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Circumpolar
Saxifrages in Iceland: On the fringe of the Arctic Circle with its
icefields and lava domes, Iceland, volcanic in
origin lies between 63° and 66° north. Half the size of
Britain and 350 miles north west of Scotland, it has the benefit of the
North Atlantic Drift to help raise the land temperature during the winter,
thereby keeping the climate relatively warm even in its arctic situation. The snow line in some areas is at an
altitude of only 600 to 700 mtrs rising to 1,250 mtrs. in others. The deeply
ridged lavafields cover some 12% of the land
varying from a few feet to hundreds of feet deep and a further
12% of the land is taken up by the mountains covered in perpetual ice.
Vegetation is confined, in the main, to narrow coastal strips. The older lavafields are partially covered in coarse grass and
heather the newer layers at higher elevations are the home for
occasional mossy growths. In spite of the shallow lava soils and
sometimes unhelpful drainage conditions, and with only a short
frost-free growing period, Saxifrages can be seen in the three National Parks
at Jokulsa Canyon, Skaftafell
and Thingveiter. Along the coastline strip on
the eastern side of the island away from the hot springs and sulphurous
geysers, starting at Freysnes northwards Saxifraga aizoides grows
in gravelly soil and cliff crevices. This specie can also be found in
the National Park at Skaftafell on the edge of
the 8,000 sq. kilometres of ice, the Vatnojokull
glacier. Amongst
widely different habitats within a height range of 20 mtrs
at Reykjaves to 800 mtrs.
in the east at Egilsstadir, S. cespitosa is
common throughout the country and is usually found to be either ssp. cespitosa or
ssp. laxiuscula, the loosely
tufted form mainly discovered at lowland levels. In the region of Reykjanes it occurs in dense masses of rough grass. Here the
lava is reduced to a grey, friable soil. S. cernua is
mainly confined to northern and eastern areas in loose, moist soil on
sloping sites at elevations ranging from 20 mtrs. above sea level up to the snowline. Still at low levels
around Eskirjordur it thrives vigorously on the
sides of the greyish black lava, its pale green leaves showing vividly
against the darkish background. S. cotyledon,
the tall, large rosetted, fleshy leaved saxifrage
inhabits areas in the east from Skaftafell
northwards closely following the coastline to Heidarvatn.
At around 150 mtrs above sea level on vertical
cliffs and rock faces its pyramidal inflorescence and flowers with the
widely spaced petals and precise circle of stamens is fairly common in the
locality. Inhabiting boggy
soils near Fijotsdalsheidl S. hirculus is widespread and
the deep golden sprays of flowers show up in the dense mixture of coarse
grass, sedge and other Icelandic ground hugging flora in the lowland areas in
the south. One of the most common saxifrages found on rocky slopes, in stony
gullies and ravines from sea level upwards is S. hypnoides. At Snefellness its white flowers and green veined petals
show up sharply where it grows at 30 mtrs. above sea level along streamsides
and among the small, gritty lava rocks.
S. oppositifolia is
common all over Iceland on rocky outcrops and screes
especially in the central highlands near to the snowline. At Oddskard at around 850 mtrs the
purple flowered plants dot the mountainside In these
areas it faces very little competition from other plant growth other than the
occasional Draba alpina. In scattered
, isolated areas on the east, west and northern coasts a small rosette form
of S. paniculata appears sometimes at
low altitudes amongst fissures in rock faces and on gorge walls, but is a
fairly rare specie in Iceland.
S. rivularis has
a wide distribution over most of the country except in the south
and grows alongside creeks, springs and on moist cliff sides. Most
frequently appears from 250 mtrs upwards. Another very common Saxifrage on the Island is the
sparsely flowered S. stellariswhich
also likes to be near mossy, cold-water springs and streams at lower levels
competing with Caltha minor. At Sprengisawdur it shows its red centred, white
flowers and dark green basal leaves at around 200 mtrs.
The alpine snow
Saxifrage, S. nivalis,
is found on cliffs and in gorges throughout the mountains, not being confined
to any particular area. The snow-white, large flowered S. decipiens is
fairly uncommon and when found is usually sharing stony ground with Silene acaulis ssp. arctica and
is at times confused with the more easily found S. cespitosa.
Saxifraga foliolosa is
another specie with limited sightings in Iceland.
Found at high elevations in damp soil it tends to flower at irregular
intervals, reproducing by bubils at the end of its
pedicels. S. granulata with
its basal bubils inhabits the region in the
Southwest at Reykjavik and is but infrequently seen. S. tenuis, looking
like a small, weaker version of S. nivalis grows
in the high, stony areas near the snowline. The 5cms.
tall S. hyperborea,
similar to S. rivularisbut
with a reddish colour also confines itself to the higher regions,
invariably near moving water above 900 mtrs.
Other than
S. oppositifolia which
has its well known Icelandic form and the S. cespitosa ssp. laxiuscula most
of the eighteen saxifraga species growing in
Iceland appear to mirror those found along the north-west American coast
although some appear to be more sparsely flowered. The
saxifrages growing at the lower levels seem quite content to share the
habitats with grasses, Sedges, Festucas, Clubmosses, Tolfieldia, Arenarias, Salix herbacea and to a much
lesser degree Platanthera hyperborea the
Northern Green Orchid. These plants appear to cover most of the heath areas
where conditions are suitable for this type of vegetation.
J.M. Jan-'98
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