Rit (Vísindafélag Íslendinga) - 01.06.1975, Side 101

ctrum shows a high A percentage, except for analysis XII. from
Hagi where the E percentage is higher. G is the dominant lifeform
everywhere, hut the Ch percentage is generally high, with the
exception of analysis XII. 1-2. On the other hand, the H percen-
tage is low. It may be asserted that despite some fluctuations this
applies as a rule to the whole C. Bmelowii sociation.
This sociation generally occurs where the ground is moist, in
the dampest part of the C. Bigelowii mýri, so that in spring at
least the mýri approximates flói in this respect. During the sum-
mer, however, the mýri is considerably drier. The slope is gentle
and the mounds are usually small. Moss is abundant and the
mounds consist mostly of moss. This sociation in many respects
resembles the flói and C. nigra mýri sociations which are rich in
C. rariflora.
Analysis 1 is from Hagi in Barðaströnd, hut the sociation is
rare in these parts. Analyses 3-7 are all from Gnúpverjaafréttur,
but in the lower reaches of Fossheiði this form of vegetation is
widely distrihuted and very typical. Analysis 4 is from the driest
area, where Bhacomitrium is conspicuous in physiognomy and the
phanerogams grow sparse, but this applies to many where there
is limited occurrence of C. rariflora. Carex saxatilis occurs in ana-
lysis 5, w'here it is in fact independent of the main sociation, he-
cause C. saxatilis grows exclusively in the vicinity of ponds, to-
gether witli Eriophorum angustifolium and C. rariflora which
constitute a separate community. There are only scattered indi-
vidual occurrences of C. saxatilis within the sociation itself. Ana-
lysis 2 is from Nes in Melrahkaslétta, from the shoreline, land-
wards of the gravel bank where it slopes towards a flói tract. Here
the sociation is clearly distinct from those occmring in highland
areas, The species are more numerous and herbaceous plants are
abundant.
Euphrasia frigida and Polygonum viviparum are both so con-
spicuous that it might have been justifiable to regard this as a
separate sociation and name it after these species. Higher up the
sociation merges with the gravel hank vegetation where C. Bige-
lowii is conspicuous everywhere. (Steindórsson 1936 p. 481.) The
sociation is not widely distributed in these parts, occurring only
on a relatively narrow strip of land.
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