Phoradendron

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Phoradendron
Phoradendroncalifornicum2.jpg
Phoradendron californicum fruit
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Santalales
Family: Santalaceae
Genus: Phoradendron
Nutt. [1] [2]
Species

About 235-240 species; see text

Phoradendron distribution.png
Phoradendron distribution by state or province.
Synonyms
  • AllobiumMiers
  • SpiciviscumEngelm. [1]
Phoradendron strongyloclados showing leathery leaves and an inflorescence resulting from one apical meristem. Phoradendron strongyloclados Eichler (11176147665).jpg
Phoradendron strongyloclados showing leathery leaves and an inflorescence resulting from one apical meristem.
Phoradendron macrophylla in Arizona sycamore Phoradendronmacrophylla-azsyca.jpg
Phoradendron macrophylla in Arizona sycamore
Multiple Phoradendron individuals parasitizing an oak tree. While lower branches show new leaf growth, the mistletoe appears to be negatively affecting the tree's budding in the upper branches. Phoradendron nc oak.jpg
Multiple Phoradendron individuals parasitizing an oak tree. While lower branches show new leaf growth, the mistletoe appears to be negatively affecting the tree's budding in the upper branches.
Phoradendron californicum (Desert Mistletoe), Granite Mountains, Mojave Desert, California Phoradendron californicum 031611.jpg
Phoradendron californicum (Desert Mistletoe), Granite Mountains, Mojave Desert, California

Phoradendron is a genus of mistletoe, native to warm temperate and tropical regions of the Americas. The center of diversity is the Amazon rainforest. [3] Phoradendron is the largest genus of mistletoe in the Americas, and possibly the largest genus of mistletoes in the world. [4] Traditionally, the genus has been placed in the family Viscaceae, but recent genetic research acknowledged by the Angiosperm Phylogeny Group shows this family to be correctly placed within a larger circumscription of the sandalwood family, Santalaceae.

Contents

They are woody hemi-parasitic shrubs with branches 10–80 cm (3.9–31.5 in) long, which grow on other trees. The foliage is dichotomously branching, with opposite pairs of leaves; these are fairly large, 2–5 cm (0.79–1.97 in) long, green and photosynthetic in some species (e.g. P. leucarpum), but minimal in some others (e.g. P. californicum). Although they are able to photosynthesize the plant relies on its host for some nutrients. The plant draws its mineral and water needs, and some of its energy needs, from the host tree using a haustorium which grows into the stems of the host. [5]

The flowers are inconspicuous and incomplete, no petals and 3-4 greenish-yellow sepals, [6] 1–3 mm (0.039–0.118 in) diameter. The fruit is a berry, white, yellow, orange, or red when mature, containing one to several seeds embedded in very sticky juice, called viscin. [4] The flowers are unisexual, and depending on the species, the plant will be monoecious or dioecious (both male and female flowers on a single plant or male and female plants with only one sex of flowers). [4] The seeds are dispersed when birds eat the fruit and remove the sticky seeds from their bills by wiping them on tree branches where they can germinate.

The foliage and berries of some species are toxic. Leafy mistletoes seldom kill but they cause stress reducing crop productions in fruits and nut trees. [7]

Phoradendron plants can be distinguished from mistletoes in other genera in Viscaceae by their inflorescences, which lack leaves and come from a single branching point or apical meristem. [4] However, it can be difficult to identify species within Phoradendron, because leaf shape and color can vary greatly even within species. [6]

Phoradendron sp. on Spanish oak Phoradendron sp. on spanish oak.jpg
Phoradendron sp. on Spanish oak

Host and symptoms

Phoradendron species can infest many taxa of plants including hackberry (Celtis spp.) mesquite (Prosopsis spp.), cedar, elm (Ulmus spp.), and Osage-orange. [8] Certain species of Phoradendron are host-specific; for example, in Arizona, Phoradendron tomentosum infests cottonwood (Populus fremontii), sycamore (Platanus wrightii), ash (Fraxinus spp.), walnut (Juglans spp.) and willow (Salix spp.). [9] P. californicum infests shrubs and trees such as acacia (Acacia spp.) and blue palo verde (Parkinsonia florida). Some species infest junipers (Juniperus spp.) and oaks (Quercus spp.). [10] Branches often become swollen and distorted, forming burls and making the tree more susceptible to insect attack. [8] Phoradendron presents serious problems along rivers, streams, parks, and golf courses with large cottonwood trees. Deciduous trees can be mistaken for evergreens during the winter if infection is heavy. [10] Other common symptoms include swelling formations of witch's broom, dieback, and weakened branches. [11]

