{{Short description|Single-species fungal genus}} {{Use dmy dates|date=June 2025}} {{Use Oxford spelling|date=June 2025}} {{Speciesbox | image = | image_caption = | grandparent_authority = Locq. ex Lücking, B.P.Hodk. & S.D.Leav. (2016) | parent_authority = Thwaites (1849) | taxon = Cystocoleus ebeneus | authority = (Dillwyn) Thwaites (1849) | synonyms_ref = | synonyms = }}
'''''Cystocoleus''''' is a fungal genus in the family '''''Cystocoleaceae'''''. The genus was established in 1849 by the British botanist G.H.K. Thwaites and is now considered to contain only one species, '''''Cystocoleus ebeneus'''''. These fungi form minute, sooty-brown to black patches made up of densely packed, brittle filaments that have a fluffy, felt-like appearance. They typically grow on shaded rock faces or damp bark near running water.
==Taxonomy==
The genus ''Cystocoleus'' was erected in 1849 by the British botanist G.H.K. Thwaites,<ref name="Thwaites 1849"/> who based it on the peculiar filamentous lichen then known as ''Cystocoleus ebeneus''.<ref name="Tian et al. 2014"/> Thwaites' concept has remained essentially intact: the type and–in modern treatments–only unequivocal species is ''C. ebeneus''. Although ''Index Fungorum'' briefly recognised up to three names in the genus, subsequent revisions have shown those extra taxa to lack convincing diagnostic traits,<ref name="Tian et al. 2014"/> and current authors regard ''Cystocoleus'' as effectively monospecific.<ref name="CoL_3Z3X"/>
Morphologically, ''Cystocoleus'' was long compared with the equally filamentous lichen ''Racodium rupestre'', but the two differ in the degree of hyphal contortion: ''Cystocoleus'' has shorter, less twisted hyphae tightly enveloping the algal filament.<ref name="Tian et al. 2014"/> Molecular work has moved the genus away from traditional lichen families. A multigene analysis placed ''C. ebeneus'' within the order Capnodiales of the class Dothideomycetes, far from most lichen-forming groups.<ref name="Tian et al. 2014"/> Crous and co-workers (2009) recovered it in the family Teratosphaeriaceae,<ref name="Crous et al. 2009"/> whereas Hyde and colleagues (2013) treated it as Capnodiales ''incertae sedis''—a phrase indicating that its exact familial position remains uncertain.<ref name="Hyde et al. 2013"/><ref name="Tian et al. 2014"/>
Robert Lücking, Brian Hodkinson, and Steven Leavitt subsequently validated the family name Cystocoleaceae in 2016, correcting Marcel Locquin's 1984 description that had been ruled invalid under the botanical Code.<ref name="Lücking et al. 2017"/>
==Description==
''Cystocoleus'' grows as minute, sooty-brown to black patches made up of densely packed, brittle filaments that sit on the surface of the substrate rather than penetrating it. Each filament measures about 9–21 micrometres (μm) across and can branch in a spiky, sympodial fashion. The fungal partner wraps the algal strand in a single, tight sheath of hyaline (colourless) hyphae whose walls are thick, smooth and characteristically corrugated, giving the filaments a distinctly nodular outline. These hyphae are themselves only 3–7 μm wide and clasp the orange-pigmented ''Trentepohlia'' photobiont along the full length of each filament. Because the thallus is entirely filamentous and lacks the flattened plates seen in many lichens, the whole colony has a fluffy, felt-like appearance when viewed with a hand lens.<ref name="Tian et al. 2014"/>
Close inspection shows no additional surface structures such as spines, and reproductive bodies have yet to be observed in confirmed collections, so the species is presently known only in its sterile state. The absence of visible spores means that identification relies on the unique filament architecture: dark, brittle strands of ''Trentepohlia'' algae entirely ensheathed by contorted, nodulose fungal hyphae.<ref name="Tian et al. 2014"/>
The family Cystocoleaceae is defined as a lichenised member of the Capnodiales with a strictly filamentose thallus: each orange-tinged ''Trentepohlia'' algal strand is wrapped in a closed, single-cell-thick sheath of slightly contorted, interlocking hyphae that resemble jigsaw pieces. No sexual (ascomata) or asexual (conidiomata) reproductive structures are yet known, and chemical spot tests have detected no secondary metabolites.<ref name="Lücking et al. 2017"/>
==Habitat & distribution==
''Cystocoleus ebeneus'' occurs on shaded rock faces or damp bark near running water.<ref name="Lücking et al. 2017"/> In 2024, this species was reported from the Prielbrusye National Park in the Mount Elbrus region of the Kabardino-Balkarian Republic, representing the first record of this family in the Caucasus.<ref name="Urbanavichene & Urbanavichus 2024"/>
==References== {{Reflist|colwidth=30em|refs=
<ref name="CoL_3Z3X">{{Catalogue of Life |id=3Z3X |title=''Cystocoleus'' |access-date=1 July 2025}}</ref>
