124 MR. G“BENTHAM ON GRAMINE X. 
spikelets almost sessile. Calotheca, Desv., with a loose spreading 
panicle, has broadly scarious awned glumes. 
60. Scuismus, Beauv. (Electra, Panz., Hemisacris, Steud.), has 
three or four species, one of them widely spread from the Medi- 
terranean region, eastwards to Afghanistan and Arabia and 
westwards to the Canary Islands, the others South African. All 
are annuals with a narrow panicle, and distinguished by the long 
empty glumes quite enclosing the flowering ones. 
61. NEPHELOCHLOA, Boiss., limited to the original Oriental 
species, is a very elegant little grass with the habit of Aira invo- 
lucrata, and is figured in the last part of Hooker's Icones. The 
species added to the genus by Grisebach, for which he was obliged 
to alter Boissier's character, are now restored to Poa. 
62. Poa, Linn., is a cosmopolitan genus, chiefly extratropical, 
which, after frequent extensions and reductions, has now become 
fairly limited to a series of about eighty species. They form a 
group natural enough as to the great majority of species, dif- 
fering from Eragrostis in their five-nerved flowering glumes, from 
Glyceria and Festuca in their glumes keeled from the base ; but 
here, as elsewhere, there are species apparently intermediate 
between these large genera, and several smaller ones are only 
separated by characters of little importance. Poa has also been 
distinguished from Festuca by the obtuse, always unawned glumes, 
and by the non-adherence of the grain to the palea. The former 
character is general, but not absolute; several species of Poa 
have acute glumes, and in P. lanuginosa, Poir., they bear a fine 
point which might almost be termed a very short awn. And as 
to the grain, though it is usually free, there are several Chilian or 
Australian species and some Asiatic ones where it is adherent to 
the palea, as in Festuca, and even in the common Poa pratensis 
it is often more or less adherent, whilst there are several true 
Festucas where it is quite free. 
Most of the widely spread species of this genus are so variable, 
that it would require much more research into specific detail 
than I can at present bestow upon them to distribute them into 
natural groups or sections; and I can only refer to the following 
as having been proposed as sections or separate genera :— Pseudo- 
poa, proposed by C. Koch as a section of Festuca, includes P. per- 
sica, Poir., and two other temperate-Asiatic species, with very 
small spikelets and with nearly the habit of Nephelochloa, to which 
Grisebach has referred them, but which appear inseparable from 
