Fróðskaparrit - 01.01.1993, Blaðsíða 93

SALIX IN THE FAROE ISLANDS AND THEIR AFFINITY WITH THE POPULATIONS IN ICELAND 97
less ascending shrub, but can be almost
prostrate in difficult conditions. Mature
leaves on Salix arctica are glabrescent al-
though there are often exceptions, and the
short wavy trichomes on the leaves of “the
eastem phase” of Salix glauca are never
found in the Icelandic material. The catkins
on Salix arctica are usually much longer,
with looser inflorescences and longer cap-
sules with reddish hue.
After studies in field and examining cul-
tivated samples it is clear how much the
populations in Iceland and the Faroe Is-
lands differs from Salix glauca, whether
compared with the populations in Scandi-
navia and Central Europe (The Central Eu-
ropean population is often considered as a
species, Salix glaucosericea B. Flod.) or
“the eastem phase” in North America and
Southeast Greenland. Nevertheless it is not
to be overlooked that Salix arctica and S.
glauca are related species. In North Amer-
ica and Greenland populations of interme-
diate character have since long mused those
who have tried to separate these species
(Simmons, 1913: 69-72; Flodems, 1923:
97-99 and pp. 121-157; Bocher, 1938: 63-
66; Polunin, 1940: 157-159 and pp. 162-
166; Scoggan, 1978: 263; Argus, 1965:
96). Whether the problems are due to hy-
bridswarm, introgression or to the fact that
the distinction between the species is not
sufficiently analysed is uncertain, but more
extensive studies are needed and most like-
ly there are different conditions at the vari-
ous places where the species meet or over-
lap.
In Iceland however the population has
been geographically isolated for such a
long time that possible hybridisation or in-
trogression in primeval times or before the
species colonized the country should since
long have coalesced, and today it is impos-
sible to regard the population otherwise
than one species. The population in the
Faroe Islands is of the same origin and sim-
ilar, except the peculiar hybridization with
Salix herbacea in historic time.
References
Argus, G.W. 1965. The taxonomy of the Salix glauca
complex in North America. The Gray Herbarium of
Harvard University, Cambridge, Mass. U.S.A: 64-
96.
Bjarnason, A.H. 1983. lslensk flóra. Iðun. Reykjavík:
250-253.
Bocher, T.W. 1938. Biological Distributional Types in
the Flora of Greenland. Meddelelser om Gronland
CVI 106: 63-66.
Elven, R. In prep. Salix glauca L., in Flora Nordica.
Floderus, B. 1923. Om Gronlands salices (in Swedish).
Meddelelser om Gronland LXIII. Kobenhavn: 97-
157.
Gronlund, C. 1881. Islands Flora. Kjobenhavn.
Hansen, K. 1966. Vascular Plants in the Faeroes.
Horizontal and vertical distribution. Dansk Bot. Ark.
24, N 3: 105.
Hulten, E. and Fries, M. 1986. Atlas ofNorth European
Vascular Plants I, III. Kónigstein.
Hylander, N. 1966. Nordisk kdrlvaxtflora II (in Swe-
dish). Stockholm.
Hamet-Ahti, L., Palmen. A., Alanko, P., Tigerstedt,
P.M.A., Koistinen, M. 1992. Woody Flora of Fin-
land (in Finnish). Helsinki.
Jalas, J. and Suominen, J. 1976. Atlas Florae
Europaeae, 3. Helsinki.
Jóhansen, J. 1985. Studies in the vegetational history of
the Faroe and Shetland Islands. Ann. Soc. Scient.
Færoensis, Sup.XI. 117. Tórshavn.
Jóhansen, J. 1989. Survey of geology, climate, and
vegetational history. In: Højgaard, A., Jóhansen, J.,
and Ødum, S.(eds.). A century of tree-planting in the
Faroe Islands. Ann. Soc. Scient. Færoensis, Sup.
XIV. Tórshavn: 11-15.
Kristinsson, H. 1986. Plontuhandbókin (in Icelandic).
Reykjavík.