{{Short description|Genus of lichen}} {{Use dmy dates|date=June 2025}} {{Use Oxford spelling|date=June 2025}} {{Automatic taxobox | image = Trapeliopsis wallrothii Jymm.jpg | image_caption = ''Trapeliopsis wallrothii'' | taxon = Trapeliopsis | authority = Hertel & Gotth.Schneid. (1980) | type_species = ''Trapeliopsis wallrothii'' | type_species_authority = (Flörke ex Spreng.) Hertel & Gotth.Schneid. (1980) | subdivision_ranks = Species | subdivisions = }}
'''''Trapeliopsis''''' is a genus of lichen-forming fungi in the family Trapeliaceae.<ref name="CoL_CF94F"/> These lichens form thin, granular crusts or tiny overlapping scales ({{lichengloss|squamules}}) that create miniature rosette patterns on their growing surface. The genus was established in 1980 by Hannes Hertel and Gotthard Schneider and includes about 20 species found worldwide.
==Taxonomy==
The genus was circumscribed in 1980 by Hannes Hertel and Gotthard Schneider, with ''Trapeliopsis wallrothii'' designated as the type species.<ref name="Schneider 1979"/>
==Description==
''Trapeliopsis'' grows as a thin, granular to minutely leaf-like crust that sits close to its substrate. In some species the {{lichengloss|granules}} enlarge into tiny, overlapping scales (squamules) that can give the colony a miniature rosette appearance; in others the thallus remains a loose dusting of coarse grains. Only those distinctly {{lichengloss|squamulose}} forms develop a true upper {{lichengloss|cortex}}—an organised skin of tangled fungal hyphae—while the purely granular morphs have no differentiated surface layer. Throughout the thallus the photosynthetic partner is a green alga of the ''Chlorella'' or ''Pseudochlorella'' type, often dividing into clusters of two to four cells whose flattened faces make them appear slightly asymmetrical.<ref name="Orange 2021"/>
Reproductive structures present as low, button-like apothecia that are yellow-brown to almost black. They are slightly pinched in at the base and lie flush with the thallus surface from an early stage, expanding outward without splitting. Some species show a pronounced rim cut from thallus tissue (a {{lichengloss|thalline margin}}), whereas others reveal only the internal {{lichengloss|exciple}}—a ring of colourless fungal hyphae set in a faintly pigmented gel that never darkens to the deep brown seen in some related genera. Inside the apothecium, delicate paraphyses thread the hymenium; these filaments branch and fuse near their tips but remain narrow and usually colourless, though an external pigment coating can make the upper layer appear slightly swollen. Each thin-walled ascus holds eight smooth, ellipsoidal ascospores that stay colourless and single-celled, staining weakly or not at all with iodine (a "''Trapelia''-type" response).<ref name="Orange 2021"/>
Asexual reproduction occurs in immersed pycnidia that release rod-shaped to thread-like conidia. Chemical analyses typically detect gyrophoric acid, with traces of lecanoric acid also common. While sterile material may be difficult to separate from the superficially similar ''Trapelia'', molecular studies show that ''Trapeliopsis'' forms a distinct evolutionary lineage, and its colourless exciple plus uniformly narrow paraphyses help distinguish it from dark-rimmed genera such as ''Placynthiella''.<ref name="Orange 2021"/>
==Species== {{As of|2025|June}}, Species Fungorum (in the Catalogue of Life) accept 16 species of ''Trapeliopsis''.