Although Anaptychia is one of the commonest foliose lichen genera in tropical and temperate regions, it has never been revised monographically from modern taxonomic principles. There are, however, several regional revisions of the species in South America (Vainio, 1890; Lynge, 1924) and Europe (Lynge, 1916, 1935; Maas Geesteranus, 1952), but these revisions, in which comparatively few species are treated, are in many respects floras rather than monographs. In these revisions as well as in publications of other lichenologists the taxonomic treatment of the genus is not entirely satisfactory. Our knowledge of Anaptychia is based on numerous fragmentary publications, in which new taxa are frequently described without adequate reference to older taxa and without sufficient comparison with type specimens. There is also much confusion among lichenologists on the recognition of the various taxa, and it has been found necessary to revise many of the names.
It is more than a century since Korber (1848) published his “Grundriß der Kryptogamen—Kunde,” in which he proposed the genus Anaptychia. In 1853, Massalongo published his “Memorie Lichenografiche.” Here he enumerated 21 species of Anaptychia, transferring to the genus the species already described in the literature and adding several new species. Massalongo’s concept of Anaptychia was rather broad, for it included some species of Physica. Before Massalongo’s publication, a number of well known species had already been described by the older lichenologists. Linnaeus, for example, described Lichen leucomelos and L.ciliaris in Species plantarum (ed.2). Acharius also devoted some attention to Anaptychia species. In his earlier papers he referred them to the genera Lichen of Parmelia. Ten species now recognized as Anaptychia, about half of which he described as new, were enumerated in his last work, the comprehensive Synopsis Methodica Lichenum.
Important contributions to our knowledge of Anaptychia were made by Taylor (1847), but few lichenologists have paid any attention to them. Taylor described under Parmelia six species now recognized as Anaptychia. Although few in number, most of these species, except for Parmelia phioglossa, are now recognized as valid. Thus, when Massalongo published in 1853 his important contribution to Anaptychia, more than 15 species, about half of the well known species, had already been described by various authors. Our knowledge of the genus has been based for the most part on the work of these classical lichenologists.
Many recent workers, including Müller Argau, Vainio, Zahlbruckner, and Lynge, have tried to identify exotic Anaptychia almost exclusively with the older well known species, A.hypoleuca, A.speciosa, A.leucomelaena, A.podocarpa, etc., to which there is sometimes no relation at all. For instance, Müller described under Physica speciosa many varieties and forms which are now usually recognized as distinct species. Vainio made a gross error in the interpretation of A.hypoleuca in his Etude Lich. Brés. Furthermore, up to the present time, no lichenologist has ventured to propose a subgeneric classification for Anaptychia, because it has been considered to be one of the simplest lichen genera.
With these points in mind, I began monographic work on Anaptychia in 1957. During the course of the study I published several regional revisions of the Japanese species, typifying wherever possible the taxa. It became evident, however, that the study should be extended to include the whole world. In the present work, therefore, I have attempted to complete a world monograph of the genus. My main objectives have been to typify each taxon already described, applying the type method, to describe new taxa, and finally to use the knowledge thus gained to erect a taxonomic subdivision of the genus. I have made considerable use of chemical components, which are one of the most important criteria used to distinguish the species.