Rit (Vísindafélag Íslendinga) - 01.06.1975, Blaðsíða 136

iically continuous from the Hvítá estuary and as far inland as the
bridge across Hvítá and it is mostly covered with Carex Lyngbyei.
The so-called Hvanneyrarfit strip constitutes a large part of this
area, which was for a long time the most important meadowland
of Hvanneyri farm. The part of the strip which is closest to the
sea is so low that it used to be flooded by the tidal wave and dikes
had to be built to prevent damage. The vegetation has, however-
long ago lost all traces of the spring floods, apart from the sporadic
occurrence of Puccinellia maritima. The strip was irrigated for a
long time, but out of the irrigating season it was drained with
canals. The first time I saw the Hvanneyrarfit strip C. Lyngbyei
was singularly tall there, in places it reached a height of up to
120 cm and 80 cm was common.
In the summer of 1964 when the analyses were made C. Lyngbyei
was smaller everywhere since the area was no longer irrigated. I
rarely sawr it reach a height of more than 50—60 cm and in many
places it was much smaller. Most of the strip is practically flat
and much of it has been very wet in earlier times. As usual in flæði-
mýri tracts there occur low, rounded elevations or ridges alternating
with shallow depressions. In the vicinity of slopes these elevations
become higher and drier, often finely mound-patterned as com-
monly happens. The species increase in number, but C. Lyngbyei
decreases in abundance although it remains a dominant species in
most places. In this case Equisetum palustre becomes rather pro-
minent in many parts.
Analyses 1, 5, 6 and 7 show the vegetation in a pure C. Lyng-
byei sociation. The species are 1-4. There Calamagrostis neglecta
is a common accompanying species. It may in fact be termed con-
stant and often attains a fairly high frequency, although its quan-
tity is negligible. The other species seem to occur more or less at
random and are inconspicuous. All these analyses are taken from
relatively damp areas and 1 probably represents an area affected
by the tides to some extent. Moss is insignificant everywhere and
in places the ground is bare between the leaves of grass. Analyses
2, 8-9 are made on the low elevations or ridges mentioned before
where the number of species increases significantly, up to 11 in
one analysis, and among them there occur species which could
belong in flói, mýri or even grassfield. A similar could be made
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