28o 



AN INQUIRY INTO THE CAUSES OF THE DEATH OF 



young branches that exhibit a shrivelled appearance, coarse 

 hyphal tlireads are abundant. These occur some time before 

 the fimgus reaches its perfect form, and before the leaves have 

 withered. 



The appearance of a l^ranch depends on the age and develop- 

 ment of the fungus (figs. 7 and 8). In an early stage it is covered 

 with an immense number of pustules whicli show the epiderm 

 tightly extended over the elevations. After a period the pustules 

 burst and disclose a mass of hyphal threads which produce conidio- 



Fi.^s. 7 and 8. Two sides of the same branch showing the different stages 

 in the development of the disease. 



spores. Later on there is a change of colour, the pustules 

 becoming very dark and even bhick. Sections of the older ones 

 show another set of spores, the spermatia, long, narrow, hyaline, 

 slightly curved bodies. At the perfect stage of this fungus flask- 



