MR. G. BENTHAM ON GRAMINEX. 91 
longation of the rhachilla into a bristle or stipes usually, but not 
always, hairy, and from Agrostis in the larger spikelets, with the 
palea nearly as long as the glume, and the usually hairy rhachilla. 
There are, however, a few species where one or another of these 
characters fail; and one or two scarcely differ from Apera except 
in the habit and in the awn being more decidedly dorsal. Bro- 
midium, Nees (to which belong Didymocheta, Steud., and Chame- 
calamus, Meyer), contains a few Andine Chilian or Australian 
species, which, with the minute glabrous and perhaps not con- 
stant continuation of the rhachilla, might almost as well be 
transferred to Agrostis, but that they have rather the habit of 
Deyeuxia. Relchela, Steud. (Agrostis sesguivalvis, E. Desv.), 
Cinnastrum, Fourn. (at least as to Deyeuxia poæformis, Kunth), 
Deyeuxia mutica, Wedd., and D. breviglumis, Benth., with a few 
other South-American species, form a little group with a glabrous 
rhachilla and the awn reduced to a small point. In Acheta, 
Fourn., two Mexican species, the awn appears to be deficient ; 
but all the other characters are those of the typical Deyeuxie with 
a hairy rhachilla, to which I would also refer the Agrostis equi- 
valvis, Trin., forming Grisebach's section Podagrostis. 
33. AMMOPHILA, Host (Psamma, Beauv,), comprises four spe- 
cies, two of them widely spread over the northern hemisphere 
chiefly near the sea, and two confined to North America. They 
are distinguished from Deyeuxia by their tall habit, their usually 
dense inflorescence, and especially by their larger paleaceous 
glumes. 
34. DromELaonnE, Endl., two Australian or New-Zealand spe- 
cies, with a narrow dense panicle, differs from Agrostis and its 
allies in the flowering glume scarcely smaller than the outer 
empty ones and often toothed, and in the long dorsal awns giving 
the inflorescence a fine bristly aspect. 
35. TRISETARIA, Forsk. (Anomalotis, Steud.), is a maritime 
Syrian and Egyptian plant, very near Dichelachne, but still more 
bristly, the lateral teeth of the flowering glumes being produced 
into fine straight awns, whilst the dorsal one is longer and flexuose. 
Labillardiére and Delile both mention two fertile flowers in the 
spikelet. I bave only been able to find one in several specimens 
examined, all from Alexandria; possibly they may have consi- 
dered the rather long continuation of the rhachilla as a second 
flower. 
36. PENTAPOGON, Br., is a single Australian species, with four 
