32 Fink: Problems of North American Lichenology 



long felt that lichens are among the most interesting of plants 

 ecologically, because they are so closely related to the unmodified 

 physical environment." A few papers on lichen ecology have 

 appeared in our country, and the writer has noted European 

 papers bearing ecological titles, not to include many others which 

 have an indirect bearing, but which may none the less prove 

 more valuable to the ecologist in the long run. The American 

 work is but a beginning, and much of it surely will not en- 

 dure the testing of ecology now in progress, but the field is a 

 most fruitful and inviting one and should attract some competent 

 workers. 



We can only mention some other problems not strictly Amer- 

 ican. A proper classification of lichens must rest upon a better 

 knowledge of general morphology of these plants than we now 

 possess, a sufficient understanding of the symbionts and their 

 phylogeny, a more thorough study of the physiological relation- 

 ship of the symbionts and a more widely extended and more 

 minute study of the sexual reproductive tracts in these plants. 



Oxford, Ohio, January 24, 1909. 



