black medick vs yellow trefoil

black medick and yellow trefoil both are nouns.

Word	Noun	Adjective	Verb	Adverb
black medick	Yes	No	No	No
yellow trefoil	Yes	No	No	No

As nouns, black medick and yellow trefoil are synonyms defined as:

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

Other synonyms of black medick include hop clover, Medicago lupulina, nonesuch clover.

black medick (noun)	yellow trefoil (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