Percy W. Zimmerman 



wavering interest in all the problems of life gave him an enduring 

 place in the hearts of his colleagues even as they recognized his oc- 

 casional very human frailties. 



Dr. Zimmerman was born at Manito, Illinois, on February 23, 1884. 

 He was trained at the University of Chicago from \vhich he received the 

 B.S. degree in 1915, M.S. in 1916, and Ph.D. in 1925. His professional 

 career included a period as public school teacher and Superintendent of 

 Schools at Westville, Illinois (1910-13), Associate Professor of Botany 

 and Dean of the College of Agriculture at the University of Maryland 

 (1916-25), and Plant Physiologist at the Boyce Thompson Institute 

 from 1925 until his death in 1958. 



This volume is afjeciionately dedicated to him as one of the 

 pioneers luho opened the door on this exciting neiu area of plant re- 

 search. Without the foresight, persistent effort, and dedication to re- 

 search of men such as he, there would have been no assemblage in this 

 conference of representatives from so many lands. No more fitting 

 memorial could be offered to his memory than this volume loherein 

 are assembled the best ideas of the distinguished leaders of today. 



George L. McNew 



