Buellia

{{Short description|Genus of lichens}} {{Automatic taxobox | image = Buellia chloroleuca 19318.jpg | image_caption = ''Buellia chloroleuca'' | taxon = Buellia | authority = De Not. (1846) | type_species = ''Buellia disciformis'' | type_species_authority = (Fr.) Mudd (1861) | subdivision_ranks = Species | subdivision = about 300 | synonyms_ref = <ref name="Species Fungorum synonymy"/> | synonyms = {{Collapsible list|bullets=yes |''Anapyrenium'' {{small|Müll.Arg. (1880)}} |''Aplotomma'' {{small|A.Massal. ex Beltr. (1858)}} |''Buelliopsis'' {{small|A.Schneid. (1897)}} |''Chrismofulvea'' {{small|Marbach (2000)}} |''Hafellia'' {{small|Kalb, H.Mayrhofer & Scheid. (1986)}} |''Kemmleria'' {{small|Körb. (1861)}} |''Lepropinacia'' {{small|Vent. (1799)}} |''Mattickiolichen'' {{small|Tomas. & Cif. (1952)}} |''Mattickiomyces'' {{small|Cif. & Tomas. (1953)}} |''Melanaspicilia'' {{small|Vain. (1909)}} |''Samboa'' {{small|Tomas. & Cif. (1952)}} |''Samboamyces'' {{small|Cif. & Tomas. (1953)}} |''Sambomyces'' {{small|Cif. & Tomas. (1952)}} }} }}

'''''Buellia''''' is a genus of mostly lichen-forming fungi in the family Caliciaceae. The fungi are usually part of a crustose lichen.<ref name=UDDA/> In this case, the lichen species is given the same name as the fungus. But members may also grow as parasites on lichens (lichenicolous).<ref name=UDDA>{{Cite web|url=http://eol.org/pages/16410/overview|title=Disc Lichen (Buellia), US Department of Agriculture}}</ref> The algae in the lichen (the photobiont partner) is always a member of the genus ''Trebouxia''.<ref name=UDDA/>

Lichens in the genus are commonly called '''disc lichens''',<ref>{{Cite web|url=https://plants.usda.gov/java/nameSearch|title=Plants 3|website=plants.usda.gov}}</ref> or '''button lichens'''.<ref name=SSFGCL>Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, {{ISBN|978-0-300-19500-2}}</ref>{{rp|229}} The genus has a widespread distribution and contains almost 1000 species.<ref>{{Cite web |title=Index Fungorum - Search Page |url=https://www.indexfungorum.org/Names/Names.asp? |access-date=2024-08-28 |website=www.indexfungorum.org}}</ref>

Genetic studies indicate that the genus ''Amandinea'' and ''Buellia'' may be the same,<ref>Scheidegger, C. 2009. Amandinea Choisy ex Scheid. & H. Mayrhofer (1993). In: C. W. Smith, A. Aptroot, B. J. Coppins, A. Fletcher, O. L. Gilbert, P. W. James and P. A. Wosley (eds.) The Lichens of Great Britain and Ireland. The British Lichen Society, Natural History Museum Publications, United Kingdom, pp. 142–144</ref> although this is not widely accepted.<ref name=KJAPJTNP>Amandinea punctata in the Joshua Tree National Park (California, U.S.A.) Map collection: Kerry Knudsen, Kocourková Jana; Czech University of Life Sciences Prague, Faculty of Environmental Sciences, Department of Ecology, Czech Republic; 2012</ref>

The genus ''Buellia'' was described by Italian botanist Gioseppe De Notaris in 1846 and named after his friend, Esperanzo Buelli.<ref>{{Cite book |last=Smith |first=Val |url=https://www.wikidata.org/wiki/Q132874317 |title=Common Ground: Who's who in New Zealand botanical names. Supplement Two: Who's who in New Zealand botanical names. Supplement Two |date=2023-01-01 |language=English}}</ref>

==Description== Genus ''Buellia'' consists of lichens that are either lichenised or occasionally lichenicolous. This means they typically form a symbiotic relationship with a photosynthetic partner, or in some cases, parasitise other lichens. Most ''Buellia'' species are independent, forming their own visible thallus (lichen body), but some start as parasites and eventually develop independent thalli.<ref name="LFGSDR 2007"/>

