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the worst defoliated orchards shows that most of the fungi, here- 

 tofore associated with the defoliation of apple trees, were either 

 not present or when present and even abundant did not bring 

 about a defoliation. However, there was a fungus, one of the 

 Tuberculariae, which was universally present in these orchards 

 and occasionally on apple trees by the roadside. While I do not 

 know that this fungus was primarily responsible for the defolia- 

 tion, it caused a large amount of damage to the foliage. It was 

 so plentiful in some orchards by the first of September that the 

 lower branches of some of the trees were nearly defoliated, the 

 remaining leaves being brown and crumpled. 



The spots caused by this fungus are so different from the spots 

 caused by other leaf-spot fungi of the apple that they can be 

 readily recognized even when the fungus is not fruiting. In 

 general, the spots are nearly circular, from five to fifteen milli- 

 meters in diameter, two or more frequently coalescing. In color, 

 the spots are brown or brown mottled with gray, the two colors 

 being arranged more or less concentrically or like contour lines 

 on a map. In the center of some of the spots is a small gray or 

 whitish spot, caused, perhaps, by a first infection of the leaf by 

 some other fungus. The larger and encircling spots may, 

 therefore, be due to secondary infection by the fungus under 

 consideration. 



The spore-fruits of the fungus might be easily overlooked, and 

 probably have been, since they are on the under side of the leaf, 

 of about the same color as the spots, minute, and hidden to a 

 considerable extent by the pubescence of the leaf. The fungus is 

 very similar to Hymemila cerealis E. & E. except that the sporo- 

 dochia are considerably smaller (1:5) and the conidia a trifle 

 plumper than those of the type specimen of Hymenula cerealis 

 which I examined in the herbarium of the New York Botanical 

 Garden. The shape and structure of the sporodochia are also 

 more like those of an Illosporiuni than a Hymcmda. On account 

 of these differences, the name lUosporium malifoliorum n. sp. is 

 tentatively proposed with the following description : 



Spots suborbicular, or coalescing and becoming irregular, 

 brown or sometimes mottled with gray and with a small gray 



