8S THE STORY OF PLANT LIFE 



zone of moorland associations and a heather whortle- 

 berry association. Above the grass moor comes the 

 true arctic-alpine association made up of the arctic- 

 alpine grassland formation with an abundance of 

 Alchemilla alpina, with Highland species, as in the 

 grassland, and sub-alpine species, with several 

 dominant grasses, and others locally abundant. 



The upper arctic-alpine formations consist of 

 two formations, that of mountain-top detritus, and 

 the arctic-alpine chomophyte vegetation, of crevices 

 and clefts. Here grow cushion plants, mat plants, 

 rosette plants, as Silene, Saxifraga, Sedum. Of the 

 chomophyte vegetation there are several types, such 

 as open communities on exposed rock-faces, associa- 

 tions of sheltered ledges, of shade chomophytes, and 

 of hydrophilous chomophytes, the latter consisting of 

 moss communities and sedge communities. 



The vegetation of the sea coast* consists of the 

 salt-marsh formation, which includes a Glasswort 

 association and a Cordgrass association, a general 

 salt-marsh association, a Sea Manna Grass associa- 

 tion, a Sea rush association (see Fig. 22). 



There are also associations of spray-washed cliffs 

 and rocks, and brackish-water associations. 



The sand dune formation includes an association 

 of strand plants, a Sea Couch Grass association, a 

 Marram Grass association, fixed dune associations, 

 and dune marsh associations. 



* As to the maritime formations consult the works of Prof. F. W. 

 Oliver. 



