heartleaf arnica vs wildflower

heartleaf arnica and wildflower both are nouns.

Word	Noun	Adjective	Verb	Adverb
heartleaf arnica	Yes	No	No	No
wildflower	Yes	No	No	No

As nouns, wildflower is a hypernym of heartleaf arnica; that is, wildflower 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
wildflower: wild or uncultivated flowering plant

Other hypernyms of heartleaf arnica include wild flower.

heartleaf arnica (noun)	wildflower (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