{{Short description|Species of lichen}} {{Use dmy dates|date=January 2021}} {{Speciesbox | image = Mustard Lichen (4501584355).jpg | status = G5 | status_system = TNC | status_ref = <ref name=NS>{{cite NatureServe |id=2.121406 |title=''Pyxine sorediata'' |access-date=5 November 2025}}</ref> | taxon = Pyxine sorediata | authority = ([[Ach.]]) [[Camille Montagne|Mont.]] (1845) | synonyms_ref = <ref name="Species Fungorum synonymy"/> | synonyms = *''Lecidea sorediata'' {{small|Ach. (1814)}} *''Lichen daedaleus'' {{small|[[Sm.]] (1810)}} *''Parmelia sorediata'' {{small|(Ach.) [[Tuck.]](1848)}} *''Placodium daedaleum'' {{small|(Sm.) [[Hook.]] (1833)}} *''Pyxine cocois'' subsp. ''sorediata'' {{small|(Ach.) Tuck. (1882)}} *''Pyxine cocois'' var. ''eschweileri'' {{small|Tuck. (1877)}} }}
'''''Pyxine sorediata''''', commonly known as '''mustard lichen''', is a widely distributed species of [[foliose lichen]] in the family [[Caliciaceae]]. It has a [[subtropic]]al to warm [[temperate]] distribution, and grows on [[corticolous lichen|bark]], [[saxicolous lichen|rocks]], and moss as [[substrate (biology)|substrates]]. ''Pyxine sorediata'' has been reported from regions of North America, Europe, Africa, Asia, and Australasia.
==Taxonomy== ''Pyxine sorediata'' was first [[species description|scientifically described]] in 1814 by [[Erik Acharius]] as ''Lecidea sorediata''. In his brief account, Acharius mentioned the circular (''orbicular'') grey crust he described as wrinkled, folded, and overlapping, the spongy black underside, and the scattered [[apothecia]]. In his understanding, the lichen occurred only in North America.<ref name="Acharius 1814"/> [[Elias Magnus Fries]] erected the genus ''[[Pyxine]]'' in 1825, assigning ''Lecidea sorediata'' as the type species,<ref name="Fries 1825"/> although he did not formally propose a transfer to that genus.<ref name="Imshaug 1957"/> [[Camille Montagne]] gave it its current name when he transferred it to ''[[Pyxine]]'' in 1845.<ref name="Montagne 1845"/> A [[common name]] used in North America is "mustard lichen".<ref name="Brodo et al. 2001"/>
The Scottish naturalist [[Archibald Menzies]] collected a specimen from Scotland, which was later named by [[James Edward Smith (botanist)|James Edward Smith]] as ''Lichen daedalus'' in 1810.<ref name="Smith 1810"/> Modern expert examination and chemical analysis of the specimen showed that the specimen actually belonged to ''Pyxine sorediata''. This raised doubt as to the provenance of the specimen, as ''Pyxine sorediata'' is not found anywhere in the British Isles. The specimen posed a problem for [[taxonomy (biology)|nomenclatural]] reasons, as its publication preceded that of Montagne's by four years, and in the [[International Code of Nomenclature for algae, fungi, and plants|rules for botanical nomenclature]], Smith's earlier name has [[Principle of Priority|priority]]. For this reason, in 2004 [[Jack Laundon]] proposed to reject the name ''Lichen daedaleus'' to safeguard the name ''Pyxine sorediata'', and to "avoid displacing a well-established lichen name for purely nomenclatural reasons".<ref name="Laundon 2004"/>
