This Peony miniature sheet was issued in Mar.2010 showing Chinese tree peony (Paeonia suffruticosa) and European peony (Paeonia officinalis)
Paeonia suffruticosa, the tree peony, is a species of peony native to China. It is known as 牡丹 "mǔdān" in Chinese and is an important symbol in Chinese culture.
Paeonia officinalis, or European peony, Common peony, is the common peony cultivated in Europe for five hundred years. It was first used for medicinal purposes, then grown as an ornamental. Many selections are now used in horticulture, though the typical species is uncommon. Paeonia officinalis is still found wild in Europe.
Another nice Peony m/s of Croatia issued in same month is here.