STUDIES ON THE VEGETATION OF ICELAND 43 
Rosenvinge records a moss heath from South Greenland (1896, 
pp- 211—214) which, on p. 214, he refers to the Icelandic Grimmia 
heath. On the distribution of the moss heath the author writes on 
p. 213, “All the aforementioned localities are situated in the coastal 
area or not very far from the coast, whereas I have never observed 
such moss heaths in the interior.” The most northerly moss heath 
is recorded from Marrak (63° 25’ N.). In East Greenland and far- 
ther north in West Greenland moss heath does not seem to occur. 
Ostenfeld records Grimmia heath from the Faeroes (1906, 
pp- 116). Here it is peculiar to high mountain plateaus and is 
most abundantly developed in the northern islands. “It is a forma- 
tion which seems peculiar to an insular and chilly climate” (p. 117). 
From the higher regions of the Scottish mountains a Grimmia 
heath of identical appearance and composition is recorded in Tans- 
ley’s Types of British Vegetation, 1911 p. 211. 
In Scandinavia the Grimmia heath seems to have been replaced 
by the Lichen heath. 
It holds good of the geographical distribution ofthe 
Grimmia heath as of its distribution in Iceland that it 
coincides with the position of the 20°/o Ch biochore, and 
is peculiar to areas with abundant rainfall. 
The Melar Vegetation. Cf. fig 5 and table 10 A-B. 
In the most exposed parts of the Grimmia patches the erosion 
of the wind in the rents of the moss carpet may often be observed. 
The single stems of the moss are loosened and carried away to- 
gether with the layer of mould below. The erosion spreads both 
downwards and round about in the adjacent parts. Its downward 
action does not stop until the whole surface is paved with the 
scattered stones dispersed in the layer of mould. In the adjacent 
parts there is probably no limit to the activity of the erosion. When 
the mosathembur vegetation has been blown away, the wind works 
in the same way on the surrounding mo. Consequently large areas 
of the most exposed parts of Lyngdalsheidi are swept bare of vege- 
tation, especially around Hrölfshölar and Thrasaborgir. These de- 
nuded areas, often termed “fell field” in phytogeographical literature, 
are called “melar” in Icelandic. 
It is peculiar to melar in contrast to other types of vegetation 
that it is the colour and appearance of the soil rather than the 
vegetation that determine the physiognomy of the landscape. Ac- 
