82 
European Ferns. 
ASPLENIUM : THE SPLEENWORTS. 
HEN describing the Parsley Fern ( Cryptogramme crispa),* we took occasion to 
remark upon the very variable extent of genera, and noticed how, while 
some included hundreds of species, others were what is termed monotypic, 
that is, containing but one species. We have now to consider the largest 
genus of ferns — a genus containing at least between three and four hundred 
species, and one which, as might be supposed from its extent, exhibits a 
very great deal of variation in the character of its members. It is, indeed, 
not easy to estimate the extent of some of our larger genera of ferns. 
These plants present great attractions to the botanical collector, and even 
to the resident in foreign countries, who is no botanist, but takes sufficient 
interest in his surroundings to collect specimens for his friends at home. Since 
the publication of the “ Synopsis Filicum,” by the late Sir W. J. Hooker and Mr. J. G. Baker 
(the second edition of which bears date 1874), and in which three hundred and thirty species 
were enumerated and described, many collections from different parts of the world — notably 
from Madagascar and Borneo — have been brought or sent to this country alone, without referring 
to the many others which have found a resting-place in Continental herbaria. The latter of 
the authors above-named has published in the “Journal of Botany” and in the “Journal of the 
Finnean Society ” numerous lists of recent collections of ferns from different parts of the 
globe ; and “ the cry is still ‘They come!’” for scarcely any collection of ferns is named without 
there being detected in it a considerable proportion of novelties. The accuracy of this 
statement is manifested the more strongly, inasmuch as Mr. Baker certainly cannot be accused 
of the slightest tendency towards the undue multiplication of species. When we remember 
that in all only about a hundred and ninety species of ferns were known to Linnaeus, and 
contrast this with the number at present described belonging to a single genus, we can form 
some idea of the rapid increase of our knowledge of the fern world. 
Of the genus Asplenium, the second edition of the “Synopsis Filicum” enumerates, as 
we have already said, three hundred and thirty species, and this number is certainly below 
the mark at the present time, if we accept a broad estimate of what constitutes a species. 
But it must be remembered that under this generic name are included many groups which 
are ranked by other authors under separate generic heads : as regards one of these, the 
Ceterach or Scale Fern, we ourselves have preferred to follow those who consider it suf- 
ficiently distinct to be ranked as a separate genus. But, with all deductions, the genus is 
a very large one, and, moreover, one which has many European representatives, while eight 
at least of our British ferns are found in its ranks. 
We have already said that the genus Asplenium presents considerable variation ; and this 
variation is equally apparent whether we consider the forms of the plants, their size, or their 
geographical distribution. Some, such as A. Hemionitis and A. Nidus, have entire fronds — of 
these we shall speak more at length when we come to consider the first-named species — in 
others the fronds are pinnate, with small pinnules, such as the Maidenhair Spleenwort (A. 
Trichomanes), or the Green Spleenwort (A. viride), or with very large ones, as in A. salicifolium / 
while some of those with pinnate fronds have the pinnae divided into almost hair-like segments. 
* See page 56. 
