245
Index 248

PREFACE.

Observations extending over a period of twenty-five years, made at
Fungus Forays and kindred meetings where Mycologists assemble together,
has led to the conviction that familiarity with the Fungi and literature
pertaining thereto, of one country only, leads to a false impression as
to the significance of the term 'species.'

It conveys the idea that species are much more sharply defined than
proves to be the case, when the entire Fungus Flora of Europe is
included.

In all large genera common to European countries, the continental
species can be sandwiched between British species. Even in large genera
there are as a rule not more than eight or ten primary differentiating
specific characters present, and it is the constant correlation of two
or three of those primary characters that constitute a species, as
understood at the present day.

If two British species are characterised respectively by the marks 1, 2,
and 3, 4, then we find that two continental species belonging to the
same genus will be indicated by the characters 1, 3, and 2, 4,
respectively.

Primary specific characters should include only those features that are
constant, and not materially modified by geographical or exceptional
local conditions as to environment, etc., and such alone should
constitute a specific diagnosis. Trivial or local characteristics should
follow the essential diagnosis as a rider.

With the introduction of characters due to local conditions, a
description ceases to be a specific diagnosis in the proper sense, and
is merely a description of a certain state of a species occurring under
a given set of conditions. Such, however, is too frequently the nature
of so-called specific characters given in local Floras.

A lengthy and laboured description suggests lack of power to grip
essentials on the part of the compiler, and does not as a rule
facilitate the recognition of the species intended.

The idea of this work is to give the essential characters of each
species as presented by pileus, gills, stem and spores respectively.
This, however, owing to the views of some authors as to the predominant
value of one feature to the exclusion of others, has not always been
possible. For this reason the species of Britzelmayr are not included,
as his descriptions, even when aided by what are presumably intended as
figures, could not in many instances be c