456 POUL LARSEN 
S.W. country, but also a smaller area in the east country. 
The finds of C. H. Ostenfeld are mainly derived from the north, 
north-west and west country, and Chr. Grønlund has visited both 
the east, north and west country. — My own investigations in the 
summer of 1922 began in the first part of June in S. W. Iceland, viz. 
in the country round Reykjavik, Hafnarfiöröur and Pingvellir. In 
the latter part of June I continued with the part round Borgar- 
fjöröur, especially the birch copses near Borg and Norötünga. But 
my main area of investigation was N. E. Iceland, the region between 
the Øfiord Valley and the east coast of Iceland, viz. the Ofiord Valley 
itself and the Fnjöskadalur running parallel to it, the depression 
near Myvatn with Laxädalur, Jökulsa a Heidi from Grimstadir to 
Môôrudalur, Jökulsa à Brü, Lagarfljöt with Iceland’s largest birch 
copse, and finally the region round Seydisfjördur. 
As will appear from this survey, the south country is the least 
explored part of Iceland as regards fungi. The extensive bare sands 
along the southern coast of the country cannot, however, be expected 
to add to the number of species, for even though there is some 
dune vegetation here, a similar vegetation occurs on the extensive 
range of dunes along Jökulsä a Heidi. The few samples of the vege- 
tation of sands and dunes derived from Helgi Jönsson’s collec- 
tion show in the main the same fungi as those occurring on the 
plants collected by me on dunes in the interior round Grimstadir 
near Jökulsa ä Heidi. And the homefields of the farms in the south 
country bear mainly the same vegetation as the homefields in the 
rest of the country, and must therefore be supposed to harbour much 
the same fungi. On the whole, such large areas of Iceland have now 
been investigated that all the different forms of vegetation are repre- 
sented, and an addition to the number of species is more likely to 
be made through a more thorough examination of details than by 
enlarging the area of investigation. 
The Special Conditions of Environment offered to 
Fungi in Iceland. 
Though the fungus flora is greatly dependent on the rest of the 
vegetation, we cannot infer from this that the more luxuriant the 
vegetation of a country is, the richer and more abundant its fungus 
flora will be. At any rate, this does not apply to the larger fungi. 
There must, therefore, be other factors besides the chlorophyllaceous 
