Type. “In America meridionali, ad corticem Bonplandiae trifoliatae (Humb. et Bonpl.) (Angostura vera officinarum)” [in South America, on bark of Bonplandia trifoliata (≡Angostura trifoliata)], Anonymous, s.n., s.d. (G G00290304; M M-0204990, M-0204991).

Description. Lichenized fungus.

Thallus crustose, thin, pale brownish with dark prothallus, vegetative diaspores absent; photobiont Trentepohlia alga.

Ascomata lirellate, branched, immersed, dark reddish brown, 0.1-0.2 x 0.5-1.5 mm; exciple absent; epithecium reddish brown; hymenium hyaline, paraphyses absent. Asci pyriform, 8-spored. Ascospores colorless, ovoid-ellipsoid, 3-5-septate, end cells larger, 25-34 x 10-14 μm.

Chemistry. Spot tests all negative, secondary metabolites unknown.

Substrate and Habitat: On bark of hardwood trunks in mesic mixed forests, often near streams.

Distribution. Eastern North America, Neotropics, Bermuda, Taiwan; in North Carolina throughout, locally common.

Notes. A morphologically similar species “Arthonia aff. rubella” has been reported from Puerto Rico (Mercado-Diaz et al. 2015); historical records from Costa Rica (Imshaug 1956) may also represent similar species. Bermuda records (Thomson et al. 1885) were verified by Scott LaGreca.

Literature

Fée, A.L.A. (1825) Essai sur les cryptogames des éscorces exotiques officinales. Pp. 1-180 (original description as Graphis rubella).

Fink, B. (1935) The Lichen Flora of the United States. University of Michigan Press, Ann Arbor.

Imshaug, H.A. (1956) Catalogue of Central American Lichens. The Bryologist 59(2): 69-114.

Mercado-Diaz, J.A., W.A. Gould, G. Gonzalez & R. Lücking. (2015) Lichens in Puerto Rico: an ecosystem approach. U.S. Department of Agriculture, Forest Service, International Institute of Tropical Forestry, San Juan, Puerto Rico. General Technical Report IITF-GTR-46.

Nylander, W. (1856) Synopsis du genre Arthonia. Mémoires de la Société Impériale des Sciences Naturalles de Cherbourg 4: 85-104.

Thomson, C.W., J. Murray, G.S. Nares & F.T. Thomson. (1885) Report on the Scientific Results of the Voyage of HMS Challenger During the Years 1873-76 Under Command of Captain George S. Nares and the Late Captain Frank Tourle Thomson, Part 4, Vol. 1. HM Stationary Office.