yellow ironweed vs crownbeard

yellow ironweed and crownbeard both are nouns.

Word	Noun	Adjective	Verb	Adverb
yellow ironweed	Yes	No	No	No
crownbeard	Yes	No	No	No

As nouns, crownbeard is a hypernym of yellow ironweed; that is, crownbeard is a word with a broader meaning than yellow ironweed:

yellow ironweed: perennial herb with showy yellow flowers; the eastern United States
crownbeard: any plant of the genus Verbesina having clustered white or yellow flower heads

Other hypernyms of yellow ironweed include crown-beard, crown beard.

yellow ironweed (noun)	crownbeard (noun)
perennial herb with showy yellow flowers; the eastern United States	any plant of the genus Verbesina having clustered white or yellow flower heads