black medick vs Medicago lupulina

black medick and Medicago lupulina both are nouns.

Word	Noun	Adjective	Verb	Adverb
black medick	Yes	No	No	No
Medicago lupulina	Yes	No	No	No

As nouns, black medick and Medicago lupulina are synonyms defined as:

black medick and Medicago lupulina: prostrate European herb with small yellow flowers and curved black pods; naturalized in North America

Other synonyms of black medick include hop clover, nonesuch clover, yellow trefoil.

black medick (noun)	Medicago lupulina (noun)
prostrate European herb with small yellow flowers and curved black pods; naturalized in North America	prostrate European herb with small yellow flowers and curved black pods; naturalized in North America