The Botany of Iceland - 01.12.1945, Blaðsíða 38

38°
STEINDÓR STEINDÓRSSON
especially in the lower parts of the country. In the highland or the
alpine region it is more distinct on account of the paucity of the aqua-
tic vegetation. Most indistinct is the limit in the vegetation complex
“flá”, which will be dealt with below. The chief plants of the mýri
series are the Cyperaceae, sometimes, especially in the highland, mixed
with Salix glauca; of the Gramineae, Calamagrostis neglecta is the only
species which is fairly abundant, and it is often dominant together
with Eriophorum polystachyum. The ground vegetation (“Botten-
skikt”) varies, but consists almost exclusively of mosses. According to
the moss samples collected by me in different places the following mos-
ses are found and are probably the commonest mosses in these plant
communities:
Amblystegium stellatum
Bryum inclinatum
Calliergon giganteum
„ stramineum
„ turgescens
Camþtothecium trichoides
Cinclidium stygium
Gymnocybe þalustris
Hyþnum aduncum
Hyþnum exannulatum
„ uncinatum
Meesea trichoides
Mnium cusþidatum
Philonotis caþillaris
„ fontana
„ tomentosa
Sþhagn.um teres
Swartzia montana
Considering the mýri series of the lowland, we shall find that the
ground vegetation is always very rich in mosses, while in the alpine re-
gions the reverse is the case. In many places the soil is so sandy that a
luxuriant moss vegetation will never develop there, and the plant-cover-
ing of the ground is therefore never approximately continuous, as may
as a rule be the case in the lowland mýri.
It may be assumed that the snow-covering of the mýri series is
mostly of a moderate depth, on the other hand it must be fairly pro-
longed; and the vegetation of this series has an uninterrupted snow-
or rather ice-covering throughout the winter. In the highland the com-
munities of the mýri series are mainly found on level ground, at the
bottom of valleys and depressions, along rivers, and often formed like
a kind of inland deltas. The mýri series described here agrees with the
moor series of Torne Lappmark defined by F r i e s. The vegetation is
described as composed mainly of xerophilous Cyperaceae and dwarf
shrubs in the “Feldschicht” but of mosses (Sphagnum, Polytrichum,
Amblystegium, and Dicranum) in the “Bodenschicht” (Fries 1913,
p. 51 ff). Two of these genera of mosses are undoubtedly represented
in the formations dealt with here. However, there is hardly any doubt