Polyblastidium casarettianum is a species of corticolous (bark-dwelling), foliose lichen in the family Physciaceae.

[2] The species was first scientifically described in 1853 by the Italian botanist Abramo Bartolommeo Massalongo, who classified it in the genus Anaptychia.

[3] Vittore Benedetto Antonio Trevisan de Saint-Léon reclassified it in genus Heterodermia in 1868.

[4] It was transferred to the newly circumscribed genus Polyblastidium in 2015 by Klaus Kalb.

This Caliciales-related article is a stub.