Western birch vs water birch

Western birch and water birch both are nouns.

Word	Noun	Adjective	Verb	Adverb
Western birch	Yes	No	No	No
water birch	Yes	No	No	No

As nouns, Western birch and water birch are synonyms defined as:

Western birch and water birch: birch of western United States resembling the paper birch but having brownish bark

Other synonyms of Western birch include Betula fontinalis, mountain birch, swamp birch, Western paper birch.

Western birch (noun)	water birch (noun)
birch of western United States resembling the paper birch but having brownish bark	birch of western United States resembling the paper birch but having brownish bark