The blackberry is an edible fruit produced by many species in the Rubus genus in the Rosaceae family, hybrids among these species within the Rubus subgenus, and hybrids between the Rubus and Idaeobatus subgenera. The taxonomy of the blackberries has historically been confused because of hybridization and apomixis, so that species have often been grouped together and called species aggregates. For example, the entire subgenus Rubus has been called the Rubus fruticosus aggregate, although the species R. fruticosus is considered a synonym of R. plicatus.
What distinguishes the blackberry from its raspberry relatives is whether or not the torus (receptacle or stem) “picks with” (i.e., stays with) the fruit. When picking a blackberry fruit, the torus does stay with the fruit. With a raspberry, the torus remains on the plant, leaving a hollow core in the raspberry fruit.