PREFACE 



The experiments and observations on rusts which are the basis of 

 the following notes were begun by Mr. Carleton several years ago, 

 and were continued at intervals until the spring of 1900, 'when the 

 pressure of other duties prevented further work of this kind up to 

 the present time. The results obtained in many instances are still 

 incomplete, but are of sufficient value to be recorded. Some of the 

 species studied are of much economic importance. The investigation 

 is a continuation of the work reported in Bulletin 16 of the Division 

 of Vegetable Physiology and Pathology, and is concerned chiefly with 

 the segregation of rust forms of economic importance on the common 

 grasses and the completion of the life history of certain species. The 

 work is to be carried on more extensively during 1904. 



A. F. Woods, 

 Pathologist and Physiologist. 

 Office of Vegetable Pathological and 



Physiological Investigations, 



Washington, I). O., March 26, 190 % 



