heartleaf arnica vs wild flower

heartleaf arnica and wild flower both are nouns.

Word	Noun	Adjective	Verb	Adverb
heartleaf arnica	Yes	No	No	No
wild flower	Yes	No	No	No

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

heartleaf arnica: wildflower with heart-shaped leaves and broad yellow flower heads; of alpine areas west of the Rockies from Alaska to southern California
wild flower: wild or uncultivated flowering plant

Other hypernyms of heartleaf arnica include wildflower.

heartleaf arnica (noun)	wild flower (noun)
wildflower with heart-shaped leaves and broad yellow flower heads; of alpine areas west of the Rockies from Alaska to southern California	wild or uncultivated flowering plant