Rubus adjacens explained

Rubus adjacens, the peaty dewberry, is a rare North American species of flowering plant in the rose family. It is native to eastern Canada (Quebec, New Brunswick, Nova Scotia) and the northeastern and east-central United States (Maine, New Hampshire, Vermont, Massachusetts, New York, Pennsylvania, Maryland.^{[1] [2] [3]}

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.^[4] Some studies have suggested that R. adjacens may have originated as a hybrid between R. setosus and R. hispidus.^[5]

Notes and References

1. http://bonap.net/MapGallery/County/Rubus%20whartoniae.png Biota of North America Program 2014 county distribution map
2. https://www.biodiversitylibrary.org/page/607474#page/336/mode/1up Fernald, Merritt Lyndon. 1940. Rhodora 42(500): 290-293
3. https://www.biodiversitylibrary.org/page/607474#page/341/mode/1up Fernald, Merritt Lyndon. 1940. Rhodora 42(500): plates 616-618
4. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=128837 Flora of North America, Rubus Linnaeus, 1754. Bramble
5. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250100446 Flora of North America, Rubus setosus Bigelow, 1824. Bristly blackberry, ronce sétuleuse