''Phoradendron californicum'', the desert mistletoe or mesquite mistletoe, is a

hemiparasitic 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 ...

plant native to southern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...

Sinaloa Sinaloa (), officially the (), is one of the 31 states which, along with Mexico City, compose the Federal Entities of Mexico. It is divided into 18 municipalities, and its capital city is Culiacán Rosales. It is located in northwest Mexic ...

and

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

. It can be found in the Mojave and

Sonoran Desert The Sonoran Desert () is a hot desert and ecoregion in North America that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the Southwestern United States (in Arizona and California). It ...

s at elevations of up to 1400 m (4600 feet). The mistletoe is a leafless plant that attaches to host plants, often

leguminous Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

woody desert trees such as '' Cercidium'' and ''

Prosopis ''Prosopis'' is a genus of flowering plants in the family Fabaceae. The current circumscription of the genus contains three species found in northern Africa, the Middle East, Central and South Asia. Previously it also contained around 40 species ...

''.Spurrier, S., Smith, K.G. (2006). Desert mistletoe (''Phoradendron californicum'') infestation correlates with blue palo verde (''Cercidium floridum'') mortality during a severe drought in the Mojave Desert. ''Journal of Arid Environments''. 69, 189-197. Desert mistletoe takes water and minerals from its host plants but it does its own

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

, making it a hemiparasite. Desert mistletoes, like mistletoes in general, weave nutrient cycles together through their unique life history.

Human Use

Common names include visco, tojí, tzavo, secapalo, injerto, and chili de espino in Spanish; aaxt in Seri.Soule, J. A. 2010. Father Kino's Herbs: Growing Them & Using Them Today. Tierra del Sol Institute. Tucson, AZ. The white to reddish fruits are edible, but native tribes ate only the fruits of mistletoes growing on

mesquite Mesquite is a common name for some plants in the genera ''Neltuma'' and '' Strombocarpa'', which contain over 50 species of spiny, deep-rooted leguminous shrubs and small trees. They are native to dry areas in the Americas. Until 2022, these ge ...

(''Prosopis''), ironwood (''

Olneya ''Olneya tesota'' is a perennial flowering tree of the family Fabaceae, legumes (peas, beans, etc.), which is commonly known as ironwood, desert ironwood, or palo fierro in Spanish. It is the only species in the monotypic genus ''Olneya''. This t ...

tesota'') or catclaw acacia (''

Acacia greggii ''Senegalia greggii'', formerly known as ''Acacia greggii'', is a species of tree in the genus ''Senegalia'' native to the southwestern United States and northern Mexico, from the extreme south of Utah south through southern Nevada, southeast Cal ...

''). Found growing on palo verdes (''

Parkinsonia ''Parkinsonia'' , also ''Cercidium'' , is a genus of flowering plants in the pea family, Fabaceae. It contains about 12 species that are native to semi-desert regions of Africa and the Americas. The name of the genus honors Kingdom of England, ...

'') or ''

Condalia ''Condalia'' is a genus of Thorns, spines, and prickles, spiny shrubs in the Tribe (biology), tribe Rhamneae of the buckthorn family, Rhamnaceae. It was named for Antonio Condal, an 18th century Spain, Spanish physician. Members of the genus are ...

'' (desert buckthorn) the fruits are considered inedible. The

Seri people The Seri or ''Comcaac'' people are an Indigenous group of the Mexican state of Sonora. The majority reside on the Seri communal property (), in the towns of Punta Chueca () and El Desemboque () on the mainland coast of the Gulf of California ...

consider desert mistletoe fruit ripe and harvestable once it turns translucent. Harvest is done by spreading a blanket below the plant and hitting it with sticks to release the fruit. Seri consumed the fruit raw. The Tohono O'odham also consumed the fruit raw. River Pima ate the fruit boiled and mashed, which made it the consistency of a pudding. The Cahuilla gathered the fruits November through April and boiled them into a paste with a sprinkle of wood ash added to the pot. Desert mistletoe plants, but not the berries, contain phoratoxins which can easily lead to death via slowed heart rate, increased blood pressure,

convulsions A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is often used as a synony ...

, or

cardiac arrest Cardiac arrest (also known as sudden cardiac arrest CA is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly Circulatory system, circulate around the body and the blood flow to the ...

. Some of these compounds can cause hallucinations, but there is no way to judge dosage. People seeking a "high" from mistletoe still turn up in morgues each year. Native peoples used plants other than desert mistletoe to seek visions. Amateur entrepreneurs in Tucson, Phoenix and other cities in the

frequently sell cuttings of desert mistletoe on street corners during the Christmas season. This is despite the fact that the species looks very different from other mistletoes traditionally used as holiday decorations elsewhere.

Pollination

Desert mistletoes are

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

and rely on insects for

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

. They produce inconspicuous, fragrant flowers during the winter. A February 2015 inventory observed 13 species of

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...

and 3 species of

Hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typi ...

observed on the female flowers of ''P. californicum'' in the catclaw acacias (''

'') of the

Eldorado Mountains The Eldorado Mountains, also called the El Dorado Mountains, are a north-south trending mountain range in southeast Nevada bordering west of the south-flowing Colorado River; the endorheic Eldorado Valley borders the range to the west, and the ra ...

in the southern

Mojave desert The Mojave Desert (; ; ) is a desert in the rain shadow of the southern Sierra Nevada mountains and Transverse Ranges in the Southwestern United States. Named for the Indigenous peoples of the Americas, indigenous Mohave people, it is located pr ...

. The most abundant pollinator was the fruit fly '' Euarestoides acutangulus,'' followed by the blowfly ''

Phormia regina ''Phormia regina'', the black blow fly, belongs to the blow fly family Calliphoridae and was first described by Johann Wilhelm Meigen. The black blow fly's wings are specialized with a sharp bend. These flies also have well-developed calypters. ...

