MR. G. BENTHAM ON GRAMINE. 74 
globe, but often only as an introduced weed. One at least of the 
glumes of the lowest pair is the largest of the spikelet, as in 
Phalaris; those of the second pair, though small and without 
flowers, have a dorsal awn. The panicle is usually cylindrical 
and spikelike. 
6. Hrerocutoa, Gmel.( Savastana, Schrank, Disarrenum, Labill., 
Torresia, Ruiz and Pav.), about eight species from the colder or 
mountain regions both of the northern and the southern hemi- 
spheres, is usually referred to Avenacee next to Holcus; but it 
appears to me to be much nearer to Anthoxanthum, from which 
it differs in its looser paniculate inflorescence, and in the glumes 
of the second pair being but little smaller than the lower ones, 
and frequently, but not always, enclosing each a male flower. 
Ataxia, Br., one or two Asiatic and two South-African species, 
forms a section of Hierochloa, differing slightly from the typieal 
form in the glumes of each pair being more unequal, the lower 
one only of the second pair (rarely both) having a male flower. 
A. mexicana, Rupr., seems to connect the two sections. 
Tribe VIII. AGRosTEZ. 
The large tribe Agrostez is one of the most difficult to circum- 
scribe satisfactorily, or to divide into definite genera. We have 
taken it nearly in the sense given to it by Trinius, so as to in- 
clude the Stipex, of which other botanists make a distinct tribe; 
and we have adopted thirty-seven genera, a number which some 
would extend to above eighty, whilst others might reduce it to 
about thirty. Their general character is to have a single flower 
in each spikelet, either apparently terminal as in Panicace&, or 
with a slight bristle-like continuation of the rhachilla beyond it; 
and from these Panicaceæ they are constantly distinguished by 
the pair of empty glumes persistent below the artieulation of the 
rhachilla, without any empty glume or male flower intervening 
between the articulation and the flowering glume. The single 
flower in the spikelet, which separates the tribe from the follow- 
ing ones, is not so positive a character, as it occurs also in one 
genus of Avene, in a few genera of Chloride&, and occasionally 
in a few exceptional species of some genera of Festucez, which 
cannot well, from inflorescence or other accessory characters, be 
included in Agrostee. There are also two species of Sporobolus 
which approach the Isanthes in having frequently two flowers ; 
and in Coleanthus the lower empty glumes are entirely deficient. 
LINN. JOURN.—BOTANY, VOL. XIX. H 
