THK HRiOPHYTA OF ICELAND 



603 



hions of Griinniid funalis, Hijpimm revohdum , Rliaconiifriiini hete- 

 rostichiim and Orthotnchnm rupestre. On Ihe basal and soniewhat 

 damper portion of Ihe rock-face there grew Gymiwslomum rupestre, 

 Philonotis tomenlella, Orlhothecihm chrijseum, Hijpniiin uncinatiim, 

 Dislichiiim montanum, Ditrichum flexicaiile, Ainphidiiim lapponiciim, 

 Pohlia cruda, Bartramia ityphijUa, Ceratodoii purpurcus. Tortella tor- 



Fig. 30. Griinmia lurqiiata on one of Ihe sides of Flokastadagil. 



tiiosa, Lophozia qninqiiedentata, L. quadriloba and eveiywhere on 

 the ledges large cushions of fruiting Tortula rnralis. 



The two last quoted examples are typical of Ihe vegetation of 

 dry rock-faces. Homalothecinm sericeum occurs there almost ahvays, 

 and is oflen dominant on exposed rock-faces as far upwards as 

 400—500 metres above sea-level, Pterhjijuandriim is also extremely 

 CO m mon,, espccially in the low land. Grimmia funalis is rarely ab- 

 sent and often forms very large and deep, fruiting tufls, and espe- 

 cially in South Iceland G. torquata is exlremely common and often 

 covers large portions of the rock-faces with its irregularly-rounded 

 cushions (Fig. 30). 



0. Low, much \veathered and fissured basalt rocks 

 near Hof in SE. Iceland. On the top of the rocks it was espe- 