'' then the

hover fly Hoverflies, also called flower flies or syrphids, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the l ...

'' Eupeodes volucris.''

Dispersal

Female desert mistletoe plants produce red to clear

berries A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone fruit, stone or pit (fruit), pit although many wikt:pip#Etymology 2, pips or seeds may be p ...

that are eaten by the

phainopepla The phainopepla or northern phainopepla (''Phainopepla nitens'') is the most northerly representative of the mainly tropical Central American family Ptiliogonatidae, the silky flycatchers. Its name is from the Greek meaning "shining robe" in r ...

(''Phainopepla nitens''), a

silky flycatcher The silky-flycatchers are a small family, Ptiliogonatidae, of passerine birds. The family contains only four species in three genera. They were formerly lumped with waxwings and hypocolius in the family Bombycillidae, and they are listed in that ...

, which then spreads the seeds. Phainopeplas cannot digest the seed of desert mistletoe, so the birds disperse the seeds when they defecate or wipe their bills. The phainopepla is a specialist dispersal agent of desert mistletoe. A dispersal survey observed phainapepla's were most common bird eating mistletoe berries, followed by the

Northern mockingbird The northern mockingbird (''Mimus polyglottos'') is a mockingbird commonly found in North America, of the family Mimidae. The species is also found in some parts of the Caribbean, as well as on the Hawaiian Islands. It is typically a permanent B ...

and Gila woodpeckers. The study noted that Phainopepla's are the most effective agent because they spend the majority of their time in host plants, while the mockingbird and woodpecker are generalists that do not spend as much time in the host plants.

Host Specialization

There is evidence to suggest that ''P. californicum'' is undergoing "host race evolution", which is a pattern of evolution which, in parasitic plants, results from specialization of different populations of the same parasite species to different hosts in an environment. Host race evolution can possibly lead to

speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...

over time. There are genetic, morphological, and phenological differences in ''P. californicum'' individuals depending on the particular host on which they are found. Isoenzymes are enzymes that perform the same phenotypic function, but vary genetically between individuals of the same species. Electrophoresis analysis has shown that isoenzymes differ significantly between ''P. californicum'' found on

catclaw acacia ''Senegalia greggii'', formerly known as ''Acacia greggii'', is a species of tree in the genus ''Senegalia'' native to the southwestern United States and northern Mexico, from the extreme south of Utah south through southern Nevada, southeast Cal ...

(''A. greggii'') and

honey mesquite ''Neltuma glandulosa'', formerly ''Prosopis glandulosa'', commonly known as honey mesquite, is a species of small to medium-sized, thorny shrub or tree in the legume family (Fabaceae). Distribution The plant is primarily native to the Southwes ...

(''N. glandulosa''), which are two common hosts that geographically co-concur. Another study utilized microsatellite comparisons for mistletoe populations growing on catclaw acacia and velvet mesquite (''P. velutina''), finding significant variation between populations depending on host, and very few instances of heterozygosity in individual mistletoes. This research suggests that mistletoe species growing on different hosts are experiencing some amount of genetic isolation, which may be contributing to their differentiation. Morphologically, there are some recorded differences in physical characteristics between ''P. californicum'' individuals collected on various hosts. Internode length, berry color, and main/lateral shoot diameter ratio were shown to vary on average between mistletoes collected from catclaw acacia compared to honey mesquite. Phenologically, the timing of mistletoe growth checkpoints appears to depend somewhat on the host it is growing on. Mistletoe growing on catclaw acacia were shown to flower about one month before mistletoe growing on velvet mesquite, even within a similar geographic area. Additionally, various species of pollinators showed consistency in the hosts of the mistletoe they visited, suggesting a level of pre-zygotic isolation between host-specialized mistletoe populations. Overall, the specific driver of host specialization in ''P. californicum'' is still unknown, but there is evidence to support dispersal bird behavior, pollinator preferences, and host defenses/signals as possible factors based on research on both P. californicum and other mistletoe species. Interestingly, there is also evidence against climate change and geographic isolation as drivers of host race evolution in both ''P. californicum'' and other mistletoe species.

Gallery

File:Phoradendron californicum 031611.jpg, Desert mistletoe in the Mojave Desert of southern California. File:Desert Mistletoe Palo Verde Tree Silver Bell Arizona.jpg, A palo verde tree with desert mistletoe in Arizona's Sonoran Desert. File:Desert Mistletoe Mesquite Tree Sahuarita Arizona 2014.jpg, A mesquite tree with desert mistletoe in the Sonoran Desert. File:Desert Mistletoe Mesquite Tree Arizona 2014.jpg, Close-up view of desert mistletoe. File:Phainopepla, Santa Rosa and San Jacinto Mountains National Monument, Mountain Center, CA, US imported from iNaturalist photo 455694524.jpg, Phainopepla with feces

References

*Bowers, Janice and Brian Wignall. ''Shrubs and Trees of the Southwest Deserts''. Arizona: Western National Parks Association, 1993.
Desert Mistletoe
Web of Science 5 October 2009 *Epple, Anne. ''A Field Guide to the Plants of Arizona''. Arizona: Lewann Publishing Company, 1995.
Viscaceae (Loranthaceae)
Arizona-Sonora Desert Museum.

External links

Jepson Manual TreatmentPhoto gallery
{{Taxonbar, from=Q7187356 californicum Parasitic plants Flora of the California desert regions Flora of the Sonoran Deserts Flora of Baja California Flora of California Flora of Arizona Flora of Nevada Flora of Utah Flora of Sonora Flora of Sinaloa Plants used in Native American cuisine Plants described in 1848 Flora without expected TNC conservation status