Some Important Pear Diseases. 



283 



165. — Ccnn'niating spores 0/ the ieaj-spot Jungns. 



II. LEAF-BLIGHT, f 



I. General Account. 



The above disease has been known in this country for many decades, 

 and throughout this period it has figured in horticultural discussions. 

 During the past ten years it has been freely discussed from the prac- 



iiothing definite upon this point at present, although other fungi hav-e been 

 found on the old leaves. 



This Septoria is very evidently to be referred either to S. piricola Desm. 

 or to .S. nigerrima Fuck. Through the kindness of Professor W. G. Far- 

 low, the American specimens have been compared with ►S". piricola in Des- 

 maziere, Herbier de la France, and with S. 7iigerrima in the Mycotheca 

 Universalis and in the Klotzsch collection No. 1755, to which Fuckel referred 

 his nigerrima in the original description. Dr. Farlow would not regard the 

 European specimens as distinct species ; and our American form, he finds, 

 differs, if at all, only in that the spores are somewhat more nearly alike at 

 both ends, whereas the European specimens may be somewhat bluntei at 

 one end. 1 have also compared the American specimens with No. 2259 of 

 the Rabenhorst Fungi Europaei, labeled kS". piricola^ and the two are identical. 

 It will be noted that Saccardo doubts the distinctness of these two species 

 from his query concerning the difference of color in the cirrae. In S. piri- 

 cola they are described as white to olivaceous, while in ►S'. nigerri}na they 

 are given as black This, however, may be of slight importance since the 

 description is evidently incomplete. The American specimen and the 

 Rabenhorst are both 2-septate, thus agreeing further with the published 

 description of S. piricola Desm. 



\ Entomosporiuin maculatiim Lev. 



