104 Transactions British Mycological Society. 



tion proceeds and the hyphae assume a resting condition upon 

 lines so closely analogous to those previously indicated when 

 speaking of Dematium pulliilans that Brefeld's account might 

 be applied as truthfully to either fungus. 



Similar stages occur in the life-cycles of Sphaerulina inter- 

 mixta (B. & Br.) Sacc. and Fumago vagans Pers. 



In dealing with Plowrightia Brefeld remarks: "Diese Neben- 

 fruchtformen bieten wiederum die grosste Uebereinstimmung 

 mit den vielgenannten Dematium pullulans, welches hiermit als 

 ein Sammelname fiir die Conidienformen verschiedener Asco- 

 myceten erweist" — and, in a footnote — "Dieses Dematium, 

 bisher als selbstandige Pilzform beschrieben, fiigt sich also nicht 

 bloss der Sphaerulina mtermixta, sondern auch anderen Asco- 

 myceten als Entwicklungsglied ein." That is to say, Dematium 

 pullulans as such is no longer regarded as a distinct entity, 

 but as a collective name for the conidial stage of several Asco- 

 mycetes. A similar view held by Berlese {loc. cit. p. 69) is 

 expressed in the following words: "D'apres les etudes faites, il 

 me semble cependant qu'on puisse plus surement affirmer que 

 Dematium pullulans est une forme collective, un etat special 

 d'un certain nombre de champignons non seulement spheriaces 

 mais appartenant aussi a d'autres groupes." 



To take the third-mentioned fungus first, Zopf(i5) has shown 

 that in the case of Fumago vagans the resemblance is a limited 

 one, and the two fungi must therefore not be confused. The 

 agreement is close up to the final stages of gemma-formation, 

 but here the comparison ends. When transferred to fresh medium, 

 the Fumago gemmae gave rise to a mycelium bearing pycnidia ; 

 in Zopf's words: "...nie aber gelang uns, trotz vielfach modi- 

 ficirter Versuche, sie" (the gemmae) "zu hefeartigen Sprossung 

 zu bewegen; hierdurch unterschieden sie sich wesentlich von 

 den iiberaus leicht sprossenden Gemmenbildung des Dematium 

 pullulans, denen sie in Uebrigen tauschend ahnlich sind." This 

 disposes of Fumago. 



During the past year the present writer has been working 

 with the fungus Plowrightia rihesia, and has attempted an 

 investigation of the relations of this form with Dematium 

 pullulans. To this end, cultures of Dematium were obtained 

 from various sources — from the surface of oak twigs, from leaves 

 of Vinca minor, from isolations from slime fluxes occurring in 

 different localities, and from an old laboratory culture. All 

 strains were grown upon various media side by side with strains 

 of Plowrightia rihesia isolated from red and black currant bushes. 

 The cultures were established in nearly all cases from the bud 

 spores. 



The six Dematium strains corresponded so closely in behaviour 



