IOWA ACADEMY OF SCIENCE 29 



several publications.^^ Tubeuf^'' refers to the injury of the fungus 

 in Great Britain on the English walnut. Massee also refers to it and 

 describes the character of the fungus. Klebahn-" not only refers to 

 injurious nature of the fungus in Germany but gives an account of 

 the life history as worked out from cultures and in the field. Lindau-^ 

 also discusses the disease, adding, "Most of the species produce dis- 

 eases hardly worth mentioning except the 31. Panattoniana on head 

 lettuce." The imperfect fungus was described by Madam Libert as 

 LeptotJiyrium Juglandis. Subsequently Saccardo-- placed it in the 

 genus Marsonia. ]\Iagnus-' called attention to the prior use of the 

 name IMarsonia for one of the flowering plants and hence cannot be 

 used. He therefore suggested that the genus be changed to Marsonina. 

 The cultural work of Klebahn demonstrated the connection of this 

 fungus with Gnomonia leptostyla (Fr.) Ces. and de Not. the ascigerous 

 form. This stage of the fungus was found on dead leaves of Juglans 

 regia in the spring. A connection with this fungus had previously 

 been suggested by Frank.-*. Winter-^ and Krieger-" suggested the 

 same conection without, hovrever, furnishing the proof. 



Characters of the Fungus 



The fungus causes brownish spots which at first are circumscribed 

 but later the spots may become confluent, the leaves turning yellow, 

 and falling. The spots contain on their lower surface small blackish 

 brown pustules appearing above the surface of the leaf. These are 

 formed by the pushing up of the stroma and the spores, the latter are 

 borne on short conidiophores. The mycelium develops between the 

 cuticle and the wall of the epidermis. Finally by the continued forma- 

 tion of the stromatic cells it is pushed up and ruptured. The mj^celium 

 is light colored, septate and branched. It secretes a ferment which 

 destroys the tissues and produces the brownish or blackish color of 

 the leaf. The eonidia are colorless, short, straight or somewhat sickle- 

 shaped, 14-26^x2x3^, usually two celled. 



Klebahn describes a second kind of spore found in these pustules. 

 It is colorless, straight or nearly so and rod-like, 6x12mx 



"Contr. Bot. Dept. 41:22. Proc. la. Acad. Sci. ]6:62. .lour. Myc. 7:103. 



"Diseases of Plants. 491. 



-"Zeitschrift fur Pflanzenkrankheiten. 11:22?,. PI. 8 and f. 1. 2. 



='Sorauer Pflanzenkrankheiten. 429. 



"Marsonia Juglandis (Lib.) Sacc. P. ital. t. 1095. 



"'Hedwigia. 4.5:88. 



"Die Krankheiten der Pflanzen. (Ed. 2) 453. 



==^Die Pilze. 2:580. 



■"Schadliche Pilze unserer Kulturgewachse. No. 87. 



