MR. G. BENTHAM ON GRAMINE. 71 
is small and hair-like or sometimes entirely wanting, and proposed 
a genus Meoschium, adopted by Nees, for the other species in which 
the awn is more developed. Trinius considered as true Ischema 
only those in which the pedicellate spikelet has only a male flower 
or empty glume, and added those in which that spikelet has two 
male flowers to his genus Spodiopogon, notwithstanding the dif- 
ference in inflorescence &c. Ischemopogon, Griseb., is T. latifolium, 
Kunth, and Hologamium, Nees, is T. laxum, Br., both species 
with two-flowered pedicellate spikelets, as is also the case in J. 
insculptum, Hochst., and T. macrostachyum, A. Rich., from tropical 
Africa, and probably also in Forskühl's genus Sehima, of which 
we have no authentic specimen. T. pectinatum, Trin., T. leersioides, 
Munro, Z. ophiuroides, Munro, with a fourth unpublished species, 
all from tropical Asia, form a distinct section (Pectinaria), with 
slender elegant simple spikes, and the larger glume of the sessile 
spikelets pectinate-ciliate. 
20. TRACHYPOGON, Nees, as limited by Andersson, and 21. 
HETEROPOGON, Pers., closely resemble each other in their simple 
spikes with appressed imbricate spikelets and long rigid twisted 
awns; but in Trachypogon the sessile spikelet of each pair is male 
or sterile and unawned, and the pedicellate one fertile and awned, 
whilst in Heteropogon the sessile one is fertile and awned, and 
the pedicellate one male or sterile and unawned. Andersson enu- 
merates eleven species of Trachypogon, one from South Africa, the 
others from tropical or subtropical America; but several of the latter 
can scarcely be regarded as more than slight varieties. Of Hetero- 
pogon there are two well-marked species, H. contortus, Reem. and 
Schult. (ZT. hirtus, Pers.), now very common in most warm regions 
and extending to the Mediterranean region and to North America, 
and H. melanocarpus, Ell. (H. Roylei, Nees, H. acuminatus, Trin., 
Trachypogon scrobiculatus, Nees), which is in North and South 
America as well as in East India. Besides these, three or four 
South-African species have been referred to Heteropogon, but are 
of somewhat doubtful affinity. 
22. ANDROPOGON, Linn., taking it within the limits assigned to 
it by Munro, including all the species of the subtribe with spike- 
like simple branches to the inflorescence, and without the pecu- 
liarities of the three preceding genera, is still a somewhat poly- 
morphous genus of perhaps a hundred species, very abundant 
within the tropies, but well represented also in Europe, temperate 
Asia, North America, South Africa, and Australia. The fourteen 
