pomme blanche vs pomme de prairie

pomme blanche and pomme de prairie both are nouns.

Word	Noun	Adjective	Verb	Adverb
pomme blanche	Yes	No	No	No
pomme de prairie	Yes	No	No	No

As nouns, pomme blanche and pomme de prairie are synonyms defined as:

pomme blanche and pomme de prairie: densely hairy perennial of central North America having edible tuberous roots

Other synonyms of pomme blanche include breadroot, Indian breadroot, Psoralea esculenta.

pomme blanche (noun)	pomme de prairie (noun)
densely hairy perennial of central North America having edible tuberous roots	densely hairy perennial of central North America having edible tuberous roots