Fungi in Winter 



fungus has killed. " Mummy " apples and plums 

 are produced when these fruits are attacked by the 

 fungi which cause "brown rot," the whole flesh 

 being filled by the mycelium, and they form resting 

 sclerotia. The ordinary mycelium itself may cease 

 to grow but still remain aUve for some time as in 

 mushroom spawn such as is sold for making mush- 

 room beds. Myriads of spores are produced by the 

 mushroom on the gills of the edible fruit, but gardeners 

 have to depend upon the white thread-like myceUum 

 of the fungus for ptirposes of propagation. We have 

 many instances of this " perennial mycelium " 

 among fungi causing plant diseases. The rust of 

 mint, the smuts of Scillas and of Carnations, 

 are examples. Once attacked these plants are 

 affected year after year and annually produce a 

 crop of spores. In these cases their utility or 

 beauty are injured but their existence not materially 

 threatened. It is otherwise with the perennial 

 myceUum of certain fungi which attack trees, such as 

 Stereum purpureum, which produces silver-leaf, or 

 Nectria ditissima, which is associated with " canker " 

 of fruit trees. 



No means of reaching the mycelium of a fungus 

 inside a plant are known. Nothing at present 

 known which can be injected or made to pass into a 

 plant wiU kill the fungus without at the same time 

 damaging the plant itself. In the treatment of 

 plant-diseases induced by fungus attack the most 



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