''Washingtonia filifera'', the desert fan palm, California fan palm, or California palm,Flora of North America Association. ''Flora of North America: North of Mexico Volume 22: Magnoliophyta: Alismatidae, Arecidae, Commelinidae (in Part), and Zingiberidae''. pp. 105–06, 116–17. . is a

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

in the palm

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Arecaceae The Arecaceae is a family of perennial flowering plants in the monocot order Arecales. Their growth form can be climbers, shrubs, tree-like and stemless plants, all commonly known as palms. Those having a tree-like form are called palm trees ...

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...

to the far

southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

and

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, Mexico. Growing to tall by broad, it is an

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

monocot Monocotyledons (), commonly referred to as monocots, (Lilianae '' sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one ...

with a

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

-like growth habit. It has a sturdy, columnar trunk and waxy, fan-shaped (

palmate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

) leaves.

Names

The Latin

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...

''filifera'' means "thread-bearing".

Description

''Washingtonia filifera'' grows to in height, and occasionally to as much as in ideal conditions. The California fan palm is also known as the desert fan palm, American cotton palm, and Arizona fan palm. The

frond A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the lar ...

s are up to long, made up of a petiole up to long, bearing a fan of leaflets long. They have long, thread-like, white fibers, and the petioles are pure green with yellow edges and ''filifera''-filaments, between the segments. The trunk is gray and tan, and the leaves are gray green. When the fronds die, they remain attached and drop down to cloak the trunk in a wide skirt. The shelter that the skirt creates provides a microhabitat for many small birds and invertebrates. ''Washingtonia filifera'' typically lives from 80 to 250 years or more.

Distribution

''Washingtonia filifera'' is the only palm native to the Western United States and one of the country's largest native palms, exceeded in height only by the Cuban or Florida royal palm. Primary populations are found in desert

riparian A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...

habitats at spring-fed and stream-fed oases in the

Colorado Desert California's Colorado Desert is a part of the larger Sonoran Desert. It encompasses approximately , including the heavily irrigated Coachella and Imperial valleys. It is home to many unique flora and fauna. Geography and geology The Colorado D ...

and at a few scattered locations in the

Mojave Desert The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily ...

. It is also found near watercourses in the

Sonoran Desert The Sonoran Desert ( es, Desierto de Sonora) is a desert in North America and ecoregion that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the southwestern United States (in Ariz ...

along the

Gila River The Gila River (; O'odham ima Keli Akimel or simply Akimel, Quechan: Haa Siʼil, Maricopa language: Xiil) is a tributary of the Colorado River flowing through New Mexico and Arizona in the United States. The river drains an arid watershed of ...

in Yuma, along the

Hassayampa River The Hassayampa River ( Yavapai: Hasaya:mvo or ʼHasayamcho:) is an intermittent river, the headwaters of which are just south of Prescott, Arizona, and flows mostly south towards Wickenburg, entering the Gila River near Hassayampa. Although the r ...

and near New River in

Maricopa County Maricopa County is in the south-central part of the U.S. state of Arizona. As of the 2020 census, the population was 4,420,568, making it the state's most populous county, and the fourth-most populous in the United States. It contains about ...

, and in portions of

Pima County Pima County ( ) is a county in the south central region of the U.S. state of Arizona. As of the 2020 census, the population was 1,043,433, making it Arizona's second-most populous county. The county seat is Tucson, where most of the populati ...

Pinal County Pinal County is in the central part of the U.S. state of Arizona. According to the 2020 census, the population of the county was 425,264, making it Arizona's third-most populous county. The county seat is Florence. The county was founded in 187 ...

Mohave County Mohave County is in the northwestern corner of the U.S. state of Arizona. As of the 2020 census, its population was 213,267. The county seat is Kingman, and the largest city is Lake Havasu City. It is the fifth largest county in the United St ...

(along the Colorado River), and several other isolated locations in Clark County, Nevada. In Mexico, it is native only to the state of

, where occurs in isolated canyons and oases as far south as Bahía de los Angeles. It is a

naturalized Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the in ...

species in the warm springs near

Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the hottest place on Earth. Death Valley's Badwater Basin is the point of lowest elevation in Nort ...

and in the extreme northwest of

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the ...

