The Botany of Iceland - 01.12.1914, Side 124

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
Svartá (674 metres) were found Archangelica officinalis and Juncus
balticus. At Herdubreidarlindir (471 rnetres), north of the lofty
mountain of Herdubreid, a rather ricli 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
plants1: — Equisetum variegatum, Phleum atpinum, Calamagrostis
stricta var. boreatis, Festuca rubra var. hirsuta, Eriophorum Scheuch-
zeri, Juncus arcticus, J. triglumis, Luzula multiflora, Tofieldia borealis,
Platanthera hgperborea var. major, Salix phglicifolia var. angusti-
folia, S. lanata, S. herbacea, AchiIIea millefolium, Erigeron uniflorus,
Hieracium murorum, Galium verum var. aspera, Thgmus serpgllum
var. prostratus, Bartsia alpina, Pirola minor, Archangelica officinalis,
Parnassia palustris, Cerastium vulgatum, Silene maritima, Epilobium
alsinefolium, Chamœnerium latifolium, and AlchimiIIa alpina. On
Odádahraun itself there are otherwise only extremely small plant-
covered patches. In Hrútsrandir near Kollótta Dyngja (653 metres),
there occurred on a bottom of Salix herbacea a few small individuals
of Polggonum viviparum 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 Dyngjufjöll 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 Odádahraun, but only a few very widely separated desert plants,
and in some places Elgmus arenarius on blown sand. Towards
Bárdardalur the vegetation increases gradually, and the sandy tracts,
as far upwards as 500 metres above sea-level, are covered with
Elgmus arenarius, Salix lanata and S. glauca, and further down-
wards till about 450 metres, Achillea millefolium grows in abnndance
on the sand. In Miklimór between Sudurárbotnar and Alftakíll
(about 450 metres) there is a considerable vegetation of different
kinds of plants and even around Svartárvatn (409 metres) there is
a rather rich vegetation like that on the sandy tracts of the lowlands.
On the north-eastern part of Vatnajökull east of Jökulsá and
close to the glaciers, oases occur —■ separated bv stretches of stony
1 Determined by Prof. Joh. Lange.