238 NEW SPECIES OF CHRESTA. 
Characters of Three New Species of CunEsTA ; with Remarks 
on the identity of PycocEPHALUM and Curesta. By 
GEORGE GARDNER, Ese., F.L.S. 
(With Two Plates. Taps. vm. 1x.) 
Among my collections from the interior of Brazil, I find 
three species of Composite, belonging to the division Alber- 
tinee, which appear to be new. One, from its characters and 
habit, is referable to the genus Chresta, a second to Pycnocepha- 
lum, and the third belongs neither to the cne nor to the other, 
but forms a kind of intermediate species. The genus Pycno- 
cephalum was established by De Candolle in the fifth volume of 
the Prodromus, on Lessing's section of Vernonie of the same 
name; but after a careful examination, not only of my own 
three species, but of the whole described species of Chresta, 
and of Pycnocephalum plantaginifolium, I have satisfied myself 
that the two genera do not differ essentially from each other. 
The only distinctive marks which the generic character in 
the Prodromus contains to separate them, are the small 
striated scales which are said to surround the base of the 
capitula, in the shape of an involucre in Pycnocephalum, and ` 
not in Chresta; and the scapose habit of the former. which 
in the latter is ramose. In Pycnocephalum plantaginifolium I 
do not find any greater developement of scales surrounding 
the capitula than is to be seen in Chresta exsucca, for ex- 
ample; and in both they are nothing more than the lower 
external scales of the involucre of the capitula themselves. 
Habit is also but of little value as a distinctive character; for 
it is no uncommon thing to find small plants of Chresta ea- 
succa with only a single branch, and then it becomes a true 
species of Pycnocephalum, particularly as the leaves in that 
group are not always radical; for, in my species which belongs 
to it, they are borne upon à suffruticose stem, which rises 
to the height of about six inches. From these considera- 
tions I propose to unite the two genera, forming the genus S° 
