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OLAI- GALLOK 



Consequently, 3 sterile fruticose lichens, 4 f'oliaceous lichens (of 

 which 1 sterile) and 3 crustaceous lichens (of which 1 sterile). 



* 



In the districts around Myvatn about Hlidarfjall I noted similar 

 /Jn/as-heaths covering large tracts alternating with bare sand. Here 

 the characteristic plants were also Dry as (F /o 100), Empelnim (F %> 

 100), Glnmiflorce (F % 100) and abundance of dwarf-birches (F o 7(1) 

 and Vaccininm nlit/inosnm (F % 50). What has been said above 

 about the factors which conditioned the life of the lichens in the 

 heaths near Einarsta5ir holds also good as regards these heaths. 

 A fairly rich lichen-covering occurred (F /o 100), viz. fruticose lichens 

 (F % 100), foliaceous lichens (F /o 50) and crustaceous lichens (F % 

 90); but, as may be seen, the larger species preponderate slightly, 

 perhaps in correlation with the fact that dwarf-birches are more 

 dominant here and determine the character of the lichen-vegetation. 



The following species were found : - 



Consequently, 5 fruticose lichens, 2 foliaceous lichens and 1 

 crustaceous lichen. 



The species of lichens are not everywhere the same, but they 

 do not vary greatly. In the neighbourhood of Mvvatn I traversed 

 large tracts of heath, still poorer in phanerogams, where the fre- 

 quency-percentage of the lichens was very great (F % 100) and where 

 the landscape displayed dark patches of blackish-brown lichens 

 (Celrarid isldiidicd, (]. niyricans and C. cornicnlata). Here we might 

 perhaps be justified in speaking of "lichen-heaths," but I think that 

 their contents of Dryas, F /o 100, make such a name superfluous. 



