258 Glomerclla ciiigulat.i and its Conidial Forjiis 



loss of the conidia bearing faculty was ultimately complete and transfers 

 on sterilized chilli stems gave only sterile aerial growth. But in the cultures 

 made from the perithecial strain of Gloeosporium piperatum incredibly 

 large and very often sudden variations have been obtained as will be 

 seen from the account given below. Such large variations have been 

 observed by Edgerton^ as well in cultures of Glomerella causing the bitter 

 rot of apples. These variations consist of the absence or presence of 

 perithecia, absence or presence of acervuli, absence or presence of setae 

 and development of aerial hyphae or of hyphae matter and confined to 

 the substance of the medium. 



In subcultures on sterilized chilli stems and maize-meal-agar from the 

 original sterile culture, which we have called A on page 253, acervuli with- 

 out setae and perithecia were freely formed, and subcultures on glucose- 

 meat-extract-agar from these perithecia bearing cultures also gave the 

 perfect form in addition to the Gloeosporium form. But in subcultures 

 on glucose-meat-extract-agar direct from the sterile culture A the growth 

 was sterile and confined to the surface. On the 30th of April and 2nd of 

 May, 1917, two subcultures, GICj and GlCg, were made on glucose-meat- 

 extract-agar from the original sterile culture A of December 1916. The 

 first sudden variation or mutation was obtained in these subcultures. The 

 growth in both was similar to each other but was radically different 

 from that of the parent culture. In these cultures a black stroma was 

 produced in which were formed acervuli with and without setae. No 

 perithecia were produced. From GIC^ a subculture, GIC3, was made on 

 the same medium on 7th May, 1917, and it was similar to its immediate 

 parent. These three series were kept going for a long time. They showed 

 remarkable variations from time to time. For the first two or three 

 months they continued to produce the conidial form, but they lost this 

 as suddenly as they gained it, and it was replaced by the perithecial stage. 

 GIC'i continued to produce perithecia on glucose-meat-extract-agar 

 till March 1918. In a subculture made on the same medium on the 16th 

 of that month a culture two months old only acervuli with and without 

 setae were formed and not |)erithecia. In the subsequent three or four 

 subcultures the conidia continued to be formed but this stage was sud- 

 denly lost in the subcultiiii' made in the end of April. The fungus in this 

 subcultiiie was stoiilc but tlic growth was not similar to the original 

 sterile culture A, but was similar to the sterile culture of Glceosporiinti 

 piperatum. The aerial growth was moderate and covered a black or 



' Edgerton, (.'. W. Physiology and Dovelopnicni of .some AnMuacncsos. Hot. (laz., 

 XLV, p. 395, 1908. 



