46 ELEVENTH REPORT. 



two routes which may be designated: The Asia-Alaskan and the Greenland- 

 Labrador. This will appear more striking from the following ])ercentages 

 which indicate the species occurring in common on Ktaadn and in the various 

 regions. 



Ktaadn and Asia 35 per cent. 



Ktaadn and Arctic Western America 54 per cent. 



Ktaadn and Northwestern America 75 per cent. 



Ktaadn and Europe 56 per cent. 



Ktaadn and Greenland 50 per cent. 



Ktaadn and Arctic Eastern America 54 per cent. 



Ktaadn and Northeastern America 98 per cent. 



Thus we may not only consider Arctic Europe as the center of distri])ution 

 of the Ktaadn alpine flora ])ut that the glacial migration was dominantly 

 by the Greenland-Laborador route and that arctic western America was 

 mainly supplied from this force. A conclusion further strengthened by the 

 fact that Avhile arctic eastern America and arctic w^estern America have 90 

 per cent of these forms occurring in l^oth regions only 46 per cent of Western 

 America forms occur in arctic Europe Avhile 76 per cent are known to he in 

 common with arctic eastern America. 



Another table will readily show further detail of the migration: 

 Arctic Western America has 90 per cent in common with Arctic Western 



America. 

 Arctic Western America has 90 per cent in common with Northwestern 



America. 

 Northwestern America has 54 per cent in common with Ktaadn. 



Arctic Eastern America has 100 per cent in common with Northeastern 



America. 

 Northeastern America has 100 per cent in common Avith Ktaadn. 



The next step is apparent from the following: 

 Northwestern America has 88 per cent in common with Northeastern 



America. 

 N. W. America and Ktaadn 90 per cent. N. E. America and Ktaadn 



100 per cent. 



It has been noted above that only 91 or 76 per cent of Ktaadn species are 

 arctic in origin; the remaining 27 or 24 per cent are of subarctic affinity 

 and mainly Northwestern American. Of these 27 species 18 are peculiar 

 to Northeastern America which thus furnishes 16 per cent of the Ktaadn 

 alpine flora. Two species as shown above are endemic. Thus the 120 

 arctic-alpine species are accounted for as summarized in the table below: 



TABLE IX. — SUMMARY OF FLORISTIC AFFINITIES OF THE 120 ARCTIC SPECIES 



OF KTAADN. 



91 species or 76 per cent are of Arctic affinity. 



18 species or 16.5 per cent are of Northeastern American affinity. 



6 species or 5 per cent are of Northwestern American affinity. 



3 species or 1.5 per cent are of Northeastern and Northwe.stern 



affinity. 



2 species or 1.0 per cent are endemic. 



120 species or 100 per cent. 



