8 



as if scorched by fire, having a dry and withered appearance and 

 being of a reddish brown color. The fungus consists as usual of 

 numerous fine filaments which grow through the tissue of the plant 

 just beneath the surface, robbing it of its nourishment and thus 

 interfering with its vital processes. Upon the surface appear 

 numerous little blisters which soon burst open and discharge a red- 

 dish brown powdery substance, consisting of the red or uredospores 

 of the fungus. Those spores fly off as a cloud of .fine dust when 

 badly rustedfplants are disturbed. They are carried in enormous 

 quantities to all neighboring plants where they germinate and spread 

 the disease. 



THE FALL OR BLACK RUST STAGE. (TELEUTO.) 



The third form of the rust appears in September and October on 

 plants which have survived thus far. It is characterized by the 

 appearance of small black excrescences upon the surface of the 

 affected plants, which are clusters of the spores of this stage. 

 These spores are very thick walled and thus suited to their function 

 of surviving over^^winter. They remain dormant until spring when 

 they proceed to germinate and reproduce the disease, now in the 

 spring stage. 



While this is the normal course of development of this fungus it 

 is by no means certain that it is confined to such a course, and in 

 fact circumstances seem to indicate that it is not. In the case of 

 the closely related wheat rust, Puccinia graminis Pers., we know 

 that it is able to pass the winter and reproduce itself again in the 

 spring in at least four different ways, viz. : 1st, by the regular 

 process of teleutospores lying over winter and producing aecidia in 

 the spring ; 2nd, by uredospores which survive the winter and pro- 

 duce the summer and fall forms in the succeeding season ; 3rd, by 

 teleutospores producing the summer stage directly without the inter- 

 vention of the spring form ; and 4th, by the fungus itself remaining 

 alive in the tissues of plants and proceeding into growth again the 

 next season. That the asparagus rust is able to reproduce itself 

 from year to year in some or all of these ways in addition to its reg- 

 ular course of development seems extremely probable in view of the 

 history of its occurrence in this State. We have, as already men- 

 tioned, never observed the spring form, and, while it may occur, we 

 believe it to be extremely rare. The red rust form, as elsewhere 



