# Diplotomma

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Diplotomma
> Markdown URL: https://mediated.wiki/source/Diplotomma.md
> Source: https://en.wikipedia.org/wiki/Diplotomma
> Source revision: 1297495231
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{short description|Genus of lichens in the family Caliciaceae}}
{{Use dmy dates|date=June 2025}}
{{Use Oxford spelling|date=June 2025}}
{{Automatic taxobox
| image = Diplotomma chlorophaeum Jymm.jpg
| image_caption = ''Diplotomma chlorophaeum''
| taxon = Diplotomma
| authority = [Flot.](/source/Flot.) (1849)
| type_species = ''[Diplotomma alboatrum](/source/Diplotomma_alboatrum)''
| type_species_authority = ([Hoffm.](/source/Hoffm.)) Flot. (1849)
| subdivision_ranks = Species
| subdivisions =
| synonyms = *''Abacina'' {{au|Norman (1852)<ref name="Norman 1852"/>}}
}}

'''''Diplotomma''''' is a [genus](/source/genus) of [lichen](/source/lichen)-forming [fungi](/source/fungi) in the family [Caliciaceae](/source/Caliciaceae).<ref name="CoL_CCXF8"/> The genus has a widespread distribution and contains 14 species. These lichens form firmly attached, crust-like patches that range from pale to dark grey and can appear smooth or cracked into an irregular mosaic pattern on their [substrate](/source/substrate_(biology)). They produce black, disc-shaped fruiting bodies that start buried in the crust and later emerge to sit roughly flush with the surface, often dusted with a greyish-white powder.

==Taxonomy==

The genus was [circumscribed](/source/circumscription_(taxonomy)) by [Julius von Flotow](/source/Julius_von_Flotow) in 1849.<ref name="Flotow 1849"/> It was later wrapped into ''[Buellia](/source/Buellia)'' before being segregated from that genus by [David Hawksworth](/source/David_Leslie_Hawksworth) in 1980.<ref name="Hawksworth 1980"/>

==Description==

''Diplotomma'' species form a firmly attached, crust-like [thallus](/source/thallus) that sits on the [substrate](/source/substrate_(biology)) as a clearly delimited patch; in a few lichen-inhabiting ([lichenicolous](/source/lichenicolous_fungus)) taxa the thallus may be very thin or partly immersed in the [host](/source/host_(biology)). The surface ranges from pale to dark grey and can appear smooth or cracked into an irregular mosaic. A dense outer {{lichengloss|cortex}} is packed with minute crystals that remain intact when a fragment is placed in [potassium hydroxide](/source/potassium_hydroxide) solution (the [K test](/source/K_test)). The algal partner ({{lichengloss|photobiont}}) is a single-celled [green alga](/source/green_alga) of the {{lichengloss|chlorococcoid}} type, which provides [photosynthetic](/source/photosynthesis) energy.<ref name="Cannon et al. 2020"/>

The [sexual](/source/sexual_reproduction) fruit-bodies ([apothecia](/source/apothecia)) start out buried in the thallus and later emerge so that the black {{lichengloss|disc}} sits roughly flush with the surface; a narrow, pale, scalloped rim of thallus tissue may encircle the disc in some species. The disc itself is often dusted with a greyish-white powder ({{lichengloss|pruina}}). Microscopic examination shows only a rudimentary {{lichengloss|true exciple}}, merging seamlessly with the underlying {{lichengloss|hypothecium}}, both of which are brown to nearly black. Thread-like [paraphyses](/source/paraphyses) stand in the clear (I+ blue) [hymenium](/source/hymenium); their tips swell and darken, giving the layer a tufted look. Each sac-like [ascus](/source/ascus) contains eight [ascospore](/source/ascospore)s that are divided by [cross-walls](/source/septum) into two or more cells (sometimes almost forming a brick pattern, {{lichengloss|muriform|submuriform}}) and have thick internal partitions ({{lichengloss|distosepta}}); mature spores are mid- to dark brown with rounded internal chambers ({{lichengloss|lumina}}). [Vegetative reproduction](/source/Vegetative_reproduction) occurs in sunken, flask-shaped [pycnidia](/source/pycnidia) that appear as tiny brown dots; these release colourless, oval [conidia](/source/conidia) capable of starting new thalli. Chemically the genus is characterised by aromatic [depside](/source/depside)s, compounds that help separate its species from superficially similar grey crustose lichens.<ref name="Cannon et al. 2020"/>

