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D. Stem wound. June 2. The two lower leaves are yellow, the 



two upper ones lighter green than normal. June 6th. 

 The two yellow leaves have fallen off. These are the 

 two just above the wound, but do not show any signs of 

 fungus. The fall may be normal. The wound seems to 

 be commencing to heal the, edges curving in, but the 

 centre portion looks dead. 



E. Young leaves smeared with spores. June 2. One of the 



young leaves wilted and turned black. June 6, the 

 other young leaf was wilting. It fell a day or two later. 

 The first mentioned had, by June 6, developed a number 

 of black pustules. I examined these and found a number 

 of pale spores not transversely divided and a few black 

 spores exactly like those of typical Diplodia. Eventually 

 it was attacked and destroyed by mildew. 



F. Bud cut off. June. 2. The uppermost leaf is yellow and 



falling. June 6. This leaf has fallen and the petiole is 

 covered with conical black pustules, scattered all over it. 



A few days later, they commenced to produce spores in exactly 

 the same way as in the original stem, in the form of strings of sooty 

 black Diplodia spores quite typical. 



In plant A., on June 20, I observe that the wound has not yet 

 healed. The centre has sunk and three longitudinal cracks extending 

 into the otherwise healthy bark have appeared. There is no sign of 

 repair along the edges of the wound, but on the uninjured portion 

 below and above the wound there is a blackish colouring. One of 

 the cracks contained a minute quantity of black substance from 

 which by scraping I obtained one Diplodia spore. The fungus 

 appears to be progressing, but slowly. 



In the others in which the cut bud was infected, the disease has 

 apparently quite stopped. The plant D has not yet healed the 

 wound. On June 20th. I cut off the tops of the two check plants 

 which were perfectly healthy, C and G, and placed a quantity 

 of spores, from the same specimen with which the other experiments 

 had been conducted on the cut end. On July 2, I find both affected. 

 In C, about half an inch of the top below the cut is dry and brown. 



In G. the top is dry and brown for one inch and is producing fully 

 developed pustules in abundance. Thus the life history of the plant 

 is not more than a week long. 



Several points are noticeable about these few observations. In 

 the first place the rapidity of the growth of the fungus is remarkable. 

 It commenced to germinate in twelve hours, and a leaf stalk infected 

 through the wound in the bud, in six days is killed. May 28 to June 

 2, and in about 4 days more produces spores. 



Secondly. No p)-eliminary infection by Gloeosporium is 

 necessary. 



