RUST FUNGI 



205 



species of violetsjn\\sia/ Europej'^North^and South America. It 

 autoecious. 



Fig. 74. — Witches' broom caused by Gymno- Fig. 75. — A, Protruding fili- 



sporangium Ellisii. {After Harshberger, Proc. form horns of the rust fungus, 

 Acad. Nat. Sci. Phila., May, 1902.) Gymonsporangiiim Ellisii on white 



cedar; B, teliospore. (May 27, 

 1916.) 



Mint Rust, Puccinia menthcB, is also an autoecious rust. 

 Maize Rust, Puccinia sorghi, is widely distributed in maize-growing 

 countries. Its secia are less common on various species of O.xalis. 



