You have misunderstood. The data stand, with only an occasional possible exception. There are dozens, probably hundreds of similar examples, especially among plants where regional differences tend to multiply more easily. Not all are rings, some are clinal.
Odds are that the source was a creative interpretation by literal creationists.
Actually, it was by a pro-evolutionist. I think there are intellectually honest evolutionists, even if I disagree with their conclusions.