MR. G. BENTHAM ON GRAMINE®. 73 
of the sections Cymbopogon and Gymnandropogon, in which the 
awn is much reduced or obsolete. Agenium, Nees, from his cha- 
racter, would also refer to one of these species without prominent 
awns. 
23. ÜHRYSOPOGON, Trin. (Rhaphis, Lour., Centrophorum, Trin.), 
and 24. Sonanvw, Pers. (Blumenbachia, Koel.), are two genera 
very nearly allied to each other and differing from Andropogon, as 
Spodiopogon does from Pollinia, chiefly in their inflorescence ; 
the branches of the panicle bear three spikelets at the end, a 
sessile one between two pedicellate ones, and occasionally only 
one or two pairs below on the same branch. They were both 
included by Linnaeus, and afterwards by Brown, in Holcus, a 
name since restricted to that portion of the old genus which 
belongs to A venacese. Chrysopogon, as now constituted, has nearly 
twenty species, chiefly tropical or subtropical, but including also 
the European C. Gryllus and some other temperate species. The 
genus may be divided into two natural sections: in the typical 
form the pedicellate spikelets usually contain a male flower; in 
the section Stipoides, exclusively American, it is reduced toa long 
hairy stipes rarely bearing a minute rudimentary glume. This 
section includes C. nutans, O. avenaceus, C. stipoides, C. Minarum, 
and a few others. Sorghum differs from Chrysopogon in habit, 
in the scarcely articulate branches of the panicle, and in the 
glumes of the fertile spikelets more hardened after flowering. 
The number of species is very uncertain, for, of the two prin- 
cipal ones, S. halepense is so widely spread as a tropical or sub- 
tropical weed, and S. vulgare so long and so generally cultivated 
in warm regions for a variety of purposes, as to have produced 
à great variety of forms, raised by many to the rank of species. 
25. ANTHISTIRIA, Linn. fil. (Lhemeda, Forsk.), if taken as a 
Whole, is a very natural genus, of about a dozen species from 
the warmer regions of the Old World, easily recognized by its 
inflorescence. The spikelets are in short dense spikes or clusters, 
usually seven together, of which the four lower ones (two pairs) 
are either empty or with a male flower in each, and are placed 
apparently in a whorl, forming a kind of involuere round the 
three inner ones, which, as in Chrysopogon, are one sessile between 
two pedicellate ones. In a few species the number of spikelets 
is raised to nine, or even to eleven, by the intervention of one or 
even two pairs of spikelets between the involucral and the ter- 
minal ones, These slight differences in the number or in the 
