72 ME. G. BENTHAM ON GBAMINE^. 



genera into which it has been divided may be fairly reduced to 

 the following five, perhaps too artificial, sections : — 1. Schizachy- 

 rium, about a dozen species, with the spikes always single upon 

 each peduncle. The genus Sohizaohyrium, Nees, was limited to 

 a few species in which the spike is slender and not very hairy. 

 Dieetomis, H. B. K., is the American A. fastigiatus, Sw., found 

 also in tropical Africa, which has a more rigid spike and the 

 second empty glume conspicuously awned. HomoeatJierum, Nees, 

 is an Asiatic species scarcely to be distinguished from the same 

 A. fastigiatus. In 2. Oymhopogon, the spikes, often very silky-hairy 

 or woolly, are in pairs on each peduncle, and the peduncle partly 

 or wholly enclosed in the sheath of a leafy or spathe-like bract. 

 The species are numerous, chiefly in the Old World, and include 

 the lemon-grass and its allies. Andersson has divided the section 

 into two genera, Qymnanihelia and ISyparrhenia, and perhaps 

 more ; but as he has never published their characters, I am unable 

 to form any clear idea of them. It would appear, however, from 

 the species quoted, that A. scJicenanthus and its allies would be- 

 long to Gh/mnanthelia, and A. Mrtus and its allies to Hyparrhenia. 

 3. Oymnandropogon, has two or more spikes sessile at the end of the 

 peduncle, without any sheathing-bract. The species are nearly as 

 numerous as those of Gymbopogon. Amongst them, A. annulatus, 

 Porsk., though closely allied to the common A. Ischcemum, forms 

 the proposed genus DicliantMum, Willem. ; A. serratus, Eetz, 

 with a broad herbaceous outer glume, is Trinius's genus Lepeo- 

 cercis ; and it is most probable that Steudel's HuJclastaxon is the 

 common American A. virginicus. 4. Amphilophis, Trin., would 

 include A. laguroides, DC, and A. argenteus, DC, from tropical 

 America, with A. scandens, Eoxb., and A. Vachellii, Nees, from 

 tropical Asia, and a few others, difflering from Oymnandropogon in 

 the more numerous, usually long and often pedicellate spikes, 

 sometimes even divided at the base, forming almost a saccharoid 

 panicle. 5. Vetiveria, Thou. {Mandelorna, Steud.), is the well- 

 known Vitiver, A. muricata, Eetz, to w hich Munro would redu e 

 as varieties A. nigritana, Benth., and Vetiveria arundinacea, 

 Q-riseb., a species frequent in East India and tropical Africa and in- 

 troduced into America, distinguished by its numerous spikes verti- 

 cillate along the axis of a long simple panicle, all glabrous or only 

 minutely hairy, and the awn of the flowering glume often very 

 much reduced. Beauvois's genus Anatherum, sometimes supposed 

 to be specially destined for this plant, included also all the species 



