46 ME. G. BENTHAM ON GEAMINE^. 



keeps them up as Ichnanthus. Two species, I. Sqffinimseggii, 

 DoeU, and I. oplismenioides, Munro, are remarkable for the long 

 spreading hairs, which give them a very peculiar aspect. There 

 are altogether about twenty species, all tropical American. 



9. OpLisMEiors, Beauv. (OriAqpoyow, Br.), though very near the 

 section Bracliiaria of Panicum, appears to be a natural genus, and 

 is well characterized by the greater development of the lowest 

 empty glume, which is, moreover, always awned, whilst in Panicv/m 

 it is much smaller than the others and always unawned. Kunth 

 adopted the genus, but, relying on the awns alone, united with it 

 JEchinocUoa, in which the proportions of the glumes are the ordi- 

 nary ones of Panicum, and which I have referred to above as a 

 section of Panicum. Fournier adopts Kunth's view. Steudel 

 and DoeU both reduce the whole to Panicum. The true Oplis- 

 meni are widely spread over the warmer regions both of the New 

 and the Old World, and are variable as to the number and length 

 of the spikes or panicle-branches, &c. Some botanists adopt 

 above thirty species, others reduce the whole to varieties of a 

 single one ; it is probable that some three or four may be fairly 

 distinguished as species. Hekaterosachne of Steudel is one of 

 the common forms of Oplismenus. 



10. Ch^titjm, Nees, to which Doell has properly referred 

 Berchtoldia of Presl as a second species, has nearly the spikelets 

 of Oplismenus, to which Kunth reduces it, the outer glumes 

 being much more developed and awned than the flowering ones ; 

 but, besides some minor points, the inflorescence appears quite 

 different enough to justify the maintaining it as a distinct genus. 

 Doell considers it as a section of Panicum, with two species, one 

 Brazilian, the other Mexican. Fournier retains the genus Serch- 

 ioldia for the Mexican one, without comparing it with Chmtium, 

 and adds two supposed new Mexican species : the one, B. Jiolci- 



formis, judging from the specimens he quotes, is one of the large 

 coarse forms of Panicum {EchinocJiloa), very nearly allied to, if 

 not varieties of, P. crus-galli; the other, B. opUsmenoides, is 

 unknown to me, but must from his description be referable also 

 to JEchinocMoa. 



11. Setaeia, Beauv., was included by the older authors in 

 Panicum, and has been restored to that genus as a section by 

 Steudel and by Doell, but is retained by most modern botanists 

 as a well-marked natural genus, easily recognized by the dense 

 spike-like panicle usually bristling with numerous setse issuing 



