Lecidea laboriosa is a species of lichen that grows inside solid rock (endolithic), with only the small black disc-like fruiting bodies (apothecia) visible above the rock surface.[1] [2] Unlike other members of the genus Lecidea, the apothecia are not lecideine in that they either lack black margins (exciples) or have gray vertically striated margins.[1] It grows all over the world in all climates.[2] It might be the most common endolithic lichen in California.[1]
It is similar in appearance to Catillaria lenticularis, Polyspora simplex, and Sarcogyne clavus.[1]
It is negative to lichen spot tests, K−, P−, C−.[1] [2]