Identifying a tree as a JM is like identifying a person as a human. We are all humans, but all have our own genetic variations. JMs are basically the same. There are some JMs that are viewed as "special" for one reason or another and these get a cultivar name that is then patented. All trees with that cultivar name have the same exact genetics. Another tree may look like a specific cultivar, but isn't that cultivar unless its a cutting or airlayer from the parent tree. If we can't identify the JM as a cultivar, its just a JM with whatever features it has. Attached is a JM I purchased this winter that I was told was a plain vanilla JM. Once the leaves opened, it was clear the tree looks different than my other plain vanilla JMs, but to me its just a plain vanilla JM because I don't know its genetics.