PHYSICAL GEOGRAPHY 309 



deserts which are as yet very little known, e. g. Thorlaksmyrar, 

 Mariutungur and Eyjabakkar (672 metres). I visited the last lo- 

 cality in 1894 and found there extensive areas covered with Cype- 

 racese, cotton-grass and other plant-growth. In Fjallasveit, east of 

 Jokulsa, a parish situated up on the plateau at an altitude of 400- 

 500 metres, the population of which is solely dependent on sheep- 

 rearing for their sustenance, very large tracts are covered with blown 

 sand which in many places is densely overgrown with Elymus 

 arenarius, Salix lanata, S. glauca and Juncus balticus, while Carex 

 incnrva grows abundantly on damp sandy flats. Near the farm- 

 stead Vidirholl (415 metres) I collected in 1895 the following plants: - 

 Junciis balticus, J. triglumis, J. trifidus, Elyna Bellardi, Carex incurva, 

 C. capitata, C. capillaris, C.vulgaris, C.rigida, C.rariflora, Poa pra- 

 tensis, P. annua, Phlenm alpinnm, Festuca rubra var. arenaria, Cala- 

 magrostis stricta, Trisetum snbspicatum , Selaginella spinulosa, Salix 

 lanata, S. glauca, Saxifraga aizoides, Gentiana tenella, Pleurogyne rotata. 

 North of Hofsjokull, at an altitude of 600 800 metres, similar 

 barren wastes occur, as around Odadahraun, consisting of ice-stri- 

 ated doleritic lava, and here also the individual plants occur widely 

 separated, but, in the neighbourhood of stream and lakes, the oases 

 are larger both in number and size. The vegetation of these oases 

 is generally confined to small swamps and pools and sometimes to 

 rather extensive mountain-bogs; in the pool-vegetation Eriophorum 

 is usually dominant, but sometimes Carices are in the majority. In 

 mountain bogs numerous large knolls (dys) often occur which are 

 usually dry at the top and covered with mosses and various rocky- 

 flat plants, but wet below and overgrown with swamp-plants. Dry 

 tracts between the swamps are generally covered with Grimmia- 

 heaths w r hich sometimes pass into lichen-heaths. Of the oases oc- 

 curring in these districts may be mentioned: Sydri Pollar, Nyrdri 

 Pollar, Geldingaa and Laugafell (with hot springs), and southwards 

 near Sprengisandur, on the eastern side there is Nyidalur, and on 

 the western side Nauthagi and Arnarfell with an unusually luxuri- 

 ant vegetation which has been described by St. Stefansson 1 , who 

 also describes the plant-formations near Laugafell and Geldingaa. 

 In Nydri Pollar (704 metres) I collected in 1896 the following 

 plants: Poa alpina, P. flexuosa, Carex rigida, Eriophorum angusti folium, 

 Salix lanata, S. glauca, S. herbacea, Pedicularis flammea, Tofteldia 



1 Geografisk Tidsskrift, XVI, 1902. pp.230 and 231. 