(Mexico). It is also reportedly naturalized in the

South South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

and

Southeast Texas Southeast Texas is a cultural and geographic region in the U.S. state of Texas, bordering Southwest Louisiana and its greater Acadiana region to the east. Being a part of East Texas, the region is geographically centered on the Greater Houston ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

and extreme southwest

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

, the U.S.

Virgin Islands The Virgin Islands ( es, Islas Vírgenes) are an archipelago in the Caribbean Sea. They are geologically and biogeographically the easternmost part of the Greater Antilles, the northern islands belonging to the Puerto Rico Trench and St. Cro ...

, and

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

Ecology

Desert fan palms provide habitat for the giant palm-boring beetle,

western yellow bat The western yellow bat (''Dasypterus xanthinus'') is a species of vesper bat found in Mexico and the southwestern United States. This species roosts in trees such as ''Populus fremontii'', ''Platanus wrightii'', and ''Quercus arizonica''. I ...

hooded oriole The hooded oriole (''Icterus cucullatus'') is a medium-sized New World oriole. The male of this species ranges in color from a bright orange to a paler yellow, with a black back, face, tail and bib, with the wing containing two white bars. The fe ...

, and many other bird species. Hooded orioles rely on the trees for food and places to build nests. Numerous insect species visit the hanging inflorescences that appear in late spring. Historically, natural oases are mainly restricted to areas downstream from the source of hot springs, though water is not always visible at the surface. Today's oasis environment may have been protected from colder climatic changes over the course of its evolution. Thus, this palm is restricted by both water and climate to widely separated

relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

groves. The trees in these groves show little if any genetic differentiation, (through electrophoretic examination), suggesting that the genus is genetically very stable.

Fire adaptations

Fan palm oases have historically been subject to both natural and manmade fires. Fires are rarely fatal for the fan palm, but it is also not completely immune to them. The fan palm's trunk is heavily resistant to burning. In most cases, the trunk is only at risk of losing some of its outer vascular layers during a fire. After those layers are ignited and burnt off, the remaining surface is left heavily charred, which fortifies the trunk against future flames. Subsequent burnings serve to char the trunk more, further increasing its fire resistance. The palm's fronds are the most flammable portion of the tree. The unchecked buildup of dead fronds as a 'skirt' around the trunk can be especially dangerous in a crown fire. A severe accumulation of them could constitute enough kindling to completely burn through the trunk, killing the tree. However, if a palm can survive the burning of its fronds, they will take time to regrow, leaving it less susceptible to fire in the meantime. Barring extreme, fatal conditions, fires are even conducive to the health and propagation of fan palms. The palms' reproduction process benefits from burnings, as fires help release saplings and clear away overgrowth from surrounding vegetation. Fires can also help palms conserve water by burning away their crowns and parts of their trunks, leading to a reduction in surface area and therefore decreased rates of evaporation and transpiration.

Threats

Grazing animals can kill young plants through trampling, or by eating the terminus at the apical meristem, the growing portion of the plant. This may have kept palms restricted to a lesser range than indicated by the availability of water. The palm boring beetle '' Dinapate wrightii'' (

Bostrichidae The Bostrichidae are a family of beetles with more than 700 described species. They are commonly called auger beetles, false powderpost beetles, or horned powderpost beetles. The head of most auger beetles cannot be seen from above, as it is down ...

) can chew through the trunks of this and other palms. Eventually, a continued infestation of beetles can kill various genera and species of palms. ''W. filifera'' appears to be resistant to the red palm weevil ('' Rhynchophorus ferrugineus'') by a mechanism of

antibiosis Antibiosis is a biological interaction between two or more organisms that is detrimental to at least one of them; it can also be an antagonistic association between an organism and the metabolic substances produced by another. Examples of antibio ...

– production of compounds lethal to the larvae. Currently, the desert fan palm is experiencing a population and range expansion, perhaps due to global warming or mustang control.

Uses

The sweet fruit pulp of the fan palm is edible. The fruit was eaten raw, cooked, or ground into flour for cakes by Native Americans. The

Cahuilla The Cahuilla , also known as ʔívil̃uqaletem or Ivilyuqaletem, are a Native American people of the various tribes of the Cahuilla Nation, living in the inland areas of southern California.thatch Thatching is the craft of building a roof with dry vegetation such as straw, water reed, sedge (''Cladium mariscus''), rushes, heather, or palm branches, layering the vegetation so as to shed water away from the inner roof. Since the bulk of ...

