Species and what to know as you buy them?

[Roberta]

If a 3N occurs in nature (a chance 4N mating with a normal 2N) it likely would be the end of the line for the genetics of that 4N plant since 3Ns are usually sterile. (The offspring won't breed) To get a chance natural 4N crossing with another chance natural 4N (to have 4N offspring) you'd have to win the genetic lottery twice... odds extremely low. So those natural 4N's will tend to stay rare and natural 3Ns equally rare.

When humans manipulate the ploidy, of course having a 4N x 4N is much more common, something that breeders do by plan, and production of 3Ns also by plan.