Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: squamulose squamules: ±peltate, flattened, adnate to ascending, scattered to crowded to imbricate, initially circular in outline but becoming incised and finally lobate, sometimes forming small rosettes up to c. 0.6 cm wide surface: orange yellow to orange, smooth upper cortex: pseudoparenchymatous, 15-20 µm thick lower cortex: similar to the upper cortex Apothecia: usually present but often sparse, lecanorine, 0.3-0.8 mm wide disc: darker yellow than the thallus, round, ±flat margin: persistent or sometimes excluded, thin to thick, even to crenate or lobulate, concolorous with the thallus exciple: prominent and often visible from the outside, ±concolorous with the disc epihymenium: yellow-brown hymenium: hyaline, 65-70 µm tall; paraphyses: simple or occasionally branched near the tips, cylindrical or with somewhat swollen, up to 3.5 µm wide tips; hypothecium: hyaline asci: clavate, 8-spored ascospores: hyaline, simple to 1-septate, narrowly ellipsoid, often poorly developed, 12-18 x 3.5-4.5 µm Pycnidia: common, appear as raised warts in the center of the squamules, darker yellow than the thallus conidia: hyaline, 2.5-3 x 1.2-1.5 µm Spot tests: K+ red, KC-, C- Secondary metabolites: calycin, pulvinic acid, pulvinic dilactone and vulpinic acid. Substrate and ecology: on calcium-free rocks World distribution: southwestern North America Sonoran distribution: on rocks in open habitats in southern Arizona, Chihuahua, Sonora, Sinaloa and Baja California Sur, up to at least 1900 m. Notes: Candelariella "complanata" is characterized by its very small, smooth and flattened squamules, its usually dark yellow-orange color, and its narrow spores. It resembles somewhat a diminiutive Candelina, and is often found in mixed stands with C. citrina, that has thicker, larger squamules, a greenish pruinose surface and different spores. It appears to replace C. rosulans south of the Mexican border.