PLANT DISEASES 



269 



scatter the fungous plant or preserve the plant through 

 the winter, or other unfavorable seasons. 



FIG. 136. The Mycelium of a Food-mold Fungus (Penicillium). 



A, mycelium which is entirely absorptive and tufts (/) of spores (reproductive tract). The 

 original spore from which the mycelium grew is seen at a. B, highly magnified view of 

 spore tuft. (After Zopf.) 



The life stones of the fungi also differ greatly. Smut 

 has a very different history from rust, and rust, again, 

 has a very different life story from the blight. It 

 cannot be too strongly pointed out that the life story 

 of each disease-causing fungus must be accurately 

 known before anything can be intelligently done to 

 fight the disease. For instance, in the case of smut, 

 the spores, which appear as the smutty mass in the 



