{{Short description|Species of lichen}} {{Use dmy dates|date=February 2021}} {{Species box | image = Pyxine cocoes 132328.jpg | taxon = Pyxine cocoes | authority = ([[Sw.]]) [[Nyl.]] (1857) | synonyms_ref = <ref name="Species Fungorum synonymy"/> | synonyms = *''Lichen cocoës'' {{small|Sw. (1788)}} *''Lobaria cocoës'' {{small|(Sw.) [[Raeusch.]] (1797)}} *''Lecidea cocoës'' {{small|(Sw.) [[Ach.]] (1803)}} *''Circinaria cocoes'' {{small|(Sw.) [[Fée]] (1825)}} *''Coccocarpia pellita'' var. ''cocoës'' {{small|(Sw.) [[Zahlbr.]] (1925)}} }}
'''''Pyxine cocoes''''', the '''buttoned rosette lichen''',<ref name="Brodo et al. 2001"/> is a widely distributed species of [[foliose lichen]] in the family [[Caliciaceae]].
==Taxonomy== It was first [[species description|described]] as a new species by Swedish botanist [[Olof Swartz]] in 1788. He called it ''Lichen cocoës'',<ref name="Swartz 1788"/> following the lead of [[Carl Linnaeus]] who, in his influential 1753 work ''[[Species Plantarum]]'', placed all lichens in the [[eponym]]ous genus ''Lichen''. Finnish lichenologist [[William Nylander (botanist)|William Nylander]] transferred it to the genus ''[[Pyxine]]'' in 1853.<ref name="Nylander 1857"/> A [[common name]] used in North America is the "buttoned rosette lichen".<ref name="Brodo et al. 2001"/>
==Description== ''Pyxine cocoes'' has a pale grayish-green [[thallus]] comprising radiating lobes that are typically less than 1 mm wide. These lobes are closely attached to the surface of the substrate, have granular [[soredia]] that protrude through the [[cortex (botany)|cortex]] in irregularly shaped regions called soralia. The [[medulla (lichenology)|medulla]] is white, while the [[apothecia]] are black with black margins in mature specimens.<ref name="Brodo et al. 2001"/> They are 1–5 mm wide, flat, and disc-shaped.<ref name="Rogers 1986"/> The tissue making up the base of the apothecia is brownish red.<ref name="Brodo et al. 2001"/> [[Ascospore]]s measure 15–22 by 6–8 [[micrometre|μm]].<ref name="Rogers 1986"/> The lichen contains [[lichexanthone]], a [[xanthone]] compound that is found in about 20 ''Pyxine'' species.<ref name="Aptroot et al. 2014"/>
==Habitat and distribution== ''Pyxine cocoes'' grows on bark and rocks.<ref name="Rogers 1986"/> The lichen has been reported from Asia (Japan and the Philippines), East Africa, North America, Central America, and South America, Hawaii, and Australia. In Australia, it is present only in coastal locations that are seasonally humid, and both wet and warm. In this continent, it is common on tree trunks growing on coral [[cay]]s; these trunks are often used as bird perches, which accumulate bird droppings. The lichenologist [[Roderick W. Rogers]] suggests that the lichen could be [[nitrophilic]], which would explain this growth habitat, as well as its tendency to prefer habitats that are at least partially [[Urbanization|urbanized]].<ref name="Rogers 1986"/> In North America, it distribution extends as far north to [[Florida]] in the United States.<ref name="Brodo et al. 2001"/>
The African species ''[[Pyxine katendei]]'' is somewhat similar in appearance to ''Pyxine cocoes'', but it has only laminal (not marginal) soralia.<ref name="Rogers 1986"/>
==Biomonitoring studies== Studies conducted in India suggest that ''Pyxine cocoes'' is a candidate for [[biomonitoring]] of [[Air pollution in India|local air pollution]].<ref name="Bajpai et al. 2010"/> It [[bioaccumulation|bioaccumulates]] toxic [[heavy metals]] that it acquires from the air and retains the pollutants in the thallus, which can then be sampled and [[assay]]ed to determine their concentration.<ref name="Bajpai & Upreti 2012"/><ref name="Daimari et al. 2019"/><ref name="Singh et al. 2019"/>
==Human uses== ''Pyxine cocoes'' is used in [[Papua New Guinea]] as a component of a [[traditional medicine]]-based remedy for [[inflammation|inflammatory]] conditions. In a chemical analysis of the lichen, the [[triterpene]] compound 6,22-hopanediol was identified.<ref name="Noro et al. 2008"/> This compound, commonly known as [[zeorin]], is a [[hopanoid]] with potent [[enzyme inhibition|inhibitory]] activity against the enzyme [[protein tyrosine phosphatase]].<ref name="Thadhani & Karunaratne 2017"/>
==References== {{Reflist|colwidth=30em|refs=
<ref name="Aptroot et al. 2014">{{cite journal |last1=Aptroot |first1=André |last2=Jungbluth |first2=Patrícia |last3=Cáceres |first3=Marcela E.S. |title=A world key to the species of ''Pyxine'' with lichexanthone, with a new species from Brazil |journal=The Lichenologist |volume=46 |issue=5 |year=2014 |doi=10.1017/s0024282914000231 |pages=669–672}}</ref>
