{{Short description|Genus of lichens}} {{Use American English|date=June 2023}} {{Use dmy dates|date=June 2023}} {{Automatic taxobox | image = Caloplaca luteominia - Flickr - pellaea.jpg | image_caption = ''Tomnashia luteominia'', Palos Verdes, southern California | taxon = Tomnashia | authority = S.Y.Kondr. & Hur (2017) | type_species = Tomnashia rosei | type_species_authority = (Hasse) S.Y.Kondr. & (Hur 2017) | subdivision_ranks = | subdivision = ''T. ludificans''<br /> ''T. luteominia''<br /> ''T. nashii''<br /> ''T. rosei'' }}
'''''Tomnashia''''' is a genus of lichen-forming fungi in the family Teloschistaceae. It has four species of saxicolous (rock-dwelling), crustose lichens that occur in southwestern North America.<ref name="CoL"/>
==Taxonomy==
''Tomnashia'' was circumscribed in 2017 by lichenologists Sergey Kondratyuk and Jae-Seoun Hur, who bestowed upon the taxon an eponym in honour of Thomas Hawkes Nash III, a significant contributor to lichenology, especially concerning North American lichen flora. The type species of this genus is ''Tomnashia rosei'', which was originally described as ''Caloplaca rosei'' by Hermann Edward Hasse in 1911.<ref name="Hasse 1911"/> Through combined phylogenetic analysis, it was determined that ''Tomnashia'' resides in the outermost position among monophyletic groups of the ''Polycauliona'' subclade of the subfamily Xanthorioideae. This genus differs notably from other members of ''Polycauliona'' with its distinct characteristics and morphology.<ref name="Kondratyuk et al. 2017"/>
==Description==
Presenting a varied range of colours, the crustose thallus of ''Tomnashia'' ranges from white, grey, and greenish-yellow to yellowish orange, or apricot orange, with some species having a unique waxy translucent appearance. The small, {{lichengloss|biatorine}} {{lichengloss|apothecia}} are usually orange to reddish-brown. Another unique attribute of this genus is its {{lichengloss|ascospores}}, which are {{lichengloss|polarilocular}} and hyaline. Its distinctive chemical composition includes substances such as parietin, fallacinal, emodin, teloschistin, and parietinic acid.<ref name="Kondratyuk et al. 2017"/>
==Habitat and distribution==
Predominantly distributed in the southwestern part of North America, ''Tomnashia'' is found mainly on calcareous rock and soil, but it can also grow on non-calcareous rocks. Some related genera, such as ''Polycauliona'' and ''Igneoplaca'', share a similar, relatively limited distribution in coastal southwestern North America. Other genera in the same subfamily, such as ''Massjukiella'' and ''Verrucoplaca'', have a much broader distribution in the Northern Hemisphere or worldwide.<ref name="Kondratyuk et al. 2017"/>
==Species== * ''Tomnashia ludificans'' {{au|(Arup) S.Y.Kondr. & Hur(2017)}} * ''Tomnashia luteominia'' {{au|(Tuck.) S.Y.Kondr. & Hur (2017)}} * ''Tomnashia nashii'' {{au|(Nav.-Ros., Gaya & Hladun) S.Y.Kondr. & Hur (2017)}} * ''Tomnashia rosei'' {{au|(Hasse) S.Y.Kondr. & Hur (2017)}}
==References== {{Reflist|refs=
<ref name="CoL">{{Catalogue of Life |id=7XLT |title=''Tomnashia'' |access-date=June 12, 2023}}</ref>
<ref name="Hasse 1911">{{cite journal |last1=Hasse |first1=H.E. |year=1911 |title=Additions to the lichen flora of southern California. No. 6 |journal=The Bryologist |volume=14 |issue=6 |pages=100–102 |jstor=3238388 |doi=10.2307/3238388}}</ref>
<ref name="Kondratyuk et al. 2017">{{cite journal |last1=Kondratyuk |first1=S.Y. |last2=Lőkös |first2=L. |last3=Upreti |first3=D.K. |last4=Nayaka |first4=S. |last5=Mishra |first5=G.K. |last6=Ravera |first6=S. |last7=Jeong |first7=M.-H. |last8=Jang |first8=S.-H. |last9=Park |first9=J.S. |last10=Hur |first10=J.-S. |title=New monophyletic branches of the Teloschistaceae (lichen-forming Ascomycota) proved by three gene phylogeny |journal=Acta Botanica Hungarica |volume=59 |issue=1–2 |year=2017 |doi=10.1556/034.59.2017.1-2.6 |pages=71–136 |url=https://www.researchgate.net/publication/315584297|hdl=10447/414429 |hdl-access=free }}</ref>
}}
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Category:Teloschistales Category:Teloschistales genera Category:Taxa described in 2017 Category:Lichen genera Category:Taxa named by Sergey Kondratyuk Category:Taxa named by Jae-Seoun Hur