196 



OLAF GALI.OI 



It must be borne in mind that Iceland is peculiar owing to 

 its great abundance of natural, free-growing pastures, both damp 

 meadows, devoid of lichens, and drier lichen-bearing areas, whilst 

 Denmark is almost devoid of uncultivated pastures, for damp mea- 

 dows are frequently more or less cultivated (drained, etc.), and most 

 of the other grasses are under intensive culture, entering into the 

 regular rotation of crops. Consequently, the lichen-bearing areas in 

 Denmark are very small and contain, according to my observations, 

 only about 16 lichen-species, vi/. 12 fruticose (CAadonm rangiferina, 

 C. rangiformis, C. uncialis, C. furcata, C. gracilis, ('.. s(]iiamosa, C. 

 pyxidata, C. fimbriata, C. Floerkeana, C. cocci fera, (lelraria aculeata, 

 and Stereocanlon paschale), 2 foliaceous (Cetraria iiivalis and Peltigera 

 canina) and 2 crustaceous (Sphyridiu.ni byssoides and Lecidea uli- 

 ginosa). 



The relationship according to percentage is consequently as 

 follows: 



As seen from the lists, the species are not the same, although 

 several are common to both countries. But the most conspicuous 

 difference is that which has regard to the growth-forms, Iceland 

 having a very great number of crustaceous lichens - - which appear 

 to play rather an important part as regards the plant-physiognomy 

 viz. 33 %>. This undoubtedly indicates that the competition 

 between grass and lichen results rather in favour of the lichens in 

 Iceland, than of those in Denmark; that is to say, the presence of 

 the great number of crustaceous lichens is not due either to climate 

 or soil, but to a less keen competition. 



Consequently, if we are to sum up in a few words a comparison 

 between the lichen-vegetation of the Danish and Iceland grass-areas, 

 we must say, that Iceland has the greater number of species, 24 

 as ;ii>ainst 16 Danish, Iceland has 11 fruticose lichens, ."> foliaceous 

 lichens, and 8 crustaceous lichens, while Denmark has 12, 2, 2 



