6 



Sometimes, and this seemed especially true when the fruit 

 experimented upon was a little unripe, the initial stages would be 

 tardy, and for some time the diseased area would increase but slowly 

 in size, assuming a darkish colour. On such occasions the pustules 

 would be slow in appearing, and would be few and scattered, the 

 first appearance of each being marked by a minute jet-black shiny 

 point. If, after some days, 

 this black body was re- 

 moved, it was found to be a 

 well-formed perithecium, 

 lens-shaped, and having a 

 dark wall. These particular 

 fruits of the fungus growth 

 were usually slow in ripen- 

 ing spores, and not infre- 

 quently they were out- 

 stripped by the spore- 

 producing portions more 

 remote from the point of inoculation. 



Fig. 5. Section of a ripe-rot pustule of Apple. 



Thus after a time the progress 



of the disease seemed to become swifter, the invaded tissue appearing 

 to become more watery and the pustules larger and very much nearer 

 together and lighter in colour. The black 

 pustules were ofttimes wholly absent from these 

 later stages. 



As it has been the custom in the past to regard 

 as separate forms worthy of distinct names so- 

 called specific names G-loeosporia that varied 

 from each other in certain features of form, 

 size, and colour, it is well worth while, now that 

 we* know what a wide range of substratum is 

 suitable for the growth of these fungi, to inquire 

 to what extent the same form may vary when 

 grown on a variety of hosts. 



The discussion may best turn largely on 

 the spores, because it is largely upon these 



relied for 

 species of 



have 

 their 



X700' 



that naturalists in the past 

 data in the establishment of 

 Gloeosporium. 



As to form, it has become very evident in the 

 course of these experiments that it is quite 

 variable, and that the variations are due to a 

 considerable extent to the resistance the fungus 

 meets in breaking through the epidermis of the 

 host. In all cases where the skin of the host 

 plant offered decided resistance to rupture, as 



evidenced, for instance, by tardiness in the appearance of loose spores, 

 there was a marked irregularity of form. The spores would be bent 

 instead of straight, clavate instead of uniform in diameter from end 

 to end, or perhaps somewhat dumb-bell-shaped instead of cylindroid. 

 In addition to this, the various spores would vary from each other in 



Fig. 6. Ripe-rot spores 

 on hyphae. 



