dog mercury vs dog's mercury

dog mercury and dog's mercury both are nouns.

Word	Noun	Adjective	Verb	Adverb
dog mercury	Yes	No	No	No
dog's mercury	Yes	No	No	No

As nouns, dog mercury and dog's mercury are synonyms defined as:

dog mercury and dog's mercury: European perennial weedy plant with greenish flowers

Other synonyms of dog mercury include Mercurialis perennis.

dog mercury (noun)	dog's mercury (noun)
European perennial weedy plant with greenish flowers	European perennial weedy plant with greenish flowers