The Botany of Iceland - 01.12.1945, Blaðsíða 102

444
STEINDÓR STEINDÖRSSON
have been erected here. I have preferred, however,to separate too few,
rather than too many, associations in order to obtain greater clarity.
The Salix—Empetrum-associaúon has high A and Ch percentages,
the latter here attains a maximum in the shrub heath. Moreover, Th
are more abundant here than in the other associations.
The individual analyses will now be treated in detail. Analysis
XIV, i is from Fagridalur, XIV, 2 from Kringilsárrani. Both were
taken in level, nearly horizontal localities probably with an inconsider-
able snow-covering. Analyses XIV, 3-4 are both from Kringilsárrani,
from the lower part of the slope; here the abundant occurrence of
Dryas octopetala is noteworthy, so we might speak of a Dryas variant.
The snow-covering is inconsiderable. Analyses XV, 1-2 are from Snæ-
fellsöræfi, from localities with a somewhat knolly surface, but almost
without inclination. There is no noteworthy difference between the
vegetation of the knolls and that of the depressions except that in the
latter the vegetation was somewhat denser than on the knolls. In these
localities Vaccinium uliginosum and Cassiope hypnoides are present
in large numbers, in analysis XV, 2 Loiseleuria procumbens is among
the dominants, and the same is the case in XV, 6. Here we aré con-
cerned with a similar type of heath to that described by Humlum
(1936, pp. 65-66) ; I can see no reason, however, to distinguish be-
tween the vegetation of the knolls and that of the depressions. Analysis
XV, 3 is from Háls near Snæfell. It was carried out on a level plain
at the base of the mountain. Analysis XV, 4 is from Eyjafell, taken
in a slightly sloping locality with a southern exposure; Grimmia heath
was found on the hill nearby. In the two last-mentioned localities the
snow-covering is thicker than in the preceding ones. Analysis XV,6 is
from Víðidalur, c. 500 m above sea-level. Here Loiseleuria is very
conspicuous, Empetrum is likewise more conspicuous both physiognom-
ically and in regard to degree of covering than Salix, the reverse of
what is otherwise the case in this association. The vegetation in this
locality is very similar to the mó vegetation as it occurs in the lowland.
Analysis XVI, 7 is from Geldingsá, from an altitude of c. 670 m. It
was made in a locality sloping towards the south. Cetraria is found in
the ground vegetation, but still the phanerogamous vegetation is quite
closed.
5. Salix glauca—Elyna Bellardi-Ass. (Tab. XIV. A-B, 5).
The community represented by this one analysis should possibly
be treated as a variant of the preceding association in spite of the