CULTURES OF GUIGNARDIA VACCINII. l7 



Ascogenous form. — Cultures produciii*; both pycnidia and asci have 

 been obtained in five cases by transphmting the fMn<2:ous hypha? from 

 diseased berries, and in three cases from affected leaves, to culture 

 media. 



The first successful culture was made from decayin*; fruit obtained 

 in the Washin<i:ton marloet. The source of the fruit is unknown, but 

 it was probably from New Jersey. The culture was made on March 

 31, 1002. The berries used were softened ; the skin was light colored 

 and watery and showed small dark-colored blotches of funo^ous 

 hyphcT on the inner surface. Two cultures were made from one of 

 these berries by transferring portions of the pulp containing the 

 hypha* to flasks of cranberry agar and corn meal. The cultures were 

 kept in the laboratory at the ordinary temperature, which varied 

 from 10 to 25° C. The course of development and appearance of 

 the fungus were the same as in the cultures pi-oducing pycnospores 

 only, as previously described. Mature pycnidia were produced in 

 about twelve to fifteen days, and at the end of twenty-two days a great 

 abundance of ascogenous perithecia was found. There is nothing 

 in the macroscopic appearance of a culture bearing ascogenous 

 perithecia to distinguish it from one bearing only pycnidia. The 

 ascogenous perithecia are practically identical in appearance with the 

 pycnidia. In mature and old cultures the color of the mycelium 

 becomes dark brown, or almost black, and the pycnidia or perithecia 

 become more exposed on the surface of the subiculum or crustlike 

 stroma. 



The second successful culture of the ascogenous form was made 

 January 20, 1903, by transferring a portion of the skin of a diseased 

 berry showing darkened spots to a flask of water-saturated, autoclaved 

 corn meal. The course of development was the same as in the culture 

 just described. Many bodies resembling pycnidia Avere produced at 

 first, but all examined were apparently sterile. Later, in addition 

 to these sterile bodies, ascogenous perithecia of Guignardia were 

 found. 



The third successful culture of ascogenous perithecia was made 

 December 23, 1903, from diseased New" Jersey berries, which had 

 been kept in ordinary storage in an unheated building in the Depart- 

 ment. These berries showed the ordinary appearance of scalded 

 fruit, and the cultures were made by transferring sections of diseased 

 berries which had been washed and soaked in a solution of corrosive 

 sublimate to flasks of sterilized corn meal. An abundance of fertile 

 pycnidia w^as produced, and at the end of nineteen days perithecia 

 containing mature asci were found. 



The fourth successful culture was also made at the same time as 

 the last mentioned, and from fruit from the same source, treated in 

 the same manner. 



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