grey birch vs Betula populifolia

grey birch and Betula populifolia both are nouns.

Word	Noun	Adjective	Verb	Adverb
grey birch	Yes	No	No	No
Betula populifolia	Yes	No	No	No

As nouns, grey birch and Betula populifolia are synonyms defined as:

grey birch and Betula populifolia: medium-sized birch of eastern North America having white or pale grey bark and valueless wood; occurs often as a second-growth forest tree

Other synonyms of grey birch include American gray birch, American grey birch, gray birch.

grey birch (noun)	Betula populifolia (noun)
medium-sized birch of eastern North America having white or pale grey bark and valueless wood; occurs often as a second-growth forest tree	medium-sized birch of eastern North America having white or pale grey bark and valueless wood; occurs often as a second-growth forest tree