Salix sericea vs willow

Salix sericea and willow both are nouns.

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

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

Salix sericea: North American willow with greyish silky pubescent leaves that usually blacken in drying
willow: any of numerous deciduous trees and shrubs of the genus Salix

Other hypernyms of Salix sericea include willow tree.

Salix sericea (noun)	willow (noun)
North American willow with greyish silky pubescent leaves that usually blacken in drying	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