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Lichens were mentioned and described down to and including Lin- 

 nfeus. Tournefort mentions 44 species, although up to the end of 

 his period about 125 species were known. Micheli made a special 

 study of cryptogams, and divided Lichens into 38 orders, and fig- 

 ured them in his " Nova Plantarum Genera." Dillenius of Oxford 

 figured and described Lichens in his Historia Muscorum, 1741. 

 Linnaeus describes Cladonia rangiferina according to the method of 

 his time, as " Lichen (rangiferinus) fruticulosus, perforatus ramo- 

 sissimus ramulis nutantibus." Over 300 species were known at this 

 time, and some of the natural groups of Lichens had been discrimi- 

 nated, and names given to genera and species which they still retain. 

 Weber distributed the Lichens among 8 genera, and with him be- 

 gan a more systematic study of them, especially with regard to the 

 fructification. HoSman's Descriptio et Adumbratio Lichenum, 1790, 

 contains many fine drawings of Lichens. The chemistry and uses 

 of Lichens began to be studied, and Lichens were collected in vari- 

 ous parts of the world. All these labors prepared the way for 

 Acharius, who has been styled the Father of Lichenography. He 

 published in 1803 his Methodus Lichenum, of which the basis is the 

 structure of the fructification. His nomenclature, however, is now 

 obsolete. In 1810 he published his Lichenographia Universalis, fol- 

 lowed in 1814 by the Synopsis Lichenum, which remain the only com- 

 plete accounts of all then known Lichens. He recognized the exist- 

 ence of the thekes and spores, but made no systematic use of them. 

 In the Synopsis he describes 904 species. In 1831 Elias Fries, a 

 great botanist, published his Lichenographia Europsea Reformata, 

 the introduction to which is a philosophical treatise on Lichens which 

 may still be read with profit, and whose descriptive portions are 

 models of clearness and exactness. He established the divisions 

 into Gymnocarpi and Angiocarpi, and separated Lichens into eight 

 tribes: (1) Parmeliacese, (2) Lecidinse, (3) Graphidese, (4) Cali- 

 eiese, (5) Sphserophorese, (6) Endocarpeae, (7) Verrucariese, (8) 

 Limboriese, of which the fourth and fifth are now considered as one, 

 and also the sixth and seventh, while the eighth is not now recog- 

 nized. He also distinguished Lichens as Myco-Lichenes and Phyco- 

 Lichenes, the latter being the gelatinous or Algse-like Lichens. These 

 were named by later writers Lichenes Heteromericse and Lichenes 

 Homceomericae. Tuckerman was, so far as we know, the first to 

 combine both these series into one. Among other noted Lichenists 



