TJl' OLAF GALL0E 



Lecidea pantlicrina. Lecidea data. 



cyanea. Bhizocarpon geograpbicum. 

 erratica. ^eminatum. 



speirea. Caloplaca vitellina. 



lapicida. Physcia aipolia. 

 elaeochroma. 



Occasionally there also occur mixed with the above: Racodium 

 rupestre, Poly blast ia hyperborea, Acorospora Heppii, A. fnscata, Catil- 

 laria alhallina and a few foliaceous lichens fParmelia lanata. Gym- 

 phora cylindrica and G. erosa). 



This association grows from the coast where it begins a 

 short distance above the Verrucaria-loell - - to far up the mountains, 

 where it stops at the snow-line. As regards its luxuriancy at various 

 heights above sea-level, very little is known, but it appears to be 

 least developed at great altitudes. I myself had a distinct impres- 

 sion of this for instance from my observations on the mountain 

 Sulur near Eyiafi6r5ur and the mountains near Husavik (on the 



mf v v \ 



north coast), and H. Jons son states the same as regards the con- 

 ditions on Snaefellsnses ; he writes: "The same is the case with the 

 crustaceous lichens as with the phanerogams; they occurred ex- 

 tremely sparsely on the stones in the upper part of the rocky flat." 

 The association is quite absent from the pebbles on the shore: it 

 cannot endure inundation by salt water. 



The Staurothele-asso elation occurs almost exclusively by 

 waterfalls, where it forms black crusts on the rocks in all places 

 where the spray from the falling water reaches. It is extremely 

 characteristic of all such localities. Mixed among the slender, black 

 lhalli of Staurothele occur crust-like thalli of various Cyanophycece, 

 so that it is often difficult to decide which of them is the more 

 abundant. I have never found any other species of lichen directly 

 connected with this association, which therefore contains only the 

 one species Slaurothele clopima. 



The Caloplaca-association (Placodium stramineum, P. alpho- 

 placum and Caloplaca innronim), which on Bornholm (Denmark) 

 is so common on the shore above the Verrncaria-belt, is very little 

 developed in Iceland. I found only slight indications of it in SeyiTis- 

 IjoiAiu. Helgi .lonsson records it from West Iceland. 



The Verrucaria-association, formed by V. nmnra and an 

 inconsiderable quantity of Lichina con finis, which is well-known 

 from Bornholm and from all the other rocky coasts of the North, 

 is ;i|so found in Iceland, where it borders the sea-shore from high- 



