Acharius, Erik

(b. Gavle, Sweden, 10 October 1757; d. Vadstena, Sweden, 14 August 1819)

botany.

Acharius was the last to defend his thesis (De planta Aphyteia, 1776) under Linnaeus, and all his life he pursued the Linnaean tradition of research in his botanical work. Like most of the university-trained botanists of his time, Acharius studied medicine, first at the University of Uppsala and then at Lund, where he received the M.D. in 1782. After that, he practiced medicine and spent the major part of his life in the province of Ostergotland, in the small town of Vadstena. He worked on botany only in his leisure time, but his scientific achievement was nevertheless considerable. He devoted himself almost exclusively to the study of lichens, and his description and classification of them laid the foundation for later scholarship.

Linnaeus had concentrated on the classification of the higher plants, and at the time of his death was the recognized authority on world flora. The generation of botanists who followed him sought to enlarge on his work by defining new areas of the plant kingdom. Some turned to new areas of the world as sources of plants for study, and others devoted themselves to the previously neglected cryptogams, which despite their large numbers and enormous variety were all placed in the twenty-fourth class of the Linnaean sexual system. As for the study of lichens, German botanists, among them J. Hedwig and H.A. Schrader, had considerably extended Linnaeus’ findings, but only Acharius laid the rational foundations of their classification.

In his first important publication, Lichenographiae suecicae prodromus (1798), Acharius still classified lichens according to the appearance of the thallus, which had been observed earlier, but he soon developed a new system based on structure. His terminology for the morphological description of lichens is still, to a large extent, valid. Using this method, he described a considerable number of new families and species, both Scandinavian and tropical. Some of the tropical specimens were collected from the bark and tissues of tropical plants that came to him in the form of botanical drugs. His advanced views on the taxonomy of lichens were presented in Methodus (1803), Lichenographia universalis (1810), and Synopsis methodica lichenum (1814).

For a long time Acharius thought that lichens were not really plants, but animals, most closely related to polyps. While this shows the vagueness of the conception still held at the beginning of the nineteenth century with regard to the “lower” organisms and their reproduction, it may also serve to illustrate the problems the lichen group posed before it was established that they are composed of an alga and a fungus living symbiotically. Since only inferior microscopes were available, the structure of lichens remained obscure to Acharius. During the decades following his death, Acharius’ scientific work was severely criticized, especially by the German botanists H.G. Floerke, G. F. W. Meyer, and K. F. W. Wallroth. Both his terminology and his classification of species were considered defective, and he was thought to have distinguished too many species. In contemporary lichenology, however, Acharius is highly respected, and many of his species are still recognized.

BIBLIOGRAPHY

I. Original Works. Acharius’ complete bibliography is in T. O. B. N. Krok, Bibliotheca botanica suecana (Uppsala-Stockholm, 1925), pp,2–4; and R. Sernander, “Acharius,” in Svenskt biografiskt lexikon, I (Stockholm, 1917–1918), 39–40. Among his works are Lichenographiae suecicae prodromus (Linköping, 1798); Methodus qua omnes detectos lichenes secundum organa carpomorpha ad genera, species et varietates redigere atque observationibus illustrare tentavit (Stockholm, 1803); Lichenographia universalis (Göttingen, 1810); and Synopsis methodica lichenum (Lund, 1814). His lichen herbarium is at the botanical museum of Helsingfors University; his correspondence is in the library of the University of Uppsala.

II. Secondary Literature. There is no complete modern biography of Acharius. Information on his life is in Svenskt biografiskt lexikon (see above). The best résumé of his work is A. von Krempelhuber, Geschichte und Literatur der Lichenologie, I-II (Munich, 1867–1869); I, 96–98, 112–114, 194–196, and passim; II, 61–68, 79–88, and passim.

Gunnar Eriksson