Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.
Life habit: lichenized Thallus: present, crustose, areolate, margin thinning at edge, slightly lobed or notched, with elongated lobes, 0.3-0.4 mm long, 0.2-0.3 mm wide; prothallus: absent surface: yellowish orange, smooth, sorediate soredia: fine, in delimited, laminal, cupuliform soralia cortex: cellular, thickness 20-30 µm, granules absent, medulla dense, without granules Apothecia: absent Pycnidia: not observed Spot tests: Thallus K+ red, H-, 10%N-, cN-, C-; medulla IKI- Secondary metabolites: unidentified anthraquinones. Substrate and ecology: on non-calcareous rocks World distribution: Central America and Caribbean Sonoran distribution: Baja California Sur, western Chihuahua, Sonora, and northern Sinaloa. Notes: Caloplaca cupulifera is species mainly is characterized by the thin, smooth, orange, continuous thallus with crateriform soralia. Apothecia are unknown.
Basionym:Placodium cupuliferum Vain., Ann. Acad. Sci. fenn., Ser. A 6(no. 7): 44. 1915; MB#401079.
Taxonomic note. According to the phylogenies presented here, ‘Caloplaca’ cupulifera clearly belongs to the subfamily Teloschistoideae.
Description. Thallus rimose-areolate to areolate, marginal areoles irregularly lobate, but not distinctly effigurate, not placodioid; surface deeply chrome yellow, smooth, but not shiny, dull, epruinose, with laminal, crateriform (‘cupuliform’) soralia, 0.2–0.4 mm in diam., often deeply eroded and ± excavate, with granular, bright yellow soredia (15–34 μm in diam.); prothallus absent. Apothecia unknown.
Chemistry. Thallus surface and soredia P–, K+ purple, C–, KC–, UV– (dull); dominated by fragilin, which is responsible for the conspicuous, chrome-yellow of the thallus and the bright yellow color of the soredia, occasionally also with small proportions of 7-chloroemodinal, 7-chloroemodic acid, 7-chloroemodin, and/or norcaloploicin.
Ecology and distribution. Possibly world-wide throughout the dry (sub-)tropics; Wetmore & Kärnefelt (1998) originally reported the species only from the new world, e.g., Mexico, Central America (incl. Caribbean), Brazil and the Galapagos, but McCarthy (2016) also cites it for Australia; in Galapagos, the species seems to be quite common, particularly along the coast and throughout the dry zone, where it generally grows below shaded, sheltered overhangs.
Notes. Based on ITS sequence data Galapagos specimens of ‘C.’ cupulifera are very uniform. Slightly different ITS sequences from Australia suggest that different genotypes may be present in various regions of the world; these deserve further scrutiny.