June lo, 1918 Experiments with Coccomyces spp. from Stone Fruits 551 



tion. The remoteness of the experimental plants from infected species 

 of Prunus apparently precluded, chance natural infection by ascospores, 

 while the delicate nature of the conidia of these fungi, and their methods 

 of dissemination and infection, account in large measure for the lack of 

 spread of the disease from plants of one series to those of another. 



The abundant infection which occurred on susceptible plants both in 

 the outdoor and the greenhouse series proves conclusively that the con- 

 ditions of the experiments were favorable for infection. There was, 

 however, no evidence to indicate that these conditions were such as to 

 predispose the experimental plants to infection, with the possible excep- 

 tion of some cases of infection in the greenhouse after much prolonged 

 incubation periods and after the experimental plants had become some- 

 what lowered in vitality. Under such conditions rare or difficult crosses 

 occurred more freely in the greenhouse than outside, and in several such 

 cases crosses which have not been duplicated outdoors were effected in 

 the greenhouse. Such results are interpreted in the light of these facts 

 and are suitably annotated in the tables. With these exceptions, the 

 results of the greenhouse series closely parallel those of the outdoor 

 experiments, and appear to be fully reliable. 



The results of the year's inoculations are best apprenended by a study 

 of Tables II to VIII. Each table contains a summary of all the inocula- 

 tions with strains obtained from one host. By reading down the 

 columns of the lower section, one may quickly trace the results by series, 

 while, by reading across columns, he may compare the results of all the 

 series on any species. The details regarding inoculations may be ascer- 

 tained by reference to the upper section of the table. 



Table II. — Summary of inocitlation experiments with Coccomyces spp. froin Primus 

 cerasus, Madison, Wis., iQiy 



INOCUI.ATIONS o 



o For details of techntc, see p. 545. 

 b See footnote b, Table I. 



» This strain was reisolated from P. cerasifera of series -.04. 

 * Crushed ascocarps in sterile distilled water. 



