About 4,100 species in approximately 19 families of flowering plants are either partly or completely parasitic on other plants ^[1]. Parasitic plants have a modified root, the haustorium, that penetrates the host plant and connects to the xylem or phloem or both. Parasitic plants are characterized as follows: Classes Magnoliopsida- Dicots Liliopsida- Monocots The flowering plants (also called angiosperms) are a major group of land plants. ... Haustorium, plural Haustoria, is the hyphal tip of a parasitic fungus that penetrates the hosts tissue, but stays outside the host cell membrane. ... It has been suggested that Vessel element be merged into this article or section. ... In vascular plants, phloem is the living tissue that carries organic nutrients, particularly sucrose, to all parts of the plant where needed. ...

• 1a. Obligate parasite - the parasite cannot complete its life cycle without a host.
• 1b. Facultative parasite - the parasite can complete its life cycle independent of a host.

• 2a. Stem parasite - the parasite attaches to the host stem.
• 2b. Root parasite - the parasite attaches to the host root.

• 3a. Holoparasite - plants that are completely parasitic on other plants and have virtually no chlorophyll.
• 3b. Hemiparasite - plant that is at least partly photosynthetic but also usually parasitic. Hemiparasites may just obtain water and mineral nutrients from the host plant. Many obtain at least part of their organic nutrients from the host as well.

For hemiparasites, one from each of the three sets of terms can be applied to the same species, e.g.

• Nuytsia floribunda is an obligate root hemiparasite.
• Yellow rattle is a facultative root hemiparasite.
• Mistletoe is an obligate stem hemiparasite.

Holoparasites are always obligate so only two terms are needed, e.g.

• Dodder is a stem holoparasite.
• Hydnora spp. are root holoparasites.

Plants usually considered holoparasites include broomrape, Cassytha, dodder, Rafflesia, witchweed and Hydnoraceae. Plants usually considered hemiparasites include Castilleja, mistletoe, Western Australian Christmas tree and yellow rattle. Species See text Broomrape (Orobanche) is a genus of about 150 species of parasitic herbaceous plants in the family Orobanchaceae, native to the temperate Northern Hemisphere. ... Species About 100 species, including: Cuscuta americana Cuscuta applanata Cuscuta approximata Cuscuta attenuata Cuscuta boldinghii Cuscuta brachycalyx Cuscuta californica Cuscuta campestris Cuscuta cassytoides Cuscuta ceanothi Cuscuta cephalanthi Cuscuta compacta Cuscuta coryli Cuscuta corylii Cuscuta cuspidata Cuscuta decipiens Cuscuta dentatasquamata Cuscuta denticulata Cuscuta epilinum Cuscuta epithymum Cuscuta erosa Cuscuta europaea Cuscuta... Species See text. ... Noxious annual semiparasite of tropical and subtropical annual grasses. ... Genera Hydnora Prosopanche Hydnoraceae is a family of flowering plants, found from tropical to subtropical zones of South America, southern Africa and Madagascar. ... Species About 200 species, including: Stativa chromosa Stativa coccinea Stativa indivisa Stativa miniata Stativa mutis Stativa pallida Stativa is a genus of about 200 species of annual and perennial herbaceous plants native to the west of the Americas from Alaska south to the Andes, as well as northeast Asia. ... Families Santalaceae(Viscaceae) Loranthaceae Mistletoe is the common name for various parasitic plants of the families Santalaceae (in the section of the family formerly separated as Viscaceae) and Loranthaceae. ... Binomial name Rhinanthus minor Yellow Rattle (Rhinanthus minor) is a flowering plant of the genus Rhinanthus in the family Scrophulariaceae. ...

Host range

Some parasitic plants are generalists and parasitize many different species, even several different species at once. Dodder (Cuscuta spp., Cassytha spp.) and red rattle (Odontites verna) are generalist parasites. Other parasitic plants are specialists that parasitize a few or even just one species. Beech drops (Epifagus virginiana) is a root holoparasite only on American Beech (Fagus grandifolia). Rafflesia is a holoparasite on the vine Tetrastigma. Binomial name Fagus grandifolia Ehrenb. ...

