140 



Mycologia 



1920, on decaying leaves of host plants cut earlier in the season. 

 On such old leaves sporodochia are apt to be overlooked because 

 of their very minute size. In some cases none is present though 

 the pycnidia are very abundant. 



There appear to be no morphological differences between the 

 strains of the conidial form found in nature on fruits of species 

 of Fragaria and Rubus. Many cross-inoculation experiments 

 from one to the other have shown conclusively that the fungus 

 can be readily transferred from the fruit of one of these hosts to 

 the other. 



Strains from dead spots on living leaves of Fragaria, Rubus, 

 Oenothera, Acer, Epilobium, Cornus, Smilax, five species of 

 Rhus and dead leaves of Vitis, and from the fruits of Fragaria 

 and several species of Rubus show practically identical characters 

 in culture. 



The pyenidium is frequently one millimeter in diameter and as 

 the wall is thick and composed of thick-walled cells it can be 

 easily handled and thoroughly sterilized before being crushed out 

 to obtain spores for cultures. When plated out and grown on 

 the ordinary culture media sporodochia in no way distinguish- 

 able from those of Hainesia appear on the surface of the medium 

 in three or four days. Such cultures have been isolated many 

 times from the dark, heavy- walled pyenidial form on dewberry, 

 strawberry, sumac, evening primrose, and other hosts and there 

 can be no question of their being the pyenidial form of the same 

 fungus that first appears as sporodochia of the Hainesia type. 



The various agar media upon which the fungus has been grown 

 do not appear to be favorable for the development of the pyc- 

 nidia although they are occasionally produced in agar. The 

 fungus grows well on the cut surface of apples and produces 

 sporodochia, some of which resemble a broadly ostiolate pyeni- 

 dium (pi. 8, fig. 6). 



Strains of the Hainesia form isolated from a number of dif- 

 ferent hosts were grown on sterilized stems and leaves of black- 

 berry in large test tubes. These cultures produced vast numbers 

 of sporodochia within a week or two and then began to produce 

 large, brown pycnidia of the Sclcrotiopsis type. 



