author's preface. vii 



(Easter, 1894), but also during the time of proof-reading up 

 till the following Christmas. 



Eeference to the book will be rendered easier by the numerous 

 illustrations, which are almost exclusively the work of the author, 

 and reproduced either from drawings or from photographs of the 

 living objects, in many cases taken in situ. I consider it more 

 essential to illustrate the habitvs of pathological objects rather 

 than to give drawings of microscopic subjects ; those one may 

 find in other works. Some of the illustrations are copied from 

 the excellent plates of Tulasne, "Woronin, De Bary, Klebs, Eeess, 

 Cohn, and Eobert Hartig ; while a number of woodcuts have 

 been borrowed from the well-known Lehrhuch der BaumkranJc- 

 heiten of the last named author. 



The grouping of the 'Fungi imperfecti,' which have not yet 

 been worked up for the German flora, is based on Saccardo's 

 Sylloge ; hence the arrangement into Hyalosporae, etc., which 

 is intended for the benefit of those having access to Saccardo. 

 Particular attention has been paid in the two Indices to the 

 scientific names of both parasites and hosts, to popular names, 

 and to technical expressions. 



In my labours I received great assistance from the following 

 sources : From the collection of pathological material begun by 

 Professor Eobert Hartig, and now carried on with my help in 

 the Botanical Institute of the Eoyal Bavarian School of Forestry 

 in Munich ; from the facilities for research and photography 

 afforded by the laboratories of the same institution ; from the 

 Eoyal Library of Munich, the Library of the University, and the 

 private pathological libraiy of Professor Hartig. 



Living material for investigation has been kindly sent to me 

 from many sources, particularly from the following gentlemen : 

 Herr Lehrer Schnabl of Munich, Geh. Oberregierungsrath Prof. 

 Kiihn of Halle, Hofgartner Kaiser of Munich, Prof. Dr. Fries 

 of Upsala, Forstrath von Plonnies and Oberforster Losch at 

 Amorbach. Preserved material came from Herr Hauptlehrer 

 AUescher of Munich, Director Dr. Goethe and Dr. Wortmann in 

 Geisenheim, Prof. Dr. Stahl of Jena, Prof. Dr. Magnus of Berlin, 

 Prof. Dr. Grasmann and Prof. Dr. Loew of Tokio. Dr. Bruns 

 of Erlangen kindly photographed some specimens in the botanical 

 museum there. Numerous botanists have greatly assisted me by 

 sending papers, especially Dr. Dietel of Leipzig; I have also to 



