756 



seen how the lamina of the Laminnrin hijperboren was sucked into 

 the waves and kept swaying to and fro when they rushed over 

 the rock; it is certainly exposed to a very strong pvill here. But 

 Laminaria hijperborea is excellently constructed for resisting this 

 attack of the sea, its stalk being bolh thick and stiff at the bottom 

 but becoming thinner and more elastic towards the apex, so that 

 the flexible lamina can easily follow the motion of the water. It 

 is firmly atlached to the bottom by aid of the strong haplera. It is 





■,m^ 



'^åF 



Fig. 160. Laminaria hiipcrborca with nunicrous epiphytical lUiodijmenia palmata rising above the surface 

 of the sea at low tide. Illustration from the neighbourhood of Thorshavn. (F. B. phot.) 



a well-known faet to anyone who has dredged among the Lami- 

 naria hijperborea, that only by a very strong pull, or by the teeth ot 

 the dredge cutting through the haptera more often through the stalk 

 itself, can the plant be torn from the bottom. I have often Iried 

 from a boat to pull up the planls that grew in shallow water, 

 but I have hardly ever succeeded in loosening them without cutting 

 through the haptera. Thus the plant may resist a very strong pull 

 without being detached from the bottom. Its gregarious growth also 

 helps to protect it from the attack of the sea. 



This association covers large areas with an almost unmixed 

 growth of its characteristic alga. It would therefore look very uni- 

 form but for the very luxuriant subvegetation of epiphyles, mainly the 



