Themeda Forssk., Fl. Aegypt.-Arab. 178. 1775.
菅屬
Perennials; culms solid, hard, glabrous. Leaf-sheaths compressed-keeled; ligule short to moderately long, membranous; blades linear, margins rough. Inflorescence a short, compact, spike-like raceme of 7-11-spikelets; raceme shortly peduncled, enclosed in spathe, terminating in short flowering branchlets, consisting of peduncled raceme, spathe and next-lower internode, solitary or in sympodial fascicles.Spikelets in alternate pairs,one of a pair pedicelled or sessile,one sessile; uppermost pair forming a triad with the terminal spikelet; spikelets dorsiventrally arranged, the lowest two pairs forming a kind of involucre, staminate or empty, muticous, sessile, all or partly persistent, the upper part of raceme 1-3-jointed, the upper joint with triad of one sessile bisexual and two pedicelled staminate or empty spikelets, occasionally lower joints except involucre, each with one sessile bisexual and one pedicelled staminate or empty spikelet. Bisexual spikelets usually terete, glumes as long as the spikelet, brown-or white-hairy at top or entirely hairy; lower glume oblong, with narrowed apex and incurved margins, chartaceous, the upper glume with narrowed apex, thin membranous, margins involute; lower lemma shorter, thin membranous, nerveless; lower palea absent;. upper lemma like lower lernma and muticous, shortly awned or having a robust, geniculate awn; upper palea wanting or small, nerveless; styles 2, free, the stigmas long, purple, exserted laterally from the middle or near apex; mature spikelets with pungent, brown-hairy callus. Caryopsis oblong, free between hardened glumes. Involucral spikelets with lower glume as long as spikelet, lanceolate, acute, margin narrowly incurved, winged or not, closely nerved; upper glume acute, hyaline, 3-6 nerved; lemmas, if pressent, thin membranous; stamens 3. Pedicelled spikelets about similar.
About ten species distribured in warmer regions of Africa and Asia.
Two species and one variety are found in Taiwan.
