64 H. MØLHOLM HANSEN 
dalur, at Björk, and at Lekjamot in the north country. The ridge 
myri I have only investigated at Lækjamåt, while I had no oppor- 
tunity of a close study of the fétmyri. 
The composition of the swampy myri in Lyngdalur and at 
Björk is shown in table 15A, 1—11. 
Fig. 11 shows the appearance of the myri at Björk. The soil 
is markedly knolly, but the knolls are smaller and more scattered 
than on the mo. 
According to the degree of moisture of the soil it is possible 
to distinguish between the following formations. The myri jadar 
(the margin of the myri) or the grass myri is first met with on 
passing from the mo on to the myri. Upwards it passes into the 
moist mo, the Calluna-Empetrum mo. The ground water hardly 
ever comes up to the surface, but the bottom is damp in spring, 
winter, and autumn, whereas, in the vegetation period, it is com- 
paratively dry. Outwards the jadar passes into the dry cypera- 
ceous myri, the Salix myri. The soil is here considerably more 
moist, in wet summers the water will perhaps cover the surface 
throughout the vegetation period; normally, however, this vegetation 
will not be covered with surface water the greater part of the vege- 
tation period, in dry summers perhaps not at all. On the dampest 
soil we find the moist cyperaceous myri or the Betula nana 
mvri. The bottom must here be assumed to be covered with 
water even in normal summers; in very dry summers dry bottom 
may no doubt be found in this formation, too. The flöi, or 
swamp, is met with in spots in this formation. Here the bottom 
is always covered with water, even in dry summers. The knolls, 
so typical of the myri, are not present in the flöi, and while the 
soil of the myri is firm to the tread, rendered solid by a dense web 
of Cyperaceae rhizomes, the ground in the flöi is soft and muddy, 
and one moves on it in constant fear of sinking into the slush. 
On a gentle slope these 4 belts will succeed each other in the 
sequence described above, adjoining the moist mo upwards, while 
outwards they will perhaps be succeeded by a collection of water, 
a “tjörn” (tarn). Where the surface is more irregular, a compara- 
tively moist formation will not rarely adjoin a comparatively dry 
one, while the intermediate formations are not developed. 
The Jadar Vegetation. Table 15 A, 1—3 shows the floristic 
composition of this vegetation in Lyngdalur and at Björk. The 