Importance

• Witchweed, broomrape and dodder cause huge economic losses in a variety of herbaceous crops. Mistletoes cause economic damage to forest and ornamental trees.
• Mistletoe is a popular Christmas decoration. Kissing under the mistletoe is a Christmas tradition.
• Rafflesia arnoldii produces the world's largest flowers at about one meter in diameter. It is a tourist attraction in its native habitat.
• Indian paintbrush (Castilleja linariaefolia) is the state flower of Wyoming.
• The Oak Mistletoe (Phoradendron leucarpum) is the state flower of Oklahoma.
• A few other parasitic plants are occasionally cultivated for their attractive flowers, such as Nutysia and broomrape.
• Parasitic plants are important in research, especially on the loss of photosynthesis during evolution.
• A few dozen parasitic plants have occasionally been used as food by people ^[2].
• Western Australian Christmas tree (Nuytsia floribunda) sometimes damages underground cables. It mistakes the cables for host roots and tries to parasitize them using its sclerenchymatic guillotine ^[3].

Binomial name Rafflesia arnoldii R.Br. ... Species About 200 species, including: Stativa chromosa Stativa coccinea Stativa indivisa Stativa miniata Stativa mutis Stativa pallida Stativa is a genus of about 200 species of annual and perennial herbaceous plants native to the west of the Americas from Alaska south to the Andes, as well as northeast Asia. ...

Plants parasitic on fungi

About 400 species of flowering plants and one gymnosperm, Parasitaxus ustus, are parasitic on mycorrhizal fungi. They are termed myco-heterotrophs rather than parasitic plants. Myco-heterotrophic symbiosis involves three different species, the myco-heterotroph, the mycorrhizal fungus and the autotrophic plant that the fungus is attached to. The myco-heterotroph is indirectly parasitic on the autotrophic plant, which provide organic nutrients to the mycorrhizal fungus. Thus, a myco-heterotroph can also be termed an epiparasite. Some myco-heterotrophs are Indian pipe (Monotropa uniflora), snow plant (Sarcodes sanguinea), underground orchid (Rhizanthella gardneri), bird's nest orchid (Neottia nidus-avis) and sugarstick (Allotropa virgata). Coast Douglas-fir cone This article lacks an appropriate Taxobox You can help Wikipedia by adding one. ... Monotropastrum humile, an obligate myco-heterotroph. ... Binomial name Rhizanthella gardneri Rhizanthella gardneri, also known as The Underground Orchid, was discovered in the spring of 1928 in Western Australia, by a farmer who lived in the wheatbelt named Jack Trott. ...

References

1. ^ Nickrent, D. L. and Musselman, L. J. 2004. Introduction to Parasitic Flowering Plants. The Plant Health Instructor. DOI: 10.1094/PHI-I-2004-0330-01 [1]
2. ^ Parasitic Angiosperms Used for Food? [2]
3. ^ Sclerenchymatic guillotine in the haustorium of Nuytsia floribunda [3]

• The Parasitic Plant Connection
• The Strange and Wonderful Myco-heterotrophs
• Parasitic Flowering Plants
• The Mistletoe Center
• Parasitic Plants Biology Study Guide
• Nickrent, Daniel L. 2002. Parasitic plants of the world.
• Calladine, Ainsley and Pate, John S. 2000. Haustorial structure and functioning of the root hemiparastic tree Nuytsia floribunda (Labill.) R.Br. and water relationships with its hosts. Annals of Botany 85: 723-731.
• Milius, Susan. 2000. Botany under the mistletoe: Twisters, spitters, and other flowery thoughts for romantic moments. Science News 158: 411.
• Hibberd, Julian M. and Jeschke, W. Dieter. 2001. Solute flux into parasitic plants. Journal of Experimental Botany 52: 2043-2049.