The Botany of Iceland - 01.12.1930, Síða 53

STUDIES OX 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 lieath 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 liave 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 lieath 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 Scottisli mountains a Grimmia
heath of identical appearance and composition is recorded in Tans-
ley’s Types of British Vegetation, 1911 p. 211.
In Scandinavia tlie Grimmia heath seems to have been replaced
by the Lichen heath.
It holds good of the geographical distribution ofthe
Grimmia heatli as of its distribution in Iceland that it
coincides wilh the position of tlie 20% Ch biochore, and
is peculiar to areas with abundant rainfall.
The Melar Vegetation. Cf. fig 5 and table 10 A-I3.
In the most exposed parts of tiie Grimmia patches the erosion
of the wind in the renls of tlie moss carpet may often be observed.
The single stems of the moss are loosened and carried away to-
gether witli the layer of mould below. The erosion spreads both
downwards and round about in tlie adjacent parts. Ils 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 tlie activity ol' the erosion. When
the mosalhembur vegetalion has been blown away, the wind works
in the same way on the surrounding mo. Consequently large areas
of the most exposed parts of Lýngdalsheiði are swept bare of vege-
tation, especially around Hrólfshólar and Thrasaborgir. These de-
nuded areas, often termed “fell field” in phytogeographical literature,
are called “melar” in Icelandic.
lt is peculiar to melar iti contrast to other types of vegetation
that it is the colour and appearance of the soil rather than the
vegetation tliat determine the physiognomy of the landscape. Ac-