Desert Fan Palm

Description:

Other common names include desert fan palm, California palm, fanpalm, petticoat palm, cotton palm, Arizona fan palm and California fan palm.[1] The specific epithet filifera means "thread-bearing". Distribution[edit source] Washingtonia filifera is the only palm native to the Western United States, and the country's largest native palm (though most palms in Los Angeles and San Diego are specimens of the closely related and very similar W. robusta).[3][4][5] The primary populations are found in desert riparian habitats at spring-fed oases in the Colorado Desert (Low Desert) and throughout a major portion of the Mojave Desert. It has been introduced to watercourses in the Sonoran Desert along the Gila River in Yuma, along the Hassayampa River and near New River in Maricopa County, and in portions of Pima County, Pinal County, Mojave County (along the Colorado River) and several other isolated locations in Clark County, Nevada. It is also known in northern Baja California.[6] It is a naturalized species in the warm springs near Death Valley and in the extreme northwest of Sonora (Mexico), and also in Florida and the U.S. Virgin Islands.</ref>[7] As an ornamental tree it is cultivated in suitable temperate climates worldwide. Description[edit source] Washingtonia filifera grows to 18 metres (59 ft) in height (occasionally to 25 metres (82 ft)) in ideal conditions. The fronds are up to 3.5–4 metres (11–13 ft) long, made up of a petiole up to 2 metres (6.6 ft) long, bearing a fan of leaflets 1.5–2 metres (4.9–6.6 ft) long. They have long thread-like white fibers and the petiole 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. If there is any red color present on petioles or trunk its not a pure filifera but a fila-busta hybrid. Washingtonia filifera can live from 80 to 250 years or more. Ecology[edit source] Fan palms provide a habitat for desert bighorn sheep, hooded oriole, Gambel's quail, coyotes, and a rare bat species Lasiurus xanthinus that is especially fond of W. filifera groves. Hooded orioles rely on the trees for food and places to build nests. Both hooded orioles and coyotes play an integral part in seed distribution. Threats[edit source] The palm boring beetle Dinapate wrightii (Bostrichidae) can chew through the trunks. Eventually a continued infestation of beetles can kill various genera and species of palms. The recent discovery of the red palm weevil (Rhynchophorus ferrugineus) in Southern California may pose a threat to many palms, with coastal garden W. filifera specimens already a known host.[8] However, it seems that this species is resistant to the red palm weevil through a mechanism based on antibiosis.[9][10] Today, due to urbanization and ground water depletion, palm oases are shrinking and disappearing. Increased agricultural irrigation has lowered aquifers, reducing or removing water availability at palm oases. This creates a threat to the species and the organisms which rely on its habitat to survive. History[edit source] Fossils of this palm are known to exist as far north as Colorado, Wyoming and Oregon. The palm apparently reached its current form by at least 50–70 million years BP making it one of the oldest known palm identifiable to taxon through morphological characteristics of the leaves, petioles and other fossilized parts. Historically, natural oases are mainly restricted to areas downstream from the source of hot springs, though water is not always visible at the surface. 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. 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 groves. The trees in these groves show little if any genetic differentiation, (through electrophoretic examination) suggesting that the genus is genetically very stable. Access[edit source] Joshua Tree National Park 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, and Anza-Borrego Desert State Park both have large and diverse W. filifera canyon oasis habitats. Native Americans[edit source] The fruit of the fan palm was eaten raw, cooked, or ground into flour for cakes. The Cahuilla and related tribes used the leaves to make sandals, thatch roofs, and baskets. The stems were used to make cooking utensils. The Moapa band of Paiutes as well as other Southern Paiutes have written memories of using this palm's seed, fruit or leaves for various purposes including starvation food

Habitat:

Palm Oasis, Mojave Desert 2000', along active faultine.

Notes:

Oasis of Mara, Twentynine Palms, CA. One mile of green along Pinto Mountain Fault. Between JOTR Visitor Center and 29 Palms Inn.