1a	From the Neotropics, parasitizing Salicaceae, tepals always in 3 whorls with (from the outside) 2, 4, and 4 tepals, the inner whorl easily deciduous, female flowers >5 mm long	1. Apodanthes caseariae
1b	From the Neotropics, Africa, Iran, or Australia, parasitizing Fabaceae, number of outer tepals usually >2, female flowers <5 mm long	2
2a	Occurring in Australia	3
2b	Not in Australia	5
3a	Tepals in 3 whorls	2. Pilostyles collina
3b	Tepals in 2 whorls	4
4a	Flower diameter >3 mm	3. Pilostyles hamiltonii
4b	Flower diameter <3 mm	4. Pilostyles coccoidea
5a	Occurring in Africa	5. Pilostyles aethiopica
5b	Not in Africa	6
6a	Occurring in Iran	6. Pilostyles haussknechtii
6b	Occurring in the America	7
7a	Tepals in 3 whorls, each with 2 to 7 tepals, anthers in 4 whorls (spiral), number of anther lobes >70, on Adesmia	7. Pilostyles berteroi
7b	Tepals in 3 whorls, each with 3 or 4 (rarely more) tepals, anthers in 2 or 3 whorls, number of anther lobes <70, not on Adesmia	8
8a	Middle tepals ovoid, on Calliandra, Dalea, Parosela or Psorothamnus, anthers in 3 whorls (at least if on Dalea, Parosela or Psorothamnus)	9
8b	Middle tepals mostly diamond-shaped, apparently never on Calliandra, Dalea, Parosela or Psorothamnus, anthers in 2 whorls (females of the three species cannot be securely distinguished)	8. Pilostyles blanchetii
9a	On Calliandra, tepals in 3 whorls, each with 4 tepals	9. Pilostyles mexicana
9b	On Dalea, Parosela, or Psorothamnus, tepals in 3 whorls, each with 3 or 4 tepals.	10. Pilostyles thurberi