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 onlv regard the areas which 



/ o 



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 Spitsbergen 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 W 7 ith 

 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 



