UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 1053 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



May, 1922 



STUDIES OF CERTAIN FUNGI OF 

 ECONOMIC IMPORTANCE IN THE 

 DECAY OF BUILDING TIMBERS 



« 



WITH SPECIAL REFERENCE TO THE FACTORS 



WHICH FAVOR THEIR DEVELOPMENT 



AND DISSEMINATION 



By 



WALTER H. SNELL, Forest Pathologist 

 Office of Investigations in Forest Pathology 



CONTENTS 



Page 



Introduction 1 



Basidiospores 4 



Mycelium 19 



Secondary Spores 26 



Occurrence of the Secondary Spores in 



Cultures of the Fungi Studied 30 



Germination Studies of the Secondary 



Spores 32 



Page 

 Experiments upon the Dissemination of 



the Oidia of Lenzites seplaria ..... 36 

 Occurrence in Buildings of the Secondary 



Spores of the Fungi Studied 38 



Summary 38 



Literature Cited : 42 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1922 



