{{Short description|Genus of lichens}} {{Use British English|date=January 2024}} {{Use dmy dates|date=December 2023}} {{Automatic taxobox | image = | taxon = Racoleus | authority = R.Sant. & D.Hawksw. (2011) | type_species = Racoleus trichophorus | type_species_authority = R.Sant. & D.Hawksw. (2011) | subdivision_ranks = Species | subdivision = ''R. trichophorus''<br /> ''R. japonicus'' }}
'''''Racoleus''''' is a genus of two species of lichen-forming fungi of uncertain familial placement in the order Capnodiales.<ref name="CoL"/><ref name="Wijayawardene et al. 2022"/> Both species of ''Racoleus'' are filamentous lichens with ''Trentepohlia'' (a genus of green algae) as the {{lichengloss|photobiont}} partner. The lichens form thalli in the form of felt-like, blackish-brown cushions that grow under shaded conditions on siliceous rocks.
==Taxonomy== The genus was circumscribed by the lichenologists Rolf Santesson and David Leslie Hawksworth in 2011. The name ''Racoleus'' is derived by combining elements from two other genera: 'Rac' from ''Racodium'' and 'coleus' from ''Cystocoleus''. This naming reflects the genus's shared characteristics with both ''Racodium'' and ''Cystocoleus'', which are also filamentous lichens. The authors placed the genus in the order Capnodiales because of morphological characteristics.<ref name="Hawksworth et al. 2011"/> ''Racoleus'' was monotypic until 2023, when a second species was added to the genus. Molecular phylogenetic analysis suggests that the new species belongs to the family Teratosphaeriaceae, but DNA sequences of the type species, ''R. trichophorus'', were not available for analysis.<ref name="Miyazawa & Ohmura 2023"/>
==Description== ''Racoleus'' is characterised by a superficial, fluffy, and filamentous thallus, which typically presents a brown colour. This genus has a unique relationship with its photobiont, ''Trentepohlia'', a type of green algae. In this symbiotic relationship, individual ''Trentepohlia'' filaments are completely encased by fungal hyphae, which are the filament-like structures of the fungus.<ref name="Hawksworth et al. 2011"/>
The structure of ''Racoleus'' is complex, with its filaments ranging from slightly upright (suberect) to spreading out across the surface (decumbent or spreading). These filaments have a branching pattern known as sympodial, where new growth emerges from the side of an older growth. The outer walls of these filaments are distinctive, with an undulating and irregularly corrugated texture, adorned with numerous spiny projections.<ref name="Hawksworth et al. 2011"/>
The fungal hyphae that envelop the algal filament form a single layer. These hyphae are oriented vertically and run parallel to the axis of the algal filament. They are brown in colour and are marked by thick, uneven walls that are corrugated but not ornamented. The spines that emerge from these filaments are notable for their stiffness, thickness, and smooth, unadorned surfaces. They protrude at angles ranging from broadly acute to almost right angles relative to the vertical axis of the filament.<ref name="Hawksworth et al. 2011"/>
As for reproductive structures, specific details about the conidiogenous cells (cells that produce conidia, a type of asexual fungal spore) and the conidia themselves are not well established or known for ''Racoleus''.<ref name="Hawksworth et al. 2011"/>
