Here is another reference which is indeed reliable, as a specialist in ancient roses from Normandie. 'Orderic Vital' was obtained in Caen. http://pagesperso-orange.fr/rosesdenormandie/villes.htm
I think the source of this discrepancy is that some contemporaneous, 19th century rose books also spelled the name as "Oderic" instead of "Orderic." I have finally found some very authoritative rose books with the correct spelling of the name of this famous 12th century medieval historian: O r d é r i c Vital.