Rit (Vísindafélag Íslendinga) - 01.06.1975, Blaðsíða 43

8. E. angustifolium — C. rariflora — Salix glauca sociation
(Tab. III A-B 6-9)
The only available observations are from Eyjabakkar (approx.
700 metres above sea level) and Holtavörðuheiði (approx. 300
metres above sea level), but the sociation is widely distributed
throughout the highland areas, and nowhere have I seen it in as
continuous covering as at Eyjabakkar, because it most frequently
occurs in small patches, e.g. amid Palsamire. It is believed to grow
exclusively in highland areas, as indeed all the wet ground socia-
bons, wherein Salix glauca occurs to any significant extent. It
distinguishes itself from the preceeding, related sociations in the
sence that S. glauca is an important species both in frequency,
physiognomy and covering. On the other hand C. rariflora de-
creases significantly, C. Bigelowii is rather frequent and Poly-
gonum viviparum is constant. A and Ch percentages are high.
As already stated the sociation is rather extensively distributed
at Eyjabakkar near the river branches and only separated by a
narrow strip of fairly dry land. The phanerogamous vegetation is
not quite continuous, the ground which is very damp and partly
covered by Sphagnum, forming small mounds here and there. This
ls almost the sole sociation of the flói in which Sphagnum is present
m noticeable abundance. In other places this sociation is the least
hygrophilous of the flói C. rariflora sociations. It should be noted
that Salix glauca has wide amplitude with respect to humidity.
Analyses no 5. and 6 are made on similar geographical locations,
!t is moister, however, where no. 5 was taken. At both sites the
flói slopes slightly, so that the water is not altogether stagnant.
E. angustifolium is more conspicuous here than at Eyjabakkar, but
Salix glauca is less noticeable despite the fact that it has the same
frequency.
9. E. angustifolium — Scirpus cæspitosus sociation
(Tab. IIIx A-B 1-8)
This sociation has in many respects a unique position vis á vis
other flói sociations. For example it is the only one among them
tvhere Scirpus occurs in some abundance. It is here a character
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