The genus
Stictis was
circumscribed in 1800 by the mycologist
Christiaan Hendrik Persoon. In his original description, Persoon characterised the genus as having receptacles that were subcupuliform (somewhat cup-shaped) or obliterated and immersed in wood. He established two species:
S. radiata, described as immersed with a prominent white opening that was either entire or split in a radiating fashion, resembling certain
Lycoperdon and
Sphaerobolus species and characterised by a white, scalloped with brownish margin; and
S. pallida, distinguished by its pustule-like form with a pale opening that gaped elliptically. Persoon noted that these simple fungi consisted only of a fructifying disc enclosed in wood, with form and substance resembling
Peziza species, though lacking a distinctly prominent margin—instead, the wood formed a nest-like structure with a shining, round opening that sometimes displayed the elliptical gaping characteristic of
Hysterium species. This circumscription established
Stictis as a genus of wood-inhabiting fungi with distinctive cup-shaped or slit-like fruiting bodies that remain largely embedded within their substrate. A
molecular study of the
Stictis–
Conotrema complex in northern Scandinavia found that three phylogenetic species included both lichenized specimens traditionally placed in
Conotrema and
saprotrophic specimens identified as
Stictis. The two forms did not resolve as separate species in analyses of multiple genetic markers, but instead represented different expressions of the same fungal species. Wedin, Döring, and Gilenstam interpreted this as evidence of "optional lichenization", in which individuals of the same species can complete their life cycle either as a lichen on bark or as a saprotroph on bark-free wood, depending on substrate. They consequently argued that these fungi should ultimately be treated in
Stictis, the older generic name, rather than in
Conotrema. Later work has shown that Persoon's broad concept of
Stictis will probably not survive modern scrutiny. Molecular and detailed
morphological studies have demonstrated that many of the once used to separate genera in the Stictidaceae—particularly the presence or absence of tiny filaments () lining the fruiting body opening—vary within
Stictis itself and therefore provide little guidance for drawing generic boundaries. Because the genus is large, taxonomically neglected, and most species are short-lived
saprobes in the
tropics, recent authors predict that the present, very broad concept of
Stictis will eventually be broken up, as several independent
lineages now grouped under the name are likely to be recognised as separate genera during a thorough revision of the family. ==Description==