''Megaspora'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

-forming

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

in the family

Megasporaceae Megasporaceae are a family of fungi belonging to the order Pertusariales. Taxa are lichenized with green algae, and grow on rocks, often in maritime climates close to fresh water. Phylogenetic In biology, phylogenetics () is the study of the ...

. It contains four species of

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

s that typically grow on soil,

bryophyte Bryophytes () are a group of embryophyte, land plants (embryophytes), sometimes treated as a taxonomic Division (taxonomy), division referred to as Bryophyta ''Sensu#Common qualifiers, sensu lato'', that contains three groups of non-vascular pla ...

s (

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

es and

liverwort Liverworts are a group of non-vascular land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry ...

s), or

plant litter Plant litter (also leaf litter, tree litter, soil litter, litterfall, or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that has fallen to the ground. This detritus or dead organic material and its constituent ...

on chalky .

Taxonomy

The genus was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

by Georges Clauzade and

Claude Roux Claude Roux is a French lichenologist, mycologist and Esperantist. He has co-authored books about the identification of lichens written in Esperanto. Career From 1969 to 1975, Roux taught biology and geology in a secondary school. From 1975 he w ...

in 1984 with '' M. verrucosa'' assigned as the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. In 2012, Linda in Arcadia and Anders Nordin proposed to conserve the name ''Megaspora verrucosa'' against ''M. verrucosa'' due to taxonomic confusion stemming from historical errors in the original

basionym In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botan ...

citation. The original introduction of ''Aspicilia'' subg. ''Megaspora'' erroneously cited ''Lecanora verrucosa'' as the basionym, when it should have been ''Urceolaria verrucosa'' 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. verrucosa'' based on ''U. verrucosa'' as the conserved name, which the

Nomenclature Committee for Fungi International Botanical Congress (IBC) is an international meeting of botanists in all scientific fields, authorized by the International Association of Botanical and Mycological Societies (IABMS) and held every six years, with the location rotati ...

eventually recommended accepting after initially considering rejection.

Description

''Megaspora'' is a genus of

s, meaning they form a crust-like growth on their substrate. The

thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...

(lichen body) is non- (lacking distinct lobes) and can appear somewhat powdery (). The , or

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

partner, in this lichen is , referring to a type of

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

. The reproductive structures of ''Megaspora'' are

apothecia An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. As ...

, which are deeply immersed in the (small, wart-like structures on the thallus). The apothecia have a , a rim composed of thallus tissue. The , or the outer layer surrounding the apothecia, is thin and either colourless or pale straw-coloured, consisting of tightly packed, vertically aligned

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e (fungal filaments). The , the uppermost layer of the apothecium, is brown-green and turns bright green when treated with a nitrogen-based reagent (N+). The

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...

, the spore-bearing layer, is colourless and turns blue with iodine (I+). The , the layer beneath the hymenium, is also colourless. The , which contains the

paraphyses Paraphyses are erect sterile filament-like support structures occurring among the reproductive apparatuses of fungi, ferns, bryophytes and some thallophytes. The singular form of the word is paraphysis. In certain fungi, they are part of the f ...

(sterile filaments among the asci), is richly branched and interconnected (anastomosing) without swollen tips, and is strongly d (stuck together). The asci (spore-producing cells) are of the ''

Biatora ''Biatora'' is a genus of lichens in the family Ramalinaceae. Originally circumscribed in 1817,Fries EM, Sandberg A. (1817). ''Lichenum dianome nova''. Lund. the genus consists of crustose and squamulose lichens with green algal photobionts, bi ...

''-type, containing 4 to 8 spores, and are (club-shaped) or cylindric-clavate, with thin walls except towards the apex. The asci have a pale (a thickened area at the tip) that reacts faintly with potassium/iodine (K/I). The are large, aseptate (without internal divisions), globose (spherical) to shortly

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

al, colourless, and have uniformly thickened walls.

Conidiomata Conidiomata (singular: Conidioma) are blister-like fruiting structures produced by a specific type of fungus called a coelomycete. They are formed as a means of dispersing asexual spores call conidia, which they accomplish by creating the blister- ...

(structures producing asexual spores) have not been observed in this genus. No lichen products have been detected through

thin-layer chromatography Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. This is called the sta ...

Habitat

''Megaspora'' lichens typically grow on soil,

s (

es and

s), or

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

(chalky) substrates. They are rarely found growing on bark (

corticolous This glossary of mycology is a list of definitions of terms and concepts relevant to mycology, the study of fungi. Terms in common with other fields, if repeated here, generally focus on their mycology-specific meaning. Related terms can be found ...

Species

* '' Megaspora cretacea'' – Armenia * '' Megaspora iranica'' – Iran * '' Megaspora rimisorediata'' – Iran * '' Megaspora verrucosa''

References

{{Taxonbar, from=Q10579845 Megasporaceae Pertusariales genera Lichen genera Taxa named by Georges Clauzade Taxa named by Claude Roux Taxa described in 1984