JACKSON: UREDIXALES OF OREGON 201 



betically under each family and the species similarly under the genus. 

 The host plants are also arranged alphabetically under each species. 



No attempt has been made to give a full list of synonyms. In 

 general, however, sufficient synonymy is given to show the origin of 

 the specific name used as well as any names which have been in general 

 use. For convenience of reference the specific nomenclature used is 

 that in use in this laboratory, and in general conforms to that used in 

 the "North American Flora." For similar reasons the generic nomen- 

 clature follows that proposed by Dr. Arthur, for use in the "North 

 American Flora," except that Melampsora, Puccinia and Uromyces, 

 are retained. In order to follow this system consistently it has been 

 found necessary to establish a number of new combinations. 



Under each host is given a list of the specimens examined, with 

 locality, county, date and collector, followed by the collector's number. 

 Numbers between looo and 3450 refer to collections in the Oregon 

 Agricultural College Herbarium, if made by members of the botanical 

 staff or by students. If no collector is given it may generally be 

 assumed that the collection was made by the writer. In order to 

 prevent unnecessary repetition, Benton County is not cited following 

 collections made at Corvallis and Philomath. Similarly Hood River 

 County is implied for all collections from Hood River or Mt. Hood 

 and all collections made at Portland are from Multnomah County. 



The writer is under great obligations to all those who have contrib- 

 uted specimens for study and especially to those whose names have 

 been mentioned previously. He is also greatly indebted to those 

 botanists who have given so generously of their time in determining 

 host plants. Dr. A. S. Hitchcock and Mrs. Agnes Chase have named 

 most of the grasses. Dr. Theo. Holm and Dr. K. K. Mackenzie 

 have each determined a considerable number of species of Carex. 

 Dr. C. R. Ball has named most of the willows. Dr. F. V. Coville and 

 Dr. K. M. Wiegand have each determined several specimens of Jiincus. 

 Mr. Paul Standley has determined a large number of specimens from 

 miscellaneous families. 



Dr. J. C. Arthur and his former associates very kindly determined 

 a considerable number of specimens of the rusts occurring on grasses 

 and sedges, and verified the determinations of others, which the writer 

 sent from Oregon at various times during the period when the col- 

 lections were being made. The greater part of the collections recorded, 

 however, have been worked over since the writer took charge of the 

 work of this laboratory. During this period it has been his privilege 

 to be able to consult freely with Dr. Arthur and to have the unre- 

 stricted use of the collections, catalogues, and manuscript notes on 

 the rusts, which have been accumulated at the Purdue University 



