The Botany of Iceland - 01.12.1945, Blaðsíða 141

THE VEGETATION OF CENTRAL ICELAND
483
Tundra. Sie erheben sich in 2 bis 3 m Höhe íiber das Niveau der
umgebenden Flache und besitzen háufig die Form von Grabhiigeln
[cf. the Icelandic name “dys”]. Die Lángenausdehnung vereinzelter
Torfriicken kann 15-20 m betragen, die Oberfláche ist im allgemeinen
von ebener Beschaffenheit” (Pohle 1903, pp. 80-81). Pohle further
says that the hills are but slightly thawed in the summer, thus in 1899
only 33 cm. Their surface is often devoid of vegetation, according
to the investigations made by Castrén the snow-covering of the
hills is either very thin or lacking in the winter. P o h 1 e lists the fol-
lowing character species from the tundra: the mosses Sphagnum,
Dicranum, and Polytrichum, which mainly constitute the turf of which
the hills are formed; the phanerogams Salix glauca, S. lanata, Betula
nana, Salix herbacea, Arctostaphylos alpinum, Vaccinium uliginosum,
V. Vitis idaea, Andromeda polifolia, Cassandra ccdyculata, and, spora-
dically, Loiseleuria procumbens; the most important, however, is Rubus
chamaemorus, the only species which forms a continuous cover of
vegetation. Furthermore there occur Trientalis europaea, Polygonum
viviparum, Pedicularis lapponica, Bartschia alpinct, Festuca ovina,
Eriophorum vaginatum, Deschampsia alpina, Juncus trifidus, Luzula
arcuata, L. Wahlenbergii (1. c. pp. 82-84). In the depressions, which
only freeze very little in the winter owing to the thick snow-covering,
there grow Sphagnum and various aquatic mosses; the most important
phanerogams are Salix glauca, S. lapponum at the margins of the
“Hiigel”, Carex rotundata, C. rariflora, and Eriophorum russeolum.
Of common occurrence are Eriophorum vaginatum, E. angustifolium,
and E. Scheuchzeri, and in addition various rarer species. These lists of
species bear a close resemblance to the Icelandic flá vegetation. Nearly
all the Icelandic species mentioned are found in the flá, but on the
whole a much larger number of species of southern origin occur in the
tundra of Kanin than in the flá. Furthermore Pohle says: “Das
charakteristische der beschriebenen Tundramoore besteht in der Durch-
dringung zweier verschiedenartiger Facies, einer xerophiler und einer
hydrophiler” (1. c. p. 103).
The difference appearing between the descriptions of tundra men-
tioned here and the flá is not greater than might be expected in view
of the different position and nature of the countries. As far as I can see,
therefore, there are sufficient reasons for referring the flá to the tundra
formation in the same way as has already been done byHannesson.
I shall then give a more detailed description of the vegetation of
the flá. The zonation found in it has already been dealt with, and the