Species: W. robusta
Washingtonia robusta (Mexican fan palm or Mexican washingtonia) is a palm tree native to western Sonora, and Baja California Sur in northwestern Mexico. It is reportedly naturalized in Spain, the Canary Islands, Réunion, Hawaii, Florida and California.
Washingtonia robusta grows to 25 m (82 ft) tall, rarely up to 30 m (98 ft). The leaves have a petiole up to 1 m (3.3 ft) long, and a palmate fan of leaflets up to 1 m long. The inflorescence is up to 3 m (9.8 ft) long, with numerous small pale orange-pink flowers. The fruit is a spherical, blue-black drupe, 6–8 mm (0.24–0.31 in) diameter; it is edible, though thin-fleshed.
Cultivation and uses
Like the closely related Washingtonia filifera (California Fan Palm), it is grown as an ornamental tree. Although very similar, the Mexican Washingtonia has a narrower trunk (which is typically somewhat wider at the base), and grows slightly faster and taller; it is also somewhat less cold hardy than the California Washingtonia, hardy to about −8 °C (18 °F).
Field research conducted on Washingtonia robusta in its native habitat on the Baja California peninsula suggests that its potential longevity may exceed 500 years.
Supporting research by Barry Tomlinson and Brett Huggett states that there is "evidence for extreme longevity of metabolically functioning cells of considerable diversity in palm stems." Many of the iconic "sky dusters" of Los Angeles that have survived the chainsaws of progress are documented in photography from the 19th century.
Unlike Washingtonia filifera, which has been cultivated as far north as Oklahoma and Southwestern Utah, the Mexican fan palm can be grown mainly around areas of the southwestern United States, such as California and the coast of Oregon, Arizona, Southern Nevada, and New Mexico. It may also be seen along the Gulf Coast from Texas to Florida and may also be found in coastal Georgia and South Carolina.
Washingtonia × filibusta is a hybrid of W. robusta and W. filifera and has intermediate characteristics of the two parents, especially greater tolerance of wet cold.