Tsuga mertensiana vs black hemlock

Tsuga mertensiana and black hemlock both are nouns.

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

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

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

Other synonyms of Tsuga mertensiana include mountain hemlock.

Tsuga mertensiana (noun)	black 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