Epilobium Linnaeus (1753: 347) is known as a complex genus with about 200 species showing disparity in almost all features like morphology, anatomy, cytology, pollen, and ecology. In a search for taxonomically important and effective characteristics, we studied seed and pollen micromorphological features of 18 Epilobium species occurring in Iran. We also tried to shed light on these traits’ evolution and changes over a phylogenetic tree. Clustering showed that these features are of taxonomic value and can be used in species differentiation. PCA identified discriminating characteristics, while character mapping and morphospace plots identified characteristics involved in Epilobiumspeciation. The rates of change in different features varied in the studied species, however many changes observed were associated with environmental coordinates.