About Caloplaca cerina (Hedw.) Th.Fr.
Caloplaca cerina (Hedw.) Th.Fr. has a crustose thallus that is typically dark grey to white. It features a thalline margin, which is sometimes thin and hard to observe. The appearance of this species can be highly variable, which means many specimens identified as Caloplaca cerina are actually other species. One study that examined 3,000 specimens identified as Caloplaca cerina found that roughly 1,000 of them belonged to other species. This lichen is very common on tree bark, particularly on poplar and elm trees.
