308 JOURNAL OF FORESTRY 



ferences in the evaporating power of the air and the water content of 

 the soil, with differences in the abundance and distribution of nutri- 

 ents occasionally playing important roles. The root development of 

 crop plants showed a nicety of correlation with the root development 

 of certain native species in similar habitats. A knowledge of the de- 

 velopment, position and competition of roots is held to be indispensable 

 in an accurate interpretation of plant succession and the indicator 

 significance of native vegetation. 



Although the monograph under review is not directly concerned 

 with trees or forest vegetation, it is deserving of more than passing 

 notice because of the most convincing results presented and the clear- 

 cut exposition of the methods followed in this extremely fruitful field 

 of ecological research. What little work has been done on the root 

 systems of forest trees and associated forest vegetation, indicates that 

 these studies are equally fruitful. The strenuous manual labor in- 

 volved in excavation should no longer preclude similar researches along 

 silvical lines. C. F. K. 