==Habitat and distribution== The reported tropical localities of ''Racoleus trichophorus'' – Africa (Ivory Coast), Asia (China), and South America (Peru) – suggest that it could have a pantropical distribution. It is often found growing on the thalli of whitish crustose lichens (including ''Dichosporidium brunnthaleri'', ''D. nigrocinctum'', and ''Pyrgillus indicus''), but is not considered to be lichenicolous (lichen-dwelling), as the contact between them seems to be superficial.<ref name="Hawksworth et al. 2011"/> ''Racoleus japonicus'' occurs in subboreal to temperate regions of Japan, where it grows on shaded rocks and rock walls.<ref name="Miyazawa & Ohmura 2023"/>
==References== {{Reflist|refs=
<ref name="CoL">{{Catalogue of Life |id=642HK |title=''Racoleus'' |access-date=7 January 2024}}</ref>
<ref name="Hawksworth et al. 2011">{{cite journal |last1=Hawksworth |first1=David L. |last2=Santesson |first2=Rolf |last3=Tibell |first3=Leif |title=''Racoleus'', a new genus of sterile filamentous lichen-forming fungi from the tropics, with observations on the nomenclature and typification of ''Cystocoleus'' and ''Racodium'' |journal=IMA Fungus |volume=2 |issue=1 |year=2011 |doi=10.5598/imafungus.2011.02.01.10 |pages=71–79 |pmid=22679590 |pmc=3317361 |doi-access=free}}</ref>
<ref name="Miyazawa & Ohmura 2023">{{cite journal |first1=Kento |last1=Miyazawa |first2=Yoshihito |last2=Ohmura |title=''Racoleus japonicus'' sp. nov. (Teratosphaeriaceae, Ascomycota), a new sterile filamentous lichen collected from Japan |journal=Taiwania |volume=68 |issue=4 |year=2023 |doi=10.6165/tai.2023.68.417 |pages=417–424}}</ref>
<ref name="Wijayawardene et al. 2022">{{cite journal |display-authors=6 |last1=Wijayawardene |first1=N.N. |last2=Hyde |first2=K.D. |last3=Dai |first3=D.Q. |last4=Sánchez-García |first4=M. |last5=Goto |first5=B.T. |last6=Saxena |first6=R.K. |last7=Erdoğdu |first7=M. |last8=Selçuk |first8=F. |last9=Rajeshkumar |first9=K.C. |last10=Aptroot |first10=A. |last11=Błaszkowski |first11=J. |last12=Boonyuen |first12=N. |last13=da Silva |first13=G. |last14=de Souza |first14=F.A. |last15=Dong |first15=W. |last16=Ertz |first16=D. |last17=Haelewaters |first17=D. |last18=Jones |first18=E.B. |last19=Karunarathna |first19=S.C. |last20=Kirk |first20=P.M. |last21=Kukwa |first21=M. |last22=Kumla |first22=J. |last23=Leontyev |first23=D.V. |last24=Lumbsch |first24=H.T. |last25=Maharachchikumbura |first25=S.S.N. |last26=Marguno |first26=F. |last27=Martínez-Rodríguez |first27=P. |last28=Mešić |first28=A. |last29=Monteiro |first29=J.S. |last30=Oehl |first30=F. |last31=Pawłowska |first31=J. |last32=Pem |first32=D. |last33=Pfliegler |first33=W.P. |last34=Phillips |first34=A.J.L. |last35=Pošta |first35=A. |last36=He |first36=M.Q. |last37=Li |first37=J.X. |last38=Raza |first38=M. |last39=Sruthi |first39=O.P. |last40=Suetrong |first40=S. |last41=Suwannarach |first41=N. |last42=Tedersoo |first42=L. |last43=Thiyagaraja |first43=V. |last44=Tibpromma |first44=S. |last45=Tkalčec |first45=Z. |last46=Tokarev |first46=Y.S. |last47=Wanasinghe |first47=D.N. |last48=Wijesundara |first48=D.S.A. |last49=Wimalaseana |first49=S.D.M.K. |last50=Madrid |first50=H. |last51=Zhang |first51=G.Q. |last52=Gao |first52=Y. |last53=Sánchez-Castro |first53=I. |last54=Tang |first54=L.Z. |last55=Stadler |first55=M. |last56=Yurkov |first56=A. |last57=Thines |first57=M. |year=2022 |title=Outline of Fungi and fungus-like taxa – 2021 |journal=Mycosphere |volume=13 |issue=1 |pages=53–453 [93] |doi=10.5943/mycosphere/13/1/2 |url=https://www.researchgate.net/publication/358798332|hdl=10481/76378 |hdl-access=free }}</ref>
}}
{{Taxonbar|from=Q107279828}}
Category:Capnodiales Category:Dothideomycetes genera Category:Taxa described in 2011 Category:Lichen genera Category:Taxa named by David Leslie Hawksworth Category:Taxa named by Rolf Santesson