Schaereria serenior is a species of saxicolous (bark-dwelling), crustose lichen in the family Schaereriaceae.

[2] Found in Finland, it was first formally described as a new species by the Finnish lichenologist Edvard August Vainio, who classified it as a variety of the species Lecidea tenebrosa.

Auguste-Marie Hue promoted it to distinct species status in 1913 as Lecidea serenior.

[3] Alexander Zahlbruckner proposed to transfer it to the genus Caloplaca in 1931.

[4] Most recently, Orvo Vitikainen transferred it to Schaereria in 2004,[5] a few years after that genus had been resurrected from a long period of disuse.