250 UNDERWOOD: REVIEW OF THE GENERA OF FERNS 
treatment of genera, it is systematically as unsatisfactory as is 
Synopsis Filicum n its treatment of species. 
With the purpose then of arriving at the foundations of the 
problem of fern genera, and actuated by the spirit of Lincoln's 
aphorism, “ If we could first know where we are and whither we 
are tending, we could better judge what to do, and how to do it," 
we shall seek for a rational basis for the system by reviewing 
historically the fern genera that successive authors have proposed, 
with a view of recognizing in accord with principles of justice the 
earlier established genera and the foundations on which they rest. 
To do this more satisfactorily we have thought it wise to separate 
the problem into two periods and treat the earlier and more funda- 
mental somewhat independently. We have selected the year 1832 
as a convenient line of separation, as that will place in the second 
period all the wholesale establishments of genera by the later 
writers, especially Presl, Fée, Moore, and John Smith. The period 
commences with 1753 and closes with the completion of Hooker 
and Greville's /cones Filicum, 1831. 
In this study of generic foundations there is necessarily little 
that is novel except that the principles which we shall follow in 
this recognition of genera involve certain elements in which there 
is neither uniformity of practice among taxonomists nor authorita- 
tive ruling. It is, therefore, best to state the basis on which the 
recognition of the rights of genera will here proceed. We will give 
sufficient data, however, selected after an extended bibliographic 
research which includes all the original publications of fern genera* 
so that others working from other principles may be enabled from 
these data to base their own conclusions. 
The principles here followed are : 
1. Only genera established in Linnaeus’ Species Plantarum ; 
1753, or later are considered. (Rochester Rules.) 
2. No genus is considered as established unless it is : (2) Based 
on one or more previously described species which are referred to 
* In addition to bome facilities, the libraries of Kew Herbarium and the Berliner 
Hof-Museum, together with the en collection of serials at the British Museum 
( Cromwell Road) have ‘urnished most of the rarer references, but a few were not to be 
found even in these extensive open For one of Kaulfuss’ rarer papers we were 
indebted to the unique library of the Surgeon-General’s Office at Washington, 
rofessor E. L. Greene's library eroii the only available copy of De/iciae Pragenses. 
