In 2013 we surveyed 116 plots under electricity pylons and 116 reference plots. The basal areas of pylons were 6 m², 21 m² or 32 m². Plots under pylons had higher total numbers of species than reference plots, with grassland plots as an exception. Herbaceous species occurring exclusively within pylon plots were more numerous than those exclusively in reference plots (with the exception of grassland). Pylon plots also had a higher Shannon's diversity index (H′) of herbaceous plant species, again with the exception of grassland plots. Species number and H′ increased with increasing plot area under pylons among cereal and maize fields. A different trend was recorded in grassland; with increasing plot size the differences in species richness and diversity between pylon and reference plots became less distinct. Regardless of plot area, the Jaccard index was usually low and did not exceed a value of 0.20. It may be concluded that electricity pylons act as refuges for many plant species, which makes them biodiversity hotspots in farmland. Species richness and diversity under pylons differs markedly from those of nearby farmland. Such vegetation patches under electricity pylons form a substantial network of floristically diverse refuges within an unfavourable matrix.