Abstract: Pollen morphology of 12 species in Iris was investigated under scanning electron microscope in this study. The results showed that：（1）Except the width of spine，the shape and size of pollen grains，shape of aperture，extine sculpture of I. lactea and I. lactea var. chinensis were similar；（2）The shape of pollen grains，extine sculpture and width of spine of I. leptophylla，I. sichuanensis and I. goniocarpa were highly approximate and no aperture was found among the three species. The pollen grain of I. goniocarpa was smaller than those of I. leptophylla and I. sichuanensis；（3）Pollen of I. japonica and I. confusa had similar size and shape，and no grains existed in the meshes of these two species. The shape of pollen grains in I. japonica was suboblate while that in I. confusa was subspheroidal；（4）I. wattii was distinctly different from I. japonica and I. confusa in pollen size and exine ornamentation，suggesting that I. wattii had relatively distant relationship with I. japonica and I. confusa.

Key words: Iris, pollen morphology, relationship, systematic signification