 On this basis they would have liked to promote it to species rank, but did not because their inferred phylogeny suggested that this taxon arose from within "B. integrifolia".They were unwilling to render "B. integrifolia" paraphyletic by elevating this taxon to species rank, and they were equally unwilling to elevate all four varieties to species rank, since the others all had significant overlaps in distribution and morphology.Therefore, they simply promoted all four to subspecies rank.