Paeonia rockii
 Rock's peony or Rock's tree peony (Paeonia rockii also Paeonia suffruticosa subsp. rockii) is a woody species of peony that was named after Joseph Rock. It is one of several species given the vernacular name tree peony and is native to the mountains of Gansu and adjoining provinces. In Chinese it is known as 牡丹 (pinyin: mǔdān) and its flower is called 牡丹花 (pinyin: mǔdān huā). It became the unofficial national flower of China following a nationwide referendum in 1994.