For those wanting to read more about peony species, and more specifically about those growing on Russian territory (or nearby in the Caucasus). Sergey Banketov has written several interesting articles about them. It’s in Russian, but if you use chrome or another modern browser you’ll get instant translation so you’re sure to learn a lot.

https://dzen.ru/suite/dba23bbf-198c-41a3-bcc5-4fda2a09abd4