PROTOBASIDIOMYCETES 



425 



XXI. CEDAR APPLES AND APPLE RUST 



Gymnosporangium macropus Lk. 



This is one of the most widespread and economically important 

 of this genus. It produces the large cedar apples on Junipenis 

 virginiana (Fig. 207). This fungus occurs practically throughout 



Fig. 207. Gymnosporangium macropus: Cedar Apple 



the range of the red cedar and its other hosts. The aecidial stage 

 occurs on the apple (Pyrns Mains) and also on Pyrus coronaria, 

 and was originally described as Rcestelia Pyrata (Schw.) Thaxter. 

 On the leaves some injury is done to these plants when the 



