In order to discuss the relationship among the wild herbaceous peonies native in China according to microscopic characteristics, the pollen grains of four wild herbaceous peonies were examined under scanning electron microscope (SEM), and the data acquired were used in clustering analysis. The result with SEM showed distinctly distinguishing extine surface pattern of taxonomic importance among the four species: reticulate pattern for Paeonia lactiflora; micro-foveolate, regulate and regulate-foveolate pattern for P. veitchii ; regulate and subcerebro-reticulate pattern for P. obovata ; regulate pattern for P. anomala var. intermedia . The result with clustering analysis suggested the close relationship between P. veitchii and P. anomala var. intermedia for their Euclidean distance was only 2.51, and the alienation between P. lactiflora and the other three species for their Euclidean distances were all more than 5.00. In addition, we deduced P. obovata may be the linkage between subsect Foliolatae and subsect Dissectifoliae for its pollen morphology was appreciably inclined to P. veitchii and P. anomala var. intermedia.
