The systematics of the worldwide endoparasite family Apodanthaceae (Cucurbitales), with a key, a map, and color photos of most species

Using morphological, nuclear, and mitochondrial data, we here revise the taxonomy of Apodanthaceae and allocate the 36 names published in the family to ten biological species in two genera, Apodanthes and Pilostyles. All species are endo-parasites that live permanently inside trees or shrubs of the families Salicaceae or Fabaceae and that only emerge to flower. Because of this life history, Apodanthaceae are among the least known families of flowering plants. Nevertheless, the World's herbaria as of 2013 hold at least 785 collections that, in combination with DNA phylogenies, permit well-founded species circumscriptions and geographic range maps. We also provide a key to all species, discuss the newly accepted or synonymized names, and make available color photos of six of the ten species.