Rit (Vísindafélag Íslendinga) - 01.06.1975, Síða 11

soil or the soil is flooded by it for at least a part of the year.” (Std.
1945, p. 379).
This definition accords in the main with Fægri’s opinion: “Jeg
forstár ved en myr i topografisk forstand ett omráde som uten á
være konstant ápent vann har en til alle árstider höj om en veks-
lende markfuktighet i de övre lag”, (l.c., p. 6) (I understand
the term mire in a topographic sense to he an area which, without
being constantly open water, has at all times of the year a variable
degree of moisture content in the upper layers.)
Sjörs 1971 phrases his definition as follows: “Mires are peat-
forming wet areas. The mire itself is “begrensad ekosystem. Myrar
aro samtidigt báde botaniskt och geografiskt definierad báde som vaxt-
plats och suhstrat för en viss typ av vegetation och som lagerföljd”,
(p. 158). (The mire itself is a delimited ecological system. Mires
are at the same time both botanically and geographically defined
both a growth place and suhstratum of a specific type of vegeta-
tíon and layer sequence.) But he also points out that the peat
layer may be so thin that there is in effect not a peat mire at all,
and also that the peat may remain in the soil although the mire is
drained and the vegetation character of the land undergoes a total
transformation.
If we agree with this paper in considering all wet areas as a
single unit, it is clear that the water content of the soil is a prime
factor which determines its existence, and it must also determine
the classification of the plant communities in wet areas. Scientists
realized this a long time ago. Thus Weher in 1902 classifies mires
according to the “height of the water table” and there he dis-
tinguishes between “aquatic, thelmatic, semi-terrestrial and terres-
trial mire vegetation”. More attention is paid there, however, to
different kinds of vegetation than to exact measurements of the
tvater level itself. It should also be noted in this connection that the
water level in the same area of land as a rule differs according to
seasons and climatic conditions, i.e. variable annual precipitation,
as long as water does not flood the top soil. Therefore Kulczynski
comes closer to the truth when he “regards the change in heigtít of
the relative water level as primary cause of the development of
several different kinds of mires”. (cit. Sjörs, 1950, p. 193). Sjörs
agrees with this as far as the extremity is concerned, i.e. those mires
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