Description from Flora of China
Andropogon brevifolius Swartz, Prodr. 26. 1788; Pollinia brevifolia (Swartz) Sprengel.
Annual. Culms delicate, erect or trailing, 10–70 cm long, copiously branched, glabrous. Leaves cauline; leaf sheaths keeled, glabrous; leaf blades yellowish green becoming reddish brown, oblong-linear, flat or folded, 1.5–4 × (0.1–)0.2–0.7 cm, glabrous, base subrounded, apex obtuse; ligule 0.5–0.8 mm, lacerate. Raceme slender, 1–2 cm, enclosed at base by spatheole, borne along most of culm length, usually several flexuous peduncles arising from each leaf axil; rachis internodes and pedicels inflated upward, ca. 3/4 length of sessile spikelet, glabrous to villous. Sessile spikelet 2.5–4 mm; lower glume linear-lanceolate, subleathery, back flat, glabrous to thinly pilose, indistinctly 4–5-veined, flanks keeled toward apex, keels wingless, apex minutely 2-toothed; upper lemma 2-lobed to near base; awn 0.7–1 cm. Pedicelled spikelet reduced to 1 or 2 glumes, up to 0.5 mm, lower glume with 3–5 mm awn. Fl. and fr. Jul–Dec.
This is a slender, weedy annual, occurring widely in warm parts of the world. The whole plant turns reddish brown at maturity. The delicate, branching habit, with very obtuse leaf blades, is distinctive.
Open grassy banks, field margins, weedy places, sometimes gregarious; below 2000 m. Anhui, Fujian, Guangdong, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Shandong, Sichuan, Taiwan, Xizang, Zhejiang [Bangladesh, Bhutan, India, Indonesia, Japan, Korea, Laos, Malaysia, Myanmar, Nepal, Philippines, Thailand, Vietnam; Africa, America, SW Asia (Oman)].