Ragweeds are flowering plants of the genus Ambrosia, most of which are native to America. The pollen of the weedy herbs is recognized as the primary cause of hay fever in eastern and middle North America. Its effects are exacerbated by the fact that ragweeds—which are anemophilous, or wind-pollinated—are each thought to be able to produce about one billion grains of pollen in a single season. For what other reasons is ragweed so difficult to eradicate? Discuss
Source: The Free Dictionary