256 Report of the Botanical Department of the 



the bark on all of the upper portion of an old callus, as well as that 

 extending several centimeters above it, was discolored, and had some 

 very small longitudinal clefts from which exuded a discolored " sap." 

 The wood underneath the bark was also blackened to the depth of 

 several millimeters. It could not be definitely determined whether 

 the clefts had resulted from drying of the dead bark or whether they 

 occurred before the bark died. On a portion of the dead bark the 

 periderm was raised to form several blisters which also contained 

 discolored " sap." The bark was not dead throughout its discolored 

 portion, especially toward the upper and lateral limits of the newly 

 injured area; in some places only the outer tissues of it were involved 

 while the inner bark was at least partially living. It looked a little 

 like a case found much later and shown in figure B on Plate XVII. In 

 the younger orchard many of the Baldwin and Ben Davis trees were 

 affected with an irregular scaling off of the periderm on the south- 

 west side of the stems from 5 to 15 cm. above the ground up to the 

 lower branches. The scaling surface was very rough and irregular, 

 and by scraping it with a knife was found to have small groups of 

 dead, brown spots scattered thickly over it and extending almost 

 to the wood. 



The Coldwater orchard. — In a medium sized 20-year-old orchard 

 near Coldwater were perhaps a dozen trees having more or less rot 

 at the crown. In this case several Northern Spy trees were prac- 

 tically dead as a result of crown-rot. The land is almost level but 

 the winter winds have a full sweep without obstruction. The soil 

 is very sandy. It was cultivated until recently, but is in sod now. 



The rot was almost wholly at or below the surface of the ground, 

 and in several instances only involved the outer bark. In other 

 cases a complete girdle of outer bark sloughed off just below the sur- 

 face of the ground, leaving a somewhat irregularly pitted or pock- 

 marked surface on the inner bark with a rather uneven cover of re- 

 generated periderm. Two such corroded trees were found on which 

 unevenness of the outer surface of the exposed irmer bark was so 

 marked that many of the pits extended to the wood. It seems as 

 though scattered groups of cells in the outer bark had died and on 

 account of their being so close together had become confluent by the 

 dying of living groups between them. In some respects it resembles 

 the distribution of groups of dead cells in cases of mild forms of so- 

 called "sun-scald," above ground, except that in case of the under- 

 ground injury the abundance of moisture favors a rapid decay of 

 dead groups, and is more favorable to the formation of wound-cork 

 over the outer limit of living tissues. 



Maples around Geneva. — During the summer of 1910 many maple 

 trees were found in the parks and streets of Geneva that had some 

 loose bark. Plates XX to XXIII give an idea of the different types; 

 including cases in which long radial clefts accompanied the loosening. 



