Thallus bright greenish yellow to bright yellow, very variable, mostly composed of small raised squamules, sometimes lobate-foliose to subfruticose, sometimes forming distinct ± adnate rosettes to 5 mm diam, frequently combining to form a granular-blastidiate crust with few distinct, well-developed branched lobules. Blastidia 30-100 µm diam, formed primarily from lobe tips. Lower cortex absent and the lower surface arachnoid and white or green, with a few short rhizine-like structures.
Anamorph: conidiomata pycnidia, visible as orange protruding warts. Conidia 2-3 x ca 1 µm, ovoid to ellipsoidal.
Teleomorph rarely formed (not known in GB&I). Ascomata apothecia, 250-650 (-800) µm diam, darker yellow than the thallus, discoid, the margin smooth or sorediate, often excluded in older ascomata. Subhymenium hyaline, epihymenium with golden yellow to orange granules. Interascal tissue of simple paraphyses 1.5-2 µm diam, rarely forked near the apex, the tips cylindrical to clavate, to 4 µm diam. Asci 37-50 x 10-16 µm, clavate, 8-spored. Ascospores (9-)10-15(-17) x 3.5-6 µm, narrlowly ellipsoidal, hyaline, aseptate.
The lobes of Candelaria concolor are larger, more distinctly lobate with neat branching, usually forming distinct rosettes. The lobes of C. pacifica are minutely squamulose, often becoming erect and subfruticose, and frequently coalescing into a mass of blastidiate squamules. The underside of C. concolor lobes have a distinct cortex and so are whitish and shiny. By contrast the underside of C. pacifica lobes lack a lower cortex and often have an eroded appearance, usually greenish due to the algal layer being visible from below, and may be arachnoid due to a poorly developed medulla. The rhizines are considerably larger and more frequent in C. concolor.
In GB&I, known from England (Shropshire) and Scotland (Angus, E Inverness). It is much more common than C. concolor in Scandinavia, but rarer than that species in Germany and Switzerland. It is also known from North and South America.
On bark of deciduous trees (known from Quercus in GB&I), rarely also on decorticated wood.