Sitka willow vs Salix sitchensis

Sitka willow and Salix sitchensis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sitka willow	Yes	No	No	No
Salix sitchensis	Yes	No	No	No

As nouns, Sitka willow and Salix sitchensis are synonyms defined as:

Sitka willow and Salix sitchensis: small shrubby tree of western North America (Alaska to Oregon)

Other synonyms of Sitka willow include silky willow.

Sitka willow (noun)	Salix sitchensis (noun)
small shrubby tree of western North America (Alaska to Oregon)	small shrubby tree of western North America (Alaska to Oregon)