Deb, I'm fairly certain that R. ulmifolius is thornless, but I see thorns on yours. Your photos look exactly like R. armeniacus, so I'll leave them in that entry and delete the photo in the R. ulmifolius entry.
As for R. discolor, it may have been a misnomer. It's now classified only as an ambiguous synonym, and for two separate species -- R. ulmifolius and R. rigidus, neither of which resembles your photos.