Brambles (Rubus) of the Bohemian Forest, central Europe: chorological and taxonomical assessment

This paper presents the first comprehensive overview of the currently known Rubus taxa of the Bohemian Forest (= Böhmerwald, Bayerischer Wald, Šumava), a mountain range located in central Europe that extends across Austria, Czechia and Germany. The study is based on a detailed field survey conducted between 2019 and 2023 and subsequent evaluation of published and database records. A total of 60 species and one hybrid of brambles are accepted for the study area. The treatment of each taxon comprises a reference to a morphological description and illustration, a description of the overall distribution, a characterization of the distribution in the study area, including a classification into regional phytochorotypes, an elevation maximum occurrence, a grid distribution map, and a list of herbarium specimens and accepted records. A total of 30 species are documented for the first time from the study area. Furthermore, the following five species are described as new to science: R. bicoloristylus, R. cammensis, R. depressinervius, R. parvidentatus and R. suavis. The morphology, drawings, photographs of holotypes and species in situ, taxonomy, ecology and overall distribution including distribution maps of these species are provided. The lectotypes of eight taxa previously described from the Bohemian Forest are designated: R. heterophyllus Utsch including its two forms, R. hirsutus J. Presl et C. Presl, R. kuenicus Utsch including its three varieties and R. plicatus f. brevispinus Tocl. A critical evaluation of the literature, databases and herbaria revealed that records of 152 taxa previously reported from the Bohemian Forest are not acceptable based on current taxonomic and chorological knowledge. The majority of these erroneous records are attributed to misidentifications, which are explained by a lack of knowledge about the variability and plasticity of individual species and the application of inappropriate taxonomic approaches. The list of unaccepted taxa, accompanied by their original localities, is provided, along with a commentary on the reasons for their rejection. From the perspective of regional biodiversity, brambles represent an essential plant group that is largely a result of regional speciation processes. This is demonstrated by the prevalence of taxa with a central European distribution pattern (44 out of 56 recorded native species). Of these, 25 are endemic to the study area and adjacent areas. Seven other species exhibit a suboceanic distribution pattern, while five taxa show wider Eurasian distribution ranges. Five of the recorded brambles are aliens that have escaped from cultivation. In general, the highest observed abundance of individual species and species richness is found in the lower elevations, with the greatest diversity concentrated in the north-western part of the mountain range. Several bramble species reach their maximum elevation within the area studied. Given that the principal habitat of brambles is the edges of forest roads, it can be surmised that their distribution is positively influenced by human activity (forestry).