' RUSTS 739 



be sprayed. Repeated spraying with 'liver of sulphur' wash 

 made by dissolving i oz. of ' liver of sulphur ' in lo gallons of 

 water, to which is added enough soft soap to make a lather, 

 is equally effectual. The wash blackens white paint. 



Repeated spraying with carbolised soft-soap, such as is used 

 for destroying insect-pests, has proved a good remedy. 



(c) P. Asparagi D. C, which is a pernicious pest of asparagus 

 beds. The secidia occur in spring on the young shoots, the 

 uredospores and teleutospores making their appearance later on 

 the fully developed stems and branches. 



(d) P. Pruni Pers., very abundant on the under surface of the 

 leaves of plums in some seasons. Teleutospores and uredo- 

 spores only known. 



Ex. 307. — The student should be made practically acquainted with the form 

 of the sori and the various chlamydospores of Puccinia glamarum, P. 

 disfersa, P. coronata and P. coronifera, which attack the common cereals. 

 Their aecidia should also be looked for and examined on their particular 

 host-plants. 



Ex. 308. — The uredospores and teleutospores of Puccinia Pruni, P. 

 Hieracii, and teleutospores of P. Malvacearum should be examined. 



Puccinia Arenarics Schum. , is sometimes met with in gardens on sweet- 

 williams and chickweed ; as the teleutospores of this species germinate as 

 soon as ripe they are convenient for the study of the basidia and basidio- 

 spores of Puccinia where P. graminis cannot be managed. 



P. Malvacearum on hollyhock and wild species of mallow is also useful for 

 a similar purpose. 



lo. Belonging to the 'rust '-fungi is another genus, namely 

 Uromyces, which requires consideration. Many of the fungi of 

 this genus possess the same number of spore-forms as those 

 belonging to the genus Puccinia, their teleutospores are, how- 

 ever, always unicellular. 



The following autoecious species do considerable damage to 

 farm crops. 



(fl) Uromyces FabcB Pers. This ' rust ' attacks the leaves and 



