8 Origin of the British Flora. 
dealt with are at present almost unknown outside Britain, 
Sweden, and North Germany, and speculation would have 
to take the place of an appeal to direct evidence. Secondly, 
that Britain is not by any means simply an outlier of the 
continent of Europe. Its flora is an insular one of peculiar 
character, unlike that of any part of Europe, and unlike 
that of an oceanic Island. Few, if any, of the species are 
confined to Britain; but the Islands contain a selection of 
the continental species best adapted for dispersal, and best 
able to hold their own in a changing climate. Britain, 
within the lifetime of existing species, has been subjected 
to many fluctuations of climate, which have left their mark 
on the flora. On these fluctuations was superimposed a 
series of orographic changes, such as must have tended 
greatly to modify local conditions, and must sometimes 
have aided, sometimes have hindered, the dispersal of the 
seeds, 
The following pages deal, therefore, with an insular 
flora of exceptional type; in the building up of which 
selection and sweeping extermination have played so 
vigorous a part, that the flora now consists largely of an 
assemblage of the more readily dispersed of the Palearctic 
species. Time has not permitted any large amount of 
variation or formation of sub-species in these Islands ; and 
in this our flora is totally different from the more ancient 
floras of oceanic islands, which were beyond the reach of 
such violent climatic fluctuations as have affected Britain. 
There is one point which needs explanation before we 
proceed further. I have been obliged in the following 
pages to go back to the popular and original use of the 
term ‘seed,’ Of the two senses the popular one seems to 
be by far the most useful scientifically, for it refers to the 
thing that is sown, not to an embryo with or without 
