102 University of California Publications in Botany t v L - 7 



In 1882 Mr. E. W. D. Holway began work on the rust flora of 

 California by an extended exploration of King's River Canon and 

 vicinity, which brought to light a large number of species, some of 

 which were published as new by Dietel and Holway, especially in 

 Erythea and Hedivigia. With the aid of Mr. Holway this work was 

 continued by the writer, and collections were made in the region about 

 San Francisco Bay (1893 and later), Shasta and Siskyou counties 

 (1894), Tuolumne and Calaveras counties (1895), Lake Tahoe (1897), 

 and Mendocino and Humboldt counties (1896 and 1899). Contempo- 

 raneously and in the succeeding years a large number of collectors 

 did work in other regions. Of these especial mention should be made 

 of A. J. McClatchie (Pasadena), S. B. Parish (San Bernardino), 

 J. Burtt Davy (Berkeley), W. R. Dudley, and C. H. Thompson (Stan- 

 ford University). In more recent years extensive collections have 

 been made by Ellsworth Bethel, Carl T. Baker, David Griffiths, E. E. 

 Heller, Dr. Meinicke of the Federal Forest Service, and Professor 

 Home of the Agricultural Experiment Station of the University of 

 California. 



II. THE NEED OF EXPERIMENTAL CULTURE WORK 



Although much more extended collections and critical studies in 

 both field and laboratory must be made before our knowledge of the 

 California representatives of this group of fungi can be considered 

 either exact or complete, it is believed that an attempt to summarize 

 the information now available will be of assistance to those working 

 on the rust flora of the state and will give at least an approximate 

 idea of its extent and content. The need of systematic culture experi- 

 ments designed to establish with certainty the life histories of those 

 species which are known to be heteroecious is a pressing one. The 

 results obtained in other regions of the United States, especially 

 by Arthur and his collaborators at Purdue University, suggest 

 the species of host plants probably concerned in the life histories of 

 many of the Pacific Coast species; but the differences in the climatic 

 conditions of the two regions and of the species of host plants found 

 in them make it extremely desirable to confirm these suggestions by 

 actual experiments. It is to be regretted that owing largely to the 

 lack of such data it has been found necessary to include in the list 

 here presented a considerable number of form species, that is, aecial 

 and uredineal forms not definitely correlated with the mature forms 



