PHYSICAL GEOGRAPHY 



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water-saturated tracts, where the ground is becoming drier, are easy 

 transitions to other plant-formations, such as grassland, heather- 

 moor, etc. 



Rocky flats. Of all plant-formations, the rocky-flat-formation 

 occupies the largest area in Iceland, and is the one which characteri- 

 zes by far the greatest part of the island. In favourably situated loca- 

 lities nearest the coast it passes into a "herb- flat" (Urtemark) with 



Fig. 29. Lake near Armuli. with Carex rostrata. 

 (Phot. A. Hesselbo.) 



a dense vegetation of different plants, and with some mosses and 

 lichens; but usually the plants are too scattered to have any influ- 

 ence worth mentioning upon the appearance of the landscape. The 

 vegetation of the rocky flat, which includes a great proportion of 

 all the plant-species of the island, may be divided into many sec- 

 tions according to soil-conditions. On climbing higher up on the 

 plateau we find that species and individuals become fewer in num- 

 ber and more scattered in growth, and as already stated, in the 

 highest parts of the plateau only a few stunted , widely separated 

 plants occur. On rocky flats situated at high levels mosses play 

 an important part, especially Grimmia hypnoides, which gradually 

 forms soil for higher plants; now and then some fruticose lichens 

 are found intermixed with the mosses, and in many places on the 



