2i8 BOTANICAL GAZETTE [September 



9. The entire xylem system of the root is bordered peripherally 

 by cambium. 



Grateful acknowledgments are due to Professor John M. Coul- 

 ter and Dr. W. J. G. Land, under whose direction the investigation 

 was conducted, and to Professor Charles J. Chamberlain for 

 abundance of material. 



The University of Chicago 



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