STUDIES OF GLOMERELLA FROM DIFFERENT HOSTS. 41 



medium. The color in these cultures never became quite so pro- 

 nounced as in some others. 



On January 6 six tube cultures were made by transfer of conidia 

 from a single acervulus in one of the single-spore cultures just 

 described. Three were on prune agar and three on a synthetic 

 medium. The cultures on prune agar made rapid growth, produced 

 an abundance of acervuli, and the medium became a decided pink 

 color. No perithecia or peritheciumlike bodies ever appeared in any 

 of these cultures. The constant white or grayish color of the myce- 

 lium, the chromogenic character of the fungus, and the variation in 

 the conidia suggested very strongly the possibility that we were 

 dealing with an organism different from the common bitter-rot fungus 

 of the apple. The conidia were very variable in size. Those which 

 were scattered were rather smaller than usual, and those borne in the 

 acervuli were large and more uniformly pointed at the ends. As no 

 perithecial form was found on the fruit from which the cultures were 

 obtained nor in any of the cultures, it is possible that this may repre- 

 sent a distinct species or variety. 



EUROPEAN FORM, 



Schneider-Orelli (69) has recently reported the results of compara- 

 tive studies of the conidial stage of Glomerella cingulata sent from 

 Virginia and Gloeosporiumfructiginum Berk, found on apples in Switzer- 

 land. He finds very little difference in the morphological characters 

 of the American and European forms. A comparison of their 

 physiological characteristics showed a difference of 5 degrees centi- 

 grade for minimum, maximum, and optimum growth. The minimum 

 temperature at which growth occurred in the European material was 

 5°, the optimum temperature 23°, and the maximum temperature 27° 

 C, while the minimum, optimum, and maximum for the American ma- 

 terial was found to be 5 degrees higher, or 10°, 27°, and 32° C, respec- 

 tively. Whether this difference would hold good with other races and 

 strains from the two countries is a question. The writers have car- 

 ried out no such comparative studies but have reason to suspect that 

 further work in this direction might show that this physiological char- 

 acter is also variable in both the American and European forms. Little 

 difference was found in the production of rot caused in stored apples 

 when inoculated with the two forms. According to the writer just 

 cited, as well as other European pathologists, the bitter-rot fungus is 

 not common in Europe and where present causes very little loss. It 

 seems probable that this is due, in great part at least, to the less 

 favorable climatic conditions prevailing in parts of Europe where 

 apples are mostly grown, the low average maximum summer tem- 

 perature being perhaps the chief factor as compared with the average 

 summer temperatures in the parts of the United States where the dis- 



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