715 



is sometimes found perfectly dry. This association may be found 

 covering large stretches of rocks as a dense, moss-like mat, some- 

 times only consisting of Enteromorphce, sometimes of Enteromorphce 

 mingled with Prasiola stipitata etc. 



In some places the latter alg?e, however, grow quite unmixed 

 with any other species, and often carpet the rock wilh a short, dark 



>«».'>;. ■,;|^' 





Fig. 152. Prasiola stipitata— associalion. From rocky coast ne.nr Hojvig. 



(F. B. phot.). 



green covering, as shown in fig. 152. Prasiola stipitata grows as a 

 rule on horizontal or slightly sloping sides of rocks, and prefers 

 places where birds live, especially the summits of rocks under 

 fowhng cliffs. This alga may also be found quite dry. 



Simmons mentions (78, p. 251) an Enteromorpha -iormaiion 

 which, judging from the species mentioned by him, must at any 

 rate partly belong to the Enteromorpha -associsiiion. But on the 

 other hand he also mentions some Cladophora-s\)ecies as belonging 

 to this association; these species, according to my observations, be- 

 long to algae-associations which grow farther down. 



Botany of the Fseroes. 



46 



