juneio, I9I8 Experiments with Coccomyces sp p. from Stone Fruits 561 



however, do not necessarily prove that inocula are ineffective, as is 

 attested by the results of the second inoculation of series 4. 



P. virginiana (PI. 59, E), P. padus, and P. mahaleb (except in series 

 121) were consistently infected. P. mahaleb, however, was uniformly 

 less severely diseased than the other species named. P. domestica and 

 P. insititia were frequently infected, usually after prolonged incubation. 

 On August 3 several leaves of P. cerasus of series iii bore scattered 

 brown spots on which occurred numerous aggregated acervuli of a 

 species of Cylindrosporium. It is uncertain whether this was the result 

 of chance infection or of delayed infection. The fact that no infection 

 occurred on the extensive control system makes the possibility of chance 

 infection remote. However, the fact that 10 other inoculations of 

 P. cerasus with strains from P. virginiana gave uniformly negative 

 results is a strong argument against fully accepting this result as positive. 

 Furthermore, the fungus when isolated possessed the cultural characters 

 typical of strains from P. cerasus, which were very different from those 

 from P. virginiana. Further experiments will be necessary before con- 

 clusions regarding this cross are justifiable. Meanwhile this apparently 

 aberrant result is not included in the summary (Table IX). No other 

 infection was observed. 



Table VIII. — Summary of inoculation experiments with Coccomyces spp.from Pruntis 

 serotina, Madison, Wis., igiy 



INOCULATIONS « 



a See footnote a. Table II. 



b See footnote b, Table I. 



ft See discussion, p. 563. 



»■ Crushed as cocarps in sterile distilled water. 



