STUDIES ON THE VEGETATION OF ICELAND 69 
and Empetrum nigrum, and in less degree Salix phylicifolia. Of 
Cyperaceae Carex Goodenoughü, C. chordorrhiza, C. rariflora, and 
Eriophorum polystachyum are particularly conspicuous. To these 
must be added Polygonum viviparum and Thalictrum alpinum. Of 
the marsh plants Carex rostrata is the most important. Comarum 
palustre, Menyanthes trifoliata and Equisetum limosum occur more 
sporadically. 
The Flôi Vegetation. Table 16 A—B, 1—5. 
The vegetation is not evenly distributed over the surface of the 
myri; a number of the species, especially the chamaephytes, are 
peculiar to the knolls, others, the Cyperaceae, only occur in the 
spaces between the knolls. Passing from the myri towards the fli, 
the spaces between the knolls grow larger and larger until the knolls 
have quite disappeared and with them their vegetation. 
In table 16 A—B are tabulated the circling results for all the low- 
land localities investigated in Iceland, from Lyngdalsheidi, Björk and 
Lækjamôt. The reason why so few localities were investigated was 
that the rainy summer of 1925 afforded very poor working con- 
ditions. In spite of the few localities, the table gives interesting 
and mutually agreeing particulars of the flöi vegetation. Compared 
with the myri vegetation it is very poor in species, the number of 
species being 2—4, the density 1—2. Geophytes and helophytic 
Cyperaceae form the bulk of the vegetation, thus especially Erio- 
phorum polystachyum, Carex Goodenoughü, C. chordorrhiza and 
C. rostrata. A few other species occur sporadically. 
The greatest interest attaches to the biological conditions when 
compared with those of the myri vegetation. The species group 
spectrum shows a strong concentration in the central part of the 
spectrum from E 3 to A 1; the lower groups, and in part the upper 
ones, are not represented in the spectrum. 
This spectrum seems to be typical of vegetations on a water- 
covered surface. The Subularia flag, whose vegetation is covered 
by a water layer as deep as that of the flöi, has practically the 
same species group spectrum as the flöi with a large predominance 
in the central part of the spectrum. The same is the case with 
the highland fléi. 
The statistical and biological conditions of the flöi are, as a 
comparison of the respective tables will show, a further development 
