213. Themeda Forsskål, Fl. Aegypt.-Arab. 178. 1775.
菅属 jian shu
Authors: Shou-liang Chen & Sylvia M. Phillips
Anthistiria Linnaeus f.
Perennial or annual, often coarse. Culms tufted. Leaf sheaths keeled; leaf blades linear; ligule short, membranous or papery. Inflorescence a leafy compound panicle composed of short racemes; each raceme on a short peduncle subtended by a sheathing spatheole, loosely arranged or gathered into fan-shaped spathate fascicles. Raceme comprising 2 pairs of large sessile homogamous spikelets at base forming an involucre, with 1–2(–5) fertile pairs above and a terminal triad, these usually deciduous, rarely raceme shed as a whole; internodes and pedicels linear. Sessile spikelet subterete or dorsally compressed; callus mostly acute to pungent, sometimes obtuse, bearded; lower glume usually leathery, margins rounded, incurving, keeled only near apex, obtuse; upper glume awnless; lower floret reduced to a hyaline lemma; upper lemma stipitiform, entire, passing into a geniculate awn with pubescent column, occasionally awnless. Pedicelled spikelet mostly larger than sessile, narrowly lanceolate, resembling homogamous; callus slender, pedicel-like; true pedicel reduced. x = 10.
Twenty-seven species:tropical and subtropical regions of the Old World, mainly in Asia; 13 species (four endemic) in China.
The number of spikelets in a raceme refers to the total of homogamous, sessile, and pedicelled spikelets. Hence racemes with seven spikelets (division 1a of the key) have only one fertile sessile spikelet and one awn. Racemes with more than one awn have more than seven spikelets.
Most species of this genus are used for forage when young.