Gold cobblestone lichen

''Pleopsidium flavum'' is a distinctively colored, bright lemon-yellow to chartreuse crustose lichen that grows in high elevations on vertical or overhanging hard felsic rock in western North America.:186 Its thallus grows in a circular outwardly radiating pattern , with 1mm wide lobed edges.:186 It was formerly classified as ''Acaraspora chlorophana''.:186 It is in the ''Pleopsidium'' genus of the Acarosporaceae family.

It is similar to ''Acarospora schleicheri'', which grows on soil and rarely on rock, and to ''Pleopsidium chlorophanum'', which favors dry arctic or alpine sandstone cliffs and boulders.:186