MICHIGAN ACADEMY OF SCIENCE. 43 



TABLE II. — DISTRIBUTIOX OF THE ARCTIC-EUROPEAN SPECIES. 



53 or 80 per cent are in common with Arctic Greenland. 



51 or 76 per cent are in common -^-ith Eastern America. 



34 or 50 per cent are in common Avitli Asia. 



31 or 46 per cent are in common with Western America. 



2. Arctic Greenland has 60 species (51%) in common with Ktaacln (Table 

 I) whose affinities are computed in the appended table. 



TABLE III. DISTRIBUTIOX OF THE ARCTIC GREENLAND SPECIES. 



53 or 80 per cent are in common with Arctic Europe. 



27 or 45 per cent are in common with Asia. 



41 or 70 per cent ai'e in common with Eastern America. 



41 or 70 per cent are in common with Western America. 



Thus Greenland as might be anticipated from Table II shows its closest 

 fioristic identity ^\'ith Arctic Europe, an identity which further research can 

 reasonably be expected to strengthen. While Eastern and Western America 

 exhibit a percentage agreement, it is misleading as they have only 90 per cent 

 of their forms in common (Table IV) which suggests a mixed origin of the 

 Western American flora, a point to Avhich we shall return. Asia, Greenland 

 and Ktaadn are weak in fioristic agreement having but 27 species in common. 



3. Arctic Eastern Atnerica shows 65 species (54%) in common with our 

 alpine flora. These 65 forms have the following arctic relationships. 



TABLE IV.— DISTRIBUTION OF THE ARCTIC EASTERN AMERICAN SPECIES. 



51 or 76 per cent are in common with Arctic Europe. 



41 or 63 per cent are in common with Greenland. 



31 or 49 per cent are in common with Asia. 



59 or 90 per cent are in common Avith Western America. 



Arctic Eastern America thus has its nearest relation with Arctic Western 

 America though more complete data from Greenland may be expected to 

 much increase the number of forms in common. It would appear from 

 Table I that Arctic America was somewhat uniform in its fioristic relation 

 Avith Ktaadn each region having 54 species (65%) in common with it, but it 

 should be noted that only 90 per cent of their 65 species occur in both regions, 

 i. e., Ktaadn has certain affinity with each which is not common to both 

 Arctic areas. In other words, each of these areas furnishes nine species 

 (10% of their arctic-alpine species) to our alpine flora; a percentage perhaps 

 too small for safe generalization Avhen one considers the suretv of incomplete 

 data but nevertheless very suggestive as will be pointed out below. When 

 this area's alliance with Asia is noticed it would appear that the arctic flora 

 of Western America was derived from western migration rather than from 

 an Asiatic center for its European character (76%) is strong while it has 

 only 49 per cent of species in common with Asia. 



4. Arctic Asia possesses 42 species (35%) of the arctic-alpine flora, Avhieh 

 are distributed in the other arctic regions as follows: 



