The authors acknowledge a great debt to Professor J. D. Rogers (WSU) for his constant support and his valuable help to this project, and for his critical review and judicious comments.

Special thanks to Dr. A. Granmo (Norway), Dr. Y-M Ju (Taiwan), Dr. T. Laessøe (Denmark) and Dr. M. Stadler (Germany) for providing specimens, precious comments and help with literature.

F. Candoussau, G. Corriol, G. Gilles, C. Lechat, P. Leroy and J. Vivant (France) are warmly thanked for having sent the collections quoted in the taxonomic parts.