Occurrence of the rare lichen Nephromopsis laureri (Parmeliaceae) at its northern limit in Europe, with the first record from Finland

Abstract

Six new localities of Nephromopsis laureri were identified within the 61–63° N latitudinal range in Northern Europe, in middle boreal forests of North Karelia (Finland), as well as in the southern parts of the Republic of Karelia and the Arkhangelsk Region (Russia). We report the first record of N. laureri for Finland, which represents the westernmost point of the species’ Northern European range. All specimens were found as single vegetative thalli (virginal stage, without ascomata, with soralia) in old-growth forests with high stand continuity (140–350 years). Repeated surveys in 2025 confirmed an extremely low population density, with no new individuals detected despite intensive searching. Phylogenetic analysis placed the Finnish specimen within the European N. laureri s. str. clade, clearly distinct from Asian lineages.