Life cycle

Phoradendron species are hemiparasites which produce their own chlorophyll but rely on the host plant to provide water, minerals, and other nutrients. [12] Birds are the primary means of dispersal of the parasite. [13] Birds consume the drupes of the mistletoe and excrete or regurgitate the seeds onto the branches of the host plant. The seeds do not need to be ingested to germinate. Germinating seeds produce a radicle, a holdfast, and eventually the germinated seeds produce haustoria. The haustorium is a root-like structure that penetrates the host plant's bark and cambium, reaching the xylem and phloem where it extracts water and minerals, primarily carbon and nitrogen compounds. A study on the nutrient ratio between Phoradendron and their hosts found that the parasite have higher concentrations of nitrogen and minerals, especially in leguminous hosts. This suggests that the parasite actively draws nutrients from the host plant through both the xylem and phloem, challenging the alternative theory of the passive uptake of nutrients by the parasite from the host xylem only. [14] The most important birds for effective dispersal include the cedar waxwing, euphonias, silky-flycatchers, bluebirds, and thrushes. [9]

Phoradendron caripense Flickr - Joao de Deus Medeiros - Phoradendron caripense (1).jpg
Phoradendron caripense

Management

Leafy mistletoe can adversely affect trees growing in urban environments and in forests. [12] It is considered a nuisance in urban environments because of its appearance on deciduous trees during winter. Severe colonization of mistletoe can affect the health of an individual tree, and a tree already stressed by other factors can be killed. Forest fragmentation can increase Phoradendron infection rates in some oak trees, as trees in lower density forests and those closer to the forests' edges are more likely to be colonized by the mistletoe. [15] Control and management regimes include watering the host plant to improve its vigor, and removing infested vegetation. Pruning infested branches is not generally effective because the haustoria can infiltrate deeply. Plucking the mistletoe herbage is a temporary treatment because it easily resprouts, but keeping its herbage sparse can help to reduce its seed production. [9]

Wildlife & human uses

Phoradendron species are larval host plants for a number of Lepidoptera. The buckthorn duskywing (Erynnis pacuvius) feeds on Phoradendron californicum. [16]

Phoradendron are the preferred food of the Phainopepla, a silky-flycatcher. The male defends territories where fruiting mistletoe is abundant. [17]

There may actually be some mutualistic interactions between the parasite and the host in some Phoradendron species. The presence of Phoradendron juniperinum on host Juniperusmonosperma, for example, has been suggested to increase dispersal of the host's seeds by birds. The mistletoe berries may attract frugivorous birds (e.g. thrushes) to eat the host juniper's seeds and disperse them. The net benefit on the hosts is difficult to quantify, however. The birds dispersing the host's seeds and benefiting the host, while at the same time dispersing the mistletoe's seeds and spreading the Phoradendron infection. [18]

Phoradendron californicum was used by Native American peoples as a food and medicinal remedy. [19]

Some Phoradendron species, such as Phoradendron serotinum and Phoradendron flavescens , are used in North America as Christmas decoration, substituting for the European mistletoe Viscum album . [20] They are harvested commercially for that purpose.

Etymology

Nuttall named the genus Phoradendron from the Greek, phor (a thief) and dendron (tree), alluding to the genus' parasitic habit. [2]

Taxonomy

There are roughly 235 [3] to 240 [21] species in the genus.

Species include: [22] [23] [24] [25]

Related Research Articles

<span class="mw-page-title-main">Mistletoe</span> Common name for various parasitic plants that grow on trees and shrubs

Mistletoe is the common name for obligate hemiparasitic plants in the order Santalales. They are attached to their host tree or shrub by a structure called the haustorium, through which they extract water and nutrients from the host plant.

<span class="mw-page-title-main">Santalaceae</span> Family of flowering plants

The Santalaceae, sandalwoods, are a widely distributed family of flowering plants which, like other members of Santalales, are partially parasitic on other plants. Its flowers are bisexual or, by abortion, unisexual. Modern treatments of the Santalaceae include the family Viscaceae (mistletoes), previously considered distinct.

