ABSTRACT
Parasitic plants are found in different plant families that are not related to each other. However, within the subclass of Rosidae and the order of Santalales, there is a group of plant families that contains a large number of species with a parasitic or hemiparasitic life style. The genus Viscum has been grouped earlier in the family Loranthaceae but it is now widely accepted to establish two different families, the Loranthaceae and the Viscaceae (Calder 1983). The major features distinguishing the two families are listed in a table by Calder (1983). According to this, the main macroscopic difference is that Loranthaceae have larger flowers that are bright coloured and represent both sexes, whereas the latter is monoecious and highly reduced. The family Viscaceae sens. str. comprises seven genera with approximately 400 species (Barlow 1983): Arceuthobium, Ginalloa, Notothixus, Korthalsella, Phoradendron, Dendrophthora, Viscum.
