苏丹草 su dan cao

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.

Naturalized. Anhui, Beijing, Fujian, Guizhou, Heilongjiang, Henan, Nei Mongol, Ningxia, Shaanxi, Xinjiang, Zhejiang [native to Africa; now widely cultivated for forage].

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.