Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 144

ciation followed by an E. arvense — Eriophormn Scheuchzeri so-
ciation in which case the succession may end in a C. Lyngbyei
flæðimýri. In the highland, on the other hand, the transition will
be to a Calamagrostis neglecta flói
Catabrosa
aquatica soc. —> Eriophorum
Equisetum —» Scheuchzeri soc.
arvense soc.
or mýri.
-^Carex Lyngbyei—-flói
—>Eriophorum angustifolivnn soc.
—>Calamagrostis neglecta soc.
-^Carex Lyngbyei flæðimýri
D. Dý — The vegetation of cold springs
Around cold springs, dý, there is usually a small patch with
characteristic vegetation. The same kind of vegetation often occurs
in a narrow strip alongside streams or on their banks. This vegeta-
tion type is always confined to tiny patches and often phases into
adjacent vegetation types without any clear limit, particularly flói
or mýri. It is fairly clear that the characteristic spring vegetation
disappears outside the area directly affected by the flowing water.
There are two factors in particular which characterise the condi-
tions of the vegetation in the cold springs. On the one hand it is
continuously pervaded by flowing water which originates deep down
in the ground, and on the other hand it enjoys a fairly stable tem-
perature all year around. It is therefore cold in summer, but the cold
springs rarely freeze over during the winter, and often they are
sheltered by rooflike snowdrifts which prevent the spring from
freezing over even when the ground is covered with snow.
Moss is the most characteristic vegetation type of the cold springs,
particularly Philonotis fontana; Pholia albicans, var. glacialis is
also common, at least in mountain regions. Apart from those there
are various species of the genus Bryum and the genus Amblys-
tegium as well as others. The phanerogamous vegetation is very
sparse and uniform, but the cold springs are generally visible from
a distance due to the light green colouring of the moss which is
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