Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 32

Calamagrostis neglecta: eutroph-mesotrophic
Salix glauca: eutroph-mesotrophic
Betula nana: indifferent
This survey shows that there is no acidiphilous species there.
Most of them are such that they do not lend themselves directly
to deduction as to the degree of acid content of the soil in which
they grow. Still it is worth noting that two of the most common
species of the mire and frequent constants in both flói and mire,
i.e. Calamagrostis neglecta and Carex nigra, are hoth eutrophic-
mesotrophic, as is Sahx glauca, which is quite constant in highland
sociations of the Eriophorum flói. No truly acidiphilous species
occurs in the Eriophorum flói.
The mosses need not be discussed in this context. It may he
mentioned, however, that among the most common kinds of mire
moss in Iceland according to Hesselbo’s survey there is no acidi-
phile, whereas a majority of them is most closely related to the
eutrophic-mesotrophic groups of the phanerogams, or the neutral
plants as Nordhagen refers to them. Besides I feel that I can safely
conclude that even the Eriophorum flói is not substantially acid
although it is doubtless among those vegetation types in Iceland
which are highest in acid content. Despite some difference in acidity
between isolated areas it is hardly suhstantial enough to exert any
measurable influence on the plant communities with perhaps a few
exceptions. The grormd water level and the snow cover are the
most active factors in determining the grouping of species in vege-
tative areas, as has already heen pointed out, and this does not only
apply generally hut rather also in particular instances where indi-
vidual sociations are involved. I will now proceed to describe these
individual sociations of the Eriophorum flói:
1. Eriophorum angustifolium sociation
(Tab. 1. A-B 1-4)
Studies of this sociation emanate from Melrakkaslétta, one ana-
lysis is from Bolungavík and in all probahility it is not widely
distrihuted in Iceland, at any rate not to the extent of covering
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