(iii) Holoparasites and Hemiparasites . Holoparasites are those which are completely host dependent like Rafflesia, Cuscuta. Hemiparasites receive only a part of the nourishment from the host, rest they manufacture by themselves e.g. Viscum, Loranthus.

(iv) Stem and Root Parasites. Plants parasites parasitic on stem are stem parasites (Cuscuta, Loranthus, Viscum) while those parasitic on root are root parasites (Rafflesia, root nematodes).

Sexual parasitism in the deep-sea angler fish. [Photocorynus spiniceps, in which the difficulty of one sex finding the other is met by permanent attachment of the much smaller male to the female. The union is so complete that the male has no independent existence at all, being nourished by the blood of the female to which he is attached].