Rit (Vísindafélag Íslendinga) - 01.06.1975, Síða 92

varies, depending on the slope of the mire, the less it slopes the
more moist the ground. Eriophorum angustifolium is a constant
species although it is not extensively found. The number of species
is average. E group constitutes a clear majority. The H percentage
is fairly high, although G is the dominant life form. The HH per-
centage in analysis 11 is high.
Analysis 11 is to some extent unique. There the ground is so
wet as to approximate flói, the soil is rich in red clay and conse-
quently C. Lyngbyei is conspicuous. The knolls are low, but they
are nevertheless favoured by Scirpus which grows mostly there
together with Equisetum palustre which is fairly frequent on the
knolls, but otherwise insignificant.
50. C. nigra — Agrostis tenuis soeiation
(Tab. XI A-B 5-7)
Observations of this sociation are all from Flói and from at the
border of Miklavatnsmýri. As I have not made any studies else-
where I cannot comment on distribution in other areas, hut in Flói
the sociation tends to grow along a narrow strip on the borderland
of mýri and flói.
Apart from the character species, the following are most con-
spicuous: Calamagrostis neglecta, Festuca ruhra, F. vivipara. The
following are also extensive: Carex panicea, Luzula multiflora,
Polygonum viviparum, Thalictrum alpinum and Cardamine pra-
tensis. Eriophorum angustifolium is fairly frequent, but small, only
a few isolated plants in hollows. Those species indicate less than
average acid content. This sociation is primarily characterised by
the extensive occurrence of Rhacomitrium lanuginosum on the
knolls, but in mires this is normally very rare. This sociation,
therefore constitutes a transitional form to heath. The sociation has
a large number of species and the E percentage is high. H is the
dominant lifeform here, so that the spectrum resembles the C. nigra
— Equisetum palustre sociations 46-47. The Ch percentage, however,
is considerably higher here.
Where this sociation grows the land is so dry as to approximate
heath, the soil is shallow, and peat formation is significant. The
92