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 Palsearctic 

 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 



