Rit (Vísindafélag Íslendinga) - 01.06.1975, Blaðsíða 100
had then investigated, feeling that it was too difficult to distingu-
ish hetween them. But now that I have made more investigations
I have undertaken to separate the sociations as they occur under
different conditions and are distinguished by a number of species,
although they do have many species in common. It should be made
clear, however, that the individual observations where Sphagnum
or Rhacomitrium occur should probably have been classified as
separate sociations despite the species of phanerogams which they
have in common with the sociations dealt with here.
55. C. Bigelowii — C. rariflora sociation
(Tab. XII A-B 1-7 and Tab. XIIIx A-B 1-4)
Most of the existing observations, or 7 in all, are made in the
mountain pastures of Árnessýsla, two originate in the west fiords
and one in Snæfellsnes and Melrakkaslétta. Apparently this so-
ciadon is more widely distributed in the southern part of the cotm-
try. I have not, for example, observed it anywhere in the east-
ern part. In the West fiords it mostly occurs in small patches
on iedges and in dells near the border of the highland, but in the
mountain pastures of Árnessýsla it often covers substantial areas.
Of the sociations belonging to the C. rigida mire this one is most
closely related to Eriophorum and C. rariflora flói. C. rariflora is
conspicuous everywhere and in places it has more covering than
C. Bigelowii. Of other species Polygonum viviparum deserves first
place; it is constant in the whole C. Bigelowii association. Other
main species are: Calamagrostis neglecta, Salix herbacea, Vacci-
nium uliginosum, Equisetum arvense, E. palustre, Eriophorum
angustifolium and Salix glauca. None of the above-mentioned spe-
cies are characteristic of this sociation, except C. rariflora which
distinguishes it from other C. Bigelowii sociations in which it is
almost nonexistent. E. angustifolium and Calamagrostis neglecta
are also more common here than elsewhere in the C. Bigelowii
mýri. This is a clear indication of affinity to flói which separates
this sociation from other sociations of the C. Bigelowii mýri. There
is a similar number of species in all the sociations of the C. Bige-
lowxi mýri, from 7 to 14 in a single analysis. The biological spe-
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