396 MR. G. BENTHAM ON COMPOSITS. 
vague in some species where the secondary ribs are present but 
much less prominent than the primary ones, that no tolerably fair 
line of demarcation can be drawn between the groups. The pappus 
in the three sections is very nearly the normal one of Vernonia: 
that of Tephrodes usually white, copious, and rather soft; that of 
Cyanopis more fragile, approaching that of Centratherum ; that of 
Lepidella with the outer short row more paleaceous, as in many 
American Lepidaploe. No American species, as far as I am 
aware, shows the 4- or 5-augled or the nerveless achenes of these 
Old-World groups. 
The Mascarene section Distephanus (two species), with a some- 
what different habit, a compact inflorescence, and a remarkably 
fimbrillate receptacle, might perhaps be maintained as a distinct 
genus; but the extreme vagueness of the character derived from 
the receptacle (a tendeney to which is observable in several African 
species) will probably justify its reduction to a section, chiefly 
geographical, of Vernonia. Another supposed Mascarene genus, 
Bechium (a single species), appears to me to be a true Lepidaploa, 
with a slight tendency to the coloured tips to the bracts of the 
involucre of Stengelia, and a somewhat peculiar habit, the leaves 
being almost radical. 
The numerous Vernonioid genera, most of them small or mono- 
typic, which have been maintained around Vernonia, partly from 
habit, but chiefly on account of more or less marked divergences 
in characters regarded as essential, but which are yet connected 
with the main group by small gradations, may be classed as follows 
according to the nature of those divergences :— 
Ist. In the mucronate or subcaudate anther-auricles.— This is 
exhibited in one American and three Old- World genera. 
The American Piptocarpha, with nearly twenty species, is closely 
connected in involucre, and in one species in inflorescence, with 
the American section Critoniopsis and the Old- World Strobocalys ; 
most species, however, have a peculiar inflorescence of a character 
much more American than Asiatic or African. The pappus is 
sometimes the normal Vernonian double one ; sometimes the outer 
series is reduced to a few fine sete, or disappears altogether, as in 
the Old-World Strobocalya. 
In the Old World the few cases of Vernoniaces with subcaudate 
anthers show a different combinationof other characters. Thethree 
genera Centauropsis from Madagascar with two species, Adenoon 
from the E.-Indian peninsula, and Pleurocarpea from N. Aus- 
