Diarthonis
genus of fungi
Diarthonis is a fungal genus in the family Graphidaceae. Originally created in 1909 but long unused, the genus was revived in 2020 to accommodate D. spadicea when molecular studies showed this species fell outside the main Arthonia clade. The species grows as a thin, greyish to greenish crust beneath tree bark, producing small black disc-like reproductive structures (apothecia) that resemble drops of tar. It is considered an indicator of ecological continuity in old-growth broadleaved forests, particularly those dominated by English oak, and is listed as near-threatened in some regions.
Taxonomy
The genus Diarthonis was established by Frederic Clements in 1909, with a minimal but nomenclaturally valid diagnosis. The type species, D. lurida (a rejected name), was based on Arthonia lurida Ach. (1803). After its establishment, the genus name remained essentially unused for over a century.
In 1981, D. lurida was formally rejected following a nomenclatural proposal by David Hawksworth and Martha Sherwood to protect the later name Arthonia spadicea Leight. (1854).
This brief starts where responsible research should: with the source description of “Diarthonis” as genus of fungi. Everything that follows is an evidence route, not borrowed authority.
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The subject matters to the science & nature register because the source frames it as genus of fungi. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated Mar 16, 2025. The linked authority identifier is Q108782359. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1909, 2020, 1803 and 1981.
A general summary may omit uncertainty, sample limits or methodological disagreement that is explicit in the technical record. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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This entry incorporates text from “Diarthonis” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.