==Description== ''Pyxine sorediata'' has a [[foliose lichen|foliose]] [[thallus]] that ranges in colour from dull bluish-grey to green-gray. The lobes comprising the thallus measure 1–2.5 mm wide, and are [[pruinose]] at the tips;<ref name="Brodo et al. 2001"/> they are in close contact, often overlapping.<ref name="Rogers 1986"/> The lobe margins also have white [[pseudocyphella]]e, that contrast with the lobe;<ref name="Moberg 1983"/> they are concentrated on the lobe margins and are rarely on the [[lamina (leaf)|lamina]].<ref name="Rogers 1986"/> The [[medulla (lichenology)|medulla]] is light yellow to yellow, and this colour is sometimes present in the soralia.<ref name="Rogers 1986"/> The underside of the thallus is black to greyish black; it has small [[rhizine]]s that help attach it to its [[substrate (biology)|substrate]]. Structures called [[soralia]] are on the margins of the lobes, but sometimes form round patches on the lamina. The [[soredia]] (reproductive structures) are coarse and grainy with a dark grey colour; they tend to impart a grey colour to the central part of the thallus.<ref name="Moberg 1983"/> [[Apothecia]] are quite rare in this species. The [[ascospore]]s measure 12–17 by 6–8 [[micrometre|μm]].<ref name="Rogers 1986"/>
''Pyxine sorediata'' is the largest species of ''Pyxine''.<ref name="Brodo et al. 2001"/> It does not have any reaction to the standard [[lichen spot test]]s.<ref name="Moberg 1983"/> [[Secondary metabolism|Secondary chemicals]] reported from the species include [[atranorin]] and unidentified [[triterpene]]s.<ref name="Rogers 1986"/>
===Similar species=== [[Molecular phylogenetic|Phylogenetic]] studies have shown that the corticolous Chinese species ''[[Pyxine hengduanensis]]'' is closely related to ''P. sorediata''. Unlike ''P. sorediata'', which has a yellow medulla and soralia that develop marginally from fissures and then become laminal and disc-shaped, ''P. hengduanensis'' has marginal labriform soralia that develop from the centre of the pseudocyphellae, with grey to bluish-grey soredia and a pale yellow medulla.<ref name="Yang et al. 2019"/> Another lookalike is ''[[Pyxine endochrysina]]'', but that species has [[isidia]] that range in form from granular to finger-like.<ref name="Wei & Hur 2007"/>
==Habitat and distribution== The lichen is widely distributed in northeastern North America.<ref name="Brodo et al. 2001"/> It [[corticolous lichen|grows on bark]], on [[acidic rock]]s, and on [[moss]]. In Europe, where it is generally rare,<ref name="Malíček et al. 2018"/> ''Pyxine sorediata'' is typically collected from mossy rocks.<ref name="Moberg 1983"/> It has been recorded in the [[Pyrenees]], the [[Caucasus]], in the [[Uholka-Shyrokyi Luh primeval beech forest]] in the Ukrainian [[Carpathians]],<ref name="Malíček et al. 2018"/> and from the eastern coast of [[Lake Baikal]] in Siberia.<ref name="Budaeva 2007"/> Its northernmost European record is from the [[Bavarian Forest|Bavarian]]-[[Bohemian Forest]].<ref name="Malíček et al. 2018"/> In Australia, it occurs in areas with uniform tropical environments, subtropics, and warm [[temperate]] areas. Specimens from [[Queensland]] have been collected from elevations up to {{convert|1000|m|ft}}. ''Pyxine sorediata'' is also known from East Africa, Japan,<ref name="Rogers 1986"/> South Korea,<ref name="Wei & Hur 2007"/> and China.<ref name="Yang et al. 2019"/>
==References== {{Reflist|colwidth=30em|refs=
<ref name="Acharius 1814">{{cite book |last1=Acharius |first1=Erik |year=1814 |title=Synopsis Methodica Lichenum |page=54 |publisher=Litteris et Sumtibus Svanborg |location=Lundin |url=https://books.google.com/books?id=QqI_AAAAcAAJ&q=Lecidea%20sorediata&pg=PA54 |language=la}}</ref>
<ref name="Brodo et al. 2001">{{cite book |first1=Irwin M. |last1=Brodo |first2=Sylvia Duran |last2=Sharnoff |first3=Stephen |last3=Sharnoff |title=Lichens of North America |year=2001 |publisher=Yale University Press |pages=617–619 |isbn=978-0300082494}}</ref>
<ref name="Budaeva 2007">{{cite journal |last=Budaeva |first=S.E. |year=2007 |title=Features of the distribution of widespread lichens of the eastern coast of Lake Baikal |journal=Siberian Journal of Ecology |volume=14 |issue=6 |pages=1025–1031}}</ref>
