PB0CEEDING8 



OF 



THE ROYAL IRISH ACADEMY. 



PAPERS READ BEFORE THE ACADEMY. 



I. 



ON TYPES or DISTRIBIJTION IN THE IRISH FLORA. 

 By R. LLOYD PRAEGER, B.A., B.E. 



[Read March 15, 1902.] 



Foe the purpose of expressing the horizontal range of flowering 

 plants in Great Britain, H. C. "Watson^ has employed eight " Types 

 of Distribution," which he has named and defined as follows : — 



1. British type — species widely spread through S.M.N. Britain. 



2. English type — species chiefly seen in S. or S.M. Britain. 



3. Scottish type — species chiefly seen in IST. or N.M. Britain. 

 Intermediate type — species chiefly seen in Mid Britain. 



4. Highland type — species chiefly seen about the mountains. 



5. Germanic type — species chiefly seen in East England. 



6. Atlantic type — species chiefly seen in West England. 

 Local species, restricted to single or few provinces. 



Watson is careful to state that in the use of the names for these 

 types he does not make any suggestion regarding the centre of dis- 

 persal or route of migration of the plant-groups which they represent ; 

 he uses them simply to express facts of present distribution. 



Since range in latitude corresponds phytologically to range in 

 altitude, it will be seen that the first five of these divisions are, to- 



1 Cybele Britannica, i. 43 (1847), iv. 409 (1859), and Compendium of the Cybele 

 Britannica, 23 (1868-70). 



R.I. A. PROC, VOL. YIII., SEC. B.] B 