<i>Arceuthobium</i> Genus of mistletoes

The genus Arceuthobium, commonly called dwarf mistletoes, is a genus of 26 species of parasitic plants that parasitize members of Pinaceae and Cupressaceae in North America, Central America, Asia, Europe, and Africa. Of the 42 species that have been recognized, 39 and 21 of these are endemic to North America and the United States, respectively. They all have very reduced shoots and leaves with the bulk of the plant living under the host's bark. Recently the number of species within the genus has been reduced to 26 as a result of more detailed genetic analysis.

<i>Viscum album</i> Flowering plant in the mistletoe family Santalaceae

Viscum album is a species of mistletoe in the family Santalaceae, commonly known as European mistletoe, common mistletoe or simply as mistletoe. It is native to Europe and western and southern Asia.

<span class="mw-page-title-main">Parasitic plant</span> Type of plant that derives some or all of its nutritional requirements from another living plant

A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the haustorium, which penetrates the host plant, connecting them to the host vasculature – either the xylem, phloem, or both. For example, plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like Cuscuta and some members of Orobanche connect to both the xylem and phloem of the host. This provides them with the ability to extract resources from the host. These resources can include water, nitrogen, carbon and/or sugars. Parasitic plants are classified depending on the location where the parasitic plant latches onto the host, the amount of nutrients it requires, and their photosynthetic capability. Some parasitic plants can locate their host plants by detecting volatile chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plants in approximately 20 families of flowering plants are known.

<i>Phoradendron leucarpum</i> Species of flowering plant

Phoradendron leucarpum is a species of mistletoe in the Viscaceae family which is native to the United States and Mexico. Its common names include American mistletoe, eastern mistletoe, hairy mistletoe and oak mistletoe. It is native to Mexico and the continental United States. It is hemiparasitic, living in the branches of trees. The berries are white and 3–6 millimeters (0.12–0.24 in). It has opposite leaves that are leathery and thick. Ingesting the berries can cause "stomach and intestinal irritation with diarrhea, lowered blood pressure, and slow pulse". This shrub can grow to 1 meter (3.3 ft) by 1 meter (3.3 ft).

<i>Arceuthobium douglasii</i> Species of dwarf mistletoe

Arceuthobium douglasii is a species of dwarf mistletoe known as Douglas fir dwarf mistletoe. It is native to western North America from British Columbia to Texas to California, where it lives in forest and woodland as a parasite. It is found mostly on Douglas fir trees, but occasionally on fir, as well.

<i>Phoradendron californicum</i> Species of flowering plant

Phoradendron californicum, the desert mistletoe or mesquite mistletoe, is a hemiparasitic plant native to southern California, Nevada, Arizona, Sonora, Sinaloa and Baja California. It can be found in the Mojave and Sonoran Deserts at elevations of up to 1400 m.

<i>Phoradendron densum</i> Species of tree

Phoradendron densum Trel. is a species of flowering plant in the sandalwood family known by the common name dense mistletoe. It is native to the western United States and northwestern Mexico, where it grows in various types of woodland habitat. It has been reported from California, Oregon, Arizona and Baja California. This mistletoe parasitizes species of cypress, including Arizona cypress, and juniper.

<i>Phoradendron juniperinum</i> Species of flowering plant

Phoradendron juniperinum is a species of flowering plant in the sandalwood family known by the common name juniper mistletoe. It is native to the southwestern United States and northern Mexico, where it grows in various types of woodland habitat. It has been reported from California, Nevada, Arizona, New Mexico, Oregon, Utah, Texas, Chihuahua and Sonora.

Phoradendron libocedri is a species of flowering plant in the sandalwood family known by the common name incense-cedar mistletoe. It is native to western North America from Oregon to Baja California, where it grows in forests on its host tree, the California incense-cedar.

<i>Phoradendron macrophyllum</i> Species of flowering plant

Phoradendron macrophyllum is a species of flowering plant in the sandalwood family known by the common names Colorado Desert mistletoe, bigleaf mistletoe, and Christmas mistletoe. It is native to western United States and northern Mexico from Oregon to Colorado to Texas to Baja California, where it grows in many types of wooded habitat at elevations up to 1700 m.

