Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
[In Vol. II color plate 79 is erroneously labeled as Placomaronea "arizonica" Westberg, a nomen nudum never published]. Thallus: crustose to subsquamulose, composed of bullate areoles developing into gomphate squamules squamules: rounded to irregular in outline, up to c. 0.6 mm across upper surface: orange yellow to brownish yellow, smooth, shiny epicortex: hyaline, gelatinous, 1-5 µm thick upper cortex: pseudoparenchymatous, 15-25 µm thick medulla: indistinct, with the photobiont is evenly dispersed throughout the interior of the thallus lower cortex: present below the raised margins of the squamules, similar to the upper cortex, 5-10 µm thick Apothecia: common, lecanorine, 0.4-0.8 mm wide disc: darker yellow than the thallus, round to irregular in outline, ±flat margin: thin to thick, uneven, concolorous with the thallus, persistent exciple: thin and indistinct epihymenium: yellow-brown hymenium: hyaline 70-90 µm tall; paraphyses simple or branched near the tips, mostly with swollen, up to 5 µm wide tips, or submoniliform; hypothecium: hyaline asci: clavate, c. 32 spored ascospores: hyaline, simple, narrowly ellipsoid, 8-11 x 2.5-3.5 µm Pycnidia: common, immersed conidia: hyaline, ellipsoid, 2.5-3.5 x 1.5 µm Spot tests: K+ pale red, KC-, C-, P- Secondary metabolites: pulvinic acid derivatives, not investigated here. Substrate and ecology: on calcium-free rocks in open montane habitats World distribution: South America to southern North America Sonoran distribution: on rocks in open habitats in the mountains of Arizona up to at least 3500 m. Notes: Placomaronea mendozae is easily confused with Candelariella vitellina, that has a smaller thallus. The smooth shiny surface of the thallus is caused by its thin gelatinous epicortex and the narrow spores, are characteristic to P. mendozae. In section it can also be recognized by the arrangement of its cortical pigments that form "hoods" on the outermost cortical cells.