Key to the Genera of Rafflesiaceae

1Ovary superior, staminal structure a tube surrounding the pistil with a series of anthers above each other. Host plants in general Fagaceae
1'Ovary inferior or half-inferior, staminal structures different. Host plants species of Tetrastigma (Vitaceae)
2Mature flower buds oblong. Perigone without diaphragm, lobes 16-18, valvate, ending in bayonets (elongate stiff pointed appendages), which are hidden in a cavity at apex of the column while flowers are in the bud stage.
2'Mature buds more or less globular. Perigone with a diaphragm, the lobes imbricate, 5-10
3Perigone lobes 5; ramenta only inside the flower tube
3'Perigone lobes 10; ramenta on top of the diaphragm