Rubus tardatus is a rare North American species of flowering plant in the rose family. It is native to eastern and central Canada (Québec, Ontario, Nova Scotia) and the northeastern and north-central United States (Maine, Vermont, Michigan, Pennsylvania).Biota of North America Program 2014 county distribution mapBlanchard, William Henry 1906. Rhodora 8(95): 214–215
The genetics of Rubus is extremely complex, so that it is difficult to decide on which groups should be recognized as species. There are many rare species with limited ranges such as this. Further study is suggested to clarify the taxonomy.Flora of North America, Rubus Linnaeus, 1754. Bramble Some studies have suggested that R. tardatus may have originated as a hybrid between R. setosus and R. hispidus.Flora of North America, Rubus setosus Bigelow, 1824. Bristly blackberry, ronce sétuleuse
References