The thallus of ''Buellia'' species is crustose, meaning it forms a crust-like layer. Its appearance can range from continuous to patchy, and it may be cracked or broken into small, tile-like segments ({{lichengloss|areolate}}). In some cases, the thallus may develop into small scales or {{lichengloss|lobes}}. Often, there is a {{lichengloss|prothallus}}, which is a preliminary growth stage that typically appears dark and may form a thin outline or a more extensive network between the {{lichengloss|areoles}}. The surface of the thallus can be colourless or various shades of brown, yellow, or green, and it may be smooth, rough, or covered in a fine powder ({{lichengloss|pruinose}}). The margins of the thallus can be clearly defined or blend seamlessly into the substrate.<ref name="LFGSDR 2007"/>

The primary photobiont (symbiotic partner conducting photosynthesis) in ''Buellia'' is usually a species of ''Trebouxia''. The medulla, or inner tissue, is typically white but may contain yellow or orange pigments. Calcium oxalate crystals, which are colourless and needle-shaped, are often present in the medulla.<ref name="LFGSDR 2007"/>

Apothecia, the reproductive structures where spores are formed, are common in ''Buellia''. They can be flat, slightly concave, or convex, and are usually black or dark brown. The margin of the apothecium can vary in appearance, sometimes containing remnants of the thallus or being edged with thallus material. The hymenium (spore-producing layer) is clear but may contain oil droplets, and the paraphyses (filamentous structures) often have a distinct pigment cap, contributing to the colouration of the {{lichengloss|epihymenium}} (top layer of the hymenium).<ref name="LFGSDR 2007"/>

The spores of ''Buellia'' are initially clear, turning olive gray and eventually dark brown, although in some species, they remain clear. They can have one or several partitions (septa) and come in various shapes, often being straight but sometimes curved. The development of the spores involves forming the septum before or after the development of pigmentation and wall differentiation. The spore wall is multilayered, sometimes with distinct thickening at the sides or septa.<ref name="LFGSDR 2007"/>

In addition to apothecia, ''Buellia'' may also reproduce asexually through structures called pycnidia, which produce simple, {{lichengloss|bacilliform}} (rod-shaped), or {{lichengloss|filiform}} (thread-like) conidia (asexual spores). The conidiophores (structures that bear the conidia) within these pycnidia can vary in length and branching.<ref name="LFGSDR 2007"/>

==Selected species== {{Main|List of Buellia species}} There are almost a thousand species accepted in the genus ''Buellia'', including: *''Buellia abstracta'' *''Buellia asterella'' *''Buellia badia'' *''Buellia concinna'' *''Buellia disciformis'' *''Buellia dispersa'' *''Buellia spuria''

==Gallery== <gallery> Image:Buellia.disciformis.jpg|''Buellia disciformis'' Image:Buellia_stillingiana.jpg|''Buellia stillingiana'' Image:Buellia disciformis-2.jpg|Photograph of a cross section of an apothecium from ''B. disciformis'' taken through a compound microscope (x400), showing numerous brown, 1-septate spores per ascus. Image:Buellia disciformis-4.jpg|Photograph of brown, 1-septate (2-celled) spores from ''B. disciformis'' taken through a compound microscope, x1000. (spores measure 27 x 11 micrometres) </gallery>

==References== {{Reflist|refs=

<ref name="LFGSDR 2007">{{cite book |title=Lichen Flora of the Greater Sonoran Desert Region |volume=III |pages=113–178 |chapter=''Buellia'' |date=2002 |publisher=Lichens Unlimited & Arizona State University |location=Tempe, Arizona |editor-first1=Thomas H. |editor-last1=Nash III |editor-first2=Corrina |editor-last2=Gries |editor-first3=Frank |editor-last3=Bungartz |isbn=978-0-9716759-1-9}}</ref>

<ref name="Species Fungorum synonymy">{{cite web |title=Synonymy: ''Buellia'' De Not., G. bot. ital. 2(1.1): 195 (1846) |url=http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=674 |publisher=Species Fungorum |access-date=29 September 2021}}</ref>

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* Category:Caliciales genera Category:Lichen genera Category:Taxa described in 1846 Category:Taxa named by Giuseppe De Notaris