Paspalum scrobiculatum Linnaeus var. longifolium (Roxburgh) Domin.

Perennial. Culms tufted, fairly robust, usually erect, 80–130 cm tall, many-noded, glabrous. Leaf sheaths broad, papery, overlapping and concealing the nodes, keeled, papillose-pilose along margins; leaf blades linear, 10–20 × 0.5–1 cm, glabrous, apex acuminate; ligule 1–2 mm, usually with tawny hairs on back. Inflorescence axis 4–10 cm; racemes 5–20, 4–8 cm, ascending; spikelets normally paired, occasionally single but 2nd vestigial spikelet present; densely overlapping; rachis broadly winged, (1.5–)2–4 mm wide, purplish, margins scabrous with conspicuous close-set teeth; pedicels scabrous. Spikelets purple or pale green, broadly obovate, narrowed to base, lightly plano-convex, 2–2.5 mm, apiculate; upper glume and lower lemma membranous, 3-veined with laterals marginal, minutely crisped-pubescent; upper lemma pallid, as long as spikelet, punctulate-striate, subacute. Fl. and fr. Jul–Oct. 2n = 40, 50.

This is a rather lush, leafy species. The broad, purplish rachis bearing very closely packed, paired, shortly hairy spikelets is characteristic.

Mountain slopes, field margins, in moist and swampy places. Fujian, Guangdong, Guangxi, Hainan, Taiwan, Yunnan, Zhejiang [Bhutan, India, Indonesia, Japan, Malaysia, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam; N Australia, Pacific Islands].