STUDIES ON THE VEGETATION OF ICELAND 125 
These 7 zones may be pointed out without difficulty wherever 
the ground does not slope too steeply. As soon as the ground be- 
comes more rugged and uneven, irregularities in the distribution 
of the zones may be observed. One or more zones will not be 
developed; thus moist myri may be observed to adjoin high mo 
without the intermediate zones having attained development. The 
interrelationship of the zones can, however, be confirmed wherever 
the mo, or the myri, is the dominant feature of the landscape. In 
hollows in the mo the jadar will always be the first type of vegeta- 
tion to be met with, and with the progressive size and depth of 
the depression the other types will follow in the above-described se- 
quence. Wherever an elevation occurs in the myri, the types of 
vegetation will succeed each other from the edge of the myri to the 
summit of the elevation in the same regular way in conformity to 
law. These conditions are repeated again and again in every part 
of the island. 
Table 26 shows the distribution of the life-forms and the spe- 
cies-groups in relation to the scale of moisture in the various series 
of investigations. The Roman numerals I—VII correspond to the 
7 zones of moisture mentioned above. 
Life Forms. Their Distribution in Relation to the 
Scale of Moisture. 
In a previous chapter (pp. 13—33) the influence of the climate 
on the prevalence of species-groups and life-forms in the flora was 
subjected to a more detailed investigation. As far as the life-forms 
were concerned Ch proved of special interest by the close correlation 
between the rise in the Ch percentage and the severity of the cli- 
mate. Passing round the coast from South Iceland by way of 
western and northern Iceland to East Iceland, the Ch percentage 
showed a continuous rise, and passing from the level of the sea 
towards the snow-line, the same was the case, only in even greater 
degree. The same was the case with the A percentage. 
The statistical investigations of the formations confirm this. 
Thus, if we compare the Ch percentage of the Elyna mo at Bjork, 
the formation in the southern lowlands which is most arctic in 
character, with the melar at Laekjamöt, the most pronounced arctic 
formation in the north country (both localities at a height of c. 100 m.), 
we shall see that in the former case the Ch percentage is 28, in 
