394 MR. G. BENTHAM ON COMPOSITAE. 
lucral bracts; but even these secondary characters are most 
frequently differently combined in the New and in the Old World 
and in the different regions of each. No other section or group of 
Vernonia can be strictly said to be common to the New and the 
Old World. Aberrant modifications of some one of the more 
important characters may indeed be observed in both the regions, 
but differently combined in the two with other characters. 
1. In the two Brazilian species of Hololepis and the single 
Mexican Leiboldia there is not the usual disproportion in the 
pappus, the outer sete being but little distinguishable from the 
inner in length, numbers, or rigidity. The Brazilian Hololepis is, 
moreover, remarkable for: the large involucres, of which the outer 
foliaceous bracts conceal the inner ones. The Mexican .Leiboldia 
has also rather large involucres; but its bracts are all acute and 
normally accrescent from the outer to the inner. In the Old 
World we have in the Vernonia calycina, Wall, from Prome, a 
close representative of the Brazilian Hololepis as to habit and 
involucre, and the pappus also abnormal, but in a direction pecu- 
liar to the Old World; the outer sete, though longer than in 
Lepidaploa, are fewer and shorter than the inner ones. In the 
tropical-African V. purpurea, Sch. Bip. the outer bracts are 
sometimes enlarged and foliaceous as in Y. calycina; but the 
pappus is normal, and the plant is in other respects a true 
Lepidaploa. 
2. The tropical-American Critoniopsis, containing five or six 
species, with a normal pappus, is distinguished by its ample 
panicles of small few-flowered capitula, the involucral bracts 
obtuse, the inner ones frequently very deciduous, as in the allied 
genus Piptocarpha. This section is not identically present in the 
Old World, but is there represented by the section Strobocalyx 
of about a dozen species, with similar inflorescence and capitula ; 
but the pappus has the tendency, so frequent in Old-World 
Vernonia, to the attenuation, reduction, or almost total disappear- 
ance of the small outer sete of the pappus. 
The aberrant forms peculiar either to the New or to the Old 
World, which, however, we have thought not sufficiently distinct 
to retain as separate genera, are the following :— 
1. In tropical America the three small sections Stenocephalum, 
Trianthea, and Eremosis have the normal pappus and other 
essential characters of the original Vernonia; but the narrow 
involucres contain but very few florets. In Stenocephalum the 
