46 MR. G. BENTHAM ON GRAMINES. 
keeps them up as Ichnanthus. Two species, I. Hoffmanseggii, 
Doell, and 7. 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. OPLISMENUS, Beauv. (Orthopogon, Br.), though very near the 
section Brachiaria 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 Panicum 
it is much smaller than the others and always unawned. Kunth 
adopted the genus, but, relying on the awns alone, united with it 
Echinochloa, in which the proportions of the glumes are the ordi- 
nary ones of Panicum, and which I have referred to above asa 
section of Panicum. Fournier adopts Kunth’s view. Steudel 
and Doell 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. Cuztrum, Nees, to which Doell has properly referred 
Berchtoldia of Pres] 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 Berch- 
toldia for the Mexican one, without comparing it with Chetium, 
and adds two supposed new Mexican species: the one, B. holci- 
Jormis, judging from the specimens he quotes, is one of the large 
coarse forms of Panicum (Echinochloa), very nearly allied to, if 
not varieties of, P. crus-galli; the other, B. oplismenoides, is 
unknown to me, but must from his description be referable also 
to Echinochloa. 
11. SETARIA, 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 sete issuing 
