Synonyms:
ragweed, ambrosia, bitterweed
Meaning: any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthma
Synonyms:
ragwort, tansy_ragwort, ragweed, benweed, Senecio_jacobaea
Meaning: widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity