Juglans cinerea vs walnut tree

Juglans cinerea and walnut tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Juglans cinerea	Yes	No	No	No
walnut tree	Yes	No	No	No

As nouns, walnut tree is a hypernym of Juglans cinerea; that is, walnut tree is a word with a broader meaning than Juglans cinerea:

Juglans cinerea: North American walnut tree having light-brown wood and edible nuts; source of a light-brown dye
walnut tree: any of various trees of the genus Juglans

Other hypernyms of Juglans cinerea include walnut.

Juglans cinerea (noun)	walnut tree (noun)
North American walnut tree having light-brown wood and edible nuts; source of a light-brown dye	any of various trees of the genus Juglans