Ornamental Plants 425 



HYDRANGEA 



Leaf-spot (Phyllosticta hydrangece E. & E.). — Large, 

 rusty, brown blotches occur upon the leaves, in some 

 cases to such extent that the tops of the plants must 

 be cut away, to the entire destruction of their decorative 

 value. 



Rust (Pucciniastrum. hydrangece (B. & C.) Arth.) is common 

 and often serious. 



Leaf-spot (Cercospora sp.). — Small, rountl, or angular 

 white spots with a very small amount of dark hyphal 

 growth in the centers are common upon this plant. The 

 spots are definite and are bordered by a narrow reddish 

 purple line. 



IRIS 



Leaf-spot ■'-'' {Didymellina iridis (Desm.) v! H., Heterospo- 

 riian). — The disease occurs only on the German iris, affect- 

 ing mainly the upper portion of the leaf with oval spots with 

 water-soaked margins. Dead leaves should be removed as 

 soon as the snow melts away. 



IVY (Hedera) 



Blight {V ermicularia trichella Fr.). — This blight usually 

 begins midway between base and apex of the leaf, and is 

 especially common upon the white portions of the variegated 

 varieties; The diseased portions turn black, and small black 

 acervuli appear. 



LAUREL, MOUNTAIN (Kalmm) 



Leaf-blight {Phomopsis kalmice Enl.). — Dead spots ap- 

 pear on the leaves and may involve the entire blade, later ex- 

 tending to the stems and even killing entire plants. Leaf- 

 spot {Septoria kahnicola (Schw.) E. & E.) is of common 

 occurrence. 



