MB. G. BENTHAM OK GEAMINBJD. 73 



of the sections Gymlopogon and Gymnandropogon, in wHcli the 

 awn is much reduced or obsolete. Agenimn, Nees, from his cha- 

 racter, would also refer to one of these species without prominent 

 awns. 



23. Chbtsopogon, Trin. {B}iapMs,Lour., Centrophorum, Trin.), 

 and 24. Sobghtjm, Pers. (SlumenhacMa, Koel.), are two genera 

 very nearly allied to each other and diii'ering 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 Linnseus, and afterwards by Brown, in Holcus, a 

 name since restricted to that portion of the old genus which 

 belongs to Avenacese. Ghrysopogon, as now constituted, has nearly 

 twenty species, chiefly tropical or subtropical, but including also 

 the European G. 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 Siipoides, exclusively American, it is reduced to a long 

 hairy stipes rarely bearing a minute rudimentary glume. This 

 section includes C nutans, G. avenaceus, G. stipoides, G. Minarum, 

 and a few others. Sorghum differs from Ghrysopogon in habit, 

 in the scarcely articulate branches of the panicle, and iu 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 

 a great variety of forms, raised by many to the rank of species. 



25. Anthistieia, Linn. fil. (JPhemeda, 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 involucre round the 

 three inner ones, which, as in Ghrysopogon, 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 



