Rit (Vísindafélag Íslendinga) - 01.06.1975, Síða 45

same predisposition to the formation of mosaics of sociations, which
appear wherever the mounds are slightly more elevated.
10. E. angustifolium — Carex dioica sociation
This sociation is extremely rare, although C. dioica fairly often
occurs in Eriophorum flói tracts, hut it is seldom found in such
ahundance that it characterizes the vegetation. The only observa-
tion which I have made of it without an analysis, however, is from
Thórðarhöfði in Skagafjörður. In the northernmost part of Thórðar-
höfði there is an Eriophorum flói, which is relatively dry for a
flói tract, but it contains water, which is ohviously stagnant. Along-
side the flói there is a border where Deschampsia cæspitosa is a
dominant species. The following species occurred in the sociation
in addition to the character species, which appeared to have similar
covering: Calamagrostis neglecta, Carex Halleri, C. panicea, Betula
nana, Festuca rubra, Polygonum viviparum, Salix herbacea, Thalic-
tcum alpinum.
11. E. angustifolium — C. Bigelowii sociation
Although I do not have an analysis of this sociation it is fairly
widely distributed in the highland areas, particularly in the lower
heaths above Húnavatnssýsla: Aðalbóls- and Víðidalstunguheiði. On
Aðalbólsheiði there are extensive flói areas with E. angustifolium
■— C. rariflora sociations, which in parts merge into an almost pure
C. rariflora sociation. But in the drier areas there is so much C.
Bigelowii that this sociation becomes predominant in the vegeta-
tion. Much the same applies to Víðidalstunguheiði, but where I
niainly observed this sociation there occurred amidst the flói tracts
quagmires with hog iron, where there was a scattered growth of
Carex Lyngbyei, although it could not be a constant species there.
C. rariflora was quite conspicuous and Equisetum palustre occurred
°n the mound ridges.
My paper of 1945 contains one analysis of this sociation from a
Palsamire in Eyvindarver. The two character species are domi-
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