You seem to be saying that if a cross has been made before crossing it
again will result in the same iris. This is not true. Every seedling
that comes from crossing two irises is a different and unique iris. No
matter how many times the cross is made, each seedling will be different.
Many of the seedlings will have similar characteristics, but will not be
identical. We have crossed a tan/brown iris with a blue-green iris and got
seedlings in a wide range of colors including tan, gold, greenish yellow,
plicata, red-violet, blue-violet, white/yellow, all with different color
beards. So, if you are buying two irises from the same cross, you are
buying two different irises.
Dorothy Willott, hybridizer and AIS judge