Rit (Vísindafélag Íslendinga) - 01.06.1975, Page 22

II. THE PLANT FORMATIONS
A. FIói — Level Mire
Definition. Of all mire types the level mire is the highest in
moisture content and therefore it is often difficult to distinguish
between its vegetation and that of aquatic growth proper as will
later be discussed in connection with specific sociations. In my
work on highland vegetation in Iceland (Std. 1945) I have traced
the definitions of older authors on this type of vegetation, and on
the basis of their observations as well as my own I have sum-
marized the definition as follows: The flói as a mire formation in
which the soil is for a part of the year at any rate flooded by water,
which is as a rule stagnant. Flói tracts which have developed on
alluvium, closely related to the alluvial flæðimýri, constitute the
onty exception to this rule. The surface is level or covered with
occasional, scattered mounds. The vegetative cover is continuous
except where the flói is in a transitory phase, when it may be in-
tersected by small pools and grooves. Peat formation is as a rule
abundant in the lowland flói, whereas it is quite insignificant in
the alpine flói, where the soil is very sandy and the decomposition
of the plant rests is very slow. No peat is found in the alluvial flói.
The moss vegetation is rather sparse, especially in the alpine flói.
The vegetation is characterized by Cyperaceae and often by Cala-
magrostis neglecta. Of the life forms the geophytes dominate, but
in the highland flói and in some sociations in the lowland the
hemicryptophytes and chamæphytes occur in abundance, while the
hyvh'ophytes and helophytes attain their maximum percentage in
the flói. Of the species groups established by Molholm Hansen
(1930) it is the E groups, i.e. the southern species, which always
dominate in the flói with the exception of a few alpine sociations.
Distributions: As has already been described the flói is almost
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