Squamulea squamosa

About

Squamulea squamosa is a species of saxicolous (rock-dwelling), squamulose lichen in the family Teloschistaceae. Found in southwestern North America, it was first formally described by Maurice Bouly de Lesdain in 1933, as Placodium squamosum. Alexander Zahlbruckner proposed a transfer to genus Caloplaca in 1940, and the lichen was known as a member of that genus for more than seven decades. Ulf Arup and colleagues transferred the taxon to the genus Squamulea in 2013, following a molecular phylogenetics-based restructuring of the family Teloschistaceae.

Summary from Wikipedia