pignut hickory vs Carya glabra

pignut hickory and Carya glabra both are nouns.

Word	Noun	Adjective	Verb	Adverb
pignut hickory	Yes	No	No	No
Carya glabra	Yes	No	No	No

As nouns, pignut hickory and Carya glabra are synonyms defined as:

pignut hickory and Carya glabra: an American hickory tree having bitter nuts

Other synonyms of pignut hickory include black hickory, brown hickory, pignut.

pignut hickory (noun)	Carya glabra (noun)
an American hickory tree having bitter nuts	an American hickory tree having bitter nuts