Minnesota Plant Life. 



235 



way to compare trees and herbs in order to understand their sim- 

 ilarity is this: Let an herb be pulled up by the roots and laid 

 down before one. Then let a fresh leaf-bearing twig of a tree, 

 such as a willow or poplar, be selected and removed from the last 

 year's branch upon which it is standing. Let one of the young 

 roots of the tree, if it is found, be attached to the end of the twig 

 that was broken from its support. Let the two specimens be 

 placed side by side and their fundamental resemblance will be- 

 come apparent. The same fact will be understood if one com- 



FIG. 105. Cottonwoods on the Minnesota. After photograph by Williams. 



In 



pares the seedlings of trees with the seedlings of herbs, 

 essential respects they will appear altogether similar. 



Other characters of plants with two-leafed seedlings. The 

 plants included in the highest class ordinarily produce leaves 

 with netted veins and the flowers are built generally upon the 

 plan of four or five rather than upon the plan of three. That 

 is to say, while one finds three sepals, three petals, six stamens, 

 and three carpels forming the fruit-rudiment in many flowers 

 of lower-class plants, one would more probably find four or 

 five sepals, four or five petals, four, eight or some other number 