<ref name="Fries 1825">{{cite book |last1=Fries |first1=E.M. |year=1825 |title=Systema Orbis Vegetabilis |volume=1 |page=267 |language=la}}</ref>
<ref name="Imshaug 1957">{{cite journal |first1=Imshaug |last1=Henry |title=The lichen genus ''Pyxine'' in North and Middle America |journal=Transactions of the American Microscopical Society |volume=76 |issue=3 |year=1957 |pages=246–269 |doi=10.2307/3223889|jstor=3223889 }}</ref>
<ref name="Laundon 2004">{{cite journal |last1=Laundon |first1=Jack Rodney |title=(1634) Proposal to reject ''Lichen daedaleus'' in order to safeguard the name ''Pyxine sorediata'' |journal=Taxon |volume=53 |issue=3 |year=2004 |pages=832–832 |doi=10.2307/4135461 |jstor=4135461}}</ref>
<ref name="Malíček et al. 2018">{{cite journal |last1=Malíček |first1=Jiří |last2=Palice |first2=Zdeněk |last3=Acton |first3=Andy |last4=Berger |first4=Franz |last5=Bouda |first5=František |last6=Sanderson |first6=Neil |last7=Vondrák |first7=Jan |title=Uholka Primeval Forest in the Ukrainian Carpathians – a keynote area for diversity of forest lichens in Europe |journal=Herzogia |volume=31 |issue=1 |year=2018 |doi=10.13158/099.031.0110 |pages=140–171}}</ref>
<ref name="Moberg 1983">{{cite journal |last1=Moberg |first1=R. |title=Studies on Physciaceae (lichens) II. The genus ''Pyxine'' in Europe |journal=The Lichenologist |volume=15 |issue=2 |year=1983 |pages=161–167 |doi=10.1017/S0024282983000250}}</ref>
<ref name="Montagne 1845">Montagne in de la Sagra. 1842. Histoire physique, politique et naturelle de l'isle de Cuba. Botanique, Plantes cellulaires.</ref>
<ref name="Rogers 1986">{{cite journal |last1=Rogers |first1=R.W. |title= The genus ''Pyxine'' (Physciaceae, Lichenized Ascomycetes) in Australia |journal=Australian Journal of Botany |volume=34 |issue=2 |year=1986 |pages=131–154 |doi=10.1071/BT9860131}}</ref>
<ref name="Smith 1810">{{cite book |last1=Smith |first1=J.E. |last2=Sowerby |first2=J. |year=1810 |title=English Botany; or, coloured figures of British plants, with their essential characters, synonyms, and places of growth: to which will be added, occasional remarks |volume=30 |pages=2089–2164, 402–403 |location=London |publisher=R. Taylor |url=https://bibdigital.rjb.csic.es/viewer/11333/#page=1&viewer=picture&o=bookmark&n=0&q=}}</ref>
<ref name="Species Fungorum synonymy">{{cite web |title=Synonymy: ''Pyxine sorediata'' (Ach.) Mont. |url=http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=403621 |publisher=[[Species Fungorum]] |access-date=26 January 2021}}</ref>
<ref name="Yang et al. 2019">{{cite journal |last1=Yang |first1=Mei-Xia |last2=Wang |first2=Xin-Yu |last3=Liu |first3=Dong |last4=Zhang |first4=Yan-Yun |last5=Li |first5=Li-Juan |last6=Yin |first6=An-Cheng |last7=Scheidegger |first7=Christoph |last8=Wang |first8=Li-Song |title=New species and records of ''Pyxine'' (Caliciaceae) in China |journal=MycoKeys |year=2019 |issue=45 |pages=93–109 |doi=10.3897/mycokeys.45.29374 |pmid=30733639 |pmc=6363720 |doi-access=free}}</ref>
<ref name="Wei & Hur 2007">{{cite journal |last1=Wei |first1=X.-L. |last2=Hur |first2=J.-S. |year=2007 |title=Foliose genera of Physciaceae (lichenized Ascomycotina) of South Korea |journal=Mycotaxon |volume=102 |pages=127–137 |url=https://www.researchgate.net/publication/286110165}}</ref>
}}
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[[Category:Pyxine|sorediata]] [[Category:Lichen species]] [[Category:Lichens described in 1814]] [[Category:Lichens of Africa]] [[Category:Lichens of Asia]] [[Category:Lichens of Australia]] [[Category:Lichens of China]] [[Category:Lichens of Europe]] [[Category:Lichens of Japan]] [[Category:Lichens of North America]] [[Category:Taxa named by Erik Acharius]]