grey willow vs gray willow

grey willow and gray willow both are nouns.

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

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

grey willow and gray willow: Eurasian shrubby willow with whitish tomentose twigs

Other synonyms of grey willow include Salix cinerea.

grey willow (noun)	gray willow (noun)
Eurasian shrubby willow with whitish tomentose twigs	Eurasian shrubby willow with whitish tomentose twigs