138 H. MØLHOLM HANSEN 
the result of the effect on the halla myri of the warm 
water in the winter. 
The Distribution of the Species in the Scale of Moisture. 
Table 27 shows the distribution of the species in the scale of 
moisture respectively at Bjørk, on Lyngdalsheidi, and on Arnarvatns- 
heidi. A special column further shows the average values for these 
three localities. 
The Lekjamot series has not been included in the table since 
the myri formations here differ in several respects from the above 
mentioned, thus causing some deviations which are not due to the 
conditions of moisture. On the whole, however, the distribution of 
the species in the scale of moisture in the Lekjamot series confirms 
the relations stated below. 
In order to facilitate a general view the species have been 
grouped according as they occur with the greater frequency in the 
lowland formations or in the highland formations, or with equal 
frequency in both. Within each of these groups the species have 
then been arranged with the least »moisture-loving« first and the 
most »moisture-loving« last. Considerations of space have, however, 
necessitated the exclusion of some more rarely occurring species. 
The figure marked against a given species in a column is the 
average F.-percentage of the species in question for the zone of 
moisture of the locality in question. Thus in the Elyna mo at Bjork, 
Festuca rubra has the frequency percentages 96, 96, 100, and 96 
in the 4 localities there examined. The sum, 388, divided by the 
number of the localities, 4, makes 97, which is the figure marked 
against Festuca rubra in table 27, Bjork I. 
If, next, we consider the distribution of the species in the scale 
of moisture, it is an extremely variegated picture that meets the eye 
both as regards quantitative distribution, that is to say, the average 
distance of the individuals, and as regards the mode of distribution 
in the scale. Some species show a low F.-percentage (i. e. a great 
average distance between the individuals), others a high F.-percen- 
tage (i.e. a small average distance between the individuals). Some 
species occur only in a small number of moisture classes, others 
in a larger number or in all classes. Some species only occur in 
the dry classes, others only in the moderately moist, others again 
only in the moist etc. But to whichever class or classes a 
