The least favorite season for "hay fever" sufferers is ragweed season. Ragweed is a summer annual that is found throughout the United States and produces abundant pollen, a primary cause of hay fever. Being a hearty noxious weed, diseