Usnea jørgenseniana Bystr. & Leśniewska sp. nova Usnea (subgen. Usnea, Parmeliaceae) in Sweden

Abstract

Usnea jørgenseniana Bystr. & Leśniewska sp. nova, an epixilic species of bushy Usnea (Parmeliaceae) in Sweden, is similar to U. hirta var. minutissima (Mer.) Bystr., but the similarity to U. hirta is apparent. U. jørgenseniana is not a species from the foveatae Mot. section. The lack of soralia and a very small thallus (0.3–2.0 cm) makes it difficult to locate U. jørgenseniana in the section Comosae Mot. It colonizes exceptionally unfavorable climatic conditions, a coprophilous species. Collected by G. Ohrstedt in 1937. Dozens of specimens from one position.