The Lichen Genus Caloplaca in Polar Regions

Abstract

Extensive material of Caloplacafrom Arctic and Antarctic regions has been critically examined. A list of 49 species is presented for Arctic regions. They are presumed to have a more or less circumpolar distribution. Twenty-two species are listed from the Antarctic region, but about ten more, probably undescribed species, are present there. About one-third of the species in the Antarctic region are bipolar or widespread in cold regions; these include mainly terricolous and muscicolous species and none of them are maritime. It is assumed that migration of the bipolar or cosmopolitan species has taken place along the Andean mountain chain, whereas the maritime polar species have evolved separately in the two hemispheres. The Caloplaca species of the Antarctic region are provisionally assigned to the following distribution types: continental Antarctic, western Antarctic, insul-Antarctic and sub-Antarctic. Caloplaca exsecuta, C. saxicola and C. phaeocarpella are recorded as new to the Antarctic region. Caloplaca johnstonii (Dodge) Søchting & Olech, comb, nov., is established as the correct name of C. tenuis Øvstedal.