, and baskets. The woody petioles were used to make cooking utensils. The Moapa band of Paiutes and other

Southern Paiute people The Southern Paiute people are a tribe of Native Americans who have lived in the Colorado River basin of southern Nevada, northern Arizona, and southern Utah. Bands of Southern Paiute live in scattered locations throughout this territory and ha ...

have written memories of using this palm's seed, fruit, or leaves for various purposes, including as

famine food A famine food or poverty food is any inexpensive or readily available food used to nourish people in times of hunger and starvation, whether caused by extreme poverty, such as during economic depression or war, or by natural disasters such a ...

. The

bud In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be spec ...

(known as

heart of palm Heart of palm is a vegetable harvested from the inner core and growing bud of certain palm trees, most notably the coconut (''Cocos nucifera''), juçara ('' Euterpe edulis''), açaí palm (''Euterpe oleracea''), palmetto (''Sabal'' spp.), and p ...

) has also been eaten.

Access

Joshua Tree National Park Joshua Tree National Park is an American national park in southeastern California, east of San Bernardino and Los Angeles and north of Palm Springs. It is named after the Joshua trees (''Yucca brevifolia'') native to the Mojave Desert. Origin ...

in the Mojave Desert preserves and protects healthy riparian palm habitat examples in the Little San Bernardino Mountains, and westward where water rises through the San Andreas Fault on the east valley side. In the central Coachella Valley, the Indio Hills Palms State Reserve and nearby Coachella Valley Preserve, other large oases are protected and accessible. The

Santa Rosa and San Jacinto Mountains National Monument The Santa Rosa and San Jacinto Mountains National Monument is a National Monument in southern California. It includes portions of the Santa Rosa and San Jacinto mountain ranges, the northernmost ones of the Peninsular Ranges system. The national ...

, and

Anza-Borrego Desert State Park Anza-Borrego Desert State Park (, '' AN-zə bə-RAY-goh'') is a California State Park located within the Colorado Desert of southern California, United States. The park takes its name from 18th century Spanish explorer Juan Bautista de Anza and ...

both have large and diverse ''W. filifera'' canyon oasis habitats.

Cultivation

''Washingtonia filifera'' is widely cultivated as an

ornamental tree Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...

. It is one of the hardiest coryphoid palms, rated as hardy to USDA

hardiness zone A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most wide ...

8. It can survive brief temperatures of with minor damage, and established plants have survived, with severe leaf damage, brief periods as low as . The plants grow best in Mediterranean climates, but can be found in humid subtropical climates such as eastern Australia and the southeastern USA. It has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nor ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

Gallery

File:Washingtonia filifera in Palm Canyon.jpg, ''W. filifera'' in Palm Canyon,

File:Washingtoniafilifera.JPG, ''W. filifera''

with fibrous threads on leaf segments File:Washingtonia filifera Anza-Borrego.jpg, ''W. filifera'' trees and fronds in

File:華盛頓椰子 Washingtonia filifera 20220815193754 01.jpg, ''W. filifera'', inflorescence and the fruiting season

References

External links

Floridata.com: ''Washingtonia filifera''

Interactive Distribution Map for Washingtonia filifera

USDA Plants Profile: ''Washingtonia filifera'' (California fan palm)

UC Jepson Manual treatment – ''Washingtonia filifera''

Calflora Database: ''Washingtonia filifera'' (California fan palm)

''Washingtonia filifera'' in Flora of North America

''Washingtonia filifera'' (California fan palm) – U.C. CalPhotos Gallery
{{Taxonbar, from=Q158389

filifera Filifera is a suborder of hydrozoans in the order Anthoathecata. They are found in marine, brackish and freshwater habitats. Characteristics Members of this suborder are characterised by the filiform tentacles of the polyps which do not termin ...

Flora of the California desert regions Flora of the Coachella Valley Flora of Riverside County, California Flora of the Sonoran Deserts Natural history of the Colorado Desert Trees of the Southwestern United States Trees of Baja California Plants described in 1879 Garden plants of North America Drought-tolerant trees Ornamental trees