Paeonia decomposita Hand.-Mazz. subsp. rotundiloba D. Y. Hong is here raised to the specific rank, P. rotundiloba (D. Y. Hong) D. Y. Hong, based on its distinctiveness of four diagnostic characters: number of carpels; height of disk; number of leaflets of the lower leaves, and shape of the terminal leaflets; and unpublished molecular data. Paeonia rotundiloba differs distinctly from P. decomposita in having carpels mostly 3, less often 2 or 4, very rarely 5 (vs. almost always 5, very occasionally 4 or 3), disk 8-15 mm high (vs. 4-9.6 mm), leaflets mostly 19-39 (vs. 29-63) in number, and ratio of length to width of the terminal leaflets 1.09-1.93 (vs. 1.81-2.99).