X, 0,2 Review 155 
have already been given names as Phymatodes; but there are 
a considerable number of species intermediate between this 
group and Goniophlebium, and Goniophlebium is an older generic 
name. It is my opinion that no natural line can be drawn be- 
tween Goniophlebium and Phymatodes, and that therefore Go- 
niophlebiwm is the better name of the two for the entire group. 
But the problem does not end here. Selliguea, as a generic 
name, antedates Gonophlebium. It is perfectly certain that the 
species commonly assigned to Selliguea, as a subgenus, are of 
diverse phylogenetic origin in the Phymatodes group, but it is 
not so certain that the smaller group, to which the name Sel- 
liguea was originally given, ought not to be retained as a genus. 
Pending a well-founded and positive opinion on this question, 
as a basis on which to decide whether Goniophlebium or Sel- 
liguea should be the generic name of the very large group, a 
botanist should be disposed to go very slowly in dissecting the 
old genus Polypodium. 
Furthermore, the ferns of the American tropics must be taken 
into account in any attempt to rehabilitate these old generic 
names. A considerable number of American ferns have been 
described under the name of Goniophlebium. If Goniophlebium 
is made a genus in any natural sense, not one of these American 
ferns can be included in it, no matter how perfectly they may 
conform with the diagnostic characters assigned to the genus. 
There is no doubt whatever, at least in my mind, that these 
American ferns are genetically related to entirely distinct species 
and groups of Eupolypodium. If, therefore, our classification is 
really natural and a genus must be a group of related species, 
the so-called Goniophlebium of the American tropics can in no 
way bear the name of the real Goniophlebium of the Old World. 
‘The problem is further complicated by the fact that the species 
assigned to Goniophlebiwm in America do not themselves rep- 
resent a single line of descent. They comprehend certainly two, 
and probably at least three, phylogenetically separate groups. 
When the “thorough revision of the generic nomenclature” 
is attempted, it must be on the basis of a knowledge of the 
ferns themselves, and it is the need of just this kind of thorough 
revision which is emphasized by the Supplement to the Index 
Filicum. As illustrations, in order to use those of which I 
feel sure, I will call attention to the treatment of some of the 
genera to which I have given particular attention. 
Acrosorus is a genus which I proposed as a necessary con- 
sequence of the recognition of the sense of the word genus which 
