vii.] CONQUEBING EACES AND NEW PLANTS. 163 



fl ora I must keep to the flora just now to so many 

 different regions,, or types, as Mr. Watson conceives, 

 but to three, namely, an European or Germanic flora, 

 from the south-east ; an Atlantic flora, from the south- 

 east ; a Northern flora, from the north. These three 

 invaded us after the glacial epoch ; and our general 

 flora is their result. 



But this will cause you much trouble. Before you 

 go a step farther you will have to eliminate from all 

 your calculations most of the plants which Watson calls 

 glareal, i.e. found in cultivated ground about habita- 

 tions. And what their limit may be I think we never 

 shall know. But of this we may be sure; that just as 

 invading armies always bring with them, in forage or 

 otherwise, some plants from their own country just as 

 the Cossacks, in 1815, brought more than one Russian 

 plant through Germany into France just as you have 

 already a crop of North German plants upon the battle- 

 fields of France thus do conquering races bring new 

 plants. The Romans, during their 300 or 400 years 

 of occupation and civilisation, must have brought more 

 species, I believe, than I dare mention. I suspect them 

 of having brought, not merely the common hedge elm 

 of the south, not merely the three species of nettle, 

 but all our red poppies, and a great number of the 

 weeds which are common in our cornfields ; and when 

 we add to them the plants which may have been brought 

 by returning crusaders and pilgrims ; by monks from 

 every part of Europe, by Flemings or other dealers in 

 foreign wool we have to cut a huge can tie out of our 

 indigenous flora : only, having no records, we hardly 

 know where and what to cut out ; and can only, we 

 elder ones, recommend the subject to the notice of the 



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