218 ASCOMYCETES. 



Physalospora laburni (Bonord.) occurs ou living twigs of Cytisus Lahurmim. 

 Ph. fallaciosa Saoc. On withering leaves of Aletris and Mtisa in Berlin 

 Botanic Garden. 



Didymosphaeria. 



Perithecia similar to Physalospora, but with two-celled spores. 



Didymosphaeria genistae Fuck, occurs on Genista pilosa. 



D. epidermidis (Fries). On living branches of Berheris, Sambucus, Salix, 

 and Eucalyptus. (Britain and U.S. America). 



D. albescens Niessl. On living branches of Lonicera Xylosteum and 

 Myricaria germanica. 



D. dryadis (Spegazz.). On living leaves of Dryas octopetala. (U.S. 

 America). 



D. populina Vuill. Prillieux and Vuillemin ' regai'd this as a parasite, 

 and the cause of a peculiar dying-off of Populus pyramidalis throughout 

 Germany ; Rostrup, on the other hand, ascribes this to Dothiora sphaeriodes 

 Fr. Prillieux regards Napicladium tremulae as a conidial form of Didymo- 

 sphaeria ; Vuillemin, however, believes it to be saprophytic. 



Venturia. 



The perithecia are embedded in the stroma, and have stiff 

 bristles round the pore ; they contain both paraphyses and 

 eight-spored asci. The spores are two-celled, with or without 

 colour. 



Venturia g^eranii Fr. occurs on the living leaves of Geranium pusillum, 

 G. molle, etc. 



V. ruraicis (Desm.). On withering leaves of llumex. (Britain). 



V. maculaeformis (Desm.). Ou living leaves of Epilohium. 



V. vermiculariaeformis Fuck. On withered leaves of Euonymus europaeus 

 and Lonicera Xylosteum. 



V. Straussii Sacc. et Roum. This I have found as a parasite on Erica 

 carnea in Tyrol. It is also said to cause a disease on Ericaceae in France. 



The various conidial forms at present placed amongst the 

 " Fungi imperfecti " as Fusicladium are probably related to 

 Venturia. 



Fusicladium dendriticum Wallr. on apple, and F. pirinum 

 Lib. on pear, are at present the subject of an investigation at 

 the hands of Aderhold,^ who has, on account of their perithecia, 



' Bullet, de la soc. mycol. de France, 1892 ; Compt. rend. , 1SS9 ; Kerne mycol. , 

 1892. 



■'Aderhold, "Die Peritliecienform v. Fiis. dtndriticmn" Vorliiufig Mittheilung, 

 Ber. d. deutsch. botan. Ges., 1894, p. 338. 



