14 



CRGANISi:. 



The fundus spores used in this research were of the 

 gloeosporium or conidial stage of Giornerella cingulata 

 (Stonem) S. and v. S., the fungue causing the disease of 

 the apple known as "bitter rot". The fungus is parasitic 

 not only upon the apple but according to Shear and Wood 

 it is also the cause of disease on other plants. Cn the 

 apple fruit it produces brown sunken areas usually nearly 

 circular in shape which may be covered with the fruiting 

 bodies of the fungus, the conidia being borne in acervuli. 

 In mass the spores appear orange colored but have a hyaline 

 appearance under the microscope. They are usually ovate or 

 oblong in shape and are 12-16 x 4-6 in diameter. Shear 

 and lood have shown that certain strains of this fungus 

 may, when grown on the proper artificial media, produce 

 conidia for generation after generation, witnout the in- 

 terpolation of the ascogenous form at any time. Cultures of 

 such a strain were secured from Dr. Shear for these 

 experiments, and throughout the investigation, which 

 lasted about eighteen months, conidia only were produced, 

 though some forty or more generations must have passed. 



Corn meal agar was used as a medium for the stock 

 cultures. This was prepared by adding 4 teaspoonsful of 

 white corn meal to one litre of distilled water, which 

 was allowed to stand at about 58°C for one hour. After 

 11. Shear, C. L. , and V/ood, Anna K. , Studies of fungus 

 parasites belonging to the genus Glomerella. U. S. Dept. 

 of Agr. Eur. of Plant Ind. Bull. 252. 



