black-eyed pea vs Vigna unguiculata

black-eyed pea and Vigna unguiculata both are nouns.

Word	Noun	Adjective	Verb	Adverb
black-eyed pea	Yes	No	No	No
Vigna unguiculata	Yes	No	No	No

As nouns, black-eyed pea and Vigna unguiculata are synonyms defined as:

black-eyed pea and Vigna unguiculata: sprawling Old World annual cultivated especially in southern United States for food and forage and green manure

Other synonyms of black-eyed pea include cowpea, cowpea plant, Vigna sinensis.

black-eyed pea (noun)	Vigna unguiculata (noun)
eaten fresh as shell beans or dried	sprawling Old World annual cultivated especially in southern United States for food and forage and green manure
sprawling Old World annual cultivated especially in southern United States for food and forage and green manure
fruit or seed of the cowpea plant