24 Proceedings of the Royal Irish Academy . 



Glancing at the maps shoTving the distribution of calcicole and 

 calcifage species, it ■will he seen that, Tv-hile the range of the "Scottish," 

 "Highland" and " Atlantic " plants corresponds broadly "vdth that of 

 the calcifuge flora, the distribution of "English" and "Germanic" 

 species offers many points of resemblance to that of the calcicole group; 

 T^hich facts -n-e should expect to be apparent ^ivhen ve consider the 

 petrological conditions prevailing in the homes of "Watson's various 

 "types." 



So far as I can gather vrithout an elaborate study of the distribu- 

 tion of the flora of Great Britain as known at present (which would 

 be outside the scope of the present paper), there is a greater overlap in 

 northern and southern forms in England than is the case with Ireland. 

 If we construct isophytic lines to represent the limit of the main body 

 of the " Scottish " and " English " floras respectively in Great Britain 

 and in Ireland, they will run somewhat like this : — 



Fig. 12. — Isophs^tic lines in the British flora. 

 AA. Northern limit of the "English" flora, eb. Southern limit of the "Scottish" flora. 



But this statement is only put forward tentatively and as a side- 

 issue of the subject in hand. The material for a proper study of the 



