82 



Journal of Agricultural Research 



Vol. III. No. I 



characteristic of the genus Macrophoma (fig. i, D). At the same date 

 an immature ascomycete was observed on material which had been 

 allowed to remain on the ground. The final collection on November 3 

 showed an ascomycetous fungus present in large amounts on the hemp 

 which had been spread for dewretting, while the two other spore forms 

 were absent, or present only in negligible amounts, having matured before 

 the development of the ascospores. The asci were borne in perithecia 

 similar in appearance to the pycnidia of the two other forms (fig. 1, B). 



Fig. I. — ^Microscopic characters of the hemp fungus Boiryosphaeria marconii. A, Sketch of a section of 

 stroma from culture, showing developing perithecia: a. microconidial stage, b, ascosporic stage, X 840. B. 

 An ascus with ascospores, X 840. C, Ascospores, X 840. D, Macroconidia. X 840. E, Conidiophores of 

 the Dendrophoma stage, X 1920. F, Microconidia. X i9?o. (Drawing by J. Marion Shull.) 



The spores were hyaline to slightly colored, nonseptate, and fusoid 

 (fig. I, C). A probable connection between these three forms suggested 

 itself to the authors, and cultures were started to prove, if possible, that 

 these stages are different phases in the life history of one fungus. The 

 spores of the Dendrophoma form are designated as microconidia and 

 those of the Macrophoma stage as macroconidia. 



Cultures were made on various media, but as the fungus developed 

 luxuriantly and rapidly upon corn meal, that medium was adopted for 



