PLU^r POCKETS 



61 



are the ones most often attacked, but all kinds are liable 

 to injury ; and the fungus is occasionally found upon 

 wild cherries. 



The m3Telium of this fungus consists of numerous 

 colorless threads which ramify through the tissues of 

 the young fruit. A special development of these threads 

 occurs just beneath the outer skin (cuticle), and from 

 this thereare sent upward numbers of short cylindrical 

 bodies (Fig. 31 a), which finally burst through the skin 

 and grow till quite long, as seen at b, being filled with a 



rm%^ 



a 



FIG. 31. PLUM POCKET FUNGUS. MAGNIFIED. 



granular matter. Then a transverse partition is j)ro- 

 duced a short distance from the upper end, and the 

 granular matter gathers itself together in six or eight 

 little spores [c). These spores finally escape from the 

 cell in which they are held, and, under favorable condi- 

 tions, germinate. In so doing each of the spores pro- 

 duces on one side a bud having a shape similar to the 

 spore itself; this bud produces another bud, and this 

 another, until the substance of the original spore is 

 exhausted. But botanists have not yet been able to 

 infect healthy plums with these spores or their buds. 



