A 2025 revision of Finnish
Protoblastenia, based on
morphology and nuclear
ITS rDNA sequences, showed that the genus is more diverse than had previously been recognised. The study accepted 20 species in Finland, including 16 species newly described there:
P. arupii,
P. borealis,
P. compressa,
P. dolomitica,
P. ekmanii,
P. fennoarctica,
P. minuta,
P. oulankaensis,
P. pseudocompressa,
P. pseudoterricola,
P. remota,
P. rikkinenii,
P. saanaensis,
P. timdalii,
P. violacea, and
P. westbergii. Many of these taxa were found to be semi-
cryptic, with only slight average morphological differences between species, so some specimens cannot be identified reliably without
molecular data. Most species of
Protoblastenia grow on
calcareous rock, although
P. terricola also occurs on calcareous soil. Species in the genus typically have
anthraquinones in the
apothecia, which usually give the an orange colour, along with convex apothecia and pale, non-
septate spores.
Protoblastenia differs from the related genus
Psora in its absent or weakly developed upper and in the lack of
calcium oxalate crystals in the . Molecular studies have supported the
monophyly of the genus, and the Finnish revision found ITS
barcoding useful for distinguishing species within
Protoblastenia. In Finland, the calcareous fells of
Enontekiö in the northwest were identified as a particular centre of diversity for the genus. Nine of the newly described species were known there alone in Finland. The study also linked
P. rikkinenii to material from Norway and
P. oulankaensis to material from Italy, suggesting that the diversity of the genus has probably been underestimated in northern and central Europe. ==Species==