45 



the systematic position of their principal species. The formgenus Plas 

 cosphaeria consists, for instance, at present chiefly of the conidial 

 fruits of Dothideaceae; it might therefore be adequate to exclude all 

 the Placosphaeries which are conidial stages of species belonging to 

 other groups. In the large formgenus Phoma v. Hehnel, Bubak, Die= 

 dicke, Sydow and others have commenced separating all those belong 

 ging to species of Diaporthe calhng them Phomopsis. Others prefer 

 to incorporate the conidial form of fruit completely in the name of 

 the ascigerous fructification (for example Nectria cinnabarina also for 

 Tubercularia vulgaris, Venturia for Fusicladiumforms etc.) as soon as 

 the genetic relation is proved, as it is performed with Uredinales, 

 Peronospora etc. But such a proceeding is possible with only so few 

 species of Ascomycetes that it would be inconvenient in the present 

 work to include so many species whose generic relations are either 

 fully evident, matters of supposition or quite unknown. 



THE DESCRIPTION of the separate species I have quite omitted, 

 as when speaking of each species I have made references to one or 

 more of the manuals where the description will easily be found. In 

 the quotations more references may generally be found. I have, 

 however, frequently reiterated Rostrup's original descriptions of his 

 species. In all cases where a fungus has been badly described I have, 

 as far as possible, contributed to give a more detailed knowledge of it. 



FIGURES. The figures in the text are reprinted from older figures, 

 made by RosTrup and especially illustrating Rostrup's species. The 

 figures on the tables are originally, drawn by Mr. O. Rostrup. 



REFERENCES. I have made as few references as possible; in the 

 splendid, upsto^date manuals by Saccardo, Rabenhorst, Schroeter, 

 Engler and Prantl, Sorauer (Phytopathology by G. Lindau), Ro« 

 STRUP (02 a) etc. numerous useful references may always be found, I 

 have, therefore, limited myself to quoting from Rostrup's works and 

 from other works published in this country, as also from such works 

 as have recently been published and which have not been quoted in 

 the said manuals. 



References to Schumacher's Enumeratio imply also that the same 

 fungi are found in the north of Seeland by Schumacher and for this 

 single book I have preferred to quote the number given to the spe? 

 cies concerned instead of quoting the number of the page. 



NOMENCLATURE. I have followed the rules for nomenclature 

 carried at the International Congress in Brussels, Belgium, May 1910 



