Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 55

This land is totally level, so that as soon as the lake has been filled
Up water has almost ceased to overflow the terrain. The largest
part of this area is a grassy Eriophorum flói, but where river tribu-
taries dissect it and on the banks of Hvítárvatn flæðimýri tracts
occur in many places. There the succession of the vegetative asso-
ciations may be traced, which will be clarified further in the
chapter on flæðimýri. The sociation in question is a transitional
form, which covers quite extensive stretches of land and appears
amazingly homogeneous. Analysis 14 is from Nauthagi, which has
already been described, and it is entirely formed hy fluvioglacial
deposits. The analysis was made in the vicinity of a geothermal
area. C. Lyngbyei was quite dense there, so that only very few
mdividual Calamagrostis plants occur among the sedge. It is so
tall here that when the observation was made at the end of July
m 1940 it was in most places 60-70 cm. tall and in rivulets and
hollows it reached a height of 100 cm. or more. Analysis 18 is
from the delta area at Eyjabakkar, which is described above. It is
rnade at the bottom of a steep slope, where water seeps down into
the flói, which is quite wet and has a heavier snow cover than
normally occurs in a flói. Finally, analysis 17 is from Fagridalur
m Brúaröræfi made above a mound-pattemed ridge.
What has now been said suffices to indicate that the C. Lyngbyei
■— Calamagrostis sociation belongs to the border between flói and
flæðimýri and is in effect one stage in the development of these
rcgetative areas. Analysis 19-21 are made in a Comarum palustre
rich variant of this sociation, but otherwise it is not different from
fhe others in any significant respects, except perhaps in the sense
that it is more numerous in species. The analyses are from Hvit-
firnes and Nauthagi.
c. Carex nigra flói — Caricetum nigræ
23 Carex nigra — Calamagrostis sociation
(Tab.VA-B 22-23)
The sociation described here does not belong to any flói socia-
fion mentioned, so that it must be considered an independent as-
sociation.
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