<ref name="Bajpai et al. 2010">{{cite journal |last1=Bajpai |first1=Rajesh |author-link2=Dalip Kumar Upreti |last2=Upreti |first2=Dalip K. |last3=Nayaka |first3=S. |last4=Kumari |first4=B. |year=2010 |title=Biodiversity, bioaccumulation and physiological changes in lichens growing in the vicinity of coal-based thermal power plant of Raebareli district, north India |journal=Journal of Hazardous Materials |volume=174 |issue=1–3 |pages=429–436 |pmid=19818555 |doi=10.1016/j.jhazmat.2009.09.071}}</ref>
<ref name="Bajpai & Upreti 2012">{{cite journal |last1=Bajpai |first1=Rajesh |last2=Upreti |first2=D.K. |title=Accumulation and toxic effect of arsenic and other heavy metals in a contaminated area of West Bengal, India, in the lichen ''Pyxine cocoes'' (Sw.) Nyl. |journal=Ecotoxicology and Environmental Safety |volume=83 |year=2012 |pages=63–70 |doi=10.1016/j.ecoenv.2012.06.001 |pmid=22762786}}</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 |page=616 |isbn=978-0300082494}}</ref>
<ref name="Daimari et al. 2019">{{cite journal |last1=Daimari |first1=Rebecca |last2=Bhuyan |first2=Pranamika |last3=Hussain |first3=Sharfaa |last4=Nayaka |first4=Sanjeeva |last5=Mazumder |first5=M. A. Jafar |last6=Hoque |first6=Raza Rafiqul |title=Biomonitoring by epiphytic lichen species—''Pyxine cocoes'' (Sw.) Nyl.: understanding characteristics of trace metal in ambient air of different landuses in mid-Brahmaputra Valley |journal=Environmental Monitoring and Assessment |volume=192 |issue=1 |year=2019 |page=37 |doi=10.1007/s10661-019-8007-x |pmid=31828442}}</ref>
<ref name="Noro et al. 2008">{{cite journal |first1=Jeffrey C. |last1=Noro |first2=Louis L. |last2=Barrows |first3=Prem |last3=Rai |first4=Chris M. |last4=Ireland |first5=Teatulohi |last5=Matainaho |first6=Tim |last6=Bugni |year=2008 |title=Isolation of 6, 22-hopanediol from ''Pyxine cocoes'', lichen used as traditional medicine in Papua New Guinea |journal=Pacific Journal of Medical Sciences |volume=5 |pages=90–95 |issn=2072-1625}}</ref>
<ref name="Nylander 1857">{{cite journal |last1=Nylander |first1=W. |year=1857 |title=Enumération générale de lichens, avec l'indication sommaire de leur distribution géographique |journal=Mémoires de la Société Impériale des Sciences Naturelles de Cherbourg |volume=5 |pages=85–146 |language=fr |url=https://www.biodiversitylibrary.org/page/12327973}}</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="Species Fungorum synonymy">{{cite web |title=Synonymy: ''Pyxine cocoes'' (Sw.) Nyl. [as 'cocoës'] |url=http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=627760 |publisher=[[Species Fungorum]] |access-date=17 February 2021}}</ref>
<ref name="Singh et al. 2019">{{cite journal |last1=Singh |first1=Pramod Kumar |last2=Bujarbarua |first2=P. |last3=Singh |first3=K.P. |last4=Tandon |first4=P.K. |year=2019 |title=Report on the bioaccumulation of heavy metals by foliose lichen (''Pyxine cocoes'') from air polluted area near Nagaon Paper Mill in Marigaon, Assam, North-East India |journal=Journal on New Biological Reports |volume=8 |issue=1 |pages=15–21 |issn=2319-1104 |url=https://www.researchgate.net/publication/332414938}}</ref>
<ref name="Swartz 1788">{{cite book |last1=Swartz |first1=O.P. |year=1788 |title=Nova genera et species Plantarum seu prodromus descriptioneum vegetabilium maximam parte incognitorum qua sub itinere in Indiam Occidentalem annis 1783-1787 digessit Olof Swartz M.D. |page=146 |location=Stockholm |publisher=Acad. M. Swederi |language=la |url=https://www.biodiversitylibrary.org/page/376865}}</ref>
<ref name="Thadhani & Karunaratne 2017">{{cite journal |last1=Thadhani |first1=Vinitha M. |last2=Karunaratne |first2=Veranja |title=Potential of lichen compounds as antidiabetic agents with antioxidative properties: a review |journal=Oxidative Medicine and Cellular Longevity |volume=2017 |year=2017 |pages=1–10 |doi=10.1155/2017/2079697|pmid=28491237 |pmc=5405387 |doi-access=free}}</ref>
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[[Category:Pyxine|cocoes]] [[Category:Lichen species]] [[Category:Lichens described in 1788]] [[Category:Lichens of Africa]] [[Category:Lichens of Asia]] [[Category:Lichens of Australia]] [[Category:Lichens of Central America]] [[Category:Lichens of New Guinea]] [[Category:Lichens of North America]] [[Category:Lichens of South America]] [[Category:Taxa named by Olof Swartz]]