416 MR. G. BENTHAM ON COMPOSIT E. 
in species, is yet far more extended in geographical range; and 
as it has established endemic species in different parts of its 
area, several of these have been raised into monotypic genera, 
sometimes with so much of the common habit and character that 
we have thought it illogical to adopt them; others are retained 
with some hesitation. The genus, as a whole (about twenty-five 
species), differs from Blumea in the corymbose inflorescence, in 
the disk-florets generally (though not always) sterile with undi- 
vided styles, and usually in the broader more coriaceous involu- 
eral bracts. It is nearly equally distributed over America, Africa, 
and Asia, chiefly within the tropics, but extending somewhat 
northwards both in America and Asia, and sparingly to the south 
of the tropic in Australia. No one species is common to the New 
and the Old World ; but the commonest species of the two hemi- 
spheres are about as near to each other as each is to the other 
species of its own region. 
The Old-World genera, chiefly d separated by charac- 
ters which we would consider as no more than specific, are:—1. 
Berthelotia, an East-Indian species which had been removed 
from the neighbourhood of Pluchea, chiefly on the mistaken sup- 
position that the anthers were not tailed. It has also been cha- 
racterized by the sete of the pappus being more or less connate 
at the base; but that is also observable, though in a less degree, 
in the common Pluchea indica. 2. Karelinia, a Caspian species 
with a narrower involucre and a long white pappus, the sets of 
the disk-florets mostly thickened at the apex, as is so often the 
case where the florets are sterile. This also had been erroneously 
presumed to have tailless anthers. 3. Oligocephalum may be given 
as a sectional name for P. pinnatifida, Hook. f., from tropical 
Africa, and P. frutescens, Benth., from Scinde, small shrubby 
species which in some respects form, as it were, a passage into 
Blumea, but are, on the whole, nearest allied to Pluchea; whilst 
the Laggeras above mentioned, intermediate in another direction, 
have the inflorescence and chief characters of Blumea, with the 
involucre rather of Pluchea—and having, in addition, no tails to 
the anthers, are retained as a distinct genus. 4. Spiropodium is 
an Australian species with the capitula generally, but not quite 
constantly, dicecious, a tendency to which arrangement is also ob- 
servable occasionally in the African P. Dioscoridis and some 
others. The Australian P. tetranthera, which is also nearly 
dicecions, diverges further in its tetramerous sterile florets and 
