genus Salix vs Salix

genus Salix and Salix both are nouns.

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

As nouns, genus Salix and Salix are synonyms defined as:

genus Salix and Salix: a large and widespread genus varying in size from small shrubs to large trees: willows

genus Salix (noun)	Salix (noun)
a large and widespread genus varying in size from small shrubs to large trees: willows	a large and widespread genus varying in size from small shrubs to large trees: willows