Flóra: tímarit um íslenzka grasafræði - 01.02.1964, Page 51

rare, and here only some pioneer sociations are described; tliese are: Eriophorum
Scheuchzeri soc., 16, and Catabrosa aquatica soc., 17—18. With further development
of the vegetation, these sociations will change with intermediate stages into either
Eriophoretum angustifoliae or Caricetum Lyngbyei.
The bog vegetation (mýri). This is a drier formation than the two previously
described. Tiie water is not stagnant and the surface is more or less knolly. The bog-
vegetation is richer in species than the swamp, especially in mosses. The following
associations are described: a) Caricetum nigrae, soc. 19, b) Caricetum rariflorae, soc.
20—21, c) Caricetum Bigelowii, soc. 22—25. Of these the C. Bigelowii ass. has by far
the widest distribution, and it covers almost as large an area as the Eriophorum an-
gustifolium ass. Often shrubs, sucli as Salix glauca, are conspicuous, and the bog
thus goes over into the heath formation without sharp limits. The C. nigra ass. and
the C. rariflora ass. are both of little importance in the highland vegetation, espe-
cially the former.
The marshborder vegetation (jaðar) is only found as a small strip on the border
of the wet formations. It is an intermediate formation between the marsh vegeta-
tion and the heath vegetation. Three sociations are described here, 26—28. The first
witli small slirubs like Empetrum, Vaccinium and Salix as dominants, tlie second
with Juncus balticus dominant and the third with Calamagrostis dominant.
The meadow vegetation (valllendi). In this formation, Graminéa and Graminé-
like plants are dominant. It is of a rather small distribution in the highland. The
soil is dry, sometimes sandy, ancl the surface is level as a rule. There are two sub
formations, the grassland (valllendi) ancl the (hillsides (brekkur). In the true grass-
land formation the following associations ere described: a) Festucetum rubrae, soc.
29—34, b) Anthoxanthetum odorata, soc. 35, c) Deschampsietum caespitosae, soc. 26,
d) Deschampsietum flexuosae, soc. 37, e) Caricetum Bigelowii, soc. 38. The last as-
sociation should probably rather be classifiecl as a marshborder association. Of these
associations the Festucetum has the widest distribution.
The hillside vegetation. Only one association is described, Kobresietum myosu-
oides which is almost the only association found in this formation. It is closely re-
lated to the heath formation, and goes over into Rhacomitrium heath in exposed
localities.
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TÍMARIT UM ÍSLENZKA GRASAFRÆÐI - FlÓra 49