388 DISEASES OF ECONOMIC PLANTS 



dies, and shrivels. The rust is conveyed from plant to 

 plant throughout the summer by spores of this stage. 



The teleutospores may appear in the same sori with the 

 uredospores or in separate sori, and in either event come 



Fig. 166. — Clover leaf showing sori of mat. Original. 



later in the season. They are recognized by their darker 

 brown color. The cluster-cup stage, which is less abun- 

 dant and less injurious than the other stages, may often 

 pass unnoticed. It appears first as pale swollen regions 

 upon the leaf or petiole. These regions soon show the 

 characteristic cups with orange-colored spores. The cluster- 

 cup stage, though not known on red clover, predominates 



