The Botany of Iceland - 01.12.1945, Blaðsíða 70

412
STEINDÓR STEINDÖRSSON
This formation has previously been described from Iceland by
Helgi J ónsson under the name “Græsli” (grassy slopes), both
from the southem part of the country and from Snæfellsnes (1900, p.
66; 1905, p. 36 ff.). However, in the “Græsli” described by J ó n s s o n
there occur a number of species which are absent from the brekkur
formation dealt with here. Thus J ó n s s o n records Anthoxanthum
odoratum, Agrostis canina, and Nardus stricta among the dominant
species of the Græsli, but they are either lacking or very rare in the
brekkur vegetation of the highland. T h o r o d d s e n (1914, p. 335-336)
mentions “Grass-slopes” as parts of the valllendi, which is quite justi-
fiable. In my opinion the brekkur formation described here is an alpine
form of the “Græsli” of earlier authors, but may be regarded as a type
of the valllendi formation. That nevertheless I do not refer the brekkur
vegetation directly to the valllendi is due to its peculiar situation.
Similar formations are recorded from several places in the neigh-
bouring countries. Kruuse (1912, pp. 246-248) describes the Græsli
of East Greenland as follows (translated from the Danish) : “steep...
sloping,... without any constant afflux of running water, with deep-
lying ground-water and a thin permanent snow-covering in the winter...
The grass slopes are found in similar places as the herb slopes. Actually
it only depends on the more or less abundant water supply whether
one or the other of these formations will occupy the space... The snow-
covering of the “Græsli” is low, but constant throughout the winter;
as a rule it does not exceed 20 cm...” As far as I can see, precisely
the same conditions under which the brekkur formation is formed, as
also its relation to the snow-patches, are described here. The “Græsli”
as described by K r u u s e has likewise many species in common with
the brekkur vegetation. Hanna Resvoll Holmsen (1914,
p. 60) describes grass fields on the mountain slopes of Foldal Moun-
tains in Norway which are very similar to the brekkur formation men-
tioned here, merely somewhat richer in species. In my opinion, how-
ever, the formation described by Resvoll Holmsen might in
part be referred to the snow-patches, but in its species composition it
bears great resemblance to Jónsson’s “Græsli”. This author agrees
with K r u u s e that the “grass field requires a constant snow-covering
in the winter” (translated from the Danish). I assume that this is the
case with the brekkur vegetation also. From the Faroes Ostenfeld
describes grassy slopes which correspond entirely to J ó n s s o n’s grassy
slopes in southern Iceland. From the examples added it appears that the