Washingtonia filifera, the desert fan palm, California fan palm, or California palm, is a flowering plant in the palm family Arecaceae, native to the far southwestern United States and Baja California, Mexico. Growing to tall by broad, it is an evergreen monocot with a tree-like growth habit. It has a sturdy, columnar trunk and waxy, fan-shaped (palmate) leaves. Names The Latin specific epithet 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 fronds 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 habitats at spring-fed and stream-fed oases in the Colorado Desert and at a few scattered locations in the Mojave Desert. It is also found near 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, Mohave County (along the Colorado River), and several other isolated locations in Clark County, Nevada. In Mexico, it is native only to the state of Baja California, where occurs in isolated canyons and oases as far south as Bahía de los Angeles. It is a naturalized species in the warm springs near Death Valley and in the extreme northwest of Sonora (Mexico). It is also reportedly naturalized in the South and Southeast Texas, Florida, Hawaii and extreme southwest Utah, the U.S. Virgin Islands, and Australia. Ecology Desert fan palms provide habitat for the giant palm-boring beetle, western yellow bat, hooded oriole, and many other bird species. Hooded orioles rely