LICHENS AND THE ROCK FLORA. 



245 



ally brown cups or heads may be found on them. 

 Generally, however, this lichen does not bear any cups. 

 It is to be found on bare wind-swept rocks, or in barren 

 places thinly covered by moss and heather. In the 

 Norwegian Highlands, Cladonia rangiferina colours the 

 landscape a yellow grey, and in the desolate wastes of 



Fig. 31. — Lichens, (i) Cladonia cenotea. (2) C. cariosa. (3) C. squamosa. 

 (4) Gyrophora cylindrica (part only of the rosette is shown). (5) Opegrapha 

 amphotera. (6) Usnea dasypoga. (7) Alectoria jubata. 



northern Siberia and Russia it forms regular " liclien 

 heaths " {flechtenheiden), and really is the main pasture 

 of the reindeer. 



The other Cladonias are divided according to the 

 colour of their cups. These are either a brilliant scarlet 

 or a rich dark chocolate-brown. The height of the 



