Hi Sookey, I think what you are thinking of is plant patents which make it illegal to asexually propagate certain plants (this means cuttings, grafting, tissue culture, etc). And it's not just illegal to sell them, it's illegal to propagate them that way at all, even for your own use (although I doubt the company that owns the patent is going to have time to search everyone' backyard so you're not as likely to get caught if you're not selling them!) Not all JM's are patented, but even for those that are, plant patents don't forbid propagation by seed, because any seedlings you get will not be genetically identical to the parent, and the patent only covers things that are genetically identical (cuttings, tissue culture, and grafting all give you things that are genetically identical).
So you can sell your seedlings, but I would be careful what you call them...for example, if your original plant that you got the seeds from was a cultivar called 'Maple Syrup', you can't call the seedlings 'Maple Syrup' because as I said before, seedlings aren't genetically identical to the parent plant (and can often grow up to look very different). You can tell people that 'Maple Syrup' was the parent, but make sure you're up front with people that the seedlings are not going to exactly be 'Maple Syrup', that way you're less likely to have people mad at you if the baby grows up to look different.
Thanks for the info. I thought that might be the case and I certainly don't want the "Plant Police" knocking on my garden gate. I will be sure to let any prospective customers know that these seeds may not be true to the parent. Thanks agin.
Here's a little information that might be relevant to this topic. The state of Arizona prohibits the shipment of morning glory seeds into the state. Not sure if the law applies to seedlings, but might be worth looking into if that's a potential destination.
I think Arizona's rules about morning glories probably are because of their invasiveness, other states have similar rules prohibiting seeds/plants that are invasive in that area. There are also sometimes restrictions in some areas based on diseases that can be carried by certain plants (or by plants grown in certain areas). I don't think Japanese maples are considered invasive anywhere or are carriers of diseases so I wouldn't think they would be subject to any restrictions like that, but it definitely doesn't hurt to check.