THE CHESTNUT DISEASE (ENDOTHIA PARASITICA) 371 



Other Grasses. The ascospores affect the ovaries in early summer. 

 In the ovary the mycehum develops, using the food material 

 which the ovary should have. The myceUum produces on the 

 surface of the ovary numer- 

 ous conidiophores which 

 produce conidia abundantly, 

 and the conidia are dis- 

 seminated largely by insects 

 which seek the honey dew 

 secreted by the mycehum. 

 After the tissues of the 

 ovary are destroyed, the 

 mycelium becomes trans- 

 formed into a dark, hard, 

 club-shaped body called 

 sclerotium which projects 

 from the spikelet as shown 

 in Figure S21. These 

 bodies, which are the so- 

 called Ergot, contain one or 



more alkaloids which are 



poisonous to both man and 



live stock. Stock are some- 

 times badly poisoned by 



eating Tirhothy, Red Top, 



and other kinds of hay 



where Ergot is abundant. 



The sclerotia fall to the 



ground and pass the winter. 



The next spring they de- 

 velop branches which bear 



rose-colored globular heads, 



called stromata, in which the 



asci are produced in sunken 



perithecia. 

 The Chestnut Disease (Endothia parasitica). — ^This disease 



was introduced from Asia and appeared in New York about 



1904. It is very destructive to Chestnut trees, and the estimated 



loss in New York City and vicinity is more than $5,000,000. 



For the entire United States, the financial loss up to 1911 was 



Fig. 321. — The Ergot Fungus, Clavi- 

 ceps purpurea, a, head of Rye, showmg 

 projecting sclerotia; b, a sclerotium which 

 has developed stalks bearing globular 

 heads in which the perithecia occur ( X 3) ; 

 c, section through one of the globular 

 heads, showing the perithecia (X 15); d, 

 ascus highly magnified, showing the 

 spindle-shaped ascospores; e, hj^pha and 

 conidia which develop on the surface of 

 the grain in the early stage of infection. 

 From Tulasne and Brefeld. 



