650 



METASPERMAE OP THE MINNESOTA VALLEY. 



C. Table Illustrating Continental Development of Genera 

 Represented in the Minnesota Yalley. Continued. 



Prom the preceding table, statistics may be compiled as from 

 the table of general generic range. Four range -elements may 

 be discovered in the genera of the Minnesota valley and the 

 mutual relations of these range-elements to the taxonomic 

 groups may be determined, as before, by percentages. The 

 four range -elements are as follows: 



A. The Northern generic element. 



B. The Southern generic element. 



C. The Eastern generic element.' 



D. The Western generic element. 



Each of these may be examined in turn 



