“We left Skjärsjö on May 22 1803 at around noon... Our journey now continued to the closely located town of Vadstena at the shore of lake Vättern to visit Acharius who lived there. During the evening of the day of our arrival we had the pleasure to visit Dr Acharius. He asked us to come next morning. Yet, before the end of the day, this kind man had already asked us to accompany him at home. We were very glad indeed to find this number one lichenologist, as we surely considered him, and appreciated him for his kindness to be introduced. With the largest willingness, Acharius at first showed us his outstanding lichen collection.”. This text is a part of an introduction from the itinerary by WEBER & MOHR (1804) of a journey through Sweden at the beginning of the 19th century to visit some of the leading scientists in natural history of that time. Acharius, using his extensive lichen collection, introduced Weber and Mohr to his work on the arrangement of all known lichens into a natural classification. The two men stayed approximately a week in Vadstena. Subsequently they visited Johan Westring, who was working on his renowned book on the economic use of lichens, in which Acharius was involved as a diligent and skilled illustrator (WESTRING 1805). Apart from the short story told by WEBER & MOHR (1804) on their encounter with this friendly local doctor, very little is known or published about Erik Acharius and his private life, but short biographical notes are provided by PALMBLAD et al. (1835), KREMPELHUBER (1868), SERNANDER (1917), LUNDMARK (1952), VITIKAINEN (1976), MAGNUSSON (1981) and GALLOWAY (1988). The only known portrait of Acharius is the engraving by Johan Gustav Ruckman which appears in Synopsis methodica lichenum (Fig 1)