Iowa crab apple vs wild apple

Iowa crab apple and wild apple both are nouns.

Word	Noun	Adjective	Verb	Adverb
Iowa crab apple	Yes	No	No	No
wild apple	Yes	No	No	No

As nouns, wild apple is a hypernym of Iowa crab apple; that is, wild apple is a word with a broader meaning than Iowa crab apple:

Iowa crab apple: wild crab apple of western United States with fragrant pink flowers
wild apple: any of numerous wild apple trees usually with small acidic fruit

Other hypernyms of Iowa crab apple include crab apple, crabapple.

Iowa crab apple (noun)	wild apple (noun)
wild crab apple of western United States with fragrant pink flowers	any of numerous wild apple trees usually with small acidic fruit