Description.Thallus crustose, whitish to pale green, continuous, thin, up to 2 cm diam; surface verrucuose. Prothallus barely distinct. Vegetative diaspores absent. Photobiont coccoid green alga (Chlorococcaceae), cells 5 – 8 μm diam. Ascomata biatorine apothecia, sometimes clustered in groups of 2-4 and becoming +/- distorted, 0.3–0.5 mm diam.; disk epruinose, plane to subconvex, black or with a bluish tinge; margin white or rarely grayish white, tomentose-arachnoid. Exciple hyaline; epihymenium blackish; hymenium hyaline, not inspersed; paraphyses indistinct; hypothecium black. Asci 8-spored; ascospores hyaline, 4-celled, ellipsoid, 10–17 × 3-5 μm. Conidiomata pycnidia, rare, sessile, ± globose, 0.05-0.15 mm diam; conidia simple, flask-shaped, 4-5 × 1.5-2 µm.
Substrate and habitat. Saxicolous on damp, shaded rocks; corticolous or foliicolous.
Distribution. Cosmopolitan; in North Carolina found throughout.
Literature
Byssoloma subdiscordans. New Zealand Plant Conservation Network: https://www.nzpcn.org.nz/flora/species/byssoloma-subdiscordans/ (accessed 13 Feb 2024).
Cannon, P., Orange, A., Aptroot, A., Sanderson, N., Coppins, B. & Simkin, J. (2022). Lecanorales: Pilocarpaceae, including the genera Aquacidia, Byssoloma, Fellhanera, Fellhaneropsis, Leimonis and Micarea. Revisions of British and Irish Lichens27: 1-48.
Nylander, W. (1879) Addenda nova ad Lichenographiam Europaeam. Continuatio una et tricesima. Flora (Regensburg) 62: 201-207, 220-224 (original description as Chiodecton subdiscordans).