CARTER: ILLINOIS TREES: THEIR DISEASES 



61 



Fig. 56. — The gall of the cedar-hawthorn rust has orange-colored, 

 tonguelike, gelatinous spore-horns. 



Fig. 57. — Cedar-hawthorn rust produces yellow- to orange-colored, de- 

 pressed spots on the upper surface of a hawthorn leaf (left), and raised, 

 orange to brown spots, covered with short hairlike appendages, on the under 

 surface (right). 



Cedar-Quince Rust.— This fungus disease is caused by Gyni- 

 nosporangium clavipes. It occurs on Jiiniperus communis, J. sibi- 

 rica, and /. virginiana. It produces swollen, elongated, spindle- 

 shaped swellings or galls on branches of juniper. The fungus is 

 perennial in these galls, which enlarge each year. It may be ac- 

 tive and produce spores annually for as long as 20 years. A stem 



