Thamnolia vermicularis is a globally widespread arctic-alpine lichen with two distinct chemotypes. The intermixing of these chemotypes at the local scale and lack of genetic variation between them is puzzling given the apparent absence of specialized reproductive structures. Apothecia and conidiomata were originally reported for Thamnolia in the second half of the 19th century, but putative apothecia proved to be parasitic in origin. This study presents conclusive microscopic evidence for the existence of pycnidial conidiomata containing conidia on thalli of Thamnolia vermicularis from geographically widespread locations. Sequences of the internal transcribed spacer (ITS) region of ribosomal DNA from excised pycnidial conidiomata matched that of thallus tips from individual Thamnolia thalli. Our examination of the historic literature found that the occurrence of pycnidial conidiomata was never disproved, but this information was lost from the post-1920s English-language literature. Our rediscovery of pycnidial conidiomata indicates that Thamnolia vermicularis possesses a reproductive strategy with the potential for long-distance dispersal of multitudes of mitotically produced conidia, providing a plausible explanation for the cosmopolitan distribution of the species and the low levels of genetic variation among populations. Reversible processes, for example alternative splicing, warrant consideration as explanations for chemotype intermixing.

This study focuses on dry acidophilous Scots pine forests, well known for their high biodiversity of cryptogams. We hypothesized that dense forests and heavy management were responsible for changes in species diversity, decreasing trends in lichen cover and increasing moss cover. This hypothesis was tested in three types of Scots pine forests maintained under three different management regimes: 1) managed forests (forest plantations regenerated by planting), 2) semi-natural forests (forest plantations regenerated naturally), both located in the Borská nížina lowland in SW Slovakia, and 3) natural forests (primordial vegetation without visible management actions from the association Cladonio-Pinetum Juraszek 1928), located in the Bory Tucholskie National Park, NW Poland.

We observed that the cover of the canopy tree layer had the most significant influence on the diversity of lichens. Managed forests are planted and maintained to achieve denser tree stocking, and although the environmental conditions created appear optimal for moss species, they are less suitable for terricolous lichens.