Carya aquatica vs hickory tree

Carya aquatica and hickory tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Carya aquatica	Yes	No	No	No
hickory tree	Yes	No	No	No

As nouns, hickory tree is a hypernym of Carya aquatica; that is, hickory tree is a word with a broader meaning than Carya aquatica:

Carya aquatica: hickory of southern United States having many narrow leaflets and rather bitter nuts
hickory tree: American hardwood tree bearing edible nuts

Other hypernyms of Carya aquatica include hickory.

Carya aquatica (noun)	hickory tree (noun)
hickory of southern United States having many narrow leaflets and rather bitter nuts	American hardwood tree bearing edible nuts