genus Salix vs Salix vitellina

genus Salix and Salix vitellina both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Salix	Yes	No	No	No
Salix vitellina	Yes	No	No	No

genus Salix (noun)	Salix vitellina (noun)
a large and widespread genus varying in size from small shrubs to large trees: willows	European willow having greyish leaves and yellow-orange twigs used in basketry