240 THE BOTANICAL MAGAZINE. [Voi. xxvi. No. 30«. 



by Massee* and many other authors.** It is a remarkable 

 and interesting fact, if Massee's view be correct, that the fungus 

 belonging to Exobasidium produces such a conidium in its life 

 CYcle. On the other hand, the basidiospores of Exobasidium 

 seem to be generally recognised to produce a septum in the 

 process of their germination. From these points, the further 

 experiments are required to decide the nature of these two-celled 

 spores. In the case of the present fungus, the two-celled spores 

 may only be observed in an old hymenium, and almost always 

 they are found germinating, but they could not be obtained 

 from a young specimen. From these facts, we may be 



justified in considering the two-celled spores as a mere stage 

 of the basidiospores — at least in the case of our fungus. 



Let us then briefly state on the differences between the 

 present disease and the related "blister-blight." 



In the macroscopical appearance they differ strikingly from 

 each other. The spot of the blister-blight is more or less 

 regular, roundish, clearly limited, and pale yellow, but some- 

 times becomes colored deep red on both sides. The circular 

 spot generally reaches to the size of 15 mm. in diam., sometimes 

 as much as 23 mm ; it becomes gradually depressed into a shal- 

 low cavity ; when matured, it gives eventually a white powdery 

 appearance on the entire convex under-surface. On the other 

 hand, the spot of the disease in question, as alread}' stated, is 

 irregular in shape, not limited, and never reddish in color ; and 

 moreover it becomes never buUated and forms a white reticula- 

 tion on the under surface. 



Microscopically these two species differ from each other in 

 the measurement of their various parts, as follows :— 



Exob. vexans. Exob. sp. 



\' Basidia 49-150x3.5-6// 100-135x3-4/^ 



Sterigmata 3-4. 5/i 2-3^« 



Basidiospores 11-16x4-6// 9-12x3-3.5/^ 



Besides these facts, these two species differ from each other 



in the number of sterigmata on a basidium. While the sterig- 



* "Tea Blights," New Gardens Bulletin. 1898. 

 -X* Watt, Mann, Speschnew and Mc Eae. 



