Fig. 2. Cross section of affected tissue, Fig. 3. Duct ironi stem, mucii enlarged, 



much enlarged, showing vessels plugged with fungus, 

 with fungus and discolored. 



interior of most oftho.se wiiich are already affected as shown by the 

 darker color, there will be seen a mass of fungus growth, which com- 

 pletely plugs up the opening and evidently prevents the free passage 

 of water or sap through the vessel. All stages leading up to this 

 final result will be seen. In the more newly aiTected vessels only a 

 few filaments of the fungus are present, but these soon increase, fill 

 up the passage and spread into new tissue until all the larger water 

 vessels are plugged up. Thus is explained the gradual wilting of the 

 plant, beginning on one side, as more and more of the water from 

 the roots is cut ofif until finally the whole plant dries up, simply from 

 lack of water and soil-food, and not directly on account of the effects 



