{{Short description|Genus of lichens}} {{Automatic_taxobox | image = Megaspora verrucosa 97523.jpg | image_caption = Close-up of thallus of ''Megaspora verrucosa'' with <br>half-hidden ({{lichengloss|aspicilioid}}) apothecia | taxon = Megaspora | authority = (Clauzade & Cl.Roux) Hafellner & V.Wirth (1987) | type_species = ''Megaspora verrucosa'' | type_species_authority = (Ach.) Arcadia & A.Nordin (2012) | subdivision_ranks = Species | subdivision = ''M. cretacea''<br /> ''M. iranica''<br /> ''M. rimisorediata''<br /> ''M. verrucosa'' | synonyms_ref = | synonyms = *''Aspicilia'' subgen. ''Megaspora'' {{au|Clauzade & Cl.Roux (1984)}}<ref name="Clauzade 1984"/> }}

'''''Megaspora''''' is a genus of lichen-forming fungi in the family Megasporaceae. It contains four species of crustose lichens that typically grow on soil, bryophytes (mosses and liverworts), or plant litter on chalky {{lichengloss|substrates}}.

==Taxonomy== The genus was circumscribed by Georges Clauzade and Claude Roux in 1984 with ''M.&nbsp;verrucosa'' assigned as the type species.<ref name="Wirth 1987"/>

In 2012, Linda in Arcadia and Anders Nordin proposed to conserve the name ''Megaspora verrucosa'' {{au|(Ach.) Arcadia & A.Nordin}} against ''M.&nbsp;verrucosa'' {{au|Hafellner & V.Wirth}} due to taxonomic confusion stemming from historical errors in the original basionym citation.<ref name="Arcadia & Norlin 2012"/> The original introduction of ''Aspicilia'' subg. ''Megaspora'' erroneously cited ''Lecanora verrucosa'' {{au|Ach.}} as the basionym, when it should have been ''Urceolaria verrucosa'' {{au|Ach.}} This misattribution led to the invalid introduction of the name ''Megaspora verrucosa'' by Hafellner & Wirth based on the wrong species. To rectify this and prevent future taxonomic issues, the proposal suggested adopting ''M.&nbsp;verrucosa'' {{au|(Ach.) Arcadia & A.Nordin}} based on ''U.&nbsp;verrucosa'' {{au|Ach.}} as the conserved name, which the Nomenclature Committee for Fungi eventually recommended accepting after initially considering rejection.<ref name="May & Lendemer 2023"/>

==Description== ''Megaspora'' is a genus of crustose lichens, meaning they form a crust-like growth on their substrate. The thallus (lichen body) is non-{{lichengloss|lobate}} (lacking distinct lobes) and can appear somewhat powdery ({{lichengloss|pruinose}}). The {{lichengloss|photobiont}}, or photosynthetic partner, in this lichen is {{lichengloss|chlorococcoid}}, referring to a type of green algae.<ref name="Cannon et al. 2023"/>

The reproductive structures of ''Megaspora'' are apothecia, which are deeply immersed in the {{lichengloss|thalline warts}} (small, wart-like structures on the thallus). The apothecia have a {{lichengloss|thalline margin}}, a rim composed of thallus tissue. The {{lichengloss|true exciple}}, or the outer layer surrounding the apothecia, is thin and either colourless or pale straw-coloured, consisting of tightly packed, vertically aligned hyphae (fungal filaments).<ref name="Cannon et al. 2023"/>

The {{lichengloss|epithecium}}, the uppermost layer of the apothecium, is brown-green and turns bright green when treated with a nitrogen-based reagent (N+). The hymenium, the spore-bearing layer, is colourless and turns blue with iodine (I+). The {{lichengloss|hypothecium}}, the layer beneath the hymenium, is also colourless. The {{lichengloss|hamathecium}}, which contains the paraphyses (sterile filaments among the asci), is richly branched and interconnected (anastomosing) without swollen tips, and is strongly {{lichengloss|conglutinate}}d (stuck together).<ref name="Cannon et al. 2023"/>

The asci (spore-producing cells) are of the ''Biatora''-type, containing 4 to 8 spores, and are {{lichengloss|clavate}} (club-shaped) or cylindric-clavate, with thin walls except towards the apex. The asci have a pale {{lichengloss|tholus}} (a thickened area at the tip) that reacts faintly with potassium/iodine (K/I). The {{lichengloss|ascospores}} are large, aseptate (without internal divisions), globose (spherical) to shortly ellipsoidal, colourless, and have uniformly thickened walls.<ref name="Cannon et al. 2023"/>

Conidiomata (structures producing asexual spores) have not been observed in this genus. No lichen products have been detected through thin-layer chromatography.<ref name="Cannon et al. 2023"/>

