Description from Flora of China
Andropogon sorghum subsp. sudanensis Piper, Proc. Biol. Soc. Washington 28(4): 33. 1915; A. sudanensis (Piper) Leppan & Bosman; Sorghum vulgare Persoon var. sudanense (Piper) Hitchcock.
Annual. Culms 1–2.5 m tall, 3–6 mm in diam. Leaf sheaths glabrous or pilose at mouth and base; leaf blades linear or linear-lanceolate; 15–30 × 1–3 cm, glabrous; ligule brown. Panicle lax, 15–30 × 6–12 cm; branches slender, branched; racemes usually tardily fragile at maturity, composed of 2–5 spikelet pairs. Sessile spikelet elliptic, 6–7.5 mm; callus hairy; lower glume leathery, thinner upward, thinly strigillose, distinctly 11–13-veined; upper lemma ovate or ovate-elliptic, apex 2-lobed, awned; awn 10–16 mm. Pedicelled spikelet male or barren, linear-lanceolate, persistent. Caryopsis elliptic or obovate-elliptic, 3.5–4.5 mm, enclosed within glumes. Fl. and fr. Jul–Sep. 2n = 20.
This taxon is a cultivated selection (Sudan Grass) from Sorghum ×drummondii (Steudel) Millspaugh & Chase. It originated in Africa, but is widely grown for forage and is now naturalized in China. Sorghum ×drummondii is a general name given to the wide variety of weedy forms that have arisen in Africa by hybridization between the cereal S. bicolor and its wild progenitor S. arundinaceum (Desvaux) Stapf.
Naturalized. Anhui, Beijing, Fujian, Guizhou, Heilongjiang, Henan, Nei Mongol, Ningxia, Shaanxi, Xinjiang, Zhejiang [native to Africa; now widely cultivated for forage].