11. Ischaemum barbatum Retzius, Observ. Bot. 6: 35. 1791.
粗毛鸭嘴草 cu mao ya zui cao
Andropogon lodicularis (Nees) Steudel; A. meyenianus (Nees) Steudel; Ischaemum aristatum Linnaeus subsp. barba-tum (Retzius) Hackel; I. aristatum var. lanuginosum A. Camus; I. aristatum var. lodiculare (Nees) Hackel; I. aristatum var. meyenianum (Nees) Hackel; I. barbatum var. hainanense Keng & H. R. Zhao; I. barbatum var. scabridulum Keng & H. R. Zhao; I. cylindricum Keng & H. R. Zhao; I. goebelii Hackel; I. imbricatum var. pubescens Keng & H. R. Zhao; I. lanuginosum (A. Camus) Keng & H. R. Zhao; I. lanuginosum var. enodulosum Keng & H. R. Zhao; I. lanuginosum var. erianthum Keng & H. R. Zhao; I. nodulosum Honda; I. nodulosum var. glabriflorum Keng & H. R. Zhao; I. rugosum Salisbury var. humidum Keng & H. R. Zhao; I. sinense Keng & H. R. Zhao; I. tientaiense Keng & H. R. Zhao; I. yunnanense Keng & H. R. Zhao; Meoschium lodiculare Nees; M. meyenianum Nees.
Perennial. Culms erect or ascending, 30–100 cm tall, often branched at base, nodes glabrous or bearded. Leaf sheaths glabrous to villous, margins ciliate or glabrous; leaf blades linear or narrowly lanceolate, 5–30 × 0.3–0.8 cm, glabrous to villous, margins scaberulous, base variable, cordate to attenuate or pseudopetiolate, apex acute; ligule 2–5 mm. Racemes terminal, paired, usually appressed back to back, 4–10 cm; rachis internodes oblong, triquetrous, ciliate along outer angle, inner angles glabrous or shortly ciliate. Sessile spikelet lanceolate-oblong, 5–7 × 1.6–2 mm; lower glume 2-keeled throughout, glabrous to villous, leathery, marginal nodules in lower 2/3, these sometimes extended into weak transverse ridges, herbaceous above with many anastomosing green veins, keels asymmetrically winged, one wing wider than the other; awn of upper lemma 1–1.5 cm. Pedicelled spikelet dorsally compressed, as large as sessile but marginal nodules less developed, awnless or awned.
Hill slopes, open grasslands, marshes; near sea level to 1000 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangsu, Jiangxi, Taiwan, Yunnan, Zhejiang [Cambodia, India, Indonesia, Japan, Laos, Malaysia, Myanmar, New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; W Africa, Australia].
This is a widespread, polymorphic species, to which many specific and infraspecific names have been applied. Variation depends mainly on the degree of hairiness of the leaves and spikelets and the number and prominence of the nodules and ridges on the sessile spikelet. In extreme cases the ridges are particularly well developed and approach the condition in Ischaemum rugosum, but such plants can be recognized as I. barbatum by their more robust, perennial habit and more oblong sessile spikelets.