Wait until they learn about nightshade
The nightshades are at least different species. Their vascular system and general physiology is similar enough that your can graft a potato, tomato, pepper, and tobacco plant together for a full meal and after dinner smoke, but they won’t really breed. Cabbage and broccoli can and will cross pollinate.
Don’t forget canola.
wait turnips are a brassica too? :O
It’s not brassica oleracea though, it’s a different species, brassica rapa. The same species as napa cabbage, brocolli rabe, and bok choy. Rutabaga is actually a hybrid of the two species.
The main reason for there being so many varieties is that at some point in the past the plants genome tripled. With three copies of the genome not only was there a higher chance of mutation but a mutation didn’t deleted the original dna segment as it was in the other copies.
