240 FARM FRIENDS AND FARM FOES 



fruits. It is seldom seriously destructive. The only spore- 

 forms known are the summer spores and the teleutospores, 

 both being of the brown color so general in the rusts. 



During the last quarter of the nineteenth century the 

 Hollyhock Rust was very destructive in the United States. 

 It is still a pest, but less so than formerly when it caused 

 the culture of hollyhocks to be almost abandoned. There 

 is good reason to hope that resistant strains of Hollyhocks 

 will soon be developed. 



The Hollyhock Rust appears . as brownish pustules on 

 the under surface of the leaves. These contain an abun- 

 dance of two-celled teleutospores, and it is an interesting 

 fact that in this form of rust fungus this seems to be the 

 only form of spore that occurs. The teleutospores are 

 also remarkable for their ability to germinate at once instead 

 of resting through the winter as do most of the teleutospores. 

 Consequently, in this case the teleutospores are both sum- 

 mer spores and winter spores. The gathering and burning 

 of affected leaves is a helpful remedial measure. 



OBSERVATIONS FOR PUPILS 

 RUSTS 



1 . Which of the following rusts do you find in your neighborhood ? 



Apple Rust Hollyhock Rust 



Asparagus Rust Oat Crown Rust 



Bean Rust Plum Rust 



Beet Rust Raspberry Rust 



Clover Rust Wheat Leaf Rust 



Corn Rust Wheat Stem Rust 



2. Set aside a page of your booklet for three of the most important 

 of these rusts, and write a brief account of your observations upon each. 



