POLYPODIUM CALIFORNICUM.—CALIFORNIAN POCLYPODY. 35 
condition on our plate. The reason is that about the time when 
our species was first discovered the condition of the veins was 
supposed to be more unchangeable than it is known to be now. 
In some places a form was found like it that did not have the 
netted veins, and it was thought therefore to be another species, 
and named by Hooker and Arnott Polyfodtum intermedium ; but 
as more specimens were discovered some of the former would 
occasionally be found with free veins and some of the latter 
with netted veins, and therefore in this case at least the character 
is worth nothing as a distinction. Consequently Hooker, in his 
“Species Filicum” published in 1864, united the two, and they are 
now both known by the oldest name P. Californicum. Our plant 
in its earlier history would have been probably known as 
FP. intermediun. 
Whether a form is to be considered as a distinct species or 
as a mere variety depends very much on experience as to the 
fixity of characters, rather than on any specific points that can be 
readily explained; and we can see in this case that only for the 
fact that a few netted veins had been found in one case, and a 
few free veins in another case, both forms would in all probability 
be regarded as distinct species to this day; and it is such facts 
as these which make observations on the range of variation in 
species of so much value to practical botanists. In ferns espe- 
cially very much has to be learned on this point. For want of 
this knowledge synonyms are very numerous. In the case of 
our present species, Professor Kunze, in a paper translated in 
« Silliman’s Journal,” new series, Vol. 6th, remarks that Hooker 
and Greville, standard authors on ferns, had united very differ- 
ent species with it. Another writer in the 6th Volume of the 
“Bulletin of the Torrey Botanical Club” suggests a doubt 
whether another species of the Pacific Coast, Polypodium falca- 
tum, may not be referred to P. Calfornicum. Botanists may not 
be wholly prepared for this view yet, although we incline to it; 
but it shows how uncertain much fern knowledge yet remains, 
A very pretty feature in our Californian Polypody is its trans- 
