154 The Philippine Journal of Science 191 s 
system of nomenclature, and of preventing them from using 
novel or antiquated systems, which they themselves may recog- 
nize as unnatural. 
It is presumably recognized by every writer on systematic 
botany that the multiplication of synonyms is in itself a nui- 
sance, and that the publication of a synonym, except as it may 
be necessary in order to place a fern in the genus where it nat- 
urally belongs, or to correct the use of a generic name which 
under recognized rules of nomenclature is untenable, is not 
entitled to be regarded in any other way than as a nuisance. 
In this supplement, whole pages are taken up with the names 
of synonyms published without the chance that they will be 
generally recognized as valid names, and without any perma- 
nent result except to encumber literature. In these days, nobody, 
not even van Alderwerelt himself, believes that Phegopteris is a 
valid genus, including the species which he has transferred to it. 
There doubtless are people who believe that Pleopeltis is a valid 
genus; but a writer should be convinced on better evidence 
than is now available that Pleopeltis, if it is to be recognized 
as a genus, includes any ferns of the Eastern Hemisphere, before 
he loads the literature with nearly two pages of mere names. 
All pteridologists are probably agreed that Polypodium, in the 
sense of the Index Filicum, is a larger and more diverse genus 
than it will be permanently convenient to recognize. Most pter- 
idologists, however, are disposed to wait until they know, from 
study of the ferns, what are the generic groups which are worthy 
of recognition; and only after they know the groups from the 
study of the ferns, to fall back on the literature for a decision 
as to the names which the groups should bear. 
In the case of Polypodium, I have given this matter consider- 
able study, and before van Alderwerelt published his wholesale 
transfers to Pleopeltis, had already published reasons for believ- 
ing that the great group which he transfers cannot possibly 
bear the name which he has used. If Pleopeltis is a genus, it 
must be a very small one, and has probably no known species 
in the Malayan region. The Old World species must have a 
different name or different names. Leaving out of account the 
groups of ferns more or less related to Drynaria, Lecanopteris, 
and other generally recognized genera, there are three names 
to be considered for the remaining species; and among these, 
the choice is altogether a matter of judgment, depending upon 
the number of groups which are to be recognized. The larger 
number of species fall into the group in which many of them 
