Introductory. 



has entered it from one quarter and another at a date 

 posterior to that great Hfeless epoch. This, then, 

 gives rise to a second set of problems, the problems 

 connected with the presence in England of certain 

 stray local t\-pcs, Alpine or Arctic, Southern or 

 Transatlantic, European or Asiatic. Questions of 

 this sort I have raised and endeavoured to answer 

 with regard to two rare English plants in the papers 

 on the hairy spurge and tl''e mountnin tuh'p. 



In short, these little essays deal, first with the 

 evolution of certain plant types in general ; and 

 secondly with their presence as naturalised citizens of 

 our own restricted petty insular floral commonwealth. 



