i v PREFACE 



The preliminary notes made by Professor Fink for the introduction were found 

 to be insufficient, and it therefore has been thought wise to reprint a large part of 

 the introductory material from The Lichens of Minnesota. Changes have been 

 made in order to bring the introduction into conformity with Fink's later ideas and 

 to incorporate his preliminary notes. Since the earlier monograph is out of print 

 it has also seemed advisable to use a number of the plates from it for this manual. 

 These have been made available through the kindness of Dr. Alexander Wetmore 

 of the Smithsonian Institution. 



The descriptions have been made as short as possible with the omission of 

 all but the diagnostic characters. Generic characters have not been repeated under 

 the specific descriptions. Only the synonyms used by Tuckerman, Hasse, Herre, 

 Willey, Fink, and occasionally others have been given. For complete synonymy 

 the student is referred to Zahlbruckner's Catalogus Lichenum Universalis, which 

 has been followed for synonymy in this manual. 



The system of classification is based on that of A. Zahlbruckner.* Modifi- 

 cations have been made following the treatment proposed by Professor Fink.t 

 The Ascolichenes are presented first, beginning with the pyrenomycetous forms, 

 which are followed by the discomycetous ones. Within the larger groups the 

 structure of the thallus is used as the chief basis of classification. The Hymeno- 

 lichenes follow the Ascolichenes and the Lichenes Imperfecti are placed at the 



end. 



Much has been written concerning the position of lichens among the families 

 of plants. Several theories have been advanced concerning the origin and com- 

 position of the lichens and especially concerning the relationship of the two com- 

 ponents, the fungus and the alga. It seems desirable here to use the term "lichen'' 

 as defined by Finkt — "The lichen is a fungus which lives during all or part of 

 its life in parasitic relation with the algal host and also sustains a relation with 

 an organic or an inorganic substratum." While this manual treats lichens as a 

 group, the underlying idea is that they could be distributed among the other 

 fungi. In some groups the relationship seems very close, in others more remote. 

 The descriptions are based on the fungus, and the alga is mentioned only as the 

 host-plant. 



The following is quoted from the preliminary notes made by Professor Fink 

 for the manual: "I wish to acknowledge my obligations to many amateur and 

 professional lichenologists whose aid and encouragement have made the difficult 

 task of preparing this manual possible. The work of the pioneer American lichen- 

 ologist, Edward Tuckerman, was the starting point for me and many others. 

 W. G. Farlow, Clara E. Cummings, A. B. Seymour, T. A. Williams, L. R. Riddle, 

 W. W. Calkins, J. W Eckfeldt, H. E. Hasse, Henry Willey, W. C. T. Herre, 

 S. H. Burnham, Annie Morrill Smith, H. A. Green, John Macoun, C. Audrey 

 Richards, Freda M. Bachman, G. K. Merrill, R. S. Williams, and A. Schneider 

 are some of the American workers who by their publications or distribution of 

 specimens have aided in the present work. 



"Among Europeans who have aided in way of determinations and publications 

 are E. A. Vainio, A. Zahlbruckner, F. Arnold, T. Hedlund, G. Lindau, 0. V. 

 Darbishire, W. Nylander, J. Muller Arg., A. Massalongo, A. M. Hue, J. Harmand, 

 H. Oliver, A. von Krempelhuber, J. M. Crombie, Annie L. Smith, G. W. Koerber, 

 W. A. Leighton, E. Acharius, E. Fries, T. M. Fries, L. E. Schaerer, E. Stizen- 

 berger, L. Scriba, H. Sandstede, M. B. de Lesdain, and others. 



*Engler and Prantl, Die Natilrlkhcn Pflanzenjamilien (2d Ed.), 8. 1926. 



fBruce Fink, 'The Ascomycetes of Ohio," Ohio Biological Survey Bulletin, 5. 191 5. 



jBruce Fink, "The Nature and Classification of Lichens. II," Mycologia, 5. 1913. 





