Lichen body (thallus) forming more or less circular rosettes up to several inches across, with gnarly radiating lobes towards the outside and breaking up into jigsaw puzzle-like pieces in the center. Color greenish yellow with the individual puzzle pieces and lobes outlined in black Fruiting bodies (apothecia) are common towards the center, bowl-shaped, less than a millimeter across, black in the center, with a thick rim the same color as the thallus. On acid (silicate) rocks in full sun.

Found worldwide, except the tropics, Australia and the Antarctica. Rare in Wildwood simply because most of our rocks are basic (limestone) and shaded. The photos are from a lovely colony on the Outdoor Classroom dedication boulder.

An easily identified lichen, based on the habitat, the faintly golden-green color, the jig-saw appearance, the radiating lobes, and the black apothecia.