genus Salix vs dwarf grey willow

genus Salix and dwarf grey willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Salix	Yes	No	No	No
dwarf grey willow	Yes	No	No	No

genus Salix (noun)	dwarf grey willow (noun)
a large and widespread genus varying in size from small shrubs to large trees: willows	willow shrub of dry places in the eastern United States having long narrow leaves canescent beneath