The Botany of Iceland - 01.12.1930, Qupperneq 103

V. THE ICELANDIC HIGHLAND FORMATIONS.
No thorough investigations of the highland vegetation which might
serve as a basis for comparison with the lowland vegetation
and the vegetation in other localities in the highlands having so far
been carried out, I have endeavoured to furnish such a basis by
my investigations. By its geographical position, its height above
sea level, and the grandeur of its scenery, Tvídagra, the highland
plateau w^est of Langjökull, seemed to me best fitted for such a pur-
pose. Hence the investigations described below have been carried
out there, that is, more precisely indicated, in the region round lílfs-
vatn on Arnarvatnsheiði.
Before I proceed to a more detailed descriplion of my own in-
vestigations I shall give an account of w'hat is known about tlie
highland vegetation. The íirst more comprehensive description is
that of St. Stefánsson (1894). On p. 199 Stefánsson writes: “At
the Vatnsdalshals and on the high plateau w7e especially meet with
three formations, viz. the mýri, melar and heather mo vegeta-
tions.” The latter I found best developed in the so-called “Helga-
vatnsnupar”, gravelly heights on the eastern margin of the Vatns-
dalshals. The depressions between these are more or less. and some-
times entirely, covered with a greenish-browm carpet formed of
Empetram nigrnm, Vaccinium uliginosiim, and Betula nana completely
mixed up with each other. Salix herbacea and gtauca also occur
almost everywhere throughout this carpet, whereas Salix lanata
appears only here and there. Loiseleuría procumbens is found in no
small quantity in several places, and Cassiope hgpnoides is met with
here and tliere. In several places the dwarf birch predominates
over the crow'berry (Empetrum nigrum), but as a rule the latter is
dominant. Of other plants I shall mention first Dryas octopetala,
which is hardly ever absent from any Icelandic heather mo, next
l'hymus serpijllum, Polygonum uiviparum, Galium siluestre, Silene