to be today. His first publication was Lichenographiae Suecia prodromus, published in 1798, which detailed all known lichen species found in Sweden. This was the first published work to detail lichens using binomial nomenclature and expand their classification beyond a single genus. While composing Lichenographiae Suecia prodromus, Acharius began communicating with Olof Swartz, another Linnaean disciple, and from 1780 to 1815 they sent nearly 350 letters to each other. Swartz is believed by many historians to have heavily influenced the development of Acharius's classification system. Additionally, Swartz introduced Acharius to many other Swedish naturalists as also several important international figures such as James Edward Smith, the head of the Linnean Society. This exposure aided Acharius in spreading his new findings on lichens to an international audience. After publishing his first work, he sent a copy to James Edward Smith who, in response, inducted Acharius as a foreign member of the Linnean Society. Subsequently, Acharius published Methodus qua omnes detectos Lichenes (1803), Lichenographia universalis (1810), and Synopsis methodica lichenum (1814) each of which he sent to the Society in London, accompanied by hundreds of the specimens described in each book. Over his lifetime Acharius collected over 5500 specimens of lichen most of which are housed today in the Botanical Museum of the Finnish Museum of Natural History. In his influential works, Acharius introduced many lichen-related terminology that remain in common use today. Starting with designating the pits on the underside of Sticta lichens as in 1794, he added the terms , , , , , and in 1803; in 1810; and in 1817. Legacy Acharius's international reputation influence many new lichenologist from all over Europe. In 1804 Friedrich Weber (1781–1823) and Daniel Matthias Heinrich Mohr (1780–1808), two German naturalists, published Naturhistorische Reise durch einen Theil Schwedens which heavily featured his work on lichens and also included four illustrations by Acharius. Furthermore, William Borrer who pioneered lichenology in Britain (and is often called the father of British lichenology) was heavily influence by Acharius's specimens and publications received by the Linnean society in London. These collections and books were studied by Borrer in 1809 and served as the basis for his own work. Additionally Thomas Gage published A Monograph of the Genus Cenomyce: Consisting of Coloured Drawings of Each Species and Variety, As Described in the Lichenographia Universalis of Acharius in 1815, which contained illustrations of every species and variation of the genus