Trifolium alpinum vs trefoil

Trifolium alpinum and trefoil both are nouns.

Word	Noun	Adjective	Verb	Adverb
Trifolium alpinum	Yes	No	No	No
trefoil	Yes	No	No	No

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

Trifolium alpinum: European mountain clover with fragrant usually pink flowers
trefoil: a plant of the genus Trifolium

Other hypernyms of Trifolium alpinum include clover.

Trifolium alpinum (noun)	trefoil (noun)
European mountain clover with fragrant usually pink flowers	an architectural ornament in the form of three arcs arranged in a circle
	a plant of the genus Trifolium
	any of several Old World herbs of the genus Medicago having small flowers and trifoliate compound leaves