The New Zealand Plant Conservation Network

Parasitic plants

Root parasite Euphrasia cuneata. Photographer: Brent Tandy.

Parasitic plants belong to about 19 families of flowering plants. The Viscaceous and Loranthaceous mistletoes comprise approximately three-quarters of all parasitic species. Several other families of parasitic flowering plants are also well known, especially the broomrapes (Orobanchaceae) and dodders (Cuscutaceae).

Parasitic plants have a modified root called the haustorium which penetrates the host plant and connects to the host's xylem and/or phloem.

• Leafy mistletoes
• Pygmy (leafless) mistletoes
• Root parasites
• Saprophytes

There are a number of terms associated with parasitism: 

• Root parasite: attaches to the host root.
• Holoparasite: completely parasitic on other plants and has virtually no chlorophyll.
• Hemi-parasite: parasitic but also photosynthesises itself. Obtains water and mineral nutrients and may obtain part of its organic nutrients from the host.
• Obligate parasites: cannot complete its life cycle without a host.
• Facultative parasite: can complete its life cycle independent of a host.
• Stem parasite: attaches to the host stem.

Ileostylus micranthus. Photo by Jeremy Rolfe.

For more information see*:

• Parasitic plant (Wikipedia)
• Plant pirates - some NZ parasitic plants by Miriam A. Aiken
• The Parasitic Plant Connection
• The Mistletoe Centre (US Forest Service)
• Parasitic plants of the world by Daniel Nickrent. Chapter 2, pp. 7-27 in: J. A. López-Sáez, P. Catalán and L. Sáez [eds.], Parasitic Plants of the
  Iberian Peninsula and Balearic Islands
• Parasitic Plants (UCLA)
• Parasitic Plants (Botanical Society of America)
• The International Parasitic Plant Society

*The Network is not responsible for the content of external internet sites

This page last updated on 25 Sep 2012