108 Report of the Botanist of the 



the latter instance the owner stated that he had had much trouble 

 from damping off. In both of these cases Rhizoctonia was 

 undoubtedly the sole cause of the trouble. We are informed that 

 the damping off of celery seedlings is a common occurrence, but 

 thus far we have had opportunity to investigate only the two 

 cases above mentioned. _ 



ON THE COTTON. 



{Gossi/pium hcrhaceum.) 



The Rhizoctonia which is the cause of " sore-shin " or damping 

 off of cotton seedlings has not yet -been secured by us; but Pro- 

 fessor Atkinson has kindly put at our disposal drawings which 

 he made while studying this fungus in Alabama. He first 

 reported upon it under the caption " sore-shin " in Bulletin 41 

 of the Ala. Agl. Exp. Sta. In describing it, he says: " The 

 diseased portion of the plant is just beneath the surface of the 

 ground., and is characterized by a shrunken area of a dull red- 

 dish-brown col'or. * * * If the injury remains confined to the 

 superficial tissues^ the plant may, and frequently does, recover," 

 The sterile fungus concerned with this disease was isolated, and 

 inoculation experiments demonstrated that the fungus secured 

 was the cause of the damping-off. The description of the fun- 

 gus in the above mentioned bulletin and the drawings which we 

 have, demonstrate beyond a doubt that the fungus is a form of 

 Rhizoctonia. 



ON THE LETTUCE, 



{Lactuca sativa.) 



Since 1896 we have repeatedly found lettuce seedlings damp- 

 ing off by a sterile fungus; but it was not until 1898 that it was 

 particularly studied, or its affinities ascertained, and the fungus 

 located as Rhizoctonia. Lettuce seedlings affected by this fun- 

 gus hiave much the same appearance as seedlings affected by any 

 damping-off fungus. At or near the surface of the ground the 

 tissues become water-soaked in appearance, they are unable 

 longer to support the plantlet, and it falls prostrate on the sur- 

 face of the ground, the fungus soon invading all parts. This 



