MARINE ALGAL VEGETATION 



65 



SW. and S. Iceland is almost double this. The warm-boreal group 

 is not represented in E. Iceland, and only with extreme rarity (1 

 species) in N. and NW. Iceland. SW. Iceland has only 4 species, 

 while S. Iceland has 8 (10 %>). 



There is a very great similarity between S. Iceland and SW. 

 Iceland, if the arctic group in SW. Iceland is excluded ; on the other 

 hand, the difference is greatest between E. Iceland and S. Iceland, 

 as is shown by the following figures : — 



East Iceland South Iceland 



Arctic group 9 % % 



Subarctic groups 54 % 30 % 



Boreal-arctic group 16 % 15 % 



Cold-boreal group 21 % 45 % 



Warm-boreal group % 10 °/o 



If we assume that the species marked (c) (Table 1) are to be 

 considered as common to all parts of the coast (see above), the 

 distribution ot the 76 not-common species becomes decisive with 

 reference to the floristic difference between the parts of the coast. 

 In the following table, therefore, it is shown how these 76 species 

 are arranged in the six plant-geographical groups of algae. 



Table 5. Group-division of the 76 not-common species (see Table 2). 



A 



E. Icel. 



N. Icel. 



NW.Icel. 



SW. Icel. 



S. Icel. 



B 















Arctic group. 



Arctic group 



8 



5 



3 



2 





Subarctic group I. 



Subarctic group I . . . . 



5 



4 



3 



3 











1 



2 



2 



2 



Subarctic group II. 



Subarctic group II.... 



2 





2 













1 



1 



1 



1 



Boreal-arctic group. 



Boreal-arctic group . . . 

















1 



6 



8 



31 



28 



Cold-boreal group. 



Cold-boreal group .... 





4 















2 



2 



6 



9 



Warm-boreal group. 



Warm-boreal group . . . 

















1 



10 



13 



40 



40 



Total number of species 



Total number of species 



15 



9 + 4 



8 



5 









16 



23 



21 



45 



40 





The figures in this table show what has been already shown 

 by those which I have given in Tables 3 and 4; but the arctic 



The Botany of Iceland. I. 5 