==Selected species==
{{Asof|2025|June}}, [Species Fungorum](/source/Species_Fungorum) (in the [Catalogue of Life](/source/Catalogue_of_Life)) accepts 14 species of ''Diplotomma'':
* ''[Diplotomma alboatrum](/source/Diplotomma_alboatrum)'' {{small|(Hoffm.) Flot. (1849)}}
* ''[Diplotomma cedricola](/source/Diplotomma_cedricola)'' {{small|(Werner) Etayo (2010)}}
* ''[Diplotomma chlorophaeum](/source/Diplotomma_chlorophaeum)'' {{small|Szatala (1956)}}
* ''[Diplotomma epipolium](/source/Diplotomma_epipolium)'' {{small|(Ach.) Arnold (1869)}}
* ''[Diplotomma glaucoatrum](/source/Diplotomma_glaucoatrum)'' {{small|(Nyl.) Cl.Roux (2015)}}<ref name="Roux 2015"/>
* ''[Diplotomma hedinii](/source/Diplotomma_hedinii)'' {{small|(H.Magn.) P.Clerc & Cl.Roux (2004)}}<ref name="Clerc 2004"/>
* ''[Diplotomma murorum](/source/Diplotomma_murorum)'' {{small|(A.Massal.) Coppins (1980)}}
* ''[Diplotomma niveum](/source/Diplotomma_niveum)'' {{small|(Anzi) Szatala (1956)}}
* ''[Diplotomma parasiticum](/source/Diplotomma_parasiticum)'' {{small|(B.de Lesd.) Diederich, Cl.Roux & Haluwyn (2014)}}
* ''[Diplotomma pharcidium](/source/Diplotomma_pharcidium)'' {{small|(Ach.) M.Choisy (1950)}}
* ''[Diplotomma porphyricum](/source/Diplotomma_porphyricum)'' {{small|Arnold (1872)}}
* ''[Diplotomma rivas-martinezii](/source/Diplotomma_rivas-martinezii)'' {{small|(Barreno & A.Crespo) Barreno & A.Crespo (2000)}}<ref name="Molina & Crespo 2000"/>
* ''[Diplotomma venustum](/source/Diplotomma_venustum)'' {{small|(Körb.) Körb. (1860)}}
* ''[Diplotomma vezdanum](/source/Diplotomma_vezdanum)'' {{small|(P.Scholz & Knoph) Coppins (2002)}}

==References==
{{Reflist|colwidth=30em|refs=

<ref name="Cannon et al. 2020">{{cite journal |last1=Cannon |first1=Paul |last2=Prieto |first2=Maria |last3=Coppins |first3=Brian |last4=Sanderson |first4=Neil |last5=Scheidegger |first5=Christoph |last6=Simkin |first6=Janet |year=2021 |title=Caliciales: Caliciaceae, including the genera ''Acolium'', ''Amandinea'', ''Buellia'', ''Calicium'', ''Diploicia'', ''Diplotomma'', ''Endohyalina'', ''Monerolechia'', ''Orcularia'', ''Pseudothelomma'', ''Rinodina'' and ''Tetramelas'' |journal=Revisions of British and Irish Lichens |volume=15 |pages=1–35 [24] |doi=10.34885/174}} {{Open access}}</ref>

<ref name="Clerc 2004">{{cite journal |last=Clerc |first=P. |year=2004 |title=Les champignons lichénisés de Suisse – Catalogue bibliographique complété par des données sur la distribution et l'écologie des espèces |trans-title=The lichenised fungi of Switzerland — A bibliographic catalogue supplemented with data on species distribution and ecology |journal=Cryptogamica Helvetica |volume=19 |page=292 |language=fr}}</ref>

<ref name="CoL_CCXF8">{{Catalogue of Life |id=CCXF8 |title=''Diplotomma'' |access-date=17 June 2025}}</ref>

<ref name="Flotow 1849">{{cite journal |last=Flotow |first=J.V. |title=Lichenes florae silesiae |journal=Jahresbericht der Schlesischen Gesellschaft für vaterländische Kultur |year=1849 |volume=27 |pages=98–143 |language=German}}</ref>

<ref name="Hawksworth 1980">{{cite journal |last1=Hawksworth |first1=D.L. |last2=James |first2=P.W. |last3=Coppins |first3=B.J. |year=1980 |title=Checklist of British lichen-forming, lichenicolous and allied fungi |journal=The Lichenologist |volume=12 |issue=1 |pages=1–115 |doi=10.1017/S0024282980000035|bibcode=1980ThLic..12....1H }}</ref>

<ref name="Molina & Crespo 2000">{{cite journal |last1=Molina |first1=M. del C.|last2=Crespo |first2=A. |year=2000 |title=Comparison of development of axenic cultures of five species of lichen-forming fungi |journal=Mycological Research |volume=104 |issue=5 |pages=595–602|doi=10.1017/S0953756299002014 }}</ref>

<ref name="Norman 1852">{{cite journal |last=Norman |first=Johannes M. |title=Conatus praemissus redactionis novae generum nonnullorum Lichenum in organis fructificationes vel sporis fundatae |journal=Nytt Magazin for Naturvidenskapene |year=1852 |volume=7 |pages=213–52 |language=la}}</ref>

<ref name="Roux 2015">{{cite journal |last=Roux |first=C. |year=2015 |title=Validigo de du kombinaĵoj publikigitaj far ROUX inter 2005 kaj 2014 — Validation de deux combinaisons publiées par Roux entre 2005 et 2014 |trans-title=Validation of two combinations published by Roux between 2005 and 2014 |journal=Bulletin de la Société Linnéenne de Provence |volume=66 |pages=91–92 |language=eo}}</ref>

}}

{{Taxonbar|from=Q5280002}}

Category:Caliciales
Category:Lichen genera
Category:Caliciales genera
Category:Taxa described in 1849
Category:Taxa named by Julius von Flotow

---
Adapted from the Wikipedia article [Diplotomma](https://en.wikipedia.org/wiki/Diplotomma) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Diplotomma?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.