appear healthy up to the time of blossoming to throw out a normal 

 crop of fiowers, then suddenly show the characteristic blight, wilt 

 and dry up in a very short time. In all these cases the disease is 

 the same. 



If affected plants in the earlier stages of the disease are pulled up 

 and examined no indication of injury can be seen except in the 

 wilted, dying lower leaves. The roots and stem appear perfectly 

 sound and healthy. It Is only on cutting open the stem, just at the 

 surface of the ground, that the seat of the trouble is found. Here 

 will be found a dark discoloration in the outer edge of the harder, 

 woody portion of the stem, where it joins the soft "bark " or cortex 

 portion which covers it. At first this is only a small spot on the 

 affected side, but may always be found when the exterior symptoms 



Fig. I. Longitudinal sections of Aster stems attacked by .Stem Kot ; showing discolora- 

 tion, a early stage. /' considerably affected. 



have begun to appear. This discoloration spreads around and up 

 the stem, always in the woody portion at first, but finally the soft 

 outer part is affected and rots away, leaving the wood intact, though 

 it was the first portion to be attacked. By this time the plant is 

 dead so that if first examined at this stage the stem is found in the 

 condition described. 



The cause of this trouble may readily be found with the micro- 

 scope. This is seen to the best advantage in a plant in the earlier 

 stages of the disease where the outer green cortex of the stem is still 

 sound and intact. By examining a thin section of the discolored 

 woody portion it will be seen that the discoloration is confined 

 mostly to the large vessels or pores through which the water passes 

 up from the roots. These are still intact and uninjured, but in the 



