The Botany of Iceland - 01.12.1945, Blaðsíða 58

400
STEINDÓR STEINDÓRSSON
the lowland mýri and the “flá” formation of the highland, which will
be described below. The knolly ridges might then be regarded as cor-
responding to the “rústir” of the “flá”.
This type of mýri resembles the “Revelkárr” mentioned by M e 1 i n
(1917, p. 168). It is in good agreement with Melin’s description
that in places where the inclination is less marked, the knolly ridges are
lower and broader, but where the inclination is more pronounced, they
are higher and narrower, and then the side turning towards the in-
clination has often been removed by erosion; this might apply to the
aforementioned knolly ridges on Síðumannaafrjettur and in Fagridalur.
According to M e 1 i n, this type of mýri is distributed in Norrland,
Sweden, and according to R a n c k e n it is also to be found in north-
ern Finland.
If we consider the distribution of the different associations within
the areas investigated by me, it will be obvious that nearly everyone
of the four regions investigated exhibits its typical associations. It is
likewise evident from the description that there is a closer agreement
between the mýri formations of Brúaröræfi and Landmannaafrjettur
than between the former and that of Snæfellsöræfi, in spite of the
greater distance and probably also the greater difference in climate
between the first-mentioned than between the last-mentioned areas. I
should think that the reason is that both on Brúaröræfi and on Land-
mannaafrjettur the areas of mýri are comparatively small and are, as
a rule, found on level ground. The soil is sandy, and the vegetation is
engaged in a constant struggle against the sand-drift and the desicca-
tion connected with it. On Snæfellsöræfi the areas of mýri are often
much inclined, there is no sand-drift worth mentioning, and the forma-
tion is on the whole much more stable than in the aforementioned
areas.
c. The Dý Vegetation (the vegetation around the springs).
Near the heads of springs and often in a narrow belt along brooks
flowing from springs a special plant formation will develop. This forma-
tion, called dý in Icelandic (dý = spring) never extends over large
areas, but as a rule passes into the surrounding formations when the
distance from the spring or the brook has become so great that the
fresh and cold spring-water loses its influence.
The dý vegetation is characterised by a continuous mossy carpet
composed almost exclusively of Philonotis fontana; Pohlia albicans var.