170 EXPERIMENT STATION. [Jan. 



presentation in Fig. 1. Here the averages are presented as 

 actual leaf forms, so that each diagram shows the average form 

 of leaf in its respective class. Where it is understood that these 

 averages are taken from a large number of measurements, and 



Fig. 1. 



that the modifications are due, so far as can possibly be seen, 

 solely to the influence of the stocks on which the trees are grow- 

 ing, it will be manifest that a distinct addition is made to the 

 knowledge of this subject. 



Makginal Serrations. 

 Not only are the leaves in different lots different in size and 

 form, but they differ also in color. This difference, though 



