Abstract
The fifth part of the series on the distributions of vascular plants in the Czech Republic includes grid maps of 106 taxa of the genera Arnica, Carduus, Cicuta, Coleanthus, Comarum, Dactylorhiza, Digitaria, Gagea, Gypsophila, Hieracium, Hydrocotyle, Leersia, Myosurus, Oenanthe, Oreopteris, Paris, Phalaris, Phegopteris, Pilosella, Polystichum, Portulaca, Pulicaria, Salicornia, Saxifraga, Suaeda, Thalictrum, Thelypteris, Tripolium, Utricularia, Veronica and Xeranthemum. These maps were produced by taxonomic experts based on herbarium specimens, literature and field records.
Almost two-thirds of the mapped taxa are on the national Red List. These include endangered plants of rather dry habitats such as Gypsophila paniculata, Thalictrum foetidum, Veronica austriaca and Xeranthemum annuum as well as species of various sorts of wetlands such as Cicuta virosa and species of the genera Dactylorhiza and Utricularia, or fens and intermittently wet meadows including Oenanthe fistulosa, Thalictrum flavum and Th. simplex subsp. galioides.
Particularly endangered are ecological specialists; for example, many species of saline habitats such as Salicornia perennans and Suaeda prostrata, both confined to saline habitats, are now extirpated from this country. In contrast, Saxifraga tridactylites, previously a rare species found mainly on base-rich rock outcrops, has become more abundant by spreading along railways during the last two decades.
Maps based solely or mainly on herbarium records revised by experts are provided for taxonomically critical groups, particularly those of the genus Pilosella. Alien species mapped in this paper include both archaeophytes and neophytes, with various modes of introduction.
For example, Carduus tenuiflorus has been introduced with wool, Digitaria ciliaris with cotton, Gypsophila perfoliata with iron ore from Ukraine, while the ornamentals G. elegans and G. scorzonerifolia escaped from cultivation. The halophytic Suaeda salsa is recorded as a new alien species for this country's flora; it has recently colonized motorway verges of which the salinity of the soil was increased by the application of de-icing salts.
Two archaeophyte species, Digitaria ischaemum and Portulaca oleracea, are now classified as invasive. Spatial distributions and often also temporal dynamics of individual taxa are shown in maps and documented by records included in the Pladias database and available in electronic appendices.
The maps are accompanied by comments, which include additional information on the distribution, habitats, taxonomy and biology of the taxa.