Sequencing of environmental samples has great potential for biodiversity research, but its application is limited by the lack of reliable DNA barcode databases for species identifications. Such a database has been created for epiphytic lichens of Europe, allowing us to compare the results of environmental sequencing with standard taxonomic surveys. The species undetected by taxonomic surveys (what we term the ghost component) amount to about half of the species actually present in hectare plots of Central European forests. Some of these, which currently occur only as diaspores or weakly developed thalli, are likely to be favoured in the course of global change. The ghost component usually represents a larger fraction in managed forests than in old-growth unmanaged forests. The total species composition of different plots is much more similar than suggested by taxonomic surveys alone. On a regional scale, this supports the well-known statement that “everything is everywhere, but, the environment selects”.

Wolffia globosa is a small free-floating aquatic plant native to the Southeast Asia and invasive in Europe. Between the years 2017 and 2022 it has been found in Czechia for the first time in this country in wetland habitats at seven sites. Occurrences of alien W . globosa were first recorded in the Central Bohemia region inside the Site of Community Importance Libické luhy, then by two sewage treatment plants and one adjacent fishpond in South Bohemia and in the Elbe River near the cities of Přelouč, Lysá and Labem, Obříství and Hřensko. At four sites, W . globosa has been recorded in flowing waters for the first time in Europe. The mode of introduction remains unknown.

Polyploidisation is an important evolutionary force in land plants. Due to its recurrent incidence, many plant species retain individuals of two or more different ploidy levels. However, particular ecological and evolutionary mechanisms facilitating intraspecific cytotype coexistence have been identified for just a handful of species and cannot yet be generalised. Our pilot data have revealed a unique complex of mixed diploid-triploid populations of the marshland perennial Butomus umbellatus in the Eastern Slovak Lowland (eastern Central Europe). Intensive flow-cytometric ploidy screening of 1,230 individuals sampled from 72 populations was conducted at both regional and local (within-population) scales to assess cytotype distribution patterns. Vegetation assessments along with phenotypic comparisons of cytotypes directly in the field and later under common garden cultivation served to provide insight into mechanisms of cytotype coexistence. Altogether 42 % of the sampled populations were mixed-ploidy, pointing to unexpectedly high rates of diploid-triploid coexistence. While the cytotype distribution was random at the regional scale, significant spatial clustering occurred at the local scale. No ecological niche differences between the cytotypes were detected. Triploids attained greater values of several morphological characters both in the field and under cultivation, differences in the shape of inner tepals even show potential for cytotype discrimination. Both cytotypes exhibited high and comparable investments into clonal traits, reproductive assurance provided by asexual reproduction likely plays a key role in cytotype coexistence and triploid predominance. The common cytotype coexistence in this region seems to be also facilitated by periodical seasonal floods promoting transport of vegetative propagules among populations (i.e. metapopulation dynamics) and providing long-term continuity of favourable sites by recurrent disturbances.