August 30, 2002
Late summer is a season for allergies, often attributed to this vibrant late bloomer - goldenrod. But goldenrod (Solidago sp.) is wrongly accused of producing the irritating pollen that bothers so may this time of year. Goldenrod's heavy, sticky pollen is suited for dispersal by bees and other insects, not likely to bother the casual passerby. It is ragweed, goldenrod's inconspicuous summer field companion that's the real culprit, producing huge amounts of pollen designed to be carried by the wind. Ragweed (Ambrosia sp.) is a humble but noxious weed that springs up in grain fields after late summer rains in the midwest, and sends many to the medicine cabinet for relief from the pungent allergenic effects of its pollen. Since Ambrosia pollen is windborn, it can be observed in sediment samples of lakes dating back thousands of years and used to infer climate, vegetation and land cover patterns since the last continental glaciation.