MARINE ALGAL VEGETATION 



63 



Rhodo- 

 phycese 



1. The arctic group 7 



2. The subarctic group: 

 Subdivision I 8 



3. The subarctic group: 

 Subdivision II 12 



4. The boreal-arctic group 10 



5. The cold-boreal group. 31 



6. The warm-boreal group 8 



Phieo- 

 phycese 



13 



Chloro- 

 phyceoe 



10 



Cyano- 

 phyceie 



11 species (5.5%) 



= 31 



(15.5%) 



17 



20 



1 



= 50 - 



- (25.0%) 



7 



3 



= 27 - 



- (13.5%) 



12 



1 



= 69 - 



- (34.5%) 



1 



1 



= 12 - 



(6.0%) 



76 



67 



51 



If we divide the six groups into two parts, A: the first three 

 groups, and B: the last three 1 groups, we obtain the following 

 figures: — 



A, 92 species (46%) and B, 108 species (54%). 



The floral district must therefore be determined as boreal, be- 

 cause more than half of the species belong to the last three groups. 

 Of these groups the cold-boreal is the most important because its 

 species form 64% of the total number of species (108) in all three 

 groups. This floral district has not, however, a purely boreal cha- 

 racter, as the subarctic group is rich in species and gives a rather 

 high percentage (41 %). The floral district, then, is characterized to 

 a very high degree by a boreal element, and next by a subarctic 

 element. 



If we consider only the red and the brown algae, 143 species 

 in all, the cold-boreal character is a little more strongly pronounced 

 than the subarctic. The figures are : — Arctic 10 species (7 %), sub- 

 arctic 50 species (35%), boreal-arctic 17 species (12%), cold-boreal 

 56 species (39%) and warm-boreal 10 species (7%). The first three 

 groups have 60 species (42 %), the last three 78 species (58 %). 



If we compare the five divisions of the coast with respect to 

 the number of species in the different groups, we obtain the figures 

 given in Tables 3, 4. 



If, for instance, we select the red and the brown algae (Table 

 4) as a basis, then the difference which exists in the different parts 

 of the coast is very evident. In E. Iceland the arctic group contains 

 the greatest number of species, and this number — if we follow 

 the divisions of the coast in the order of the tables — decreases 



1 The boreal-arctic group is included in the boreal groups, as its species, 

 though common in the arctic district, have a far larger area of distribution out- 

 side this. 



