PLATE IV 

 The Effect of Soil Moisture upon Early Development 



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

 derosa (S. D. ). Ten plants grown in (I) medium dry soil, (2) wet soil. 

 y 2 natural size. 



Fig. 2. The effect of soil moisture upon the development of Robinia 

 pseudacacia. Three plants grown (1) in wet soil, (2) in medium dry soil. 

 V2 natural size. 



