154 ILLINOIS ACADEMY OP SCIENCE 



It is certain, however, that the fungus of SchAveinitz is 

 what we now know as sooty blotch. Sturgis (1898) trans- 

 lates Schweinitz' description of D. pomigena as follows: 

 ''Spots orbicular, loose, (in texture?) (composed of) a 

 radiating network of very delicate black fibrils, for the 

 most part sterile. Cells in the center aggregated, ex- 

 panded, comparatively large. Spots hardly over i/t "^ch 

 (in diameter). Common on ripe apples known as 'New- 

 town Pippins', Pennsylvania;" and concludes that "the 

 sooty disease * * * * is probably identical with the fungus 

 observed by cle Schweinitz on Newtown Pippins". 



Clinton (1901) in his study of apple scab, after an ex- 

 amination of Schweinitz' original specimen of B. pomi- 

 gena, concludes it is not scab as some botanists have sus- 

 pected, "being more like the fly speck fungus in its 

 macroscopic appearance". Clinton's statement has 

 misled many succeeding investigators who have reasoned 

 that Dothidea pomigena Schw., later changed to Pliyl- 

 lachora pomigena by Saccardo, (1883) is indeed fly 

 speck. The writer was not convinced as to this fact and 

 correspondence brought out the following: Clinton in 

 a recent letter^ states mth regard to Dothidea pomigena, 

 "What I wished to satisfy myself of at the time, was that 

 it was not apple scab. I am not sure that at that time 

 I had a very distinct idea of sooty blotch so may have 

 thought it resembled the fly-speck fungus because I did 

 not distinguish between them". 



In a letter* from Harshberger, he states after an ex- 

 amination of D. pomigena Schw., at Philadelphia, that 

 the fungus is in all probability sooty blotch, rather than 

 fly speck, since the areas are diffused and there are no 

 specks. 



Since Schweinitz included D. pomigena under the sec- 

 tion Asteroma as he understood it, (cf. original descrip- 

 tion), Sprague (1856) lists sooty blotch as Asteroma 

 pomigena Schw., among a number of fungi collected near 

 Boston and named by M. A. Curtis. Later in the same 

 year, Sprague (1856) describes, with a specimen, the 



3 Letter of April 14, 1919. 

 ^Letter of March 14, 1919. 



