The Botany of Iceland - 01.12.1945, Síða 128

470
STEINDÓR STEINDÓRSSON
an ordinary snow-patch vegetation should have developed here. I as-
sume that the main cause is to be found in the soil. Prior to the ad-
vance of the glacier in 1890 the land area now occupied by the moraine
was covered by a fairly luxuriant vegetation. This soil with all its
organic contents was pushed along in front of the glacier, and the
present terminal moraine is largely made up of these soil remains; this
could be seen from some blocks of earth which lay beside it and which
consisted entirely of turf interwoven with abundant plant remains and
with a good deal of stones and clay. Thus the morainic ridge is
exceptionally rich in organic substances, from which the vegetation
benefits and which gives it the character of manured soil. The abundant
occurrence of mushrooms lends support to the conjecture that the soil
is particularly rich in decaying organic matter.
Inside the ridge lies the ground moraine, in which the other analyses
were made, analysis 6 being made nearest the ridge, the others at
greater distances from it, all at equal intervals, analysis 1 nearest the
glacier’s edge. In the localities for analyses 5 and 6 the vegetation has
the same physiognomy. It is found in large, vigorous tufts, and
Gramineae dominate everywhere. Nearest the terminal moraine these-
tufts are densest and largest, but gradually they grow more scattered
and of less extent. Analysis 5 was made in a place where this decrease
of the vegetation is becoming conspicuous, at a distance of c. 1 km
from the terminal moraine. Here the surface was uneven, though in
a less degree than nearer the front of the glacier, many of the hills hav-
ing been levelled by the action of water and wind. The depressions
found along pools and brooks harbour a special vegetation. There we
find the species of the mýri and flói formations such as Eriophorum
Scheuchzeri, Calamagrostis neglecta, and furthermore Carex lagopina,
C. rufina, and some few Saxifragaceae. Some vegetation of mosses,
especially Philonotis, occurs also. Unfortunately I had no time to
examine this form of vegetation more carefully; I assume, however,
that it is very closely related to the Pohlia—Philonotis-íissocÁíition
described by Fægri from the moraines near Jostedalsbræ (1933,
pp. 72-75, etc.).
The analyses from this moraine were chiefly made in its driest parts,
which are the most widely distributed, so analyses from such localities
give the best picture of the moraine vegetation as a whole. In all these
places the ground vegetation is but slightly developed. Dominant
phanerogams are the grasses: Poa alpina, Deschampsia alpina,
Festuca ovina, and F. rubra; in addition Saxifraga groenlandica and