Rit (Vísindafélag Íslendinga) - 01.06.1975, Síða 84

distribution, but it probably occurs in places on the fertile moraines
in the south and south-east of Iceland.
45. C. nigra — Menyanthes trifoliata — Comarum palustre soc.
(Tab. XIx A-B 5-7)
Analyses 5—6 are from Kaldárholt in Rangárvellir; both were
taken from the same mire tract. In 5, which is the original mýri
(sloping mire) the ground is moderately moist, knolly and with
abimdant moss, including a little Sphagmnn. C. nigra is dominant
in physiognomy and covering, but other species are also notice-
able. Analysis 2 is from a piece of land which had been irrigated
for about 50 years. There the land has become flat, the number
of species has decreased considerably and C. nigra is completely
dominant, although the other character species are also fairly
frequent.
Analysis 7 is from Hrafnkelsstaðir in Mýrar. It is made on the
bank of a small stream where the mýri is comparatively dry, as is
in fact indicated by the presence of the gramineous vegetation. The
land must be subject to inundation, however, when the stream is
high and the whole area is probably flooded in spring. The socia-
tion grows on a relatively narrow strip of land. Apart from the
character species the main accompanying species is Calamagrostis
neglecta. Environmental differences make any comparison of the
analysis and the other two very difficult. The number of species
is average, the HH percentage is high, but apart from that there
is some fluctuation in the percentage of other life forms. Nothing
can be stated as to distribution.
46. C. nigra — Equisetum palustre sociation
(Tab. X. A-B 1-11 and Tab. Xx A-B 1-7)
This is one of the most common lowland-mire sociations in the
country as a whole. In the highlands, however, it is rarely found,
if ever. Observations have been made in all parts of the country
and have shown it to be common everywhere except in the west
fiords where it is not as commonly found as far as my studies indi-
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