harebell vs campanula

harebell and campanula both are nouns.

Word	Noun	Adjective	Verb	Adverb
harebell	Yes	No	No	No
campanula	Yes	No	No	No

As nouns, campanula is a hypernym of harebell; that is, campanula is a word with a broader meaning than harebell:

harebell: perennial of Northern Hemisphere with slender stems and bell-shaped blue flowers
campanula: any of various plants of the genus Campanula having blue or white bell-shaped flowers

Other hypernyms of harebell include bellflower.

harebell (noun)	campanula (noun)
perennial of Northern Hemisphere with slender stems and bell-shaped blue flowers	any of various plants of the genus Campanula having blue or white bell-shaped flowers
sometimes placed in genus Scilla