Rit (Vísindafélag Íslendinga) - 01.06.1975, Síða 132

and sinks with the river. Thus the flæðimýri soil is continuously
permeated hy fresh water. However weak the current may he it
always seeks the estuary and the flæðimýri water flows continu-
ously in the same direction and never stagnates. The flæðimýri is
therefore topogenous.
I have above roughly described the formation of flæðimýri along-
side rivers and in their estuaries. The same process occurs, hut on
a small scale, where a river or a stream flows into a stagnant lake.
As stated before, this formation is extensive at fiordheads, hut it
is also encountered along the south coast of Iceland, inside the
lagoons which are common along that stretch of coast, and in ex-
tensive areas such as Landeyjar, and to the east of that district in
the vicinity of Eyjafjöll and in Mýrdalur. There, however, the
water has stagnated in places and the vegetation of the flói has
become dominant. A similar formation occurs on vegetation clad
glacial gravel flats, located in Skaftafellssýslur where the Carex
Lyngbyei mýri is less common.
The flæðimýri always has a gentle slope with is, however, suf-
ficient to keep the water moving. The bottom is always submerged
during some part of the year and often throughout the year. In
winter the flæðimýri is usually covered by a sheet of ice. Where
the conditions are favourable, however, it may in srnnmer dry out
to such an extent that it can be traversed without much trouble,
and hay can be dried there if proper care is exercised. There is no
peat formation. A thick and tough turf layer is formed, however,
from the roots and rhizomes of the plants, mostly Carex Lyng-
byei. This may later attain a thickness of 0.5 m or even more.
Immediately below it there is muddish clay, mixed with humus
which is replaced deeper down by pure sand and clay. The sur-
face of the flæðimýri is mostly flat, although it is often charac-
terised by low, flat undular formations whose height is so insigni-
ficant that there is no vegetation difference between them and the
depressions. Sometimes they rise by a few centimetres and as a
result ridges appear which are more or less covered by dry-ground
vegetation. Later on those ridges may become finely mound-pat-
terned; their main species is Equisetum palustre which is also gen-
erally dominant on dry strips along river banks. Often Trifolixnn
repens accompanies Equisetum, and where the banks are most
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