Rubus Strigosus - Classification

Classification

Botanists have long debated the taxonomic treatment of the Eurasian and American red raspberries, with some viewing all of these plants as members of a single, circumboreal species Rubus idaeus, and others recognizing two (or more) species within this group. The two species share many similarities, and probably recently diverged from a common ancestor, leading to differences in taxonomic interpretation, particularly regarding the more intermediate eastern Asian plants. A common current treatment, followed here, is to classify the North American red raspberries as Rubus strigosus, and include only the Eurasian plants in Rubus idaeus. When the species are combined, as done in some recent publications, the Eurasian plants are Rubus idaeus ssp. idaeus (or Rubus idaeus var. idaeus), and the American plants R. idaeus ssp. strigosus (or R. idaeus var. strigosus). Different interpretations are also sometimes made regarding placement of various eastern Asian populations of this group, by some considered to represent additional varieties or subspecies, if not different species altogether. The most distinctive physical difference among these plants is usual presence of gland-tipped hairs on first-year canes, petioles, pedicels, and calyces of R. strigosus, lacking in R. idaeus.