Orchids have minute seeds and can disperse over long distances. Hedrén et al. use genetic markers to track how the marsh orchid Dactylorhiza
These multiple colonization events have resulted in a mosaic pattern of genetic variation, such that adjacent populations are not necessarily closely related. Hedrénet al. also find that the genetically most diverse populations are located at older sites, suggesting that genetic diversity builds up over time.
Hedrén, M., Olofsson, S. N., & Paun, O. (2018). Orchid colonization: multiple parallel dispersal events and mosaic genetic structure in Dactylorhiza majalis ssp. lapponica on the Baltic island of Gotland. Annals of Botany. https://doi.org/10.1093/aob/mcy111