Black- Knot of Plums and Cherries- 



645 



.? — Forms of 

 Black-Knot 



1, knots in 

 the forks of 

 branches ; 



2, at the 

 u ni o n of 

 yearly 

 g ro wt hs ; 



3, on spi4r; 



4, on large 

 wood, en- 

 t r a nee 

 ^ a t n e d 

 throng h a 

 spur. 



the spore finds 

 still deeper lodge- 

 ment. It germi- 

 nates and sends thread 

 downward, the layer of 

 cork is passed and the 

 entrance into the host plant is 

 effected. It may also be true 

 that spores succeed in entering 

 growing shoots during the summer 

 at the bases of the leaves and through 

 the crevices about the buds. Knots 

 frequently appear in places not 

 mentioned on page 640, and this may 

 be the point where their formation 

 begins. 



