196 OLAF GALLGE 
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, viz. 12 fruticose (Cladonia rangiferina, 
C. rangiformis, C. uncialis, C. furcata, C. gracilis, C. squamosa, C. 
pyxidata, C. fimbriata, C. Floerkeana, C. coccifera, Cetraria aculeata, 
and Stereocaulon paschale), 2 foliaceous (Cetraria nivalis and Peltigera 
canina) and 2 crustaceous (Sphyridium byssoides and Lecidea uli- 
ginosa). 
The relationship according to percentage is consequently as 
follows: — 
| Fruticose | Foliaceous | Crustaceous 
lichens lichens lichens 
Danish lichen-bearing grass-areas (in dunes, etc.) 75 °/o 13770 | 13% 
Icelandic — PAR rennes | 46 % 21 % | 33 °/o 
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 against 16 Danish, Iceland has 11 fruticose lichens, 5 foliaceous 
lichens, and 8 crustaceous lichens, while Denmark has 12, 2, 2 
