Jon, I think the order you discover the plants totally depends on how you combine the seeds....no game will be the same, as you always get different seeds to start with....don't you?
I haven't spent a lot of time playing PT so far, but see that other seasoned users have two trains of thoughts. SOme track their plants through spreadsheets, so remembering how to get certain plants, and others seem to have enough luck just breeding with no plan
Savi