90 



State Horticultural Society. 



such a spore sprouts on an apple, the threads grow into the cells of 

 the skin. The}- give oft" a peculiar substance, called a ferment, which 



dissolved the starch grains of the ap- 

 ple ; (these in the ripe fruit completely 

 fill the cells). In figure 3 you see some 

 starch grains from a health}- apple 

 and in figure 4 similar starch grains 

 after the bitter rot fungus has dis- 

 solved away most of the starch. The 

 threads attack the sugar in the cells, 

 likewise the cell walls. These cells 

 are at first united into one mass, but 

 ver}^ soon after the fungus has begun 

 to grow in them the cells fall apart. 

 They have turned brown by this time. 

 You will now readily understand why 

 it is that the little spot where the 

 fungus started looks brown, and why 

 the flesh underneath is mushy and 

 soft. All the starch and sugar has disappeared and this has left the 

 cells empty. The starch and sugar serve as food for the fungus 

 and cause it to giow more rapidly. Starting from a center 

 the threads radiate out as described, and that explains why we find 

 the black rotted spots increasing in such a very regular circular man- 

 ner. 



AMien the spot is as large as a five cent piece, enough starch and 

 sugar has been absorbed to allow of the formation of fruiting bodies. 

 Certain of the threads near the point where growth began form dense, 

 black masses, which consist of hollow 

 more or less flask shaped bodies. In 

 their interior, the spores are formed, 

 growing on short stalks. During the 

 night Avhen it is moist, these spores flow 

 out thiough the openings of the little 

 flasks, and there we see them the next 

 morning as glistening drops. Such is 

 the manner in which the fungus grows. 

 Xow, wdiat is it that happens 

 after this? Rain or dew may wash 

 thousands of these spores from one diseased fruit to another, and that 

 may account for the many infections. The spores may also spread 

 tlirousfh the air and thus affect otherwise sound fruits. We have 



^/y- ^ 



