The Botany of Iceland - 01.12.1945, Blaðsíða 54

396
STEINDÓR STEINDORSSON
quency percentage of ioo for C. rigida, ioo for Polygonum viviparum,
and 68 for Salix herbacecn described by Resvol 1-H o 1 m s e n is in
good agreement with analyses V, 2-3. Probably the C. rigida-“Nieder-
moore” in Torne Lappmark described by F r i e s are also closely
related communities.
4. Calamagrostis neglecta-Ass., rich in Eriophorum Scheuchzeri.
(Tab. IV. A-B, 1-4).
The two character species are dominants in this association, though
Calamagrostis plays by far the most prominent part both physiog-
nomically and in regard to degree of covering. Other conspicuous
species are: Eriophorum polystachyum, Equisetum arvense, Juncus
balticus, and Agrostis alba. Thus analysis 1 shows a variant very rich
in Salix glauca, Equis. arvense, and Junc. balticus; accordingly it much
resembles the jaðar vegetation. Analysis 2, however, shows a variant rich
in Agrostis alba. Similarly as the mýri association 1, this association is
closely related to the flói associations 6-7. It is found in localities similar
to those of the latter, but only in the drier places, which results in a
greater abundance of species and a more luxuriant moss vegetation
than in the flói. The greater number of the associations rich in Eriopho-
rum Scheuchzeri and Calamaigrostis mentioned here both from the mýri
and the flói formation can be said to be formed on fluvial sandy
ground. That I refer some of these associations to the flói and others
to the mýri, is solely due to the different degrees of humidity of the
soil, the greater abundance of species resulting from decreasing hum-
idity, and the more abundant moss vegetation. Thus the driest localities
belong to the mýri formation, the others to the flói. In the mýri associa-
tions Calamagrostis moreover attains the greatest degree of covering.
As regards the relationship of this association with other plant com-
munities the reader is referred to what was stated about the Eriophorum
Scheuchzeri—Calamagrostis-association under the description of the flói
formation. Of the species groups, A is predominant, which shows a
difference from the flói. H is the dominant life-form, but the HH
percentage is relatively very high, on account of the abundant occur-
rence of E. Scheuchzeri. The HH percentage is lower and the Ch
percentage higher than in the flói spectrum. This association has main-
ly been met with on Brúaröræfi, where it is rather widely distributed;
in addition it is sparsely represented on Landmannaafrjettur, whence,
however, no analysis is at hand. Nowhere does it cover large areas, but