' I
VI PRErACE. PREFACE. Vll
most part entirely avoided, as being calculated to perplex
ratlier than instruct those who are but acquiring the rudiments
of the subject.
Abstruse questions of identity or of specific distinctions
have also been regarded as foreign to the purposes of this
' History.’ On these points we have been content to follow
the generally received opinions of Pteridologists. In one
or two instances, in which perhaps this course has been
departed from, the reason has been made suificiently obvious.
These explanations may serve to acquaint more advanced
students why so little of novelty has been prominently
introduced, and why several recently described plants have
been rather treated as varieties than as species. The
consideration of the specific distinctness of these plants
opens up questions involving much doubt and difficulty,
and leading different inquirers to widely different conclusions.
Of the difficulties of such questions the uninitiated
can have but a faint idea, neither could they be expected
to see clearly through them in any form in which they
could possibly be presented to them. It has, therefore,
been thought best to simplify the matter by regarding such
dubious species as varieties, ranging them with those admitted
species in whose company, it appeared to us, they
would be most easily recognized. In doing this, however,
we record no opinions as to the questions really involved.
One novel species — a less dubious addition to our
British Ferns—has been announced while these pages have
been going through the press. This will be found described
in an Appendix.
One word more.— I f it so happens that any of those who
may be led by the perusal of these pages to study the Ferns
of Britain, should, in the course of their inquiries, meet
with difficulties or perplexities which we may be able to