These 4 species (Spotted Reptans, Citrus Reptans, Spotted Ball Cactus, Citrus Ball Cactus) cannot be created from any of the plants that you can breed from the seeds that you start the game with. In other words, if you don't already have, for example, a Spotted Reptans, you can't create one by breeding other species.
If you need any of these species and don't have them, the best chance to get one is to buy common seeds from the Supply Shop. You can get them by using Mutation Liquid on other plants, but that's expensive and requires luck.
The Citrus species can be bred once you can afford the Extinct Seeds from the Supply Shop, but (again) that's a very expensive option and also requires luck in getting the right seeds.
Actually, the Spotted Reptans can be a good plant... My favorite is Citrus Pitcher, but, that is like my 10th favorite (which doesn't seem so bad once I tell you there are a total of
plants on the game
) I like Spotted Reptans Because it can't be cross bred. I bought 37 Reptans seeds from the store and only ONE was spotted!
Is this bad luck or 1 in 30-ish is the chances of getting it?!?!
... oh yeah, I counted! LOL!