624 



METASPERMAE OF THE MINNESOTA VALLEY 



widely dispersed over both distal and central regions. Mono- 

 cotyledones and Metachlamydeae, therefore, characterise the 

 central family-element of the Minnesota valley, and Monoco- 

 tyledonesand Archichlamydeae the distal family-element of the 

 valley. This seems to be the most useful generalisation that 

 can be made from the statistics of families. 



II. EXAMINATION OF GENERA REPRESENTED IN THE 

 MINNESOTA VALLEY. 



The total number of genera represented in the valley of the 

 Minnesota is 407. Of these 105 or 25.8 per cent, are monoco- 

 tyledonous; 174 or 42.7 per cent, are archichlamydeous; and 128 

 or 81.2 per cent, are metachlamydeous. The following table 

 presents these points in a condensed form. 



1*. Table Illustrating the Distinctive Range of 



