GEOGRAPHICAL DISTRIBUTION; LIFE FORM 435 



and Finland, with outlying species penetrating in the south 

 to the Mediterranean and in the north to the White Sea and 

 SeaofMurman. 

 (5) A warm boreal group, the species of which extend as far 

 south as the Mediterranean and Atlantic coast of North 

 America, some perhaps even farther south. Their northern 

 limits are to be found in south Iceland, the Faeroes, north- 

 west Norway and Scotland. 



Although Iceland is so far north, nevertheless the flora is pre- 

 dominandy boreal because 54 per cent belongs to the last three 

 groups. If the different districts of Iceland are compared with 

 neighbouring floras it is extremely interesting to see how the floras 

 of the various parts of the Icelandic coast show resemblances to 

 floras from a number of widely separated areas. 



Since these early studies, additional work has been carried out. 

 Stephenson (1946) has shown how there are different elements in 

 South Africa based on temperature (see p. 341)5 the cold Antarctic 

 current on the west being responsible for the presence of Ecklonia, 

 Laminaria pallida and Macrocystis. A similar cold upwelling on the 

 coast of California enables cold water kelps to grow much further 

 south than they do at corresponding latitudes on the east coast. In 

 recent years an increase of sea temperature has resulted in very 

 poor growth of Macrocystis. The southern limit of this cold up- 

 welling is around Point Concepcion but other upwellings occur in 

 Baja California. By contrast the impact of the Gulf Stream on 

 Great Britain enables a number of Mediterranean and other warm 



