MR. G. BENTHAM ON GRAMINEZX. 48 
The genus Dimorphostachys of Fournier is founded upon the 
above P. monostachyum and some other American species, which we 
should refer to the sections Digitaria or Brachiaria, but which 
he connects generically by the small lowest glume being more 
developed or differently shaped in one spikelet of each pair than 
in the others; but the difference is often exceedingly slight, 
and the character so little connected with any other or with 
habit, that it seems difficult to attach any more than specific 
importance to it. 
(6) Brachiaria. This section, sometimes referred to as Paspaloid 
Panica, comprises a large number of species both from the New 
and the Old World, in which the inflorescence is that which is 
regarded as specially characteristic of Paspalum: the panicle con- 
sists of a number of spike-like simple branches, distributed along 
a simple common peduncle ; but the small lowest glume of Pani- 
cum is always present. If we regard only such typical species as 
P. flavidum or P. fluitans of Retz, or P. paspaloides of Persoon, 
the section appears a most distinct one; but, on the other hand, 
several such species as P. adspersum, Trin., P. argenteum, Br., 
P. Petiveri, Trin., P. polyphyllum, Br., &c. so closely connect it 
with some of the sparingly-flowered species of Eupanicum, as to 
make it impossible to drawa precise line of demarcation between 
the two. Amongst these intermediate forms, Paractenum, pro- 
posed as a genus by Beauvois, appears to be only a starved state 
of P. gracile, Br. 
P. helopus, Trin., bears on the obtuse apex of the flowering 
glume a short point, like that of most species of Eriochloa, and 
was therefore joined by Beauvois to the P. (Trichachne) semi- 
alatum, Br., to form his genus Urochloa ` but the two are in other 
respects too dissimilar to be united in one section, and L. helopus 
appears to be altogether a true Brachiaria. 
(7) Echinochloa, was regarded by Beauvois as a distinct genus, 
founded chiefly on two very widely-spread and most variable 
species, P. colonum, Linn., and P. crus-galli, Linn., the former 
often cultivated, the latter a most abundant tropieal aud sub- 
tropical weed. Both have nearly the inflorescence of the section 
Brachiaria but they are coarser plants, with the spikelets densely 
crowded ou the partial spikes or branches of the panicle, and the 
second and third empty glumes, in the one rarely, in the other 
very generally, terminating in long awns. It was probably on 
this account that Kunth united Beauvois's Echinochloa with his 
