PLATE III 

 The Effect of Soil Depth upon Early Development 



Fig. i. The effect of soil depth upon the development of Pinus pon- 

 dcrosa (S. D.). Ten plants grown (i) in deep, (2) in medium, and (3) 

 in shallow soil. V 2 natural size. 



Fig. 2. The effect of soil depth upon the development of Robinia pseu- 

 daeacia. Three plants each (1) grown in shallow, (2) in medium, (3) in 

 deep soil. Va natural size. 



