sheep sorrel vs sheep's sorrel

sheep sorrel and sheep's sorrel both are nouns.

Word	Noun	Adjective	Verb	Adverb
sheep sorrel	Yes	No	No	No
sheep's sorrel	Yes	No	No	No

As nouns, sheep sorrel and sheep's sorrel are synonyms defined as:

sheep sorrel and sheep's sorrel: small plant having pleasantly acid-tasting arrow-shaped leaves; common in dry places

Other synonyms of sheep sorrel include Rumex acetosella.

sheep sorrel (noun)	sheep's sorrel (noun)
small plant having pleasantly acid-tasting arrow-shaped leaves; common in dry places	small plant having pleasantly acid-tasting arrow-shaped leaves; common in dry places