Themeda 菅屬
型態特徵
Perennials; culms solid, hard, glabrous. Leaf sheaths compressed-keeled; ligule short to moderately long, membranaceous; 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 pedicelate or sessile,one sessile; uppermost pair forming a triad with terminal spikelet; spikelets dorsiventrally arranged, lowest two pairs forming a kind of involucre, staminate or empty, muticous, sessile, all or partly persistent, upper part of raceme 1-3-jointed, upper joint with triad of one sessile bisexual and two pedicelate staminate or empty spikelets, occasionally lower joints except involucre, each with one sessile bisexual and one pedicelate staminate or empty spikelet. Bisexual spikelets usually terete, glumes as long as spikelet, brown-or white-hairy at top or entirely hairy; lower glume oblong, with narrowed apex and incurved margins, chartaceous, upper glume with narrowed apex, thin membranaceous, margins involute; lower lemma shorter, thin membranaceous, nerveless; lower palea absent;. upper lemma like lower lernma and muticous, short awned or with a robust, geniculate awn; upper palea wanting or small, nerveless; styles 2, free, stigmas long, purple, exserted laterally from middle or near apex; callus of mature spikelets pungent, brownhairy. Caryopsis oblong, free between hardened glumes. Lower glume of involucral spikelets 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 membranaceous; stamens 3. Pedicelate spikelets ca. similar.
About ten species in the warmer regions of Africa and Asia; two species in Taiwan.
