HISTORY OF LICHENOLOGY. 



27 



general or external characters, physical and chemical,— that 

 we can hope to succeed in founding a natural system of clas- 

 sification, consisting of a chain of natural groupings or small 

 families, not only more or less closely allied to each other 

 but to other Cryptogamic families, especially the Algse on the 

 one hand and Fungi on the other. Such a system has hitherto 

 been a desideratum in Lichenology, a want which could not, 

 until the invention of the microscope, have been supplied ; 

 such a system has not yet been attained, though the labours 

 of recent investigators in Germany, Trance, and England, 

 have contributed much in this direction. One of the first 

 attempts at a natural system, composed of Natural Orders or 

 sections, was made by Hoffmann at Gottingen, towards the 

 close of the era which we have been describing. The advent 

 of the second era was marked by the works of a distin- 

 guished Swede, Eric Acharius, works which gave an impetus 

 to the study of Lichenology, and which have, to a greater or 

 less extent, formed the basis of all subsequent lichenological 

 literature. But these works were too much mere systems 

 of classification, — mere catalogues of names and lists of 

 specific characters : there is a deficiency of information 

 regarding minute anatomy. The same remark is appli- 

 cable to the e Lichen ographia Europsea Reformata' of Fries 



