Fraxinus nigra vs black ash

Fraxinus nigra and black ash both are nouns.

Word	Noun	Adjective	Verb	Adverb
Fraxinus nigra	Yes	No	No	No
black ash	Yes	No	No	No

As nouns, Fraxinus nigra and black ash are synonyms defined as:

Fraxinus nigra and black ash: vigorous spreading North American tree having dark brown heavy wood; leaves turn gold in autumn

Other synonyms of Fraxinus nigra include basket ash, brown ash, hoop ash.

Fraxinus nigra (noun)	black ash (noun)
vigorous spreading North American tree having dark brown heavy wood; leaves turn gold in autumn	vigorous spreading North American tree having dark brown heavy wood; leaves turn gold in autumn