11 



GEOGRAPHICAL DISTRIBUTION. 



The Strumella disease has been studied from specimens col- 

 lected at widv^} separated points in Pennsylvania. The first 

 specimens studied were collected in Somerset county in the 

 southwestern part of the State. In this region the disease was 

 prevalent on both chestnut and chestnut oak. A little later the 

 trouble was found on chestnut oak in Mifflin county in the cen- 

 tral part of the State. It is common on the red and black oaks, 

 and occasional on the white oaks in the State forest in Hunt- 

 ingdon county. It has been observed in Elk county in the north- 

 western part of the State, where it is especially severe on the 

 chestnut in a number of localities. Studies made in Carbon 

 county in the eastern part of the State show that the trouble is 

 fairly common. It has also been reported from Pike county. 

 The known occurrence of the disease at localities in the southern, 

 middle, northern and eastern portions of Pennsylvania suggest 

 that a more detailed scouting of our forests will show a rather 

 general distribution throughout the State. 



The causal fungus, Strumella coryneoidea^hsis been collected 

 in the fruiting stage on both chestnut and oak species in several 

 of the localities studied. The specimens received from some of 

 the localities represent only the canker type, probably due to 

 the fact that only conspicuous examples of the trouble were 

 observed by the collectors. In the localities worked in detail 

 by the writers, the fruiting stage has always been found. In 

 this connection reference may be made to the first collections of 

 the fungus in Missouri, and its later collection from Ontario, 

 Canada, as indicating a wide range. All of the evidence at 

 present points to the parasite as a native of the northeastern 

 portion of North America. If this supposition is correct, the 

 disease is less likely to prove as virulent as though it were in- 

 troduced from some foreign country. The behavior of the 

 chestnut bark disease is prophetic of what might happen if the 

 Strumella disease should be introduced into new localities. 



The supposition concerning the wide distribution of the dis- 

 ease has been further substantiated by the collection of authentic 