<i>Phoradendron pauciflorum</i> Species of flowering plant

Phoradendron pauciflorum is a species of flowering plant in the sandalwood family known by the common name fir mistletoe. It is native to coniferous forests in California, Arizona, and Baja California.

<i>Dendropemon</i> Genus of mistletoes

Dendropemon is a genus of mistletoes which is endemic to the Caribbean. Members of the genus are hemi-parasites which normally grow on trees and shrubs, although self-parasitism is known to occur. The approximately 31 species range from The Bahamas and Cuba in the north and west, to Barbados and St. Vincent in the southwest. Diversity and endemism is highest on the island of Hispaniola.

<i>Phoradendron tomentosum</i> Species of mistletoe

Phoradendron tomentosum, the leafy mistletoe, hairy mistletoe or Christmas mistletoe, is a plant parasite. It is characterized by its larger leaves and smaller berries than dwarf mistletoe. Leafy mistletoe seldom kill but they do rob their hosts of moisture and some minerals, causing stress during drought and reducing crop productions on fruit and nut trees. Leafy mistletoe has the ability to photosynthesize on its own but it relies on other plants in order to obtain its nutrients. It attaches itself to a tree and then grows haustoria, in order to get the food and water it needs.

<i>Arceuthobium pusillum</i> Species of dwarf mistletoe

Arceuthobium pusillum is a perennial, obligate parasitic plant in the sandalwood family. Its common names include Dwarf mistletoe or Eastern dwarf mistletoe. It is one of the most widespread dwarf mistletoes within its range which covers the eastern United States and Canada, from Saskatchewan to Nova Scotia and New Jersey. The species name "pusillum" derives from Latin "pusillus", meaning very small.

<span class="mw-page-title-main">Daniel Lee Nickrent</span>

Daniel Lee Nickrent is an American botanist, working in plant evolutionary biology, including the subdisciplines of genomics, phylogenetics, systematics, population genetics, and taxonomy. A major focus has been parasitic flowering plants, particularly of the sandalwood order (Santalales). His interest in photographic documentation and photographic databases has led to several photographic databases including Parasitic Plant Connection, Phytoimages, Plant Checklist for the Rocky Mountain National Park, and Plant Checklist for the Crab Orchard National Wildlife Refuge.

<i>Dendrophthora</i> Genus of mistletoes

Dendrophthora, the tree destroyers, is a genus of flowering plants in the sandalwood family Santalaceae, native to tropical and subtropical Latin America and the Caribbean. They are hemiparasitic mistletoes that grow on a wide variety of host plants.

Phoratoxins are a group of peptide toxins that belong to the family of thionins, a subdivision of small plant toxins. Phoratoxins are proteins present in the leaves and branches of the Phoradendron, commonly known as the American variant of the mistletoe, a plant commonly used as decoration during the festive season. The berries of the mistletoe do not contain phoratoxins, making them less toxic compared to other parts of the plant. The toxicity of the mistletoe is dependent on the host tree, since mistletoe is known to be a semi-parasite. The host tree provides fixed inorganic nitrogen compounds necessary for the mistletoe to synthesize phoratoxins.

