Salix alba caerulea vs willow

Salix alba caerulea and willow both are nouns.

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

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

Salix alba caerulea: Eurasian willow tree having greyish leaves and ascending branches
willow: any of numerous deciduous trees and shrubs of the genus Salix

Other hypernyms of Salix alba caerulea include willow tree.

Salix alba caerulea (noun)	willow (noun)
Eurasian willow tree having greyish leaves and ascending branches	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