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