mayweed vs composite plant

mayweed and composite plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
mayweed	Yes	No	No	No
composite plant	Yes	No	No	No

As nouns, composite plant is a hypernym of mayweed; that is, composite plant is a word with a broader meaning than mayweed:

mayweed: widespread rank-smelling weed having white-rayed flower heads with yellow discs
composite plant: considered the most highly evolved dicotyledonous plants, characterized by florets arranged in dense heads that resemble single flowers

Other hypernyms of mayweed include composite.

mayweed (noun)	composite plant (noun)
widespread rank-smelling weed having white-rayed flower heads with yellow discs	considered the most highly evolved dicotyledonous plants, characterized by florets arranged in dense heads that resemble single flowers