BULLETIN OF, THE 



No. 2i7 



Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. 

 July 20, 1915. 



(PROFESSIONAL PAPER.) 



A DISEASE OF PINES CAUSED BY CRONARTIUM 



PYRIFORME. 



By GEORGE G. HEDGCOCK, Pathologist, and WILLIAM H. LONG, Forest Pathologist) 

 Investigations in Forest Pathology. 



CONTENTS. 



History of the fungus 



Morphology of the fungus 



Synonymy and description of the fungus 



Inoculation experiments with the fungus 



Distribution of the fungus 



Distribution of the social form 



Distribution of the uredinial and telial 

 forms... 



Page. 

 1 

 2 

 3 

 5 



Dissemination of the fungus 



Effect of the fungus on its host plants 



Effect of the social form on pines 



Effect of the uredinial and telial forms on 



Comandra plants 



Eradication and control of the fungus 



Literature cited... 



Page. 

 12 

 13 

 13 



16 

 16 

 20 



HISTORY OF THE FUNGUS. 



In 1875 Peck (10) 1 described as a new species under the name Peri- 

 dermium pyriforme a caulicolous or stem-inhabiting Peridermium with 

 obovate to pyriform spores from a specimen collected by J. B. Ellis 

 (No. 2040). In 1882 Ellis issued in his North American Fungi under 

 No. 1021 a caulicolous Peridermium which he called "Peridermium 

 pyriforme on small branches of Pinus virginiana," and in the Ellis 

 Herbarium, now at the New York Botanical Garden is a specimen 

 labeled "Peridermium pyriforme on small branches of Pinus rigida, 

 Newfield, New Jersey, May, 1890." Both of these latter specimens 

 appear to be Peridermium comptoniae; at any rate, neither of them is 

 the true P. pyriforme originally described by Peck. Arthur and Kern 

 (1) in 1906 described as P. pyriforme Peck what is now known as P. 

 comptoniae. 



In 1913 the writers received from Prof. E. Bethel a caulicolous 

 species of Peridermium on Pinus contorta, which they described as a 



1 Reference is made by number to " Literature cited," p. 20. 



NOTE. This bulletin discusses an important disease of pines which is now for the first time fully de- 

 scribed. It is intended for circulation among botanists, foresters, nurserymen, State inspectors, and horti- 

 culturists. 



93041 Bull. 247 U 



437637 



