Ornamental Plants 423 



GLADIOLUS 



Hard-rot ''^" (Septoria gladioli Pass.). — Leaves are af- 

 fected with brown or purplish, irregularly circular spots 

 having gray centers and bearing numerous, black pycnidia. 

 On the corms lesions appear as water-soaked, dark spots 

 which later become sunken and black. The diseased tissue is 

 extremely hard. Spraying of seedlings is effective, but a 

 simpler method is to plant the seed in soil that has not borne 

 Gladioli, and to bring to it no infective material. 



HAWTHORN 



Rust {Gymnosporangium sps.). — The rust, similar to that 

 of the apple, is often abundant. 



HEPATICA 



Rust {Transchelia, Mcidium). — This is perennial in the 

 plants which should therefore be burned when the rust ap- 

 pears. See p. 96. 



HIBISCUS, ROSE-OF-SHARON 



Canker (Cytospora). — Death of twigs or of whole plants 

 results. Diseased parts are thickly covered with wart-like, 

 black pycnidia. 



HOLLYHOCK 



Rust {Puccinia malvacearum Mont.). — This rust, native 

 to Chili, was introduced into France about 1868. It spread 

 rapidly over all Europe, from whence it came to the United 

 States about 1886 upon infected seed. It was rapidly dis- 

 seminated throughout this country, and is now known from 

 Maine to Louisiana, in many places rendering the plants un- 

 sightly. It is easily recognized by its yellow to brown sori, 

 each sorus considerably raised above the surface of the leaf 



