buffalo clover vs trefoil

buffalo clover and trefoil both are nouns.

Word	Noun	Adjective	Verb	Adverb
buffalo clover	Yes	No	No	No
trefoil	Yes	No	No	No

As nouns, trefoil is a hypernym of buffalo clover; that is, trefoil is a word with a broader meaning than buffalo clover:

Other hypernyms of buffalo clover include clover.

buffalo clover (noun)	trefoil (noun)
clover of western United States	an architectural ornament in the form of three arcs arranged in a circle
low-growing annual herb of southwestern United States (Texas) having silky foliage and blue flowers; a leading cause of livestock poisoning in the southwestern United States	a plant of the genus Trifolium
	any of several Old World herbs of the genus Medicago having small flowers and trifoliate compound leaves