References

  1. 1 2 "Genus: Phoradendron Nutt". Germplasm Resources Information Network. United States Department of Agriculture. 2010-08-25. Archived from the original on 2012-10-10. Retrieved 2011-03-08.
  2. 1 2 Nuttall, T. 1848. Journal of the Academy of Natural Sciences of Philadelphia ser. 2, 1 185.
  3. 1 2 Coder, K. D. American mistletoe (Phoradendron serotinum var. serotinum) infection in trees. WSFNR08-25. Tree Health Series. University of Georgia. 2008.
  4. 1 2 3 4 Kujit, Job (2003). "Monograph of Phoradendron (Viscaceae)". Systematic Botany Monographs. 66: 1–643. doi:10.2307/25011253. JSTOR   25011253.
  5. ↑ Hiller, J. B. (2010). Marvelling at mistletoe. Highlights for Children. 65(12) 40-41.
  6. 1 2 Kellogg, Elizabeth A. (1991). "Why Study Mistletoes?". Arnoldia. 51 (3): 11–17. JSTOR   42954407.
  7. ↑ Krautwurst, T. (2003) The truth about mistletoe. Mother Earth News 195 26-29.
  8. 1 2 Turner, M. W. Remarkable Plants of Texas: Uncommon Accounts of our Common Natives. University of Texas Press. 2009. pg. 261.
  9. 1 2 3 Geils, B. W., et al. Mistletoes of North American conifers. Gen. Tech. Rep. RMRS-GTR-98. Ogden, Utah: USDA, Forest Service, Rocky Mountain Research Station. 2002.
  10. 1 2 Hine, R. Diseases of Urban Plants. Adapted by M. Olsen. Plant Disease Publications. University of Arizona Cooperative Extension. Revised 1999.
  11. ↑ Call, R. E. Mistletoe. Archived 2010-07-26 at the Wayback Machine Home Horticulture. University of Arizona Cooperative Extension, Cochise County.
  12. 1 2 Watson, W. T. and T. Martinez-Trinidad. (2006). Strategies and treatments for leafy mistletoe (Phoradendron tomentosum (DC.) Engelm ex. Gray) suppression on cedar elm (Ulmus crassifolia Nutt.). Arboriculture and Urban Forestry 32(6) 265-70.
  13. ↑ Aukema, J. E. (2004). Distribution and dispersal of desert mistletoe is scale-dependent, hierarchically nested. Ecography 27 137-44.
  14. ↑ Panvini, A. Darlene; Eickmeier, William G. (1993). "Nutrient and Water Relations of the Mistletoe Phoradendron leucarpum (Viscaceae): How Tightly are they Integrated?". American Journal of Botany. 80 (8): 872–878. doi:10.1002/j.1537-2197.1993.tb15307.x. JSTOR   2445506.
  15. ↑ Barbosa, Jomar M.; Sebastián-González, Esther (2016). "Hemiparasite--host plant interactions in a fragmented landscape assessed via imaging spectroscopy and LiDAR". Ecological Applications. 26 (1): 55–66. doi:10.1890/14-2429. JSTOR   24701220. PMID   27039509.
  16. ↑ Soule, J. A. Butterfly Gardening in Southern Arizona. Tierra del Sol Institute. Tucson, Arizona. 2012. ISBN   0-9758554-3-3
  17. ↑ Soule, J. A. Father Kino's Herbs: Growing Them & Using Them Today. Tierra del Sol Institute. Tucson, Arizona. 2010. ISBN   0-9758554-2-5
  18. ↑ van Ommeren, Ron J. (January 1, 2002). "Changes in interactions between juniper and mistletoe mediated by shared avian frugivores: parasitism to potential mutualism". Oecologia. 130 (2): 281–288. Bibcode:2002Oecol.130..281V. doi:10.1007/s004420100792. PMID   28547152. S2CID   31003727.
  19. ↑ Phoradendron californicum. Native American Ethnobotany. University of Michigan, Dearborn.
  20. ↑ Solomon, J. D., et al. Ash pests: A guide to major insects, diseases, air pollution injury and chemical injury. Gen. Tech. Rep. SO-96. New Orleans, Louisiana. USDA Forest Service, Southern Forest Experiment Station. 1993.
  21. ↑ Phoradendron. The Jepson Manual eFlora 2012.
  22. ↑ "GRIN Species Records of Phoradendron". Germplasm Resources Information Network. United States Department of Agriculture. Retrieved 2011-03-08.
  23. ↑ "Phoradendron". Integrated Taxonomic Information System . Retrieved 2011-03-08.
  24. ↑ Phoradendron. Bolivia Checklist. eFloras.org
  25. ↑ "Phoradendron Nutt. | Plants of the World Online | Kew Science". Plants of the World Online. Retrieved 2019-12-03.
  26. ↑ Wiens, D. and C. L. Calvin. (2011). Two epiparasitic species of Phoradendron (Viscaceae) from Honduras: one new and for the other a range extension and host determination. Aliso 29(2) 119-23.
  27. ↑ Kuijt, J. (1997). Phoradendron olae Kuijt, a new species from Mexico pivotal in the taxonomy of the genus, with comments on P. californicum Nutt. Brittonia 49(2), 181-88.
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