Vol. 33 



BULLETIN 



No 8 



OF THE 



TORREY BOTANICAL CLUB 



AUGUST, 1906 



North American species of Peridermium* 



Joseph Charles Arthur and Frank Dunn Kern 



No descriptive account of the species of Peridermium found in 

 North America has ever been published. The species have been 

 listed by Farlow and Seymour in their Index issued fifteen years 

 ago, f and again within the year. % The pine-inhabiting forms 

 were the subject of a paper before this association in 1896 by Un- 

 derwood and Earle, § in which the forms of the eastern United 

 States were described under three species, and three other species, 

 not described, were said to occur in western North America. No 

 other general survey of this part of the North American flora is at 

 present available in any form. 



There has been, and still is, great uncertainty regarding the 

 number of valid species. The study and comparison of these spe- 

 cies is rendered very difficult owing to the absence of detailed de- 

 scriptions and figures, the original descriptions especially contain- 

 ing few diagnostic characters. There are also inherent difficulties 

 due to the slight morphological differences between some of the 



g 



species, and, furthermore, a full understanding of the subject can- 

 not be expected until the microscopic examination is liberally sup- 

 plemented by cultures. Although there has been no mono- 



*Read before the Botanical Section of the American Association for the Advance- 

 ment of Science, New Orleans meeting, January I, 1906. 



t Farlow, W. G., & Seymour, A. B. A provisional host index of the fungi of 

 the United States. Part 3. 1891. 



J Farlow, W. G. Bibliographical index of North American fungi. Vol. I, 

 Part 1. 1905, 



§ Underwood, L. M., & Earle, F. S. Notes on the pine-inhabiting species of 

 Peridermium. Bull. Torrey Club 23 : 400-405. 1896. 



[ The Bulletin for July 1906 (33 : 367-402) was issued 1 Au 1906.] 



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