46 WHITE RUST. 



a. The irregular thickness of the mycelial filaments, 

 or hyphae. 3 



b. The absence of transverse partition walls. 



c. Draw a few hyphae. 



9. The groups of conidiophores. 



a. The manner in which the conidiophores arise 

 from the vegetative hyphae. 



b. The successive degrees of abstriction of the 

 conidiophores resulting in the formation of the 

 spores. 



c. Draw a group of conidiophores with the attached 

 hyphae. 



Prepare a slide as before, using the immature terminal 

 part of the branch bearing the Cystopus, preferably a 

 flowering branch ; search among the untorn tissues of the 

 youngest organs, particularly in the pedicels of the young 

 buds, for the extremities of the advancing hyphae. 4 

 After noting the more direct course of the hyphae, and the 

 fewer branches, observe 



10. Very small globular bodies lying along the side of the 

 hyphae, haustoria or sucking organs. 5 They usually 

 appear brighter than the hyphae, and are quite abund- 

 ant. If the illumination is sufficiently strong, observe 



a. The very delicate stalks by which the haustoria 

 are connected with the hyphae. 



b. Draw some hyphae with haustoria. 



*Hypha is the name applied to a single filament, while mycelium is a col- 

 lective term for a number of hyphae. 



4 If properly stained there will be no difficulty in distinguishing the 

 mycelium from the tissues of the host. 



6 It is difficult to demonstrate these without proper staining. 



