summer 



1908] EDGERTON—ANTHRACNOSES 391 



The composition or density of the substratum or the humidity 

 seems to have but little influence in the production of this stage. How- 

 ever, the interesting fact was noted that, with but few exceptions, 

 all the forms known to have perfect stages are southern or greenhouse 

 forms. Almost everything affected with anthracnose when brought 

 from the greenhouse and placed in a moist chamber produced peri- 

 thecia. Apples from ]\Iissouri and southern Illinois produced this 

 stage; but apples, tomatoes, fruit of Podophyllum peUatmn, and 

 various other fruits and stems found out of doors in New York and 

 brought into the laboratory, produced conidia in abundance but no 



^ — - ^w ^ m -^ ^ 



perithecia. The form from quince from Ithaca, 

 perithecia, but only after it had been grown in the laboratory for 

 more than a year. Perithecia were also developed on Asdepias 

 syriaca from Ithaca, but this form was found late in the fall, after a 



It may be that a long-continued 



production of the conidial stage or a long-continued growth at a 

 rather high temperature are factors in perithecial development. 

 However this may be, it is certain that the ability to produce peri 

 thecia may be acquired or lost by the fungus. Sub-cultures have 

 been made from single conidia from a culture in which perithecia 

 were produced in abundance. Some of these would produce the 

 perfect stage, while by no treatment known could others be made to 

 produce it. However, as a general rule, it is an easy matter to ob- 

 tain perithecia in sub-cultures from a culture that has already pro- 

 duced them. To me it appears as if in this group the ability to develop 

 perithecia is one of the characters that may be acquired if conditions 

 are right, one that is inherited for some time but will be lost eventually 

 if the environment is not suitable. When it is known that these 

 forms vary in other ways, as described later, this seems all the more 

 plausible. 



CULTURAL CHARACTERS 



There has always been great difficulty in determining the species 

 in this type. As a result many species have been determined by the 

 host. Recently botanists have been questioning the vahdity of the 

 method, especially since the perfect stages of several have been found 

 to be very much aUke. At present Shear and Wood (40) take the 

 extreme ground that aU whose perfect stage has been found repre 



