Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 79

and flói. Along a brook there are several patches with almost pure
C. nigra, where the brook obviously floods when swollen. Dry
banks covered with grass field vegetation adjoin the brook where
the current is strongest. Agrostis stolonifera and Festuca rubra be-
come dominants there, but sometimes there is a liberal springling
of Deschampsia alpina. On ungraded, flat stretches in this mire
tract E. angustifolium — Betula nana —• Vaccinium uliginosrun
sociation 13 often occurs resulting in the almost total disappearance
of mýri species proper. Where the analysis was taken there was
little slope. E. angustifolium is conspicuous there in physiognomy,
but C. nigra has more covering. Analysis 9 is from Vatnsskarð,
niade at approx. 350 metres above sea level. Carices are dominant
there, but some shrubs occur. The area was never harvested, so
that the vegetation is altogether natural.
This sociation shows a significant relationship with Carex Good-
enoughii — Drepanocladus intermedius sociation in Sikilsdalen
(Nordhagen 1943, p. 493). There it is stated i.a. that the sociation
‘has been created by a succession of turf formations by an atrofusca
or a Saxatilis sociation.” But both at Kaldidalur and in Miklavatns-
niýri C. saxatilis is quite noticeable in the adjacent Eriophorum
flói. Still more harmony appears to be between this sociation and
C. Goodenoughii grasmyr (Resvoll — Holmsen 1920, p. 159), con-
fer also Nordhagen 1928, p. 403, which contains a description of
synecology of C. nigra mýri apparently resembling the description
given here. (cf. also Melin 1917, p. 54).
38. C. nigra — E. angustifolium — Vaccinium uliginosum
sociation (Tab. Vffl A-B 1-5)
Observations of this sociation are exclusively from the Flói. On
the other hand it is by no means uncommon in many parts of the
country under similar circumstances, where sociations of mýri and
flói intertwined. The terrain is quite wet and slope at a minimum.
Moss is abundant and Sphagnum is quite conspicuous. It is obvious
that there is a close relationship with the shrub mýri, with the
difference, however, that the shrubs here are in a minority, both
m physiognomy and covering. Apart from the character species
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