Washingtonia filifera

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Washingtonia filifera

Washingtonia filifera growing wild near Twentynine Palms, California

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Liliopsida
Order:	Arecales
Family:	Arecaceae
Genus:	Washingtonia
Species:	W. filifera

Binomial name

Washingtonia filifera
(Lindl.) H.Wendl.

Washingtonia filifera (filifera - Latin "thread-bearing", also known as Desert Fan Palm', American Cotton palms, or Arizona fan Palm, or California fan Palm) is a palm native to the desert oases of Central, southern and southwestern Arizona, southern Nevada, extreme northwest Mexico and inland deserts of southern California. It grows up to 23 m (exceptionally 30 m) tall in good growing conditions and is the only palm native to the contiguous United States West of San Antonio Texas. The leaves have a petiole up to 2 m long, bearing a fan of leaflets 1.5-2 m long, with white, thread-like fibers between the segments. When the leaves die they bend downwards and form a skirt around the trunk. The shelter that the skirt creates provides a microhabitat for many invertebrates. Washingtonia filifera can live from 80 to 250 years or more and its name honors George Washington, the first President of the United States.

[edit] Ecology

Fan palms provide a habitat for Bighorn Sheep, Hooded Oriole, Gambel's Quail, Coyotes, and the palm boring beetle Dinapate wrightii (Coleoptera: Bostrichidae), and A rare Bat Lasiurus xanthinus especially fond of W. filifera groves. Hooded Orioles rely on them for food and places to build nests. Both Hooded Orioles and Coyotes are integral part in seed distribution. Dinapate beetles can be problematic and chew through the trunks of palms. Eventually a continued infestation of beetles can kill a palm, opening up space for a new palm to grow.

Today due to urbanization, palm oases are disappearing. Increased agriculture has lowered ground water supplies and decreased the amount available in palm oases. This creates a threat not only to The Far Western United State's only native palm, but also all the organisms that rely on them in order to survive. Fossils of this palm are known to exist as far north as Colorado, Wyoming and Oregon and the palm apparently reached current form by at least 50 - 70 million years BP. Natural Oases environs are mainly restricted historically to the general area surrounding warm or hot springs near the source or shortly downstream from sources. Grazing animals including deer and cattle and more anciently Giant Sloths and other extinct herbivores are known to kill young plants through trampling or by eating the terminus at the apical meristem which is the growing portion. This may have kept oases restricted to lesser ranges than would have been expected if one simply accounts for water sources. Typically the oases environ found today is one which could have been protected from colder climatic changes over the course of its evolution. Thus it is restricted by both water and climate to widely separated relict groves which show little if any genetic differentiation. This suggests the genus is genetically very stable.

[edit] Cultivation and uses

The fruit of the fan palm was used by Native Americans. It was eaten raw, cooked, or ground into flour for cakes. The Cahuilla tribe used the leaves to make sandals, thatch roofs, and for making baskets. The fan palm was a valuable resource and the stems were used to make utensils for cooking. The Moapa band of Paiutes as well as other Southern Paiutes have stated memories of grandparents also using this palm's seed, fruit or leaves for various things. It should be noted that The Southern Paiutes are related linguistically and by ancient trade routes to the Cahuilla.

It is widely cultivated as an ornamental tree though not as widely as the Mexican Fan Palm Washingtonia robusta - a close cousin throughout the lower elevations of Nevada, California, Arizona,New Mexico and extreme southwestern Utah, it is one of the hardiest of palms and repeatedly survives dips into the teens and even several inches of snow, making it a favorite of Cold Hardy Palm enthusiasts. The less hardy cousin needs much milder winters and is visibly damaged at 19 degrees Fahrenheit. It is not so widely grown along the Gulf Coast, in states such as Texas, Louisiana, and Florida, and the Mediterranean region as its cousin the Washingtonia robusta which is loved for its tall thinner trunk waving in the breeze. It is however, widely grown in interior Texas, as it is sufficiently hardy in such places as San Antonio, Austin, and El Paso.^{[citation needed]} The plants grow best in warm temperate climate with winter rain and dry summers. Specimens outside of Mediterranean climates do not grow as large, rarely exceeding 15 m. The plants are tolerant of considerable frost and the species is rated as hardy to USDA zone 8b; it will survive temperatures of -10 °C with minor damage, and established plants have survived brief periods of temperatures as low as -12 °C but with severe damage to the foliage.