CHESTNUT BARK DISEASE. 363 



new to science. It was among the species described by him, 

 since *the relationships of many of them are now somewhat 

 obscure, that we made a search for some fungus that might 

 throw additional light on Diaporthe parasitica. In this search 

 we asked the aid of Professor Farlow, whose knowledge of 

 American fungi is unsurpassed, and who has some of the 

 Schweinitzian specimens in his herbarium, and from him we 

 first learned of the close relationship of the chestnut blight to 

 Endothia gyrosa (Schw.) Fr. This fungus was first described 

 by Schweinitz as Sphaeria gyrosa, from North Carolina on 

 Fagus and Juglans. He sent specimens to Fries, a famous 

 authority on fungi in Europe, who later recognized it as a 

 European species, and finally placed it under a new genus, 

 Endothia. This possible relationship of the blight was brought 

 out for the first time in the writer's Report (6) for 1908. 

 Neither Farlow nor the writer had at that time examined the 

 ascospore stage of the true Endothia gyrosa, so the exact 

 relationship of our blight fungus to this species was not posi- 

 tively determined, though the writer called attention to the 

 fact that, so far as one could tell from the Cytospora stage, 

 it was impossible to distinguish between Diaporthe parasitica 

 collected on chestnut in America and Endothia gyrosa found on 

 the same host in Italy. 



Previous to this, however, Rehm (61) had decided that 

 Diaporthe was not the proper genus for our chestnut blight, 

 and had placed it under the genus Valsonectria, but had not 

 questioned its identity as a new species or its relationship to 

 Endothia. 



Von Hohnel (29) seems to have been the first to definitely 

 state that Diaporthe parasitica was not distinct morphologically 

 from Endothia gyrosa, for in the latter part of 1909 he wrote: 

 "Diese Pilz ist in Rehm Ascomyc., No. 1710, ausgegeben unter 

 dem Nahmen Valsonectria parasitica (Murr.) Rehm. Es ist 

 aber nicht anders als E. gyrosa mit schwach entwickelten 

 Stroma." Since then Farlow (20), Shear (65), Saccardo, and 

 Rehm, the last two in letters to the writer, have also decided 

 that the chestnut blight fungus is not distinct morphologically 

 from Endothia gyrosa (sometimes called E. radicalis) of 

 Europe. 



