First, the plant in the picture looks like a Poncirus cultivar for sure, but it certainly does not look like Flying Dragon. Second, Flying Dragon is quite difficult to root, much more difficult than other citrus varieties,.

According to the nursery, FD was their rootstock. But who knows! It doesn't look particularly twisted, though the thorns do curve significantly.

Here's a closeup:

That doesn't surprise me at all..I've definitely read that FD is only partly nucellar. And in the nursery industry I am sure they don't really care what's true FD. Either way, I'd like to try grafting onto it or generating clones for grafting -- curious as to the best way to go about it.

That is water sprout flying dragon. It is good. The lack of zigzag is due to the abnormally fast growth.

Steve

IF it is indeed a water sprout (on FD ???) than It is not a true Flying Dragon cultivar. Non dwarfing.