florist's willow vs genus Salix

florist's willow and genus Salix both are nouns.

Word	Noun	Adjective	Verb	Adverb
florist's willow	Yes	No	No	No
genus Salix	Yes	No	No	No

florist's willow (noun)	genus Salix (noun)
much-branched Old World willow having large catkins and relatively large broad leaves	a large and widespread genus varying in size from small shrubs to large trees: willows