Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 114

62. S. cæspitosus — E. angustifolium — C. nigra sociation
(Tab. XIV A-B 9-11)
The observations are all from the southern part of Vestfirðir.
The sociation is primarily distinguished from the preceding ones
by the fact that C. nigra is dominant here and in most places
more prominent than E. angustifolium. Other species which are
more stable here than in 61 or completely absent there are the
following: Juncus alpinus, Agrostis canina, Selaginella selaginoides,
Carex panicea, C. rariflora, C. microglochin and C. capillaris. Of
the species in 61 the following, on the other hand are ahsent here:
C. Bigelowii, Pinguicula vulgaris and for the most part Calamag-
rostis neglecta. Consequently this sociations may he considered to
be quite clearly distingushed. The percentage of A compared to
other groups is similar to the preceding sociation. The Ch percen-
tage is abnormally high in 9, but otherwise it is low. The H and G
percentage is similar to 61.
This sociation grows on rather dry ground, flat and generally
sloping; the slope is steeper than in 61. Carex nigra and C. rari-
flora are generally more conspicuous in physiognomy than Scirpus.
Eriophorum is nearly always sterile and consequently insignificant
in physiognomy.
63. S. eæspitosus — C. nigra — C. rariflora sociation
(Tali. XIV A-B 12)
Only one observation is available, from Búlandsnes in Beru-
fjörður, but as stated earlier Scirpus occurs to a considerable ex-
tent on peninsulas in Austfirðir, although the Scirpus mire appears
to be much less extensive there than in Vestfirðir. It is a matter
of opinion whether this should not be considered a mere variant
of sociation 61, for all the constant species of that sociation occur
here, the only difference being that Carex nigra and C. rariflora
are dominant species here with the same frequency as Scirpus and
similar in physiognomy and covering. Those species, however, were
rare in 61. The sociation appears to have a fairly large number
of species. The A percentage is higher here than in any other ana-
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