desert sunflower vs wild flower

desert sunflower and wild flower both are nouns.

Word	Noun	Adjective	Verb	Adverb
desert sunflower	Yes	No	No	No
wild flower	Yes	No	No	No

As nouns, wild flower is a hypernym of desert sunflower; that is, wild flower is a word with a broader meaning than desert sunflower:

desert sunflower: slender hairy plant with few leaves and golden-yellow flower heads; sandy desert areas of southeastern California to southwestern Utah and western Arizona and northwestern Mexico
wild flower: wild or uncultivated flowering plant

Other hypernyms of desert sunflower include wildflower.

desert sunflower (noun)	wild flower (noun)
slender hairy plant with few leaves and golden-yellow flower heads; sandy desert areas of southeastern California to southwestern Utah and western Arizona and northwestern Mexico	wild or uncultivated flowering plant