The Botany of Iceland - 01.12.1945, Side 39

THE VEGETATION OF CENTRAL ICELAND
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that the moss flora of the alpine region of Iceland is much poorer than
in Scandinavia, which, as stated above, can be ascribed to the effects
of the blown sand.
Of Raunkiær’s life-forms, the geophytes are as a rule predominant,
though surpassed by the hemicryptophytes in the driest localities. In
the early botanical literature on Iceland the mýri series of the high-
land is but rarely mentioned. According to Icelandic usage and in
accordance with earlier authors I divide the mýri series into two main
divisions, the flói and the mýri, and with these the formations dý and
jaðar are then connected.
a. The Flói Vegetaition.
In Icelandic the moistest part of the mýri series is called flói. Most-
ly its surface shows no inclination, so the water of the soil stagnates, and
it is entirely or almost without knolls. It is so damp that the surface is
flooded at any rate for some time of the year. Molholm Hansen
defines the flói vegetation as follows, the best definition given by the
earlier authors: “...the soil is constantly covered with water all the year
round, the surface is level without knolls. The vegetation is very scat-
tered and poor in species and consists almost exclusively of southern
plants. The dominant life-form is G. The hydrophytes and helophytes
likewise attain their maximum development in the flói” (1930, p. 180).
Stefánsson (1894, p. 182) describes the flói as “such level and wet
soil that the water cannot be drained on any side, but remains in the soil
all the year round” (translated from the Danish). Helgijónsson’s
definition (1900, p. 20) is in all essentials identical with that of Mol-
holm Hansen. Finally Thoroddsen (1914, pp. 323-324) describes
the flói as follows: “...the soil is rotten, and more loosely connected...
the water reaches to the surface or slightly above it, consequently here
pools of all sizes abound. Upon the flat surface of the “mýrar” small
cone-shaped knolls usually occur, and in “flóar” water-channels and
swampy holes are often found between the knolls. The vegetation is
far denser and more continuous in the former than in the latter. The
dominant species in the swampy “flói” are: Carex chordorrhiza, Erio-
phorum angustifolium, and Scirpus caespitosus, and frequently occur-
ring species are, C. rostrata, C. saxatilis, C. Goodenoughii, C. limosa,
C. rariflora, and several other Carices, as also Menyanthes trifoliata,
Equisetum limosum, Heleochfiris palustris etc.”
It will be seen that all these authors point out the most characteristic