed to fertile floret. Fl. and fr. Mar–Nov.

River valleys, fields, banks, roadsides, and thicket on hills; 200–1000 m. Guangdong, Guangxi, Hainan, S Taiwan, S Yunnan [Afghanistan, Bhutan, India, Indonesia, Malaysia, Myanmar, Nepal, New Guinea, Pakistan, Philippines, Sri Lanka, Thailand; N and NE Australia].

Enteropogon has traditionally been separated from Chloris on the basis of inflorescence form. Enteropogon has a single raceme, whereas Chloris has several digitate racemes. Thus this species has frequently been placed in Chloris. However, this inflorescence character is unreliable for separating the two genera, and a better separation is achieved on the basis of lemma and caryopsis compression, in which case this species falls within Enteropogon.