Rit (Vísindafélag Íslendinga) - 01.06.1975, Síða 118

in covering. Both of them were similar in quantity. There the so-
ciation covered a fairly large area. It might be more correct to
regard it as a variant of the Scirpus cæspitosus as sociation, instead
of classifying it as an independent association, although this is done
here.
b. Equisetum mýri — Equisetétum palustris
The fourth main association of the Icelandic mires is Equisetétum
palustris. It is widely distributed in many parts of the country,
hut does not occur as widely as the Carex nigra mire although
their distributions is similar in some regions. Those two associa-
tions are so closely related that it is sometimes difficult to distin-
guish one from the another, the same species being dominant in
both; i.e. Equisetum palustre and Carex nigra. I have adopted the
following method of classification. When Equisetum palustre he-
comes more prominent both in covering and physiognomy I regard
the association as an Equisetum mire. It always characterises the
topography whereas C. nigra is inconspicuous, but on close ob-
servation it tums out to he high in frequency. The gramineous
vegetation is always more prominent in the Equisetum-mire than
in the C. nigra mire. Thus is presents a transitional stage between
Carex-mire and Graminé-mire. It is hard to determine differential
species beyond what has already been said ahout the gramineous
vegetation. The Equisetum-mire abounds in species and it is gen-
erally grassy like the C. nigra mire, but here the grass in usually
more lush. It generally occurs in comparatively dry areas, often on
the border of mire tracts which can be either Carex mýri or flói.
The ground is always somewhat sloping so that water never stag-
nates. The surface is pattemed and there is some difference in
vegetation between the mounds and the hollows, except in the
driest spots. E. palustre grows on the mounds together with grami-
neous vegetation, but Cyperacea occurs in the hollows. The gra-
mineous vegetation is evenly distributed in the drier areas, but E.
palustre always tends to favour the mounds. The Equisetum-mire
has been much utilized for haymaking purposes which probably
explains in part why scrub-plants occur so rarely there. Scrub-plants
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