{{Short description|Species of lichen-forming fungus}} {{Use mdy dates|date=January 2026}} {{Use American English|date=January 2026}} {{Speciesbox | image = | image_caption = | taxon = Gyalectidium areolatum | authority = Ferraro & [[Robert Lücking|Lücking]] (2001) }}

'''''Gyalectidium areolatum''''' is a species of [[lichen]]-forming [[fungus]] in the family [[Gomphillaceae]].<ref name="CoL_3HNNB"/> It is a [[foliicolous lichen|leaf-dwelling lichen]] found in the [[Neotropics]], particularly common in northern Argentina and Paraguay, with records also from Mexico and Brazil. The species is distinguished by its strongly segmented thallus that breaks into discrete, whitish polygonal patches separated by thin greenish zones, with well-developed scale-like reproductive structures developing at the margins of these segments.

==Taxonomy== ''Gyalectidium areolatum'' was [[species description|described]] as a new species in 2001 by Lidia Ferraro and [[Robert Lücking]]. The [[type (biology)|type]] material was collected in northern Argentina ([[Formosa Province]]), at {{ill|Estancia Guaycolec|es}}, a privately managed [[nature reserve]]. The species was separated from similar members of the genus by its strongly {{lichengloss|areolate}} thallus (broken into discrete, polygonal patches) combined with well-developed, scale-like {{lichengloss|hyphophores}} that develop at the margins of the crystalline {{lichengloss|areoles}}.<ref name="Ferraro et al. 2001"/>

==Description== The [[thallus]] (the main body of the lichen) forms rounded patches about 1–3&nbsp;mm across and is distinctly areolate. It consists of flattened, whitish, polygonal crystalline clusters that are separated (or bordered) by thin, greenish parts of the thallus. The areoles usually develop first near the centre and may become confluent as the thallus matures.<ref name="Ferraro et al. 2001"/>

The hyphophores (specialised, scale-like structures that produce dispersal [[propagule]]s) are submarginal. Their scales are well developed and arise from the outer edge of crescent-shaped areoles. They are obliquely oriented and typically {{lichengloss|squamiform}} with two acute lateral projections, measuring about 0.2–0.5&nbsp;mm wide by 0.15–0.2&nbsp;mm long. Color ranges from whitish translucent to pale yellowish or orange, sometimes grayish. [[Apothecia]] are rare overall but can be abundant on thalli that produce them. They are rounded (sometimes confluent), about 0.1–0.2&nbsp;mm in diameter, with a grayish-brown {{lichengloss|disc}} and margin. The [[ascospore]]s are [[ellipsoid]], measuring 35–45 × 12–18&nbsp;[[μm]]. [[Pycnidia]] have not been reported for this species.<ref name="Ferraro et al. 2001"/>

==Habitat and distribution== Ferraro and colleagues reported ''G.&nbsp;areolatum'' from multiple localities in the [[Neotropics]], with records including Mexico and several parts of South America. Within that range, it appears to be most common in northern Argentina and adjacent Paraguay,<ref name="Ferraro et al. 2001"/> and has also been recorded in Brazil.<ref name="Santos et al. 2020"/>

In ecology it was described as broadly similar to ''[[Gyalectidium filicinum]]'', but tending towards slightly more open situations. The authors also noted that the thin greenish thallus zones separating the crystalline areoles may help explain why the hyphophores end up positioned on the thallus surface rather than remaining strictly marginal.<ref name="Ferraro et al. 2001"/>

==References== <references>

<ref name="CoL_3HNNB">{{Catalogue of Life |id=3HNNB |title=''Gyalectidium areolatum'' L.I. Ferraro & Lücking |access-date=January 27, 2026}}</ref>

<ref name="Ferraro et al. 2001">{{cite journal |last1=Ferraro |first1=Lidia I. |last2=Lücking |first2=Robert |last3=Sérusiaux |first3=Emmanuël |year=2001 |title=A world monograph of the lichen genus ''Gyalectidium'' (Gomphillaceae) |journal=Botanical Journal of the Linnean Society |volume=137 |issue=3 |pages=311–345 |doi=10.1111/j.1095-8339.2001.tb01126.x |doi-access=free}}</ref>

<ref name="Santos et al. 2020">{{cite journal |last1=Santos |first1=Viviane M. |last2=da Silva Cáceres |first2=Marcela E. |last3=Lücking |first3=Robert |title=Diversity of foliicolous lichens in isolated montane rainforests (Brejos) of northeastern Brazil and their biogeography in a neotropical context |journal=Ecological Research |volume=35 |issue=1 |year=2020 |doi=10.1111/1440-1703.12071 |pages=182–197}}</ref>

</references>

{{Taxonbar|from=Q17388081}}

[[Category:Gyalectidium|areolatum]] [[Category:Lichen species]] [[Category:Lichens described in 2001]] [[Category:Lichens of Argentina]] [[Category:Lichens of Brazil]] [[Category:Lichens of Chile]] [[Category:Lichens of Mexico]] [[Category:Lichens of Central America]] [[Category:Taxa named by Robert Lücking]]