Mycorrhizal fungi are needed for germination and seedling establishment in orchids, so associations may be involved in determining hybridization between species. Jacquemyn et al. show that in three species of the genus Orchis (O. anthropophora, O. militaris and O. purpurea) seeds originating from hybrid crosses readily germinate in the field, and protocorms show overlap in mycorrhizal associations with their respective parents. Thus associations appear to contribute little to reproductive isolation in these species.
