THE UREDINALES OF OREGON ^ 



H. S. JACKSON 

 Purdue University 



Since no account of the rusts of any of the states bordering on the 

 Pacific coast is available for reference by the students of the flora of 

 that region, it has seemed desirable to bring together in the form of 

 an annotated list the results of a study of the species occurring in 

 Oregon, which has extended, intermittently, over a period of eight 

 years. 



The account is the result of a study begun by the author in 1909 

 at the Oregon Agricultural College and finally prepared in the form 

 here presented at the Purdue University Agricultural Experiment 

 Station. 



On account of the great diversity of conditions the State of Oregon 

 presents a wonderful field for work in any phase of botanical study. 

 The area of the State is approximately 96,000 square miles, an area 

 considerably greater than that included in all the New England states 

 combined. The great range of climatic and topographical features 

 existing in the State offers favorable conditions for the development 

 of a flora not only large in number of species, but very diverse in char- 

 acter. Within the confines of the State is to be found a range in alti- 

 tude from sea level to perpetually snow-capped mountains. The 

 annual rainfall varies from over 80 inches in some localities to below 

 10 inches in others, resulting in the development of a flora almost 

 tropical in its luxuriance on the one hand, and one having many of 

 the characteristics of a desert on the other. 



The diversity of the Phanerogamic flora which has developed 

 under these conditions offers an especially attractive field for the 

 student of the parasitic fungi. Many species of all groups are to be 

 found especially in those portions of the State having a heavy annual 

 rainfall. 



Rusts are found in great profusion in all sections of the State. 

 The first collections of this group made by the writer were accumu- 

 lated in connection with an effort to obtain general material for class 

 use. The greater part of the collections have been made in connection 

 with local excursions, the primary object of which was recreation. 



' Contril)ution from the Botanical Department of Purdue University Agri- 

 cultural Experiment Station. 



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