The Botany of Iceland - 01.12.1914, Page 120

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THORODDSEN
the lowlands may be mentioned, Carex rostrata, C. lagopina, C. saxa-
tilis, C. rigida, Eriophorum polgstachyum, Luzala arcuata, Salix her-
bacea, Alsine biflora, Papaver nudicaule, Draba nivalis, Arabis alpina,
A. petrœa, Saxifraga cœspitosa, S. oppositifolia, S. nivalis, Epilobium
anagallidifolium, Gentiana nivalis, Sibbaldia procumbens, Gnaphalium
Norvegicum, G. supinum, and others. As already mentioned, many
of the most common plateau-species are distributed on rocky flats
throughout the country, both at high and at low levels; for instance,
Silene maritima is as common along the coast as at the highest
levels in the interior wastes, as also Polggonum viviparum, Cerasti-
um alpinum, Armeria maritima, Draba alpina, Oxyria diggna, and
several others. Therefore, speaking generally, it is not easy to dis-
tinguish the species of the rocky ílats of the plateau from those of
the lowland. The main difference consists especially in the more
scattered growth of the individual plants and their partially stunted
appearance on the plateau; moreover, in the lowlands several spe-
cies are found intermixed with the above, often abundantly, which
rarely appear on the plateau, for example, Drgas oclopetala. Fur-
ther, where the situation is favourable, very luxuriant patches may
occur on the rocky flat of the plateau, at any rate in the centre of
the island below 600—700 metres. As we have already seen, the
altitude of the snow-line differs greatly in different districts, con-
sequently, the characteristics of the plateau vegetation are met with
at different altitudes in different parts of the island. In central Ice-
land the plateau-character often does not begin until at 600—800
metres, but on the northern peninsulas and headlands the plateau-vege-
tation often descends to an altitude of300metres, and in some places
even lower. On the lower-Iying parts of the plateau, especially in
the neighbourhood of large glaciers, from which the melting snow
and ice has not sufficient outlets, there are often found groups of
lakes and extensive stretches of boggy and swampy land with a
luxuriant vegetation of mosses and sedges. Such swampy tracts
are found among other places on Tvidægra (450 metres), in the neigli-
bourhood of Grimstungnaheidi (500 metres), Miklumyrar near Hrep-
par (400—500 metres), Eyjabakkar near Snæfell (650 metres), Fljóts-
dalsheidi (400—500 metres), and several other places. The vegeta-
tion of these plateau-bogs is as yet very little known.
All the highest mountain summits and plateaus are covered with
snow and ice, but along the edge of the plateau and in a few’ places
upon the plateau itself there are several i’ather high mountaín tops