178 MICEOSCOPIC FUJ; GI. 



and there witli minute granular cells. It first 

 attacks either the upper surface of the petioles^ or 

 the margins of the leaf^ gradually extending over 

 the lamina^ and matting together the whole leaf 

 into a greyish-^YhiteJ felty mass. At .first it attacks 

 the young shoots and tender leaves^ preventing 

 them from expanding. The extension of the para- 

 site deprives the plant of its juices, and eventually 

 either destroys or renders it sterile. The spores 

 seem to be derived fi^om the atmosphere_, and 

 finding the plant in a state fit to receive them, 

 from either the results of excessive cultivation, or 

 from the efiects of heat and want of moisture 

 rendering it unhealthy, and thus favouring the 

 reception of the spores of the fungi. Another 

 variety speckles the leaves with whitish dots. 

 These remain separate, but the lamina is covered 

 with them, and in time the leaf changes colour, 

 becomes yellowish, and eventually dies away. This 

 is evidently the disease called Bunt, or some variety 

 of it, as it is seated beneath the epidermis, and 

 eventually the spores escape. Under the micro- 

 scope they seem to consist of smaU dark cells or 

 spots attached to a thread-like mycelium.^' 



The writer seems certainly to have made a 

 mistake in its affinities, and on the faith of the 

 above quotation we should be more disposed to 

 regard it as an Erysijphe. It is to be hoped that 

 specimens of the affected leaves wHl be forwarded 

 to this country for examination. 



