THE LARCH CANKER 



49 



MYCELIUM AT DIFFERENT TEMPERATURES 



twigs of other conifers in damp chambers. The conifers 

 which I experimented with were spruce, silver fir, Scots 

 pine, and Corsicari pine. In all these the mycelium grew 

 freely, and on silver fir apothecia were produced. 



Cultures were also obtained on sterilized leaves of larch, 

 spruce, and Scots pine. These showed no tendency to grow 

 for several weeks ; but ultimately masses of dead leaves 

 became covered with mycelium, and on sectioning the needles 

 hyphae were found to have ramified the mesophyll, though 

 they had not penetrated into the vascular bundle region. 



This shows that the mat of dead larch needles lying on 

 the floor of larch plantations forms a suitable substratum 

 for the mycelium of Dasyscypha,, and the mycelium which 

 is commonly found growing on these needles may belong to 

 this fungus. It is not suggested that the fungus can reinfect 

 the trees by this means, since no fructifications are formed. 

 But it may assist in the decomposition of the foliar debris. 



Artificial infection with the canker fungus. The first 



