PROTOBASIDIOMYCETES 425 



XXI. CEDAR APPLES AND APPLE RUST 

 Gymno sporangium macropus Lk. 



This is one of the most widespread and economically important 

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

 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 secidial stage 

 occurs on the apple (Pyrus 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 



