名詞 ragweed:

1. widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity
   同義詞：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
   同義詞：ambrosia, bitterweed

rag.weed

n.（名詞）
Any of various weeds of the genusAmbrosia having small, greenish, unisexual flower heads and producing abundant pollen that is one of the chief causes of hay fever.
豚草：一種豚草 屬的雜草，有綠色、單性花朵，能產(chǎn)大量花粉，是引起花粉熱的主要原因之一
Chiefly British Ragwort.
【多用于英國】 千里光屬

來源：
[From the ragged shape of its leaves]
[源于其葉片破裂的形狀]