Jahresber. Schles. Ges. Vaterl. Cultur 2: 1-400 (1879).
Basionym: Lichen concolor Dicks., Fasc. Pl. Crypt. Brit. (London) 3: 18 (1793).
Thallus: dispersed as an indeterminate, scurfy, + areolate crust, closely attached, often forming extensive colonies, corticolous. Lobes very minute, often only visible at margins of thallus, margins partly entire to completely and densely granular-sorediate. Upper surface lemon-yellow to mustard-yellow, often greenish in shaded habitats, + densely granular-sorediate or minutely granular-isidiate. Medulla very thin, white. Lower surface whitish. Rhizines simple, pale, sparse. Apothecia rare (not seen in New Zealand material) minute, yellow orange-brown with a yellow, sorediate margin. Ascospores elliptical 6-15 x 4-6 µm (Galloway 1985: 72).
Photobiont: Green alga trebouxioid.
Chemistry: Calycin and pulvinic dilactone (Galloway 1985: 72).
Ecology: On eutrophic bark in parks and gardens (Galloway 1985: 72).
Distribution Type: Subcosmopolitan. "Cosmopolitan" (Galloway 1985: 72).
Taxonomy: "The main distinguishing characters between C. concolor and C. pacifica is that the former has polyspored asci and a thallus that possess a lower cortex, whereas C. pacifica has 8-spored asci and a thallus that lacks a lower cortex. When fertile, the species are thus easily separated. Candelaria concolor is usually larger and more distinctly lobate, with branched lobes with a smooth, flattened surface, forming small, adnate rosettes. Under the dissecting microscope the lower side is shiny, whitish (in the herbaria turning pinkish in older specimens) and with well-developed, sometimes numerous rhizines. Candelaria pacifica is usually composed of very small, raised, squamule-like lobes but often appears like a granular-blastidiate crust with few distinct and well-developed lobes. The lower side of C. pacifica has an arachnoid appearance with a whitish or greenish colour as the green algae shines through. A few short rhizine-like structures are often found. As the lobes are often very small and poorly developed the absence of a lower cortex is not always an easy character to use" (Westberg & Arup 2010: 38).
Note:
Lichens of the Pacific Northwest
There are different author citations even in very recent publications:
C. c. (Dicks.) Stein in Wirth et al. 2011: Red List of Germany; in Hafellner, Internet
C. c. (Dicks.) B. Stein in Atlas Baden-Würtemberg, in Wirth et al. (2013: 320) "Die Flechten Deutschlands" and in GBIF .
C. c. (Dicks.) Arnold in Index Fungorum, 16.7.2017 and earlier, based on Flora 62: 364 (1879). 13 November 2017 in Mycobank .
As the combination was made by Stein and F. Arnold almost at the same time, and the exact dates for their publications are not known, we follow the monographer (e.g. Westberg & Arup 2010: 39) and accept "Candelaria concolor (Dicks.) Stein". The authority name is "Stein", not "B. Stein".