The Botany of Iceland - 01.12.1945, Page 88

43°
STEINDÓR STEINDÓRSSON
TABLE
showing the species-group and life-form spectra arranged according to
altitude, and, for comparison, the same spectra computed from the
flora in the same altitudinal groups.
I II III IV 5 6 7
A 47-95 72.83 61.66 77-36 59-6 69.2 73-6
E 52-05 27.17 38.34 22.64 40.4 30.8 26.4
A3 20.80 46.23 25-58 41.38 23.6 29.1 35-2
E3-2-1 31 -74 4.23 16.01 2.76 21.7 I I.I 5-5
Ch 29-51 26.14 2i-35 37.12 21.6 25.0 29.2
H 51-69 5°-°3 58.10 40.72 54-9 56.3 53-9
G 17.60 20.43 18.03 20.08 12.4 8.9 11.2
HH 5-2 5-4 3-2
Th 1.20 3.40 2-53 2.08 5-2 4-5 2.2
minority in the flora spectrum; it should, however, be pointed out that
the analyses from Síðumannaafrjettur (XII, i, 2, and 6), which are
from extreme snow-patches, considerably increase the A percentage in
this group. From this we might perhaps draw the conclusion that,
although a more than normal snow-covering at this altitude furthers
the growth of the southern species, the life conditions in the extreme
snow-patches are unfavourable to them. In the other groups, II-IV,
the proportion between the A percentage and the E percentage is in-
verse, the A percentage considerably surpassing the E percentage,
though the A percentage does not increase gradually, group III show-
ing a comparatively high E percentage. If we compare these results
with the flora spectra from the respective altitudes, we shall find that
in group II the A percentage is somewhat higher than in the flora
spectrum, whereas group III shows a much lower A percentage than
the flora spectrum for 600-700 m, while group 4, again, shows a some-
what higher A percentage than the flora spectrum for 600-700 m. This
might show the same as is pointed out by H u m 1 u m (1936, p. 75),
who says: “Only to a certain altitudinal region will a relatively long-
lasting snow-covering favour and foster a vegetation of a pronounced
southem character. At greater altitudes the snow might probably be
able to protect the southem species during the period in which they
do not tolerate the extreme degrees of cold; but at the same time the