9. Panicum sumatrense Roth ex Roemer & Schultes, Syst. Veg. 2: 434. 1817.
细柄黍 xi bing shu
Panicum flexuosum Retzius; P. psilopodium Trinius; P. psilopodium var. coloratum J. D. Hooker; P. psilopodium var. epaleatum Keng ex S. L. Chen, T. D. Zhuang & X. L. Yang.
Annual. Culms erect or decumbent, 20–60(–150) cm tall, nodes dark in color, glabrous. Leaves cauline; leaf sheaths loose, glabrous; leaf blades linear, flat, 8–40 × 0.4–0.8 cm, glabrous, base cordate to straight, apex acute or tapering; ligule ca. 1 mm, a ciliolate membrane. Panicle terminal, oblong or ovate in outline, 10–40 cm, densely branched and drooping or sparsely branched and erect; branches slender, scaberulous. Spikelets oblong in outline, 2.5–3.5 mm, glabrous; lower glume broadly ovate or cufflike, 1/4–1/3 length of spikelet, 3-veined, bluntly acute; upper glume as long as spikelet, 9–13-veined; lower lemma similar to upper glume, palea present or absent; upper floret brown or yellow, smooth, shiny. Fl. and fr. Jul–Oct. 2n = 54.
Rather dry situations. Guizhou, Taiwan, Xizang, Yunnan [India, Malaysia, Philippines, Sri Lanka].
Special forms of this variable species have been selected for cultivation. Plants with a denser and more profuse panicle, which droops at maturity under the weight of the spikelets, are grown as a cereal crop. Wild plants with more lightly branched, erect panicles and sparse spikelets may be distinguished as Panicum psilopodium. Although the cultivated types are readily identifiable, there are sufficient intermediates to make a clear boundary with the wild types impossible to define.
Panicum cristatellum Keng (Sinensia 11: 412. 1940), described from Jiangsu (Jiangyin), may be referable to P. sumatrense.