mountain hemlock vs Tsuga mertensiana

mountain hemlock and Tsuga mertensiana both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain hemlock	Yes	No	No	No
Tsuga mertensiana	Yes	No	No	No

As nouns, mountain hemlock and Tsuga mertensiana are synonyms defined as:

mountain hemlock and Tsuga mertensiana: large evergreen of western United States; wood much harder than Canadian hemlock

Other synonyms of mountain hemlock include black hemlock.

mountain hemlock (noun)	Tsuga mertensiana (noun)
large evergreen of western United States; wood much harder than Canadian hemlock	large evergreen of western United States; wood much harder than Canadian hemlock