Abstract: Micro-morphology characteristics of ten species，one variation and one outgroup species of Iris were studied, also discussing the relationship between the micro-morphology of seed surfaces and the evolution of Iris. The results showed that seed coat micro-morphology had the stable characteristics, which was not relative to the distribution zone.The characteristics of concave and convex surface micro-morphology of a species were different significantly. Therefore, we should choose the same spot of the seeds for comparison observation. All of species were reticulate grain(reticulate grain or negative net grain). Micro-morphology characteristics can be used to classify genus and series of genus, but not for variations. The characteristics of micro-morphology of seed surfaces were very important for classification and systemic evolution of Iris.

Key words: Iris, seed coat, micro morphology