The present work is the first large-scale study of the in situ effects of high-tension power transmission lines on the natural flora species. The study focused on pollen mother cell meiosis, meiotic product, pollen fertility, and leaf anatomy. The test specimens showed significantly higher percentages of meiotic abnormalities. The mean meiotic abnormalities and mean percentages of sterile pollen grains showed strong positive correlation with the increase in voltage, but not with the strength of magnetic field. The leaf anatomy showed rather inconsistent results; however in majority of test specimens, wider vessels and thicker leaves were detected, suggesting a positive effect of high-tension lines. This in situ study has revealed that the genotoxic effects associated with high-tension transmission lines are not solely due to the EMF, but other factors associated with these lines like Ozone, NO,NO2 and UV radiation may in fact be more responsible. The high rates of meiotic abnormalities and pollen sterility due to genotoxic effects of high-tension lines indicate the risks not only to plant species in the natural and semi natural ecosystems; but other organisms are also at risk.