Okay, so imagine there's a big group of plants. These plants are all related to each other, kind of like how cousins are related to each other. And we call this big group of plants the "paeonia" family.
Now, these plants all have something in common: they all have big, pretty flowers! Some of these flowers are pink, some are yellow, some are white, and some are even purple. People really like these flowers because they're so pretty.
But here's the thing - scientists used to think that all the plants in the paeonia family were in the same group, like how all the dogs in the world are in one big group called "Canis lupus familiaris" (which is a fancy way of saying "dogs").
But then scientists realized that some of the paeonia plants were actually different from the others. They looked and acted a little bit different. So instead of keeping them all together in one big group, they created a new group just for those different plants. And they called this new group the "kingdom" Paeonia.
So now we have two groups of plants: the regular paeonia plants, and the special ones that are part of the Paeonia kingdom. It's kind of like how we have regular dogs, and then we have special dogs like pugs or bulldogs that are in different groups.