106 H. MØLHOLM HANSEN 
the more conspicuous species includes: Empetrum nigrum, Salix 
herbacea, S. glauca, Betula nana, Vaccinium uliginosum, Dryas octo- 
petala, Silene acaulis, and Armeria vulgaris. The species Cassiope 
hypnoides and Loiseleuria procumbens occur more frequently than in 
melar even though they are not as dominant as in the knolly mo. 
Of hemicryptophytes and geophytes the following occur: Poly- 
gonum viviparum, Juncus trifidus, Luzula spicata, Festuca ovina, 
Viscaria alpina, Galium Normanni, Thalictrum alpinum, Elyna Bel- 
lardi, Carex rigida, Festuca rubra, and Poa alpina. Of pteridophytes 
Selaginella selaginoides, Equisetum arvense, and E. variegatum are 
met with. 
Along the upper margin of the large snow patches there occurs 
a narrow belt in which Betula nana is the physiognomic dominant. 
This formation will be dealt with later, under the geiri vegetation. 
The Knolly Mo. Cf. fig. 19 and table 
This type of vegetation commonly occurs on ‘flat ice slopes, 
on the lower slopes of elevations and ridges with melar above, in 
small hollows in the Betula nana mo, and on the borders of the 
snow patches. The surface is always knolly, but the knolls are 
neither very large nor very high. Judging by the position the snow- 
covering is deeper than in the two preceding types, the melar and 
the level mo, though less deep than in the snow patches. As re- 
gards moisture, the knolly mo occupies an intermediate position 
between the level mo and the jadar vegetation. 
The change in number of species and in density is continued 
from melar through the level mo to the knolly mo and here we 
have the values 35 and 15 respectively for the number of species 
and the density. Biologically the change is likevise continued: the 
Ch percentage has decreased, while the G and H percentages have 
increased. The E and A percentages have remained constant, while 
there is still a decrease in the A 3 percentage. There is a rise in 
the E 3 percentage. 
While in the Betula nana mo Ch were dominant and H were 
the subordinate element, the reverse is the case in the knolly mo. 
Here H are the dominant. The respective averages for Ch and H 
in the two types of vegatation are 47:38 and 37 : 47. 
The predominant chamaephytes are Empetrum nigrum, Vacci- 
nium, and Salix herbacea. In more scattered growth there occur 
Salix glauca, Silene acaulis, Armeria vulgaris, Dryas octopetala, Thy- 
