THE IJIU'OPHYTA OF ICELAND 



hions of Grimmia funalis, Hypnum revolutum, Rhacomitrium hete- 

 rostichum and Orthotrichum rupeslre. On the basal and somewhat 

 damper portion of the rock-face there grew Gymnoslomum rnpestre, 

 Philonotis tomentella, Orthothecium chryseum, Hypnum uncinatum, 

 Distichium montannm, Ditrichum flexicaule, Amphidium lapponicum, 

 Pohlia cruda, Bartramia itgphylla, Ceratodon purpurciis, Tortclla tor- 



Fig. 30. Grimmia torquata on one of the sides of Flokastadagil. 



tuosa, Lophozia quinquedcntata, L. quadriloba and everywhere on 

 the ledges large cushions of fruiting Tortula rnralis. 



The two last quoted examples are typical of the vegetation of 

 dry rock-faces. Homalotheciiim sericeum occurs there almost always. 



*/ */ / 



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

 400 500 metres above sea-level, Pterigynandrum is also extremely 

 common, especially in the low land. Grimmia fnnalis is rarely ab- 

 sent and often forms very large and deep, fruiting tufts, 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). 



6. Low, much weathered and fissured basalt rocks 

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



39* 



