The genus was
circumscribed in 1855 by the German lichenologist
Gustav Wilhelm Körber, who assigned
Lecanactis abietina as the
type species. In his original description, Körber characterised
Lecanactis as having pseudolecideine
apothecia (fruiting bodies) that are initially closed, then become widely open, with a rounded to somewhat irregular form. He noted that the apothecia typically have a prominent margin and distinguished the genus by its spore-bearing structures and thallus characteristics. Körber initially included several species in the genus, including
L. abietina,
L. dilleniana, and
L. biformis. He recognised
Lecanactis as a transitional genus that connects the lichens with the forms, noting the unique combination of initially closed apothecia that later expand and the distinctive thalline characteristics that separate it from related genera such as
Opegrapha. The genus name
Lecanactis reflects the -like appearance of the apothecia combined with their distinctive radiating or star-like (
actis) arrangement when mature. A later nomenclatural review showed that the name
Lecanactis had a complicated early history. Although the genus came into general use in the sense adopted by Körber in 1855, Anders Tehler pointed out that the name had earlier been used by
Franz Gerhard Eschweiler in a different sense. To preserve the long-established usage of
Lecanactis for the genus as understood by lichenologists, Tehler proposed
conserving the name with
Lecanactis abietina as its conserved type, rather than allowing it to be displaced by little-used alternatives such as
Scolecactis or
Lecanactiomyces. In 1988, the Committee for Fungi and Lichens recommended adoption of
Lecanactis in Körber's sense, with
L. abietina as type, over the earlier
homonym published by Eschweiler, concluding that failure to conserve the name would greatly upset lichen nomenclature. In the broad concept used by
Alexander Zahlbruckner in the early 20th century,
Lecanactis had become a heterogeneous assemblage containing about 140 species and numerous infraspecific taxa (
forms,
varieties, and
subspecies). During the 1990s, that circumscription was narrowed as several
segregate genera, including
Cresponea,
Lecanographa and
Sipmania, were removed from
Lecanactis,
Catarraphia was reinstated, many species were transferred to
Bactrospora, and eight former
Schismatomma species were moved into
Lecanactis. In a 1997
cladistic study based on
morphological, anatomical and chemical characters, Tehler and José Egea recovered
Lecanactis sensu stricto as a
monophyletic group, but found that relationships within the genus were only weakly supported, so they did not propose any subgeneric classification. ==Description==