178 MICROSCOPIC FUNGI. 



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-white^ 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 from 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 small 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 Erysiphe. It is to be hoped that 

 specimens of the afi^ected leaves will be forwarded 

 to this country for examination. 