<ref name="Crous et al. 2009">{{cite journal |last1=Crous |first1=P.W. |last2=Summerell |first2=B.A. |last3=Carnegie |first3=A.J. |last4=Wingfield |first4=M.J. |last5=Groenewald |first5=J.Z. |title=Novel species of Mycosphaerellaceae and Teratosphaeriaceae |journal=Persoonia |volume=23 |issue=1 |year=2009 |pmid=20198165 |pmc=2802729 |doi=10.3767/003158509X479531 |doi-access=free |pages=119–146}}</ref>
<ref name="Hyde et al. 2013">{{cite journal |display-authors=6 |last1=Hyde |first1=Kevin D. |last2=Jones |first2=E. B. Gareth |last3=Liu |first3=Jian-Kui |last4=Ariyawansa |first4=Hiran |last5=Boehm |first5=Eric |last6=Boonmee |first6=Saranyaphat |last7=Braun |first7=Uwe |last8=Chomnunti |first8=Putarak |last9=Crous |first9=Pedro W. |last10=Dai |first10=Dong-Qin |last11=Diederich |first11=Paul |last12=Dissanayake |first12=Asha |last13=Doilom |first13=Mingkhuan |last14=Doveri |first14=Francesco |last15=Hongsanan |first15=Singang |last16=Jayawardena |first16=Ruvishika |last17=Lawrey |first17=James D. |last18=Li |first18=Yan-Mei |last19=Liu |first19=Yong-Xiang |last20=Lücking |first20=Robert |last21=Monkai |first21=Jutamart |last22=Muggia |first22=Lucia |last23=Nelsen |first23=Matthew P. |last24=Pang |first24=Ka-Lai |last25=Phookamsak |first25=Rungtiwa |last26=Senanayake |first26=Indunil C. |last27=Shearer |first27=Carol A. |last28=Suetrong |first28=Satinee |last29=Tanaka |first29=Kazuaki |last30=Thambugala |first30=Kasun M. |last31=Wijayawardene |first31=Nalin N. |last32=Wikee |first32=Saowanee |last33=Wu |first33=Hai-Xia |last34=Zhang |first34=Ying |last35=Aguirre-Hudson |first35=Begoña |last36=Alias |first36=S. Aisyah |last37=Aptroot |first37=André |last38=Bahkali |first38=Ali H. |last39=Bezerra |first39=Jose L. |last40=Bhat |first40=D. Jayarama |last41=Camporesi |first41=Erio |last42=Chukeatirote |first42=Ekachai |last43=Gueidan |first43=Cécile |last44=Hawksworth |first44=David L. |last45=Hirayama |first45=Kazuyuki |last46=De Hoog |first46=Sybren |last47=Kang |first47=Ji-Chuan |last48=Knudsen |first48=Kerry |last49=Li |first49=Wen-Jing |last50=Li |first50=Xing-Hong |last51=Liu |first51=Zou-Yi |last52=Mapook |first52=Ausana |last53=McKenzie |first53=Eric H. C. |last54=Miller |first54=Andrew N. |last55=Mortimer |first55=Peter E. |last56=Phillips |first56=Alan J. L. |last57=Raja |first57=Huzefa A. |last58=Scheuer |first58=Christian |last59=Schumm |first59=Felix |last60=Taylor |first60=Joanne E. |last61=Tian |first61=Qing |last62=Tibpromma |first62=Saowaluck |last63=Wanasinghe |first63=Dhanushka N. |last64=Wang |first64=Yong |last65=Xu |first65=Jian-Chu |last66=Yacharoen |first66=Supalak |last67=Yan |first67=Ji-Ye |last68=Zhang |first68=Min |title=Families of Dothideomycetes: In loving memory of Majorie Phyllis Hyde (affectionately known as Mum or Marj), 29 August 1921–18 January 2013—without mum's determination, a character passed on to children, this treatise would never have been completed—K.D. Hyde |journal=Fungal Diversity |volume=63 |issue=1 |year=2013 |doi=10.1007/s13225-013-0263-4 |pages=1–313}}</ref>
<ref name="Lücking et al. 2017">{{cite journal |last1=Lücking |first1=Robert |last2=Hodkinson |first2=Brendan P. |last3=Leavitt |first3=Steven D. |year=2017 |title=The 2016 classification of lichenized fungi in the Ascomycota and Basidiomycota–Approaching one thousand genera |journal=The Bryologist |volume=119 |issue=4 |pages=361–416 [401] |doi=10.1639/0007-2745-119.4.361 |jstor=44250015}}</ref>
<ref name="Thwaites 1849">{{cite journal |last=Thwaites |first=G.H.K. |year=1849 |title=Note on ''Cystocoleus'', a new genus of minute plants |journal=Annals of Natural History |series=2 |volume=3 |issue=16 |pages=241–242 |doi=10.1080/03745485909494754}}</ref>
<ref name="Tian et al. 2014">{{cite journal |last1=Tian |first1=Qing |last2=Chomnunti |first2=Putarak |last3=Bhat |first3=Jayarama D. |last4=Alias |first4=Siti. A. |last5=Mortimer |first5=Peter E. |last6=Hyde |first6=Kevin D. |title=Towards a natural classification of Dothideomycetes 5: The genera ''Ascostratum'', ''Chaetoscutula'', ''Ceratocarpia'', ''Cystocoleus'', and ''Colensoniella'' (Dothideomycetes incertae sedis) |journal=Phytotaxa |volume=176 |issue=1 |year=2014 |doi=10.11646/phytotaxa.176.1.7 |doi-access=free |pages=42–54}}</ref>
<ref name="Urbanavichene & Urbanavichus 2024">{{cite journal |last1=Urbanavichene |first1=I.N. |last2=Urbanavichus |first2=G.G. |year=2024 |title=Cystocoleaceae (Mycosphaerellales, lichen-forming Ascomycota), a new family to the lichen flora of Caucasus |journal=Botanicheskii Zhurnal |volume=109 |issue=11 |pages=1163–1166 |doi=10.31857/S0006813624110056}}</ref>
}}
{{Taxonbar |from1=Q10465229 |from2=Q10660981}}
Category:Capnodiales Category:Dothideomycetes genera Category:Lichen genera Category:Taxa described in 1849 Category:Taxa named by George Henry Kendrick Thwaites