72 MR. G. BENTHAM ON GRAMINE, 
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 Schizachyrium, Nees, was limited to 
a few species in which the spike is slender and not very hairy. 
Diectomis, 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. Homceatherum, Nees, 
is an Asiatic species scarcely to be distinguished from the same 
A. fastigiatus. In 2. Cymbopogon, 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, Gymnanthelia and Hyparrhenia, 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. schenanthus and its allies would be- 
long to Gymnanthelia, and A. hirtus and its allies to Hyparrhenia. 
3. Gymnandropogon, 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 Cymbopogon. Amongst them, A. annulatus, 
Forsk., though closely allied to the common A. Zschemum, forms 
the proposed genus Dichanthium, Willem.; A. serratus, Retz, 
with a broad herbaceous outer glume, is Trinius's genus Lepeo- 
cercis ; and it is most probable that Steudel's Euklastaxon is the 
common American 4. virginicus. 4. Amphilophis, Trin., would 
include A. laguroides, DC., and A. argenteus, DC., from tropical 
America, with A. scandens, Roxb., and 4. Vachellii, Nees, from 
tropical Asia, and a few others, differing from Gymnandropogon 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, Retz, to which Munro would redu e 
as varieties Æ. nigritana, Benth., and Vetiveria arundinacea, 
Griseb., 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. Beauyois’s genus Anatherum, sometimes supposed 
to be specially destined for this plant, included also all the species 
