Additions to Rubus series Suberecti (P.J.Müll.) Focke (Rosaceae)

The series Suberecti of the genus Rubus consists of three classic species, which are surrounded by similar but not identical forms. Some of these deserve a separate status. Rubus transitorius (close to R. ammobius) and R. cubirianus (close to R. scissus) were already described. To these two a new species, R. lucidicaulis (close to R. nessensis) is added. In addition, a form of R. scissus with deep red prickles from the British Islands has been described here as f. rubrisetus to clarify that this form is not a representative of the R. scissoides complex but is closely related to R. scissus. For the old name R. polonicus, belonging to the R. nessensis group, an epitype is designated. However, its precise taxonomic position must be clarified before drawing any further nomenclatorial conclusions.