Cymbopogon 香茅屬
型態特徵
Perennials; culms solid, terete, glabrous, often farinose beiow nodes. Leaves aromatic when crushed due to essential oils; sheath of leaf terete, glabrous, often red inside; ligule developed, truncate or narrowed, usually ciliate; blades linear, base narrowed or not, apex acute, midnerve stout, pale. Inflorescence at ultimate branchlets, racemes short, spike-like with common peduncle enclosed in a spathelike uppermost leaf; racemes often widely spreading or deflexed, unequally peduncled; terminal raceme short and spikelets dorsally compressed, in alternate pairs along hairy, articulate rachis, one of a pair pedicelate, other sessile, upper breaking up at maturity, 3-6 jointed; joints dorsally compressed, usually with a convex dorsal side and flat to concave ventral side, apex dentate, membranaceous, obliquely cupuliform; 1-2 lowest sessile spikelets of short-peduncled raceme, and all pedicelate spikelets staminate and muticous; all other sessile spikelets bisexual and awned or muticous. Bisexual spikelets oblong to ovate-lanceolate, shortly white-hairy at base; lower glume as long as spikelets, apex narrowed with 2 prominent marginal nerves; upper glume equally long or slightly shorter, boat shaped-keeled, 1-3-nerved; lower lemma shorter than lower glume, thinly membranaceous, margins inflexed, ciliolate, 2-nerved; upper lemma thinly membranaceous, short, halfway divided into 2 narrow lobes, with geniculate awn from sinus, or entire and muticous; paleas absent; lodicules 2, small, glabrous; stamens 2, free; stigmas laterally exserted. Caryopsis. oblong, dorsally compressed, convex on embryo-side, flat on hilum-side; embryo ca. 1/2 as long as caryopsis. Pedicelate spikelets oblong-lanceolate, apex narrowed; lower glume as long as spikelets; upper glume equally long or slightly shorter, often less convex than in sessile spikelets, 3-nerved; lower lemma shorter; upper lemma and paleas wanting.
About 60 species in tropical and subtropical regions of Africa and Asia; four species in Taiwan, most of them are aromatic grasses.
Several species yield essential aromatic oils, e. g. C. nardus, C. winterianus (citronella oil), C. citratus (lemongrass oil), C. martini (palma rosa or geranium oil), which are used in soaps, perfumery, etc.
