ragweed

n 1: widespread European weed having yellow daisylike flowers;

sometimes an obnoxious weed and toxic to cattle if

consumed in quantity [syn: {ragwort}, {tansy ragwort}, {benweed},

{Senecio jacobaea}]

2: any of numerous chiefly North American weedy plants

constituting the genus Ambrosia that produce highly

allergenic pollen responsible for much hay fever and

asthma [syn: {ambrosia}, {bitterweed}]