deer's-ears vs deer's-ear

deer's-ears and deer's-ear both are nouns.

Word	Noun	Adjective	Verb	Adverb
deer's-ears	Yes	No	No	No
deer's-ear	Yes	No	No	No

As nouns, deer's-ears and deer's-ear are synonyms defined as:

deer's-ears and deer's-ear: any of various tall perennial herbs constituting the genus Frasera; widely distributed in warm dry upland areas of California, Oregon, and Washington

Other synonyms of deer's-ears include American columbo, American gentian, columbo, pyramid plant.

deer's-ears (noun)	deer's-ear (noun)
any of various tall perennial herbs constituting the genus Frasera; widely distributed in warm dry upland areas of California, Oregon, and Washington	any of various tall perennial herbs constituting the genus Frasera; widely distributed in warm dry upland areas of California, Oregon, and Washington