any of a genus (Ambrosia) of chiefly North American plants of the composite family, having tassel-like, greenish flowers which yield large amounts of wind-borne pollen, a major cause of hay fever
Origin of ragweedfrom the tattered appearance of the leaves
- Any of various weeds of the genus Ambrosia of the composite family, having small, greenish, unisexual flower heads and producing abundant pollen that is one of the chief causes of hay fever.
- Chiefly British Ragwort.
Origin of ragweedFrom the ragged shape of its leaves
top: common ragweed
bottom:pollen grains of western ragweed