gravelweed vs crown-beard

gravelweed and crown-beard both are nouns.

Word	Noun	Adjective	Verb	Adverb
gravelweed	Yes	No	No	No
crown-beard	Yes	No	No	No

As nouns, crown-beard is a hypernym of gravelweed; that is, crown-beard is a word with a broader meaning than gravelweed:

gravelweed: perennial herb with yellow flowers; southern and south central United States
crown-beard: any plant of the genus Verbesina having clustered white or yellow flower heads

Other hypernyms of gravelweed include crown beard, crownbeard.

gravelweed (noun)	crown-beard (noun)
perennial herb with yellow flowers; southern and south central United States	any plant of the genus Verbesina having clustered white or yellow flower heads