308 THORODDSEN 



In Hvannalindir (656 metres) there occur along small streams 

 a great many grasses and an abundance of tall specimens of Arch- 

 angelica officinalis, but unfortunately I was prevented by a snow- 

 storm from collecting plants there. At Vadalda at the springs of 

 Svarta (674 metres) were found Archangelica officinalis and Juncus 

 balticus. At Herdubreidarlindir (471 metres), north of the lofty 

 mountain of Herdubreid, a rather rich vegetation occurs as a border 

 along springs and branching streams while the surroundings consist 

 of gravel quite bare of plant-life. Here I collected the following 

 plants 1 : Equisetum uariegatum, Phleiim alpinum, Calamagrostis 

 stricta var. borealis, Festuca rubra var. hirsuta, Eriophorum Scheuch- 

 zeri, Juncus arcticus, J. triglumis, Luzula multiflora, Tofieldia borealis, 

 Platanthera hyperborea var. major, Salix phylicifolia var. angasti- 

 folia, S. lanata, S. herbacea, Achillea millefolium , Erigeron uuiflorus, 

 Hieracium murorum, Galiiim verum var. aspera, Thymus serpyllum 

 var. prostratus, Bartsia alpina, Pirola minor, Archangelica officinalis, 

 Parnassia palusiris, Cerastmm uulgatum, Silene maritima, Epilobium 

 alsinefolium , Chamcenerium latifolium, and Alchimilla alpina. On 

 Odadahraun itself there are otherwise only extremely small plant- 

 covered patches. In Hrutsrandir near Kollotta Dyngja (653 metres), 

 there occurred on a bottom of Salix herbacea a few small individuals 

 of Polygonnm vwiparum and Salix glauca and far out on a neigh- 

 bouring lava-stream a single specimen of Taraxacum officinale 

 the only one for miles round. Along some mountain-streams in 

 the south-eastern corner of Dyngjufjoll small patches of a similar 

 vegetation were found, only Salix glauca was far more vigorous 

 here. Otherwise no continuous oases are found in the higher parts 

 of Odadahraun, but only a few very widely separated desert plants, 

 and in some places Elymus arenarius on blown sand. Towards 

 Bardardalur the vegetation increases gradually, and the sandy tracts, 

 as far upwards as 500 metres above sea-level, are covered with 

 Elymus arenarius, Salix lanata and S. glauca, and further down- 

 wards till about 450 metres, Achillea millefolium grows in abundance 

 on the sand. In Miklimor between Sudurarbotnar and Alftakill 

 (about 450 metres) there is a considerable vegetation of different 

 kinds of plants and even around Svartarvatn (409 metres) there is 

 a rather rich vegetation like that on the sandy tracts of the lowlands. 



On the north-eastern part of Vatnajokull east of Jokulsa and 

 close to the glaciers, oases occur separated by stretches of stony 



1 Determined by Prof. Joh. Lange. 



