Huntingdon willow vs genus Salix

Huntingdon willow and genus Salix both are nouns.

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

Huntingdon willow (noun)	genus Salix (noun)
large willow tree of Eurasia and North Africa having greyish canescent leaves and grey bark	a large and widespread genus varying in size from small shrubs to large trees: willows