The genus Parvoplaca is extended with four new species: P. candanii from Antarctica, P. lamprocarpa from Alaska, and P. macroborealis and P. tenebrosa from Oregon. Collections identified as P. tiroliensis are shown to form two independent clades when DNA was analyzed, but it is currently not clear which clade represents the species in a strict sense. Parvoplaca athallina has been considered an Antarctic species, but according to our analyses, the species is shown to be bipolar occurring also in northern Europe, Greenland, Alaska and in California.