Leaf Curl and Plum Pockets. 341 



Where the leaves are fully expanded or nearly so before they 

 are seriously attacked the injury is confined chiefly to the base of 

 the leaf and the petiole. Sometimes isolated spots nearer the tip 

 of the leaf are also affected. If the leaves are seriously attacked 

 when quite young they become killed, still clinging to the branch 

 and with no development of asci dry, become crisp, and black. 

 The blades of leaves only partially affected also become black, the 

 lamina first and the petiole later, especially when the serious at- 

 tack is chiefly confined to the base of the leaf. This dying of the 

 affected parts often continues into the shoot, which presents also 

 a blackened appearance. One of these shoots with blackened 

 leaves in different stages of development is reproduced from a 

 photograph in fig, 17, Plate VIII. 



The mycelium is perennial in the young branches, and occurs 

 in the intercellular spaces of the affected parts. 



See figurus 74-77, Plate XIX, for details. 



Fig. 5, Plate III, shows also the fruits of /*. americana deformed 

 by Exoascus lotigipes Atkinson, growing from the same shoot as 

 Exoascus decipiens and very near it. In the shoot the mycelium 

 of the two species is probabl}^ somewhat intermingled, but there 

 can be no doubt about the two being different species, for they 

 represent very remote types of Exoascus. 



Exoascus decipiens var. superjicialis n. var. 



On half formed fruits of Prunus a7nerica7i a Marshall, at Aetna, 

 N. Y., I have found an E.voascus yvhich. may prove to be a distinct 

 species. I have not had as yet sufficient material to give it the 

 careful study to determine this point. .1 therefore prefer at the 

 present to place it as a variety of E. decipiens Atkinson, especially 

 as it occurs in the cases thus far observed on the same tree on 

 which I collected E. decipiens at Aetna, N. Y. The first speci- 

 mens were collected July 6, 1894, At this time the E. decipiens 

 on the leaves had nearly disappeared, at least the fruiting condi- 

 tion of it. The fungus on the fruit at this time was not matuie, 

 but was collected in a mature condition on July 28. The fruits 

 as stated above are half formed and the stone is normal, or at least 

 not wanting. For this reason I have proposed the name superfi- 



