{{Short description|Species of lichen-forming fungus}} {{Use dmy dates|date=January 2026}} {{Use Oxford spelling|date=January 2026}} {{Speciesbox | image = | image_caption = | taxon = Gyalectidium verruculosum | authority = [[Sérus.]] (2001) | mapframe = yes | mapframe-zoom = 4 | mapframe-coordinates = {{coord|5|54|S|145|20|E}} | mapframe-caption = [[Holotype]]: Southern side of [[Ramu]] River, [[Brahman, Papua New Guinea|Brahman Mission]], Papua New Guinea }}

'''''Gyalectidium verruculosum''''' is a species of [[lichen]]-forming fungus in the family [[Gomphillaceae]].<ref name="CoL_3HNPK"/> It is a [[foliicolous lichen|leaf-dwelling lichen]] known from Australasia and the western Pacific, including Papua New Guinea, Australia ([[Queensland]] and [[New South Wales]]), and [[Vanuatu]]. The species is distinguished by its triangular reproductive scales that typically develop from the inner side of a crescent-shaped crystalline bulge on the [[thallus]] surface, a feature that separates it from the externally similar ''[[Gyalectidium filicinum]]''.

==Taxonomy== ''Gyalectidium verruculosum'' was [[species description|described]] as a new species in 2001 by [[Emmanuël Sérusiaux]]. It was separated from the externally similar ''[[Gyalectidium filicinum]]'' by the form of its {{lichengloss|hyphophores}} ([[asexual reproduction|asexual reproducive]] structures), whose triangular scale typically develops from the inner side of a crescent-shaped crystalline bulge on the thallus surface. The author noted that the species had probably been overlooked in Australasia because it could be confused with ''G.&nbsp;filicinum''.<ref name="Ferraro et al. 2001"/>

==Description== The [[thallus]] forms rounded patches about 2–5&nbsp;mm in diameter. It is finely {{lichengloss|verrucose}} and pale greenish to greyish in colour.<ref name="Ferraro et al. 2001"/>

Hyphophores are produced on the thallus surface. Their scales are well developed and usually arise from a crescent-shaped, whitish crystalline bulge. The scales are obliquely to almost horizontally oriented and triangular, measuring about 0.15–0.25&nbsp;mm long and 0.1–0.15&nbsp;mm broad at the base. They are whitish translucent to pale greyish, only rarely with a bluish tinge. [[Apothecia]] (fruiting bodies) are rare overall but can be numerous on some thalli. When present, they are angular to rounded, about 0.15–0.25&nbsp;mm in diameter, with a pale yellowish-brown to greenish-grey {{Lichengloss|disc}} that may be slightly {{Lichengloss|pruinose}}, and a whitish margin. The [[ascospore]]s are [[ellipsoid]] with dimensions of 25–35 × 10–15&nbsp;[[μm]]. [[Pycnidia]] were not reported.<ref name="Ferraro et al. 2001"/>

==Habitat and distribution== ''Gyalectidium verruculosum'' was reported from [[lowland]] forest along the northern coast of Papua New Guinea, where it occurs together with ''[[Gyalectidium caucasicum]]'' and ''[[Gyalectidium flabellatum|G.&nbsp;flabellatum]]''. It was also recorded from Australia ([[Queensland]] and [[New South Wales]]) and from the [[Vanuatu]] archipelago.<ref name="Ferraro et al. 2001"/>

==References== <references>

<ref name="CoL_3HNPK">{{Catalogue of Life |id=3HNPK |title=''Gyalectidium verruculosum'' Sérus. |access-date=27 January 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>

</references>

{{Taxonbar|from=Q21271049}}

[[Category:Gyalectidium|verruculosum]] [[Category:Lichen species]] [[Category:Lichens described in 2001]] [[Category:Lichens of Australia]] [[Category:Lichens of New Guinea]] [[Category:Lichens of Malesia]] [[Category:Taxa named by Emmanuël Sérusiaux]]