202 Report of the Botanist of the 



were five checks on the same tree. On November 1 the five 

 inoculated shoots were all gumming freely at the points of inoc- 

 ulation and the wood was disclored, while on the checks there 

 was no exudation of gum and no discoloration of the wood. 



It has already been mentioned that the trunks and branches of 

 apricots and peaches are often infested by a species of Cytospora 

 which we suspect is parasitic upon them.' To all appearances, 

 the Cytospora found on apricots and peaches is the same as that 

 found on plums; but the apple Cytospora mentioned on page 175 

 is different. The above experiments indicate that the Cytospora 

 of stone fruits may not be the harmless saprophyte which it has 

 heretofore been considered. On the plum it probably aggravates 

 the injury caused by sunscald. 



Hail Injury. — In April, 1900, while making some observa- 

 tions in a plum orchard near Geneva we found that the plum 

 branches, both large and small, were quite thickly covered with 

 circular spots which were about one-eighth inch in diameter, 

 reddish brown and generally a trifle elevated above the surround- 

 ing bark. They were not conspicuous and yet easily detected 

 by one looking for them. On the surface, the bark was smooth 

 and sound, but when cut into it was found to be brown and corky 

 to a depth of 1-2 millimeters. 



At first we were puzzled to account for the spots, but upon 

 further examination it was found that they occurred only upon 

 the northwest side of the limbs and were intermingled with hail- 

 stone wounds made in the summer of 1898. Underneath the 

 hailstone wounds there was the same brown, corky tissue. Then 

 it became clear that the spots had been caused by hailstones 

 which bruised the bark without breaking it. 



Similar spots were found also on the bark of apple, cheri-T', 

 peach, pear and quince; but, with the exception of cherry, the 

 spots were not externally visible. They were revealed only when 

 the bark was cut into. On the cherry and plum the majority 

 of the spots were visible externally, but on both there were some 

 other spots which could not be located until after the outer layer 

 of bark was removed. 



