Tsuga mertensiana vs mountain hemlock

Tsuga mertensiana and mountain hemlock both are nouns.

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

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

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

Other synonyms of Tsuga mertensiana include black hemlock.

Tsuga mertensiana (noun)	mountain hemlock (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