Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 134

annually. It has to be admitted, however, that it often was — and
still is — so wet as to render haymaking difficult; e.g. Oddaflóð
and parts of Safamýri in earlier times. But the mire did not only
yield hay. There was the turf as well, which was formed from
roots and rhizomes. The tm-f was used as a building material and
later for insulating houses. The quantity of vegetation in the flæði
mýri was unaffected, even if it was mown every year and the same
applies to the type of vegetation. I have examined flæðimýxi pat-
ches which have never been harvested and compared them to areas
which were utilized for haymaking without finding any vegeta-
tion difference. Interspersed with the tracts of flæðimýri there are
often rills, ponds and deep pools full of water where the moss cover
completely disappears. C. Lyngbyei grows in the shallow ponds,
taller and dark greener as mentioned before, but there it is often
mingled with Equisetum fluviatile. In the deep pools E. fluviatile
gains the upper hand, sometimes slightly intermixed with Scirpus
palustris, Menyanthes trifoliata and Hippuris vulgaris in which
case Potamogeton, Myriophyllum and Callitriche float on the sur-
face. At this point we are dealing with purely aquatic vegetation.
The E. fluviatile community is however so closely related to the
flæðimýri that it almost becomes part of it, and I cannot recall
having encountered a continuous E. fluviatile sociation except in
the ponds and deep pools of the flæðimýri.
The preceding description is mostly based on observations of
extensive flæðimýri tracts in river estuaries within fiordheads. But
as mentioned before flæðimýri is formed, albeit on a smaller scale,
beside lakes and ponds all over the country. Of course the same
should apply with respect to the highland lakes. But there the en-
vironment seems unsuitable for C. Lyngbyei so that a C. Lyngbyei
flæðimýri is rare in such parts. Instead Eriophorum angustifolium
flói occurs, for example at Hvítárvatn and Eyjabakkar.
There is no plant community in Scandinavia which can be looked
upon as a vegetation form related to the C. Lyngbyei flæðimýri,
but there occur similar wet tracts, at least on the northem coast
of Finland, Alluvialgesellschaften (Kalela). Those Alluvialwiesen
which he describes (Kalela 1939 pp. 302—323) are related to the
Icelandic flæðimýri in various respects and many of the pioneer
sociations are the same, although C. Lyngbyei is absent from their
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