Carya tomentosa vs hickory tree

Carya tomentosa and hickory tree both are nouns.

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

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

Carya tomentosa: smooth-barked North American hickory with 7 to 9 leaflets bearing a hard-shelled edible nut
hickory tree: American hardwood tree bearing edible nuts

Other hypernyms of Carya tomentosa include hickory.

Carya tomentosa (noun)	hickory tree (noun)
smooth-barked North American hickory with 7 to 9 leaflets bearing a hard-shelled edible nut	American hardwood tree bearing edible nuts