348 



Mycologia 



Another fact might well be considered in this connection. The 

 author recognizes that there are species of Mycosphaerella which 

 have been found to have Ascochyta or Diplodina and Cylindro- 

 sporium as lower spore forms, and he also finds Phyllosticta 

 pycnidia present in species of his Sept oris phacrella and Ramulari- 

 sphaerella. The experience of the reviewer has shown that in 

 Glomerella, Melanops and other ascomycetes the same species will 

 sometimes produce one form of conidial or pycnidial fructification 

 and at other times another form, and occasionally two or three 

 forms in succession in a single culture. It appears, therefore, that, 

 in pure cultures from single ascospores, there is at present no cer- 

 tainty of securing all the spore forms belonging to the life history 

 of the organism in a single culture, or in a few cultures. Some- 

 times no lower spore form is obtained, as the author indicates in 

 some of his species, and he concludes as a result that the species 

 possesses no such form. He cites in support of this conclusion 

 the fact that in closely related rusts certain spore forms are lack- 

 ing, whereas in others they are present. Evidence of this sort is 

 entirely untrustworthy in the reviewer's opinion. It seems much 

 more reasonable to expect that, if at one time we obtain a Ramu- 

 laria or Cercospora and at another time, from the same or a very 

 similar species, obtain a Septoria or Phleospora, both the conidial 

 and pycnidial form may belong to both species ; but for some un- 

 known reason have not both developed in either case. Potebnia, 

 a former worker in Klebahn's laboratory, also expresses this view 

 in discussing Mycosphaerella ccrasella, in which only a Cercospora 

 type was produced. He says that by analogy we must assume the 

 existence of the Phleospora-Septoria type in this species also. 

 The reviewer has demonstrated (in MSS.) that such cases occur 

 in Melanops, where in one series of cultures from ascospores only 

 a Dothiorella is produced and in another series from the same 

 species, so far as can be determined by morphological characters, 

 and from the same host, only a Sphaeropsis or Diplodia spore form 

 is produced. 



It is a notorious fact that ascocarps are rarely produced in cul- 

 ture when the conidiospores or pycnospores are used as a starting 

 point; but one would scarcely feel justified in concluding from 



