Additamenta ad floram Republicae Bohemicae. XV.

This fi  fteenth part of fl  oristic contributions includes newly published data of critically endangered species and data unpublished so far. The species Sorbus collina, S. cuculifera, S. moravica, S. pontis-satanae and S. thayensis described from the Czech Republic as new to science, data of taxa newly iscovered on the territory of the Czech Republic (Rubus adornatus, R. ambulans, R. fasciculatiformis, R. perlongus, R. stohrii) and data of alien species found in the Czech Republic for the fi  rst time (Cephalaria transsilvanica, Chenopodium aristatum, Epilobium brachycarpum, Mimulus ringens, Phlomis russeliana) are summarized. Furthermore, critically endangered species (according to the Red List of Vascular Plants of the Czech Republic) are reported from new sites (e.g. Cardamine amara subsp. opicii, Centunculus minimus, Cerastium tenoreanum, Himantoglossum adriaticum, Limodorum abortivum, Ophrys apifera, Veronica opaca). Finally, less rare and threatened species are reported from areas where they had not been recorded yet (Carex fritschii, Myosotis stenophylla, Veronica agrestis).