They are fan palms (subfamily Coryphoideae), with petioles armed with sharp thorns terminating in a rounded fan of numerous leaflets. The flowers are in a dense inflorescence, with the fruits maturing into a small blackish-brown drupe 6–10mm diameter with a thin layer of sweet flesh over the single seed.[6]
Extant species
There is one accepted species in the Genus Washingtonia: Washingtonia filifera. Phylogenetic testing conducted on populations of Washingtonia palms across their native range showed four distinct genetic populations. Existing morphological distinctions between the previously accepted species did not match the distinct populations. [4][7][8]
Washingtonia was previously divided into two species: Washingtonia filifera and Washingtonia robusta. The morphological differences between these two former species also graded into each other, and specimens with combined attributes were named Washingtonia × filibusta, assumed to be a hybrid between the two.
Washingtonia filifera var. sonorae (S.Watson) M.E.Jones[9][10]W. f. var. sonorae is native to the central coast of Sonora state, near the city of Guaymas.[9] This population of the species is genetically distinct.[4]
Species
Description
Current distribution
California fan palm or desert fan palmWashingtonia filifera (Lindl. ex André) H.Wendl.A grove of Washingtonia filifera in Castle Creek, Arizona
Tree to 23 m tall; leaves large, with petiole up to 2 m long, and leaflets up to 2 m long. Inflorescence to 5 m long; flowers white; fruit oval. Palms are often found at the base of mountains, hills and form around desert oasis in the southwest. They are used in landscaping, particularly in southern counties of California.
Southwestern USA, just into extreme northwest Mexico.
Tree to 25 m tall; leaves smaller, with petiole up to 1 m long, and leaflets up to 1 m long. Inflorescence to 3 m long; flowers pale orange-pink; fruit spherical.
The fruit is edible, and was used by Native American people as a minor food source. They are also eaten by birds, which disperse the seeds in their droppings after digesting the fruit pulp. Washingtonia species are also used as food plants by the larvae of some Lepidoptera species, including Paysandisia archon.
Washingtonia palms are cultivated as ornamental trees, widely planted in California, Florida, Texas, extreme southwest Utah, Arizona, southern New Mexico, South Carolina, and southern areas of North Carolina. It is also cultivated in the Mediterranean region in southern Europe and north Africa, parts of Australia, and the leeward sides of the Hawaiian Islands. W. filifera is modestly hardy in drier climate and able to survive brief temperatures in the vicinity of -15°C (10°F), provided the air and soil are not too wet, and the afternoon temperatures are not too cold. Intolerance of wet, prolonged cold is the main reason the Washingtonia palms do not grow in many temperate climates.
↑Jon P. Rebman, Judy Gibson, and Karen Rich. Annotated checklist of the vascular plants of Baja California, Mexico. 2016. Proceedings of the San Diego Society of Natural History. number 45. page 275.
123Lorena Villanueva-Almanza, Jacob B Landis, Daniel Koenig, Exequiel Ezcurra. Genetic and morphological differentiation in Washingtonia (Arecaceae): solving a century-old palm mystery, Botanical Journal of the Linnean Society, Volume 196, Issue 4, August 2021, Pages 506–523, https://doi.org/10.1093/botlinnean/boab009
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
