{{Short description|Single-species fungal genus}} {{Use dmy dates|date=March 2026}} {{Use Oxford spelling|date=March 2026}} {{Speciesbox | image = Nevesia sampaiana 1622119288.jpg | image_caption = | parent_authority = P.M.Jørg., L.Lindblom, Wedin & S.Ekman (2014) | taxon = Nevesia sampaiana | authority = (Tav.) P.M.Jørg., L.Lindblom, Wedin & S.Ekman (2014) }}

'''''Nevesia''''' is a single-species fungal genus in the family Pannariaceae.<ref name="CoL_47BPK"/> It contains the species '''''Nevesia sampaiana''''', a lichen. The lichen forms small, chestnut-brown scales over a conspicuous blue-black base, and reproduces mainly by powdery vegetative propagules (soredia) rather than spores. It is found in western Europe, where it grows on the bark of mature trees in humid woodlands.

==Taxonomy== ''Nevesia'' was circumscribed in 2014 by Per M. Jørgensen, Louise Lindblom, Mats Wedin, and Stefan Ekman to accommodate its sole species, ''N.&nbsp;sampaiana'', which had previously been treated as ''Pannaria sampaiana'' and later as ''Fuscopannaria sampaiana''. The authors concluded from their revised phylogeny of the Pannariaceae that this lichen represented a distinct lineage rather than a member of ''Fuscopannaria''.<ref name="Ekman et al. 2014"/>

The generic name honours the Portuguese lichenologist Carlos das Neves Tavares,<ref name="Ekman et al. 2014"/> who had first recognized the species at species rank in 1950 as ''Pannaria sampaiana''.<ref name="Tavares 1950"/> Within the family, ''Nevesia'' was recovered in clade 2a and placed as sister to a larger group containing mainly ''Leciophysma'', ''Protopannaria'', and ''Fuscopannaria''.<ref name="Ekman et al. 2014"/>

==Description== ''Nevesia'' is a crustose to squamulose lichen forming closely appressed, chestnut-brown {{lichengloss|squamules}} about 2–3&nbsp;mm wide and up to 200&nbsp;μm thick over a conspicuous blue-black {{lichengloss|hypothallus}}.<ref name="Ekman et al. 2014"/> The squamules are usually rounded, but rarely develop distinct elongate blunt marginal lobes up to 3–4&nbsp;mm long.<ref name="Cannon et al. 2021"/> The soralia are cream-coloured and coarsely granular, occurring both along the margins and on the upper surface of the thallus. In specimens that are densely sorediate, the soredia may spread to form an nearly continuous cream-coloured crust.<ref name="Cannon et al. 2021"/> Its upper {{lichengloss|cortex}} is cellular, while the {{lichengloss|photobiont layer}} contains clustered cells of ''Nostoc''. Beneath this lies a medulla of loosely interwoven hyphae that merges gradually into the {{lichengloss|hypothallus}}. The thallus also develops cream-coloured, granular soralia.<ref name="Ekman et al. 2014"/><ref name="Cannon et al. 2021"/>

Fruiting bodies (apothecia) are extremely rare and are known only in an immature state, so mature asci have not been observed. When present, the apothecia have a {{lichengloss|thalline margin}}, and the hymenium is hemiamyloid, showing only a partial iodine reaction. Pycnidia are unknown, and no lichen products have been detected using thin-layer chromatography.<ref name="Ekman et al. 2014"/>

==Habitat and distribution== Ekman and colleagues treated ''Nevesia'' as an Atlantic-Mediterranean European genus and one of the few genera in the Pannariaceae confined to the Northern Hemisphere. In the same work, ''N.&nbsp;sampaiana'' was characterized as a nearly always sterile species. The type material was collected in the Serra do Gerês of northern Portugal, where Carlos das Neves Tavares first recognized it as distinct at species rank.<ref name="Ekman et al. 2014"/> In the British Isles, ''N.&nbsp;sampaiana'' grows on smooth or mossy bark of mature trees, especially beech, elm, and ash, more rarely on mossy rock in humid relict woodlands, and occasionally on wayside trees. It is locally frequent in the Scottish Highlands, but scarce and decreasing in Wales and south-west England; it is also recorded from south-west Ireland.<ref name="Cannon et al. 2021"/>

''Nevesia sampaiana'' is the only known host of the lichenicolous (lichen-dwelling) fungus species ''Arthonia sampaianae''.<ref name="Cannon et al. 2021"/>

==References== <references>

<ref name="Cannon et al. 2021">{{cite book |last1=Cannon |first1=P. |last2=Aptroot |first2=A. |last3=Coppins |first3=B. |last4=Sanderson |first4=N. |last5=Simkin |first5=J. |year=2021 |title=Peltigerales: Pannariaceae, including the genera ''Fuscopannaria'', ''Leptogidium'', ''Nevesia'', ''Pannaria'', ''Parmeliella'', ''Pectenia'', ''Protopannaria'' and ''Psoroma'' |series=Revisions of British and Irish Lichens |volume=9 |page=7 |url=https://britishlichensociety.org.uk/sites/default/files/Pannariaceae.pdf}}{{Open access}}</ref>

<ref name="CoL_47BPK">{{Catalogue of Life |id=47BPK |title=''Nevesia sampaiana'' (Tav.) P.M. Jørg., L. Lindblom, Wedin & S. Ekman |access-date=18 March 2026}}</ref>

<ref name="Ekman et al. 2014">{{cite journal |last1=Ekman |first1=Stefan |first2=Mats |last2=Wedin |first3=Louise |last3=Lindblom |first4=Per M. |last4= Jørgensen |title=Extended phylogeny and a revised generic classification of the Pannariaceae (Peltigerales, Ascomycota) |journal=The Lichenologist |volume=46 |issue=5 |pages=627–656 |year=2014 |doi=10.1017/S002428291400019X |doi-access=free}}</ref>

<ref name="Tavares 1950">{{cite journal |last=Tavares |first=C.N. |year=1950 |title=Líquenes da Serra do Gerês |trans-title=Lichens of the Serra do Gerês |journal=Portugaliae Acta Biologica |volume=3 |pages=1–189 [76] |language=pt}}</ref>

</references>

{{Taxonbar |from1=Q30094928 |from2=Q30094932}}

Category:Pannariaceae Category:Lichen genera Category:Monotypic Lecanoromycetes genera Category:Taxa described in 2014 Category:Taxa named by Stefan Ekman Category:Taxa named by Per Magnus Jørgensen Category:Taxa named by Mats Wedin