LICHENOLOGY OF ICELAND 237 
number of species as Iceland, which is about 22 times smaller. 
These figures are in themselves striking enough, but they give no 
information concerning the equality of the distribution of the species 
in the areas of these three countries occupied by the lichens. We 
know, it is true, from other sources, that all three countries have 
a larger or smaller area covered with inland-ice, which however, 
in proportion to the entire area of the country, is most strongly 
developed in Greenland. Even this alone naturally brings about a 
heterogenous lichen-colonization in these countries. But even if we 
do not take this into consideration, but only regard the areas which 
are free from ice, the figures do not state anything about the equa- 
lity of the distribution of the lichens: whether we can meet with 
all the species of Greenland, of Iceland or of Spitzbergen within 
every lesser area or whether the distribution is quite otherwise. 
We have in this respect a small hint from Greenland, where at 
least the north-eastern area, which has been investigated by the 
“Danmark Expedition,’ gives only about 100 species, which with 
tolerable certainty can be taken as an indication of the fact, that 
the difference between South and North in this country of great 
length is of importance. But a reliable comparison of the distribu- 
tion within the three countries in question, cannot be obtained until 
equally large areas from each of them have been compared with 
one another, which has not yet been done. 
On comparing the number of species from Iceland with those 
from Denmark — to take a well-investigated area from another 
climate-belt — we find that Denmark, on her 38000 square km., has 
397 species against Iceland’s 285 species on 104000 square km., or 
0.0021 species per square km. in Iceland and 0.0104 species per 
square km. in Denmark. Nor do these figures give any insight into 
how the species are distributed within each country. In this case 
also it will be necessary to compare equally large areas of the two 
countries (taking their characteristic plant-associations into con- 
sideration). 
But until such a comparison has been made, it must suffice to 
substantiate the fact, that the abundance of species in the whole 
of Iceland is less than in the whole of Denmark, in spite of Iceland 
being 2!/2 times the size of Denmark. In the same way it may be 
said that Greenland is far poorer in species than is Denmark, al- 
though it is many times the size of Denmark, whilst, for instance, 
Germany, France and Great Britain, with their greater stretch of 
