Hybridization and Gene Flow Between Distantly Related Species of Rubus (Rosaceae): Evidence from Nuclear Ribosomal DNA Internal Transcribed Spacer Region Sequences

Hybridization has long been considered a source of taxonomic complexity in Rubus. This study uses molecular data to examine natural hybridization between R. caesius, a facultatively agamospermous tetraploid of subgenus Rubus (blackberries) and R. idaeus, a sexual diploid of subgenus Idaeobatus (raspberries). Both species are widespread in Europe, and hybridization between them is postulated to have given rise to numerous species, including R....