404 MR. G. BENTHAM ON COMPOSITAE. 
on structural grounds, might perhaps be restored to it as sec- 
tions,—the N.-American Sericocarpus of 5 species, and the Asiatic 
monotypic Callistephus. 
Six other genera, not diverging more or perhaps even so much 
as the above two in essential characters, but with a very different 
geographical range and apparent origin as well as a distinct habit, 
have been by several botanists reunited with Aster, because they 
have no distinct character which is not liable to exception. But 
the species are numerous and the exceptions few ; and, geographical 
considerations coming in aid, it would seem to be more in confor- 
mity with the evidences of affinities thus obtained to maintain them 
as distinct genera. These are :— 
(1) The South-African genus Felicia (including the greater por- 
tion of Agathea), about 45 species, much branched shrubs, or, if 
herbaceous, small annuals branching from the base, all very unlike 
any American true Asters, retaining the achenes but not the 
pappus of that genus, which is more like that of Erigeron, but 
different from either in its fragility. The very few exceptions in 
their case consist in one or two eastern species approaching in some 
respects the alpigenous Asters represented in the same country 
by. A. natalensis. Closely connected with these Felicias, and 
perhaps not separable, is the monotypic extratropical S.-American 
Sommer feltia, : 
(2) The Australian genus Olearia, about 85 species, mostly 
shrubby, like the S.-African Felicias, but larger and retaining, not 
the achene but the pappus of the American Asters. This achene 
is no longer flattened, but terete or nearly so. There is also an 
occasional tendency to extreme acuteness or even fine points to 
the auricles of the anthers, never observable in any true Aster, 
but traceable sometimes in another Antarctic or Australasian 
genus, Celmisia, to be presently referred to. The exceptions in this 
case are a very few Australian herbaceous Olearie, but with a 
very different habit from any American Asters, and a very few N. 
American Asters (Biotie) with subterete achenes, but accompanied 
by a typical American involucre and other characters not to be 
met with in Olearia. These circumstances taken together consti- 
tute a much greater difference between Aster and Olearia than is 
observable between the alpine Asters and Erigerons. 
(3) The antarctic or subantarctic American genusChiliotrichium, 
a genus of three species, one of the numerous connecting links 
between the Australian and the extratropical or AndineS.-American 
