288 Rkpokt of the Botanical Department of the 



phloem region was affected all around the base of shoots, and to such 

 a degree as to be almost entirely loosened in a girdle one or more 

 centimeters in width. The affected region in the phloem had a 

 rusty brown color just like that in injured areas of the larger crotches. 

 But there wer? no radial clefts in any of the affected regions. 



Probably more than half of the trees in the other young apple 

 orchard which had been set about 6 or 7 years were crotch-injured. 

 In this case, however, the affected areas in the larger crotches often 

 involved the bark on the inner side of the branches and below the 

 angle to the extent of 8 to 10 cm. The injuries around the bases of 

 young ascending shoots on these trees were also more extensive and 

 severe than in the above younger orchard. 



There were probably a half dozen of the large trees in the oldest 

 apple orchard (set 8 to 14 years) found injured in the crotches, but 

 only on two of them had the injury been severe. In these cases areas 

 of bark as large as a man's hand were sufficiently affected in the phloem 

 region to be partially loosened. In another instance the bark on a 

 normal looking callus surrounding an old crown-rot scar was also 

 much discolored in the irmer phloem and looked as though it had 

 been sufficiently isolated by the affected tissues to result in the death 

 of the entire outer bark over the injured area, thus probably giving 

 rise to a canker-like region of successive stages of development as is 

 shown on maples in figures B of Plates XXIV and XXV, and to a 

 less degree in figure A of Plate XIX. A similar injury was also 

 found on callus growths of large sour cherry trees on the north side 

 of this apple orchard. 



In none of the cases of this type of bark injury in any of the orchards 

 could a trace of radial clefts be found. The loosening of the bark 

 seemed to have been brought about by injury or partial rupture in 

 the inner phloem thus isolating the bark from the wood. 



Since it had proved difficult to prepare sections for microscopic 

 study from such injured regions of large trunks and branches on 

 account of the fact that the injured bark usually drops off before 

 pieces small enough for fixing and sectioning can be cut, suitable 

 sized pieces were prepared from the basal parts of some of the injured 

 one- and two-year-old shoots in the two younger apple orchards. 

 Pieces of typical examples of such shoots were fixed and infiltrated 

 for sectioning at intervals until the latter part of May, and will be 

 made the chief basis for a subsequent report on the histological modi- 

 fications resulting in crown-rot and certain types of cankers. 



By the first part of May it became evident that most of the larger 

 areas of injured bark in the crotches of the apple trees were dying. 

 Various sized brown spots appeared on the outer surface of the most 

 severely affected regions and it was found that these places of exter- 

 nal browning were only an extension of the internal discoloration of 

 disorganizing phloem. By the latter part of May many injured 



