Plant names are interesting and often insightful. Thunbergia alata, for instance, has a winged petiole. Acer macrophylla has large leaves. Ginkgo biloba has leaves with two lobes. I think you get the point.
Here are silhouettes I sketched of the two species of Washingtonia that exist. One is Washingtonia filifera, the other Washingtonia robusta. Guess the identites.
Well, here are the answers.