What Exactly is the Name of that Buckthorn?

There are two species of buckthorn on this woodlot. By their Latin names they are Rhamnus frangula and Rhamnus Cathartica. There is ample confusion about their names for me anyway since I tended to use European buckthorn to name one of them and thus the Latin names were very helpful. For that matter, even for R. frangula there is also another Latin name: Frangula alnus, considered by some to more accurately describe the plant. I will stick with R. frangula for this blog's sake. Listed here are some common names used and their origins:

	R. cathartica	R. frangula
Brief description as I know them on our woodlot.	Small thorny tree, purple/brown shiny stem less invasive than R.frangula	Thicket with no thorns and gray bark, very invasive here on this woodlot.
Books:	Underlined = principle name used	b. = buckthorn
Shrubs of Ontario, Soper & Heimburger, Royal Ontario Museum ISBN 0-88854-283-6	Common b.	Glossy b.
Trees in Canada, Farrar ISBN 1-55041-199-3	European b. Common b. Purging b.	Glossy b. Alder b.
Trees of Ontario, 2001, Kershaw, Lone Pine ISBN 1-55105-274-1	European b. Common b. Purging b. European waythorn Hart's thorn Carolina b.	Glossy b. European alder-b. European Alder, Columnar b. Fen b. Arrow-wood Black dogwood.
Trees and Shrubs, 1972, Petrides ISBN 0-395-35370-X	Common b.	European b.
Websites:
http://en.wikipedia.org/wiki/Rhamnus_%28plant%29	Common b. Purging b.	Alder b.
http://www.ipaw.org/invaders/buckthorn/index.aspx	Common b.	European b.
http://www.treecanada.ca/tree-killers/plants.htm	Common b. European b.	Glossy b. Black b.

In conclusion, it seems that the name that is least confusing or most common in English for Rhamnus Cathartica is Common buckthorn and for Rhamnus frangula is Glossy buckthorn which I will endeavour to use from now on. I was inclined to use European buckthorn which really didn't help my situation as you will see from the list. Both buckthorns are imports from Europe and its adjacent continents so they both can be called European I suppose.