Salix alba vs willow

Salix alba and willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
Salix alba	Yes	No	No	No
willow	Yes	No	No	No

As nouns, willow is a hypernym of Salix alba; that is, willow is a word with a broader meaning than Salix alba:

Salix alba: large willow tree of Eurasia and North Africa having greyish canescent leaves and grey bark
willow: any of numerous deciduous trees and shrubs of the genus Salix

Other hypernyms of Salix alba include willow tree.

Salix alba (noun)	willow (noun)
large willow tree of Eurasia and North Africa having greyish canescent leaves and grey bark	a textile machine having a system of revolving spikes for opening and cleaning raw textile fibers
	any of numerous deciduous trees and shrubs of the genus Salix