REVIEWS 599 



subsoil and to the extreme variations in major constituents in dilierent 

 soils, and even in soils of the same type. 



J. W. T. 



Systematic Invcstujations of Tropical American Plants. Contribu- 

 tions from the United States National Herbarium, Vol. i8, 1914-1917. 

 Washington. D. C. Pp. 494. , 



Contains articles by W. E. Sanford on xA.nnonaceae ; by H. Pittier, 

 dealing principally with Columbian and Central American trees and 

 other plants ; by P. C. Standley on certain Panama plants, and by A. S. 

 Hitclicock on West Indian grass tlora. 



