in Frisch, Biblitheca Lichenol. 92: 82 (2006).

Basionym: Thelotrema auratum Tuck., Proc. Amer. Acad. Arts & Sci. 5: 408 (1862) [1860].

Type locality: Cuba, Wright, Wright: Lichenes Cubae 133 as Thelotrema auratum (FH-TUCK - lectotype; BM, G, H-NYL 22553, L, M, PC, UPS - isolectotypes). Designated by Hale (1978b: 41).

Thallus: corticolous, dark grey-olive, often somewhat browned, fissured, c. 0.15-0.2 mm thick, verrucose to warty, with a slightly glossy, compact surface; a thin white medullary layer present. Prothallus line thin, brownish. Phenocortex c. 20-25 µm thick, continuous, dense, strongly conglutinated, formed predominantly from periclinal hyphae. Photobiont layer 65-125 µm thick, with dense photobiont cells and with large clusters of calcium oxalate crystals mainly concentrated in the thallus warts. Medulla endophloeodal. Pycnidia unkown. Apothecia frequent, dispersed, rounded, strongly emergent to adnate, c. 1-1.3 mm in diam., with steep flanks and a moderately wide to wide pore. Margin concolorus with the thallus, incurved to rim-like, entire to jagged or deeply fissured, often with an incomplete black ring formed from the proper exciple at the top, Columella absent. Disc exposed, covered by dense, coarse, lemon to deep yellow pruina. Phenocortex c. 25 µm thick. Photobiont layer 50-100 µm thick, with dense photobiont cells and numerous large calcium oxalate crystals mostly concentrated towards the base. Periderm layer 25-40 µm thick, comprising a moderately dense, brown conglutinated prosoplectenchyma. Proper exciple cupular, 25-45 µm deep and hyaline at the base, 25-70 µm wide laterally, carbonised to the base. Subhymenium c. 10 µm high. Hymenium c. 140 µm high, inspersed. Ascospores 8/ascus, 1 seriate, hyaline, muriform, 4-6 x 2 loculate, 14-21 x 8-10 µm, with rounded ends, I+ purplish-blue. Asci narrowly clavate, c. 125-140 x 11-15 µm. Paraphyses simple, straight, c. 2 µm wide; tips with 1-2 irregularly thickened cells or slightly branched. Epihymenium 10-12 µm high, inspersed by numerous yellow granules and with diffuse yellow to yellow-green pigmentation in the hymenial gelatine (Frisch 2006: 82).

Photobiont: Data lacking.

Chemistry: Protocetraric acid (major), virensic acid (trace) detected by TLC. Yellow pigment in the pruina of the apothecia. The pigment dissolves in K resulting in bright yellow solution and in C without colour reaction. It shows no colour reaction nor does it dissolve in HNO₃ (Frisch 2006: 82).

Ecology: On bark. - In Florida exclusively on Prunus myrtifolia. The species occurs pantropically in undisturbed rain forests in open situations (Kalb 2004). - For more details see (Frisch 2006: 83).

Distribution type: Pantropical (Frisch 2006: 83). Often on islands: Cuba, Malesia: Borneo, New Caledonia, Philippines, Samoa, Sri Lanka, but also on mainlands: Australia: Queensland, Brazil: Rio de Janeiro, Guiana, Solomon Islands, Tanzania, USA: Florida, Venezuela.

Taxonomy: Data lacking.

Note:

Distribution Database: Distributions

Picture Database: Tropical Lichens

Molecular Database: Genbank

Synonym Database: Index Fungorum

Synonym Database: Mycobank