BULLETIN OF THE 



PAMNTOFAfflll 



No. 247 



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

 July 20, 1915. 



(PROFESSIONAL PAPER.) 



A DISEASE OF PINES CAUSED BY CRONARTIUM 



By George G. Hedgcock, Pathologist, and William H. Long, Forest Pathologist, 

 Investigations in Forest Pathology. 



CONTENTS. 



History of the fungus 1 



Morphology of the fungus 2 



Synonymy and description of the fungus 3 



Inoculation experiments with the fungus 5 



Distribution of the fungus 8 



Distribution of the fecial form 8 



Distribution of the uredinial and telial 



forms 9 



Dissemination of the fungus 12 



Effect of the fungus on its host plants 13 



Effect of the ai-cial form on pines 13 



Effect of the uredinial and telial forms on 



Comandra plants 16 



Eradication and control of the fungus 16 



Literature cited 20 



HISTORY OF THE FUNGUS. 



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

 dermiwn 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 



i 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—15 1 



