49 MR. G. BENTHAM ON GRAMINEA. 
are few: P. semialatum, Br., is widely spread over the Old World, 
for I am unable to distinguish the Asiatic Coridochloa, Nees, and 
the South-African Bluffia, Nees, from Brown's Australian species ; 
P. Gayanum, Kunth, is confined to tropical Africa; P. leuco- ` 
pheum, H. B. K., is frequent under various names in the tropical 
and subtropical regions of the New and the Old World. Itisa 
very variable species ; and specimens gathered at different stages 
of development look very different from each other, but are not 
separable into marked varieties. İt was included by Beauvois in 
his genus Urochloa, and appears to have been the type of the 
proposed genera Acicarpha, Raddi, Eriachne, Philippi, and Holo- 
setum and Mesosetum, Steud., md is | probably the prineipal ele- 
ment of Presl’s supposed genus Alloteropsis. 
(3) Diplaria. This section is proposed for a few American species 
with a simple terminal spike-like inflorescence. The spikelets 
are sessile along the rhachis in two rows and distichous, as in the 
section Anastrophus of Paspalum, from which Diplaria differs 
technically in the presence of the small outer glume characteristie 
of Panicum. lt comprises P. rottboellioides, H. B. K., P. exaratum 
and L. ferrugineum, Trin., P. pappophorum, Nees, and a few others. 
(4) Thrasya, distinguished as a genus by Kunth, has a simple 
terminal spike-like inflorescence as in Diplaria ; but the rhachis is 
more or less dilated as in the section Ceresia of Paspalum, and 
the spikelets, sessile along the midrib, although really alternate 
and biseriate, have all the appearance of being in a single row. 
The species are few, all American, and include, besides the ori- 
ginal Thrasya paspaloides, Kunth, the P. ansatum, Trin., which 
is searcely specifically distinct inn it, P. Jc Trin P. 
petrewn, Trin., and perhaps two or three others. The E: Ne 
forms the genus Tylothrasya of Doell, which he characterizes by 
a callous thickening of the pedicel like that of Eriochloa ; but the 
plant is in all other respects too closely allied to the typical 
Thrasya to be generically separated, and the callosities are slightly 
prominent in various species of Panicum. 
(5) Harpostachys. The inflorescence is again simple and spike- 
lie; but the spike is more or less faleate, with the spikelets 
crow eae in two or four rows along one side of the slender rhachis, 
as in Chloride, and the common peduncles are usually long and 
often clustered two or three together in the upper axils. To 
this section belong P. monostachyum, H. B. K. , P. decumbens, R. 
et Schult., and P. subfalcatum, Doell. 
