MR. G. BENTHAM ON GRAMINE. 45 
vaguely distinguished chiefly by their inflorescence and general 
habit. Amongst the somewhat exceptional species are P. unci- 
natum, Trin. (Echinolena polystachya, H. B. K.), in which the 
three empty glumes are nearly equal to each other, though shorter 
than the flowering ones, and 2, pterygodium, Trin. (forming the 
genus Ofachyrium, Nees), in which the two lower empty glumes 
are about equal, but shorter than the third. Inall the others the 
lowest empty glume is much the shortest. Coleatenia, from 
extratropical South America, is proposed asa genus by Grisebach 
as having dicecious flowers. I have not seen any specimen; but 
from his description it seems to be in all other respects a true 
Panicum (Eupanicum) ; and as be has only seen the male, evidently 
with the flowers still young, he may have overlooked the pistil, or 
its abortion may not be constant. At any rate that character 
standing alone can scarcely be sufficient to separate it generically. 
Several of the cultivated Millets are species of Eupanicum with 
large, loose, often nodding panicles. 
(11) Tricholena (including Nees’s genus Rhynchelytrum), raised 
by Parlatore and some others to the rank of a genus, has the loose 
panicle of Ewpanicum; but the fruiting glumes are not much 
hardened, and the whole inflorescence is ciliate with long hairs 
as in Trichachne, on which account the oldest known species, the 
widely-spread P. Teneriffe, was originally published as a Saccha- 
rum. There are now about fifteen species known, chiefly South- 
African ; but one, the above-mentioned P. Teneriffe, extends to 
the Mediterranean region, two are East-Indian, and two or three 
South-American. Rhynchelytrum, Steud., is a different genus 
from Nees's, and belongs to the Tristeginex. 
8. İOHNANTHUS, Beauv., is so closely allied in habit and general 
character to some species of Panicum (Eupanicum) that it is 
perhaps rather in deference to the authority of all the principal 
recent agrostologists, than from any conviction of our own, that 
we retain it asa distinct genus. The character is a purely technical 
one—a thin hyaline auricle or wing to the rhachilla on each side 
close under the flowering glume, as is observed in some species 
of Cyperus. In the species forming the section Macropteris of 
Doell these auricles are often more than half as long as the glume 
itself; in Z. longiflora (Lanicum longiflorum, Trin.) they are very 
small, but prominent ; in Z. pallens and its allies, forming Doell's 
section -Mjeropteris, they are often scareely perceptible, and 
_ Fournier has restored these species to Panicum, though Munro 
LINN. JOURN.—BOTANY, VOL. XIX. z F 
