Plants perennial. Culms 20-50 cm takkm straggling, ascending from a prostrate base. Leaves: sheaths usually densely tuberculate-hairy, sometimes glabrous; ligules about 1 mm long; blades 1-15 cm long, 0.3-3 cm wide, glabrous or hairy, lanceolate to narrowly ovate, base somewhat rounded to oblique, tip acute. Panicles 9-15 cm long, glabrous or hispdulous; branches 4-9, up to 2 cm long, axes often setose, spikelets in 3-5 pairs. Spikelets lanceolate, hispidulous. Lower glumes 3-5-veined, awned, awn 5-10(15) mm long; upper glumes 5-veined, awned, awn 2-5 mm long; lower lemmas herbaceous, 5-9-veined, mucronate, mucro 1-2 mm long; upper lemmas subcoriaceous, smooth.
Oplismenus uyndulatifolius grows in moist, lightly shaded areas in forests. It is native in warm-temperate and subtropical regions of Asia, India, and Africa and has become an invasive weed in the eastern United States. It is treated in FNA 25 as a subspecies of O. hirtellus in accordance with the treatment by Scholz (1981) but differs in its shorter panicle branches as well as in being hairy. It is treated as a species in Australia and China. Preliminary results from work in the U.S. by Vanessa Beauchamp (Townson University) and Sharon Talley (APHIS). The description is taken from Chen and Phillips (2006).