The Botany of Iceland - 01.12.1930, Síða 29
STUDIES ON THE VEGETATION OF IGELAND
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í'egions. For \ve cannot take it for granted that a species, because
it has come to a certain region, will at once assume the most pro-
nounced life form of the region in question. The dominating life
form in arctic regions is Ch, yet we find species with another life
form, and these species must be supposed to be just as well adapted
to arctic regions as several of the chamaephytes growing there.
Conversely, in regions having a liemicryptophyte climate, we may
find Ch. A species like Calluna vulgaris must be assumed to be
just as well adapted to the Danish climate as many hemicrypto-
phytes. Even though Raunkiær’s life forms give an ex-
cellent biological picture of the climate, they do not
give the most accurate picture of it. The distribution of the
species must rank first in this respect. However, there must be no
disagreement between results obtained by means of Raunkiær’s life
forms and those obtained by investigations based on the geographical
distribution of the species, though at the outset we must expect
the latter to give tlie more pronounced result. Raunkiær’s life
forms picture the morphological adaptation of the spe-
cies, the species groups give expression to tlieir physio-
logical adaptation, both, however, express their adap-
tation to the same life conditions.
Various enquirers in various countries have at different times
worked out a classiíication of the floras of their respective countries.
Thus Watson divided the Brilish flora into groups according to the
geographical distribution of the spécies. A. Blytt divided the Nor-
wegian llora on a somewhat similar principle, and various Swedish
enquirers, i. a. Gunnar Andersson and H. Hesselman, have clas-
sified the Swedish flora. Ostenfeld has classified the ílora of the
Faeroes, Porsild and Ostenfeld the Greenlandish ílora. The
principle acted upon by all tiiese enquirers was to separate all spe-
cies having a pronounced northern or southern distribution from all
sucli as showed an equal distribution over the entire area. This
resulted in the first instance in the setting up of three groups, while
Watson and Blytt in addition classified the species according as
they had a pronounced Atlantic or continental distribution.
An attempt to bring together the species groups of the various
autliors and thus arrive at a classification of the Icelandic flora
proved impossible, since their species groups overlap to such a de-
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