<ref name="CoL_CF94F"/> *''Trapeliopsis aeneofusca'' {{small|(Flörke ex Flot.) Coppins & P.James (1984)}} *''Trapeliopsis bisorediata'' {{small|McCune & F.J.Camacho (2002)}}<ref name="McCune et al. 2002"/> – North America *''Trapeliopsis californica'' {{small|McCune & F.J.Camacho (2002)}}<ref name="McCune et al. 2002"/> – North America *''Trapeliopsis colensoi'' {{small|(C.Bab.) Gotth.Schneid. (1980)}} *''Trapeliopsis congregans'' {{small|(Zahlbr.) Brako (1989)}} *''Trapeliopsis flexuosa'' {{small|(Fr.) Coppins & P.James (1984)}} *''Trapeliopsis gelatinosa'' {{small|(Flörke) Coppins & P.James (1984)}} *''Trapeliopsis glaucolepidea'' {{small|(Nyl.) Gotth.Schneid. (1980)}} *''Trapeliopsis glaucopholis'' {{small|(Nyl.) Printzen & McCune (2004)}} *''Trapeliopsis granulosa'' {{small|(Hoffm.) Lumbsch (1983)}} *''Trapeliopsis gymnidiata'' {{small|Aptroot & Schumm (2012)}}<ref name="Aptroot & Schumm 2012"/> – Macaronesia *''Trapeliopsis gyrocarpa'' {{small|Elix (2013)}}<ref name="Elix 2013"/> – Australia *''Trapeliopsis percrenata'' {{small|(Nyl.) Gotth.Schneid. (1980)}} *''Trapeliopsis pseudogranulosa'' {{small|Coppins & P.James (1984)}}<ref name="Coppins & James 2007"/> – Europe *''Trapeliopsis steppica'' {{small|McCune & F.J.Camacho (2002)}}<ref name="McCune et al. 2002"/> – North America *''Trapeliopsis studerae'' {{small|Aptroot & M.Cáceres (2018)}}<ref name="Aptroot et al. 2018"/> – Brazil *''Trapeliopsis thermophila'' {{small|Rambold & Elix (2013)}}<ref name="Elix 2013"/> – Australia *''Trapeliopsis viridescens'' {{small|(Schrad.) Coppins & P.James (1984)}} *''Trapeliopsis wallrothii'' {{small|(Flörke ex Spreng.) Hertel & Gotth. Schneid. (1980)}}
==References== {{Reflist|colwidth=30em|refs=
<ref name="Aptroot & Schumm 2012">{{cite journal |last1=Aptroot |first1=André |last2=Schumm |first2=Felix |title=A new terricolous ''Trapelia'' and a new ''Trapeliopsis'' (Trapeliaceae, Baeomycetales) from Macaronesia |journal=The Lichenologist |volume=44 |issue=4 |year=2012 |pages=449–456 |doi=10.1017/S0024282912000084|bibcode=2012ThLic..44..449A }}</ref>
<ref name="Aptroot et al. 2018">{{cite journal |last1=Aptroot |first1=André |last2=Barreto |first2=Flávia Maria Oliveira |last3=Peña |first3=Dolores Angélica Ramírez |last4=Cáceres |first4=Marcela Eugenia da Silva |title=A new lineage of fruticose lichens that belongs to the Trapeliaceae (Trapeliales, Ascomycota) from Alagoas, NE Brazil |journal=The Bryologist |volume=121 |issue=4 |year=2018 |pages=529–535 |doi=10.1639/0007-2745-121.4.529}}</ref>
<ref name="CoL_CF94F">{{Catalogue of Life |id=CF94F |title=''Trapeliopsis'' |access-date=20 June 2025}}</ref>
<ref name="Orange 2021">{{cite book |last1=Orange |first1=A. |last2=Cannon |first2=P. |last3=Aptroot |first3=A. |last4=Coppins |first4=B. |last5=Sanderson |first5=N. |last6=Simkin |first6=J. |year=2021 |title=Baeomycetales: Trapeliaceae, including the genera ''Coppinsia'', ''Placopsis'', ''Placynthiella'', ''Rimularia'', ''Trapelia'' and ''Trapeliopsis'' |series=Revisions of British and Irish Lichens |volume=18 |page=3 |url=https://britishlichensociety.org.uk/sites/default/files/Trapeliaceae.pdf}}{{Open access}}</ref>
<ref name="Coppins & James 2007">{{cite journal |last1=Coppins |first1=B.J. |last2=James |first2=P.W. |title=New or interesting British lichens V |journal=The Lichenologist |volume=16 |issue=3 |year=2007 |pages=241–264 |doi=10.1017/S0024282984000451}}</ref>
<ref name="Elix 2013">{{cite journal |last=Elix |first=J.A. |year=2013 |title=New crustose lichen taxa (lichenized Ascomycota) from Australia |journal=Australasian Lichenology |volume=73 |pages=45–53 |url=https://www.anbg.gov.au/abrs/lichenlist/AL_73.pdf}}</ref>
<ref name="McCune et al. 2002">{{cite journal |last1=McCune |first1=B. |last2=Camacho |first2=F. |last3=Ponzetti |first3=J. |year=2002 |title=Three new species of ''Trapeliopsis'' on soil in western North America |journal=The Bryologist |volume=105 |issue=1 |pages=78–85|doi=10.1639/0007-2745(2002)105[0078:TNSOTO]2.0.CO;2}}</ref>
<ref name="Schneider 1979">{{cite book |last=Schneider |first=Gotthard |year=1979 |title=Die Flechtengattung ''Psora'' sensu Zahlbruckner |trans-title=The lichen genus ''Psora'' sensu Zahlbruckner |series=Bibliotheca Lichenologica |volume=13 |page=149 |publisher=Lubrecht & Cramer |isbn=978-3-7682-1257-1 |language=de}}</ref>
}}
{{Taxonbar|from=Q7835559}}
Category:Baeomycetales Category:Lichen genera Category:Baeomycetales genera Category:Taxa described in 1980 Category:Taxa named by Hannes Hertel