The Botany of Iceland - 01.12.1945, Page 83

THE VEGETATION OF CENTRAL ICELAND
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E percentage is high though the A-groups are in the majority. H dom-
inates among the life-forms. The two analyses were taken in Kýlingur
on Landmannaafrjettur in localities with a distinctly southward ex-
posure, analysis 6 c. 600 m above the sea, analysis 7 c. 100 m higher,
which is possibly the cause of the high Ch and A percentages of this
analysis. The association is widely distributed in Kýlingur up to 700 m
above the sea, both on the east and the south side of the mountain.
The snow-covering in these snow-patches is much deeper than in the
Geranium association. The Alchemilleta described by B ö c h e r (1933,
pp. 28-36) are very closely related to this association but somewhat
poorer in species. The Ch percentage is much lower than here, at any
rate as regards Alchemilletum filicaulis.
8. Salix glauca—Carex rigidat-Ass. (Tab. XI. A-B, 5-6; XII. A-B, 2).
This association resembles the shrubby heath in many respects. It
is less rich in species than the snow-patch associations mentioned so far.
Its A and Ch percentages are high. On the other hand it is found
in localities where, judging from the terrain, there must be a con-
siderable snow-covering, and several of the dominant species of the
association are undoubtedly snow-patch species. In addition to the
two character species, the following species are of importance: S.alix
herbacea, Polygonum viviparum, Festuca rubra, Taraxacum croceum,
Equisetum variegatum, E. arvense, Pyrolct minor, and Euphrasia laíi-
folia; several of these species occur chiefly in snow-patches in the
highland.
Analysis XI, 5 is from Víðidalur, altitude c. 550 m above the sea.
The snow-patch was not deep and had a southward exposure. It is
adjacent to the Grimmia heath, but at this altitude the boundary be-
tween the brekkur vegetation and the Grimmia heath occurs in Víðidal-
ur. At this height the snow-patch vegetation, also, changes. The
Geranium associations disappear, while the present association occupies
their place in the snow-patches that are not very deep; the Salix
herbacea—Sibbaldial-associaúon dominates in the deepest snow-patches
at this and higher altitudes, especially at 700-800 m, where it is the
only snow-patch association. Analysis XI, 6 was made on Snæfellsöræfi
near Laugar. The locality is a sheltered depression southwest of a low
hill. This kind of snow-patches are very common on Snæfellsöræfi,
where the association is by far the commonest, but at greater altitudes
it is replaced by the Salix herbacea association. In a few places with
The Botany of Icland. Vol. III. Part IV.
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