THE LICHEN-FLORA OF CHICAGO AND VICINITY. 13 



there was not in the United States any lichenological hterature 

 worthy of the name; no system of classification of American origin, 

 under which our vast and rich lichen-flora could be arranged. 

 Students were dependent entirely upon the works of Euporean 

 authors, and these were mostly in foreign languages not easily to be 

 obtained or understood here, except by the very few, who, like 

 Tuckerman, lived under the shadow of a great university and had a 

 liberal education. Thus it was that New England almost wholly 

 absorbed the study of this branch of science. Also, every Euro- 

 pean lichenologist had a system of his own, and no two could 

 agree on a uniform method of classification applicable to the 

 species known and the many new forms being constantly dis- 

 covered. 



In ancient times nothing was known of lichens as a distinct 

 order of plants, but one or two species have been found in coffins, 

 no doubt used for padding. A reference to the old herbalists of the 

 twelfth and fifteenth centuries show that lichens then went under 

 the names of " f uscus ' or "muscus," and were considered allied 

 to the mosses. They began to attract more attention in the six- 

 teenth century, and over twenty species were described. The gen- 

 eral revival of all learning after the dark, middle ages, stimulated 

 the study of botany, and lichens shared in the benefit. It was 

 then that Tournefort separated them from the musci, and included 

 all then known under the general name. Lichens. This distinctive 

 term was accepted and used by the great Linnaeus. From sixteen 

 hundred to the Acharian period, about 1802, rapid progress was 

 made in the study. During this period lived Micheli, Webber, 

 Dillenius, of Oxford, Hoffman, Linnaeus and Acharius, the 

 " Father of Lichenology." All these were celebrated for their 

 learning and published works upon lichens. Over three hundred 

 species became known up to 1750, and were arranged in natural 

 groups and genera, many of which still stand. Their chemistrj' 

 and economic uses were studied, and collections of lichens made. 

 But the best thoughts of investigators in the latter part of the 

 eighteenth and the first years of the nineteenth century found a 

 truer expression at last in 1803, when Acharius published the re- 

 sult of his studies in the Methodus Lichenum, followed in 1810 by 

 his Lichenographia Universalis, and in 1814 by the Synopsis 

 Lichenum. These gave full accounts of all the then known species, 

 over nine hundred. A number of American species are mentioned. 



