gray goldenrod vs grey goldenrod

gray goldenrod and grey goldenrod both are nouns.

Word	Noun	Adjective	Verb	Adverb
gray goldenrod	Yes	No	No	No
grey goldenrod	Yes	No	No	No

As nouns, gray goldenrod and grey goldenrod are synonyms defined as:

gray goldenrod and grey goldenrod: a dyer's weed of Canada and the eastern United States having yellow flowers sometimes used in dyeing

Other synonyms of gray goldenrod include Solidago nemoralis.

gray goldenrod (noun)	grey goldenrod (noun)
a dyer's weed of Canada and the eastern United States having yellow flowers sometimes used in dyeing	a dyer's weed of Canada and the eastern United States having yellow flowers sometimes used in dyeing