Carya illinoensis vs pecan tree

Carya illinoensis and pecan tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Carya illinoensis	Yes	No	No	No
pecan tree	Yes	No	No	No

As nouns, Carya illinoensis and pecan tree are synonyms defined as:

Carya illinoensis and pecan tree: tree of southern United States and Mexico cultivated for its nuts

Other synonyms of Carya illinoensis include Carya illinoinsis, pecan.

Carya illinoensis (noun)	pecan tree (noun)
tree of southern United States and Mexico cultivated for its nuts	tree of southern United States and Mexico cultivated for its nuts