The Botany of Iceland - 01.12.1942, Blaðsíða 83

THE PTERIDOPHYTA AND SPERMATOPHYTA OF ICELAND
81
to the influence of the warm Gulf Stream and the cold Polar Stream
respectively, are mentioned on p. 28 et seq.
Another factor which may also in some degree have exercised its
influence on the distribution of certain species is the nature of the soil
in the various parts. Thus several of the species mentioned in the sequel
seem to be confined especially to those parts where the basaltic rocks
are predominant. So far, however, this very interesting problem has not
been subjected to a detailed investigation, and therefore nothing definite
can be said about it here.
Species with a C h a r a c t e r i s t i c Distribution
in Iceland.
As far as is known, Eggert Ólafsson was the first to draw attention
to the fact that E. Iceland had its characteristic species; later on other
authors dealing with the Icelandic flora have made observations on the
same lines, with respect to the other parts of Iceland too.
Below will be found a schematic view of species which show a
characteristic distribution in Iceland, with an indication of the districts
in which they occur. See also the distribution maps in the special part,
and the map fig. 13.
Species occurring in S. Iceland only, or having their main distribu-
tion there:
Arrhenatherum elatius, D. 9.
Festuca pratensis, D. 9.
Glyceria fluitans, D. 1, 2, 10-
Sieglingia decumbens, D. 10.
Carex flacca, D. 1, 7, 9, 10.
Lychnis Flos-cuculi, D. 1, 8, 9, 10.
Ranunculus auricomus, D. 1, 8.
Cardamine flexuosa (? D. 9)
„ hirsuta, D. 1, 2, 4, 8, 9, 10-
Vicia sepium, D. 2, 9.
Valeriana officinalis, D. 1, 3, 8, 9, 10.
Succisa pratensis, D. 1, 7, 9, 10.
Species occurring in S.W. Iceland only, or having their main distri-
bution there:
Isoetes lacustris, D. 1, 2.
Sesleria coerulea, D. 1, 8.
Scirpus setaceus, D. 1.
Polygonum amphibium, D. 1, 2.
„ Persicaria, D. 1, 3, 10.
Cerastium glomeratum, D. 1, 4, 10.
Crassula aquatica, D. 1.
Sanguisorba officinalis, D. 1, 2, 3.
Anthyllis Vulneraria, D. 1, 2, 7.
Hydrocotyle vulgaris, D. 1, 2, 10.
Myosotis collina, D. 1.
Galeopsis Tetrahit, D. 1, 4, 8, 9, 10.
Veronica Anagallis-aquatica, D. 1, 2.
Litorella uniflora, D. 1, 10.
Gnaphalium uliginosum, D. 1, 2, 10.
Matricaria matricarioides, D. 1, 4, 5,
8, 10.
The Botany of Iceland. Vol. IV. Part I.
6