The picture on the left is of Goldenrod (Solidago canadensis). It is a member of the Composite family of weeds as is Giant Ragweed (Ambrosia
trifida) shown on the right. Goldenrod is a perennial herb with numerous brilliant yellow flowers. It is often blamed for fall hay fever (or
pollinosis), but is unlikely the cause, as it has a sticky pollen which is not airborne. The pollen of Goldenrod is carried from one plant to another by insects such as bees and butterflies.
Ragweed is a wind pollinated plant. The Giant Ragweed shown may grow 10 to 15 feet tall and is often found along corn fields, on stream banks, and in flood plains. Giant Ragweed produces copious amounts of pollen. The pollen has been reported to travel up to 500 miles from the original plant. There are other versions of it: Short or Common Ragweed (Ambrosia
artemisiifolia), Southern Ragweed (Ambrosia bidentata), Western Ragweed (Ambrosia
psilostachya), Slender Ragweed (Ambrosia confertiflora), False Ragweed (Ambrosia
acanthicarpa), and Desert Ragweed (Ambrosia dumosa). Ragweed is by far the most troublesome allergenic plant on the planet. Doctors report that 75% of atopic (or allergic) patients will react positively to ragweed on a skin test. It begins to pollinate in mid August and quits pollinating after the first heavy frost. Ragweed reaches its peak (for air saturation) the first two weeks of September, which is also the peak for Alternaria mold or leaf mold (not shown). These two culprits (ragweed and mold) are probably the biggest contributors to missed school and work days due to illness.
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