996 



other hånd it is very economical in its vegetative development. It 

 is probably self-pollinaled. 



b. The alpine-bog formation. 



The depressions of the mountain-plateaux will naturally receive 

 water from their surroundings, and in the event of the drainage 

 being defective, a small tårn or a bog will be formed. There are, 

 however, few tårns on the plateaux, and their vegetation does not 

 difler essentially from that of the small lakes of the lovv^er regions, 

 except that it is still poorer. 



Bogs on the other hånd are of more common occurrence, al- 

 though they play quite a subordinate part when compared to the 

 numerous bogs of the lowland. The upland bogs as a rule closely 

 resemble the lowland, and only those situated at the highest alti- 

 tudes show a slight variation in their composition. The vegetation 

 of the lowland bogs has already been described, so that we need 

 only add some notes on the upland form. 



The chief difference between the alpine bog and the ordinary 

 bog or swamp is the occurrence of Careæ piilla on some of the 

 islands, as the dominant species in the alpine. 



Examples of the alpine-bog formation (Eriophorum-Carex-pulla 

 a ssocin t ion): 



1. l^ejafjæld on Ostero; flat stretches at about 400 and 360 ni. 

 above the sea. Nakcd rocky ground with depressions occupied by bog- 

 vegetation or pools. Eriophonim polystachyiim and Nardiis alternate as 

 dominant species; Carex pulla is subdominant, forming now and Iben 

 pure growths in shallow moist hollows. There is also much Grimmia 

 hypnoides and a great many large tufts of Sphagnum. Scirpus caespi- 

 tosus may occasionally be a dominant species. 



2. The pass (Skard) above Fuglefjord, Ostero, about 495 m. 

 altitude. An extensive wet flat, parts of which are grass-moor associa- 

 tion with Nardiis, Jiinciis squarrosus, Grimmia and in piaces Scirpus cae- 

 spitosus; part of the area is a swamp vegetation of Eriophonim and 

 Sphagmim ; Carex pulla is subdominant in both of tliese associations, 

 but it also forms small pure growths along with Carex Goodenoiighii. 



Carex pulla is a medium-sized sedge with a distinct capacity 

 for wandering. It resembles Carex Goodenoiighii as regards shoot- 

 structure and method of wandering. It is not common, except in 

 the mountains of Stromo and Ostero. 



With the exception of the occurrence of this sedge, the peculi- 

 arities of the alpine bogs in comparison to those of the lowland 

 are mainly negative. Quite a number of species of the ordinary 



