Rubus fruticosus L. is the ambiguous name of a European blackberry species in the genus Rubus in the rose family. The name has been interpreted in several ways:

• The species represented by the type specimen of Rubus fruticosus L., which is also the type specimen of the genus Rubus. This specimen is considered to match the species R. plicatus, in Rubus subgenus Rubus, section Rubus.
• Various species consistent with Linnaeus' original description of the species, which was based on a mixture of specimens now considered to match Rubus ulmifolius and R. plicatus
• a species aggregate (group of similar species) Rubus fruticosus agg. that includes most of a group called either Rubus subgenus Rubus or Rubus section Rubus:
  • in a narrow sense, sometimes separated as the section Glandulosus, with about 289 microspecies. In this sense the species aggregate does not include the type of the genus Rubus, which is a hybrid.
  • in a broad sense including subgenus Rubus sections Glandulosus, Rubus (about 20 microspecies), and Corylifolii (about 24 microspecies). Section Rubus are probably hybrids involving members of section Glandulosus with either R. idaeus or R. allegheniensis. Section Corylifolii are probably hybrids involving members of section Glandulosus with R. caesius.
  • even more broadly as a nomen ambiguum including all the taxa in the subgenus (or section) Rubus