TYPE. UNITED KINGDOM. England, Durham, Harriman s.n. ‘‘On Whinstone near Eggleston, D[urham], [J.] H[arriman]’’ (HAMU—isotypes, two specimens) (Coppins & Aptroot 2008).
Description.Life form: lichenized fungus.
[modified from Thüs & Schultz 2009] Thallus crustose, brownish olive to blackish, minutely rimose-areolate to granulose or effuse especially towards the margin; areoles indistinct or very small, 0.12-0.2(-0.35) mm wide, +/- angular, thin, flat or slightly convex, sometimes with slightly lifted margins, surface usually smooth or finely granular; attached by rhizohyphae originating from the lower surface; thallus anatomy paraplectenchymatous, hyphal cells small, roundish to broad ellipsoid or angular, ~3-5 μm wide. Photobiont chroococcoid cyanobacterium, cells up to 10 μm wide in thin, gelatinous yellowish-brown sheath. Ascomata thalline apothecia, 1 per areole, conical to hemispherical, eventually disk-shaped and sessile with broad base, filling the entire areole, 0.15-0.4(-0.6) μm diam.; thalline margin smooth, persisting, 50-75 μm thick, apically thinner, eroding to expose pale exipular rim; disk punctiform, 0.08-0.15 mm wide, opening to 0.25-0.35(0.40) mm diam., slightly concave to flat, dark reddish brown to blackish, old disks may become rough and umbonate. Exciple distinct, small celled subparaplectenchymatous, 10-15 μm wide at margin and below, apicaly ~25-35 μm thick, hyaline laterally and basally, dark reddish or yellowish brown apically, paler than disk. Epithecium faintly reddish brown; hymenium hyaline, clear, 125-150 μm high, I+ faint blue, sometimes indistinct or rapidly fading; subhymenium extending downward as a small stipe; paraphyses thin, septate, branched and anastomosing, apical cells ~3 x 5 μm. Asci cylindrical to narrowly clavate, I-, 8-spored; ascospores hyaline, simple, ellipsoid to broadly ellipsoid, 10-22.5 x 7-10 μm, with thin walls. Conidiomata pycnidia, small, immersed, with pale ostiole, ~75 μm diam.; conidia ~3 x 1 μm.
Chemistry. Spot tests negative; no substances detected by TLC.
Substrate and habitat. Amphibious on semi-inundated rocks (calcareous or siliceous) in and along rivers and streams.
Distribution. Europe and North America; in North Carolina found in the Piedmont rocky rivers.
Literature
Coppins, B.J. & A. Aptroot (2008) New species and combinations in The Lichens of the British Isles. The Lichenologist 40(5): 363–374.
Jørgensen, P.M. (2007) Lichinaceae. Pp. 46-76 in Nordic Lichen Flora. Volume 3. Cyanolichens. Nordic Lichen Society, Uddevalla (as Pyrenocarpon flotowianum).
Khodosovtsev A.Ye. & A.A. Kuzemko (2023) First records of Anema nodulosum, A. tumidulum, and Pyrenocarpon thelostomum (Lichinales, Lichinaceae) in Ukraine and a contribution to Collematetea cristati communities. Ukrainian Botanical Journal80(1): 98–107.
Thüs, H. & M. Schultz (2009) Fungi: Lichens Pt. 1 (Süßwasserflora Von Mitteleuropa / Freshwater Flora of Central Europe). Spektrum Akademischer Verlag, Heidelberg, Germany. 223 pp (as Pyrenocarpon flotowianum).