Naevia
Naevia is a small genus of three recognized species at world level. Two species are known from Norway. Naevia is lichenized with a trentepohlioid photobiont or non-lichenized.
- Innhold
- Description
- Ecology
- Remarks
Description
Thallus
Naevia species have a thin and indistinct thallus that is hardly altering the color of the host bark. Depending on the species, the thallus is non-lichenized or lichenized with a trentepohlioid photobiont. A thin brownish line delimiting the thallus is occasionally present when in contact with other lichens.
Fruitbodies
The apothecia of Naevia are brownish black, rounded (maculate) to clearly lirellate to sparsely branched, and level with the thallus surface to slightly raised. The size is 0.2–2.0 × 0.2–1.2 mm. Pruina is absent.
A well-defined margin is absent.
The hymenium is unpigmented.
The epithecium is olive-brown and formed of branched tips of the paraphysoids that are upright to slightly extending horizontally above the asci. The tips of the paraphysoids are slightly widened to 2.5 µm and often bear distinct pigment caps. Fragments of the host bark are often present in the epithecium and the apothecial margin.
The hypothecium is colorless.
Asci are of the Arthonia-type, broadly clavate to subglobose, and contain 4–8 spores.
The spores are narrowly obovoid and divided by 1–5 transverse septa. They are persistently colorless and lack an enlarged apical cell.
Anamorph
Pycnidia are known from all species. They are up to 0.1 mm in diameter, immersed in the thallus and have an olive-brown wall. The conidia are rod-shaped and 3–8 × 0.5–1.0 μm in size.
Chemistry
The thallus does not react with C, K, KC, Pd or UV (C–, K–, KC–, Pd–, UV–). Lichen secondary compounds have not been detected by TLC.
The hymenial gels react I+ blue or I+ blue mottled with red, and KI+ blue. A KI+ blue ring structure is present in the tholus of the asci. The brown pigment in the wall of the pycnidia changes to greenish in K solution.
Spore drawings, from left to right: Naevia punctiformis, Coniocarpon fallax, Reichlingia anombrophila and Bryostigma muscigenum. The spores of Bryostigma muscigenum are 10 µm long.
Ecology
The genus Naevia is widely distributed in mediterranean to boreal climates of the northern Hemisphere. Its species are mostly pioneers growing on thin, smooth bark of deciduous and coniferous trees. Naevia is common and widespread in the lowlands across Norway, with few records from mountain areas. Common host trees include alder (Alnus spp.), aspen (Populus tremula), European ash (Fraxinus excelsior), European beech (Fagus sylvatica), birch (Betula spp.), common hazel (Corylus avellana), oak (Quercus spp.), rowan (Sorbus aucuparia), sea buckthorn (Hippophae rhamnoides), small-leaved lime (Tilia cordata), willow (Salix spp.) and wych elm (Ulmus glabra).
Remarks
Naevia has been included in Arthonia until recently. Based on molecular systematic studies, it has been reinstated as an independent genus by Thiyagaraja et al. (2020). The genus comprises non-lichenized or weakly lichenized pioneer species on smooth bark of mainly deciduous trees, which are characterized by brownish black to black, maculate to lirellate to sparsely branched apothecia, olivaceous brown apothecial pigments, and unpigmented spores with 1 to 5 transverse septa without enlarged apical cell. While N. punctiformis is common and widespread throughout Norway, N. dispersa is only known from scattered and often old collections in the Oslo area and along the cost up to Vega Island.
Literature
Frisch A, Thor G, Ertz D and Grube M (2014). The Arthonialean challenge: restructuring Arthoniaceae. Taxon 63: 727–744.
Stornes Moen V (2019). Molecular systematics and species delimitation in Coniocarpon and Arthonia punctiformis s.lat. in Norway. Master’s thesis, NTNU, Faculty of Natural Sciences, Department of Natural History, 61 pp.
Sundin R (1999). Phylogenetic and taxonomic studies within Arthonia Ach. (Ascomycetes, Arthoniales). Botaniska institutionen, Stockholms universitet, Stockholm.
Thiyagaraja V, Lücking R, Ertz D, Wanasinghe DN, Karunarathna SC, Camporesi E and Hyde KD (2020). Evolution of non-lichenized, saprotrophic species of Arthonia (Ascomycota, Arthoniales) and resurrection of Naevia, with notes on Mycoporum. Fungal Diversity 102: 205–224.