3 



under such comprehensive terms as muscus, bryum, sphagnum. 

 The term lichen (hiyyv) was doubtless used to designate various 

 liverworts, especially species of Marchantia. Only after a much 

 later period was this term employed exclusively in application to 

 lichens. Historians are uncertain as to what plant or plants Dios- 

 corides and Plinius intended to designate by the term lichen ; it was 

 in all probability a species of Marchantia or other liverwort. 



The first somewhat authentic references to lichens are to be 

 found in the writings of Theophrastus, 1 a pupil and follower of 

 Aristotle. It is generally conceded that this eminent naturalist de- 

 scribed several plants which were doubtless lichens. The very im- 

 perfect descriptions are supposed to refer to Usnca barbata and Ro- 

 cclla tinctoria. No further record seems to have been made of 

 lichens until the first century of our era when Dioscorides and 

 Plinius again mention the lichens supposed to have been described 

 by Theophrastus. There is little doubt that these authors referred 

 to Rocella tinctoria as a "marine fungus growing upon rocks, pos- 

 sessing coloring properties." Usnca no dovibt attracted attention be- 

 cause of its remarkable development. 



During the dark ages few observations were made on lichens, 

 in fact all scientific progress came to a standstill. Only plants of 

 evident or imaginary medicinal or economic uses were studied. It is 

 remarkable that a period of over seventeen centuries elapsed during 

 which nothing was added to the knowledge of lichens. Ruellius,' 1 

 Dorstenius 3 and Gesner, 4 the first commentators on the writings of 

 Theophrastus, Dioscorides and Plinius did little more than to reiterate 

 what had been known of the two lichens above mentioned. We may 

 safely state that up to time of Fuchsius 5 scarcely anything was known 

 of lichens. There can be little doubt that various lichens came to 

 the notice of botanists and herbalists of the time, but they were not 

 thought of sufficient importance for special study. 



Then followed a number of botanists who incidentally observed 

 and described a few lichens with which they came in contact during 



] A Latin translation byj. Bodaeus. Theophrasti Eresii de Ilistoria Plantarum 

 Libri Decem. 156. Amstelodami. 1644. 



2 Ruellius,J. De Natura Stirpium Libri III. Paris. 1536. 



3 Dorstenius. Botanicon continens Herbarum aliorumque Simplicium quorums 

 usus in Medicinis est, etc. Frankfurt. 1540. 



4 Gesner, K. Historia Plantarum. Basel. 1541. 



5 Fuchsius, L. De Stirpium Historia Commentarii. Basel. 1549- 



