152 
ASPIDIACE.E. 
Africa, in Asia, North America, and many of the islands of the 
Pacific Ocean : it is true that these have been frequently de- 
scribed as distinct species, but the evidence on the subject is at 
present scarcely sufficient to induce me to admit them as such. 
There are many very beautiful and characteristic figures of 
this fern : those in Bolton’s ‘ Filices,’^ under the names of Po‘ 
lypodium rli(Blicmn and P. fragile, yield to none in excellence : 
I think his P. rhaeticum may be regarded as the normal form of 
fragilis. 
The little ferns constituting the present group were comprised 
under the name of Polypodium fragile by Linneus and our ear- 
lier authors ; Sprengel, Willdenow, Schkuhr, Wahlenberg, and 
other eminent botanists, make them Aspidiums. Bernhardi was 
the first to separate them from these unmanageably extensive 
groups, under the generic name of Cystopteris ; Roth gave them 
the name of Cyatliea, and Smith that of Cystea, the latter being 
a mere alteration from Bernhardi’s prior name, because Cystop- 
ieris is “ compounded of another established ” name, Pteris.\ 
The name has been spelled Cistopterishj several modern authors, 
an orthography whose evident deviation from the Greek appears 
to render inadmissible : in fact there is no sufficient reason for 
altering or modifying a name that possesses the acknowledged 
right to adoption on account of its priority. 
My views having in more than one instance undergone con- 
siderable modification as regards the limits of species, I turned 
my attention to the beautiful little ferns I had previously grouped 
together under the name of Cystopteris fragilis, in the hope of 
discovering some characters whereby the various forms might be 
satisfactorily distinguished from each other. Several botanists 
of eminence have undertaken somewhat too readily the establish- 
ment of new species ; dwarf size, imperfect fructification, or 
even, in more than one instance, mere accidental deformity, 
having furnished the chief diagnostic. Now, as in Zoology we 
endeavour to refer the females and young, and even individuals 
that have undergone mutilation, to the same species as the adult 
male, so would I, in ferns, rather refer specimens which appear 
* Bolt. Fil. tab. 44, 45 & 46. 
f Eng. Flor. 285. 
