A STUDY IN CEREAL RUSTS: 



PHYSIOLOGICAL RACES 



A THESIS SUBMITTED TO THE FACULTY 



OF 

 THE GRADUATE SCHOOL 



OF 

 THE UNIVERSITY OF MINNESOTA 



BY 



ELVIN CHARLES STAKMAN 

 IN PARTIAL FULFILMENT OF THE REQUIREMENTS 



FOR THE DEGREE OF 

 DOCTOR OF PHILOSOPHY 



MINNEAPOLIS, MINN. 

 JUNE 1913 



