vi PREFACE 



(2) to make clear the life history of the causal fungus ; and (3) to 

 indicate the approved or suggested methods of prevention or con- 

 trol. The author fully recognizes that in any complete discussion 

 of a fungous disease there are definite theoretical subdivisions, 

 such as symptoms, pathological morphology, etiology, life cycle of 

 the causal organism, etc. Nevertheless, such a system does not at 

 present recommend itself. In the nomenclature of popular names 

 of diseases uniformity, or special fitness, at a sacrifice of estab- 

 lished usage, has been avoided. An extensive host index has been 

 included in order to present in a succinct form all of the diseases 

 discussed upon any host. It is, perhaps, needless to add that the 

 chapters upon culture methods, technique, and physiological rela- 

 tions are designed primarily for reference, and to stimulate the 

 most complete use of the available material. The bibliography is 

 intended to be suggestive, and the titles are made prominent that 

 the suggestion may not be avoided. 



Aside from photographs and drawings made by the author, the 

 illustrations have been derived from a variety of sources. Special 

 acknowledgment is made to Mr. F. C. Stewart, of the New York 

 Agricultural Experiment Station, and to Professors H. H. Whetzel 

 and George F. Atkinson, of Cornell University, for the privilege 

 of using many negatives from their collections. Many others have 

 kindly furnished material for one or more illustrations, as credited 

 in the legends. In the preparation of the drawings much assistance 

 has been given by Mrs. B. M. Duggar. For helpful suggestions 

 respecting the manuscript and for a first draft of the synopsis of 

 species among the Uredinales, the writer is indebted to Professor 

 George M. Reed, of the University of Missouri. 



B. M. DUGGAR 