==Habitat== ''Megaspora'' lichens typically grow on soil, bryophytes (mosses and liverworts), or plant litter on calcareous (chalky) substrates. They are rarely found growing on bark (corticolous).<ref name="Cannon et al. 2023"/>

==Species== * ''Megaspora cretacea'' {{au|Gasparyan, Zakeri & Aptroot (2016)}}<ref name="Zakeri et al. 2016"/> – Armenia * ''Megaspora iranica'' {{au|Haji Moniri & S.Y.Kondr. (2017)}}<ref name="Haji Moniri et al. 2017"/> – Iran * ''Megaspora rimisorediata'' {{au|Valadb. & A.Nordin (2011)}}<ref name="Valadbeigi et al. 2011"/> – Iran * ''Megaspora verrucosa'' {{au|(Ach.) Arcadia & A.Nordin (2012)}}

==References== {{Reflist|colwidth=30em|refs=

<ref name="Arcadia & Norlin 2012">{{cite journal |last1=Arcadia |first1=Linda in |last2=Nordon |first2=Anders |year=2012 |title=(2053) Proposal to conserve the name ''Megaspora verrucosa'' (Ach.) L. Arcadia & A. Nordin against ''M. verrucosa'' Hafellner & V. Wirth (lichenised Ascomycota) |journal=Taxon |volume=61 |issue=2 |pages=464–465 |doi=10.1002/TAX.612018 |jstor=23210538}}</ref>

<ref name="Cannon et al. 2023">{{cite book |last1=Cannon |first1=P. |last2=Nordin |first2=A. |last3=Coppins |first3=B. |last4=Aptroot |first4=A. |last5=Sanderson |first5=N. |last6=Simkin |first6=J. |year=2023 |title=Pertusariales: Megasporaceae, including the genera ''Aspicilia'', ''Aspiciliella'', ''Circinaria'', ''Lobothallia'', ''Megaspora'' and ''Sagedia'' |series=Revisions of British and Irish Lichens |volume=34 |page=11}}</ref>

<ref name="Clauzade 1984">{{cite journal |last1=Clauzade |first1=G. |last2=Roux |first2=C. |title=Les genres ''Aspicilia'' Massal. et ''Bellemerea'' Hafellner & Roux |journal=Bulletin de la Société Botanique du Centre-Ouest |year=1984 |volume=15 |pages=127–141 |language=fr}}</ref>

<ref name="Haji Moniri et al. 2017">{{cite journal |last1=Haji Moniri |first1=M. |last2=Gromakova |first2=A.B. |last3=Lőkös |first3=L. |last4=Kondratyuk |first4=S.Y. |title=New members of the Megasporaceae (Pertusariales, lichen-forming Ascomycota): ''Megaspora iranica'' spec. nova and ''Oxneriaria'' gen. nova |journal=Acta Botanica Hungarica |volume=59 |issue=3–4 |year=2017 |doi=10.1556/034.59.2017.3-4.5 |pages=343–370}}</ref>

<ref name="May & Lendemer 2023">{{cite journal |last1=May |first1=Tom C. |last2=Lendemer |first2=James C. |year=2023 |title=Report of the Nomenclature Committee for Fungi: 22 |journal=Taxon |volume=72 |issue=6 |pages=1356–1363 |doi=10.1002/tax.13099 |doi-access=free}}</ref>

<ref name="Valadbeigi et al. 2011">{{cite journal |last1=Valadbeigi |first1=Tahereh |last2=Nordin |first2=Anders |last3=Tibell |first3=Leif |title=''Megaspora rimisorediata'' (Pertusariales , Megasporaceae), a new sorediate species from Iran and its affinities with ''Aspicilia'' sensu lato |journal=The Lichenologist |volume=43 |issue=4 |year=2011 |doi=10.1017/S0024282911000211 |pages=285–291 |url=https://www.researchgate.net/publication/231850289}}</ref>

<ref name="Wirth 1987">{{cite book |last=Wirth |first=V. |title=Die Flechten Baden-Württembergs. Verbreitungsatlas |year=1987 |publisher=Verlag Eugen Ulmer |location=Stuttgart |isbn=978-3-8001-3305-5 |language=de |page=511}}</ref>

<ref name="Zakeri et al. 2016">{{cite journal |last1=Zakeri |first1=Zakieh |last2=Gasparyan |first2=Arsen |last3=Aptroot |first3=André |title=A new corticolous ''Megaspora'' (Megasporaceae ) species from Armenia |journal=Willdenowia |volume=46 |issue=2 |year=2016 |doi=10.3372/wi.46.46205 |pages=245–251|doi-access=free }}</ref>

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Category:Megasporaceae Category:Pertusariales genera Category:Lichen genera Category:Taxa named by Georges Clauzade Category:Taxa named by Claude Roux Category:Taxa described in 1984