DØ H. MØLHOLM HANSEN 
A 1 comprises such species as must be termed arctic though 
they do not extend very far north in Greenland. Their northern 
limit in West Greenland lies south of 66° N. In Iceland the species 
are equally distributed through all altitude zones, though with a 
slight maximum in the lowlands. The A 1 species occur most com- 
monly north of the “jökull line”, especially in North Iceland. 
III. Investigation of the distribution of the species, partly in 
the North European and the adjacent arctic countries, and partly 
in Iceland, gave the result that the 7 subgroups show a fairly smooth 
gradation from A 3, which is adapted to the coldest conditions, to 
E 1, which requires the greatest amount of heat. The increasing 
adaption to arctic conditions may, however, be demonstrated in 
another way, too, viz. by a comparison of the individual groups 
with respect to their content of Raunkizr’s life forms. If the groups 
and subgroups express an increasing degree of adaption to the 
arctic climate, this must appear by the fact that that group or those 
groups which are best adapted to the arctic climate shows or show 
the greatest content of arctic life forms and fewest temperate life 
forms, whereas the reverse must be the case with the remaining 
groups. 
Against each species in the above list is given the life form of 
the species in question, and in table 7 are stated the biological 
spectra of the groups. 
According to Raunkiær (1908, 1912), Ch is the life form which 
is best adapted to the arctic climate, while H and G are indifferent, 
and Ph, HH, and Th are adapted to non-arctic conditions. By com- 
parison of the biological spectra of the A and E groups with the 
spectrum of the entire flora, it will be seen that the A group is 
more arctic in character, the E group more temperate in character 
than the flora as a whole. The subgroups under A and E bear the 
same relation to their respective main groups as these to the whole 
flora. The high HH percentage in E 4 and partly also in E 1 is 
however, worth noting. 
On reviewing the biological spectra of the various parts and 
zones of Iceland we saw that the Ch °/o was lowest (15 °/o) in the 
south country where the amount of warm water at the coasts was 
greatest, that it then rose gradually as the amount of Polar water 
