Sunken rim-lichen is native to North America.
Identification: Lichen is whitish to pale gray. It appears as a thin layer directly on rock surfaces (crustose), looking a bit like paint that dried and cracked. Its fruiting bodies (apothecia) are black and slightly sunken. There may be more than one per “tile.”
Lecanora oreinoides on Stephen Sharnoff Photography
Lecanora oreinoides on Discover Life
Lecanora oreinoides at the Australian Government's Australian National Botanic Gardens
Lecanora oreinoides description by Thomas H. Kent, last updated 12 Oct 2018.