Dictionary.net

• wosh-ing-t[=o]'ni-a, n. a Californian genus of palms, valued for ornament in lawns--from George Washington (1732-99).

1908 - Chambers's Twentieth Century Dictionary of the English Language
By Thomas Davidson

• Californian palmtree named after George Washington.

1919 - The concise Oxford dictionary of current English
By Sir Augustus Henry