Description from Flora of China
Megathyrsus maximus (Jacquin) B. K. Simon & S. W. L. Jacobs; Panicum hirsutissimum Steudel; P. jumentorum Persoon; P. maximum var. hirsutissimum (Steudel) Oliver; P. poly-gamum Swartz.
Perennial, rhizomatous; rhizome stout. Culms robust, erect, 1–3 m tall, nodes glabrous or pilose. Leaves basal and cauline; leaf sheaths glabrous to hispid; leaf blades linear to narrowly lanceolate, flat, 20–60 × 1–3.5 cm, narrowed at base, glabrous or pilose, margins scabrid, apex acuminate; ligule 1–3 mm, membranous, with dense cilia dorsally. Panicle oblong or pyramidal in outline, 10–45 cm, much branched; branches spreading, lowest arranged in a whorl. Spikelets oblong, 3–4.5 mm, glabrous or pubescent, often tinged purple, obtuse or acute, occasionally overtopped by long hairs from apex of pedicel; lower glume broadly ovate, 1/3–1/2 length of spikelet, 3-veined, obtuse or acute; upper glume ovate-oblong, as long as spikelet, 5-veined, acute; lower floret staminate, lemma similar to upper glume, palea well developed; upper floret thinly coriaceous, pale yellow or green, shiny, finely transverse rugulose. Fl. and fr. Aug–Oct. 2n = 32.
Widely cultivated for forage. Guangdong, Taiwan [native to tropical Africa and America].