genus Salix vs pussy willow

genus Salix and pussy willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Salix	Yes	No	No	No
pussy willow	Yes	No	No	No

genus Salix (noun)	pussy willow (noun)
a large and widespread genus varying in size from small shrubs to large trees: willows	small willow of eastern North America having greyish leaves and silky catkins that come before the leaves
	much-branched Old World willow having large catkins and relatively large broad leaves