STUDIES ON THE VEGETATION OF ICELAND 31 
tered sunny slopes. In Iceland most of the E 1 species are rare, 
they only occur in the lowlands especially towards the south, and 
thrive best near the hot springs. 
E 2. Like the E 1 species, the species of this group are restricted 
to the lowlands in Iceland, and occur more commonly south of 
than north of the »jökull lines. However, these species occur more 
commonly than the species of the previous group. In Scandinavia 
and Finland they extend right up to the northern coasts, but none 
of them have reached Greenland. 
E 3. Like E 2 the species of this group have no northern limit 
in Scandinavia and Finland. In Iceland they are common lowland 
species which still thrive well in the lower zone of the highlands 
but disappear higher up; they occur commonly and with equal 
frequency in the various parts of the country. The species are found 
in South Greenland as pronounced southern types. 66° N. has been 
chosen as the northern limit of the group in West Greenland. 
E 4 is the subgroup which has most common species in Ice- 
land, and the species are of common occurrence right up into the 
upper zone of the highland tracts. In Greenland, too, the species 
are of common occurrence, some species even extend right up into 
North Greenland. 
The A group comprises arctic and subarctic species having 
their main distribution near, north of, or above the forest limit, the 
20°/o Ch biochore. The species are common in Greenland, Spits- 
bergen, Iceland, and on the Scandinavian and Scotch mountains. 
In more southerly countries the species are either absent (and this 
applies to the majority), or they occur sporadically and in small 
quantity. 
A 3 comprises the species which extend farthest north in the 
arctic region and are therefore capable of withstanding the severest 
cold. In Scandinavia these species are confined to the most markedly 
arctie localities; in Iceland they are a characteristic feature of the 
upper highland zone. 
A 2 comprises most of the common species of the A groups in 
Iceland. The species of this group are more in evidence north of 
than south of the “jökull line” and seem to thrive better in the 
lower highland tracts than above and below. In Greenland these 
species are of common occurrence though they do not, like the A 3 
species, extend into North Greenland. 
