Psoroma femsjonense (Fr.) Trevis., a misunderstood species possibly extinct from Europe

Abstract

Psoroma femsjonense, long considered to be a synonym of P. hypnorum, is shown here to represent a distinct, misunderstood species. The collections seen are from the lowlands of southern Sweden, Denmark, Germany, the Czech Republic, and France. In these areas, the species has not been collected since 1945 and may prove to be regionally extinct from these countries. However, a report indicates that the species has recently been collected in high-altitude steppes in Anatolia of NE Turkey. Psoroma femsjonense is most similar to P. tenue var. tenue, known from Antarctica and adjacent areas of the Southern Hemisphere, and obviously has different climatic demands, in addition to having different apothecium margins and paraphyses. In Europe, P. femsjonense can be distinguished from P. hypnorum by the chestnut-brown thallus, crenulate (but not squamulose) apothecium margins, low perispore verrucae, and the presence of porphyrilic acid methyl ester and pannaric acid in the thallus. Psoroma tenue var. boreale differs from P. femsjonense by the distinct cinnamon-brown colour, strongly glossy thallus, and a predominantly alpine and arctic distribution.