GENERAL MORPHOLOGY OF PLANTS 



471. Cedar apples and cedar rust. "Cedar apples" are 

 galls formed on the leaves and young twigs of the cedar, through 

 the stimulus of the mycelium of one of the rust fungi. These 

 belong to the genus Gymnosporangium. In early spring, the 

 teleutospores formed in the gall the previous year, in little nests, 

 ooze out in strings in wet weather, because of the large amount of 



Fig. 278. 



Cedar apples after the spring rains begin. The mass of gelatin swollen by the rains is 

 oozing out in strings and carrying with it the teleutospores of the fungus (Gymnosporangium 

 macropus). 



gelatinous substance formed in the stalks of teleutospores, 

 which absorbs water and swells. These gelatinous strings of 

 teleutospores are yellow in color. The teleutospores germinate 

 while in the mass, and the sporidia are carried to the apple, to 

 hawthorns, and other trees where they produce the cluster-cup 

 stage known as apple rust, etc., which occurs both on the leaves 

 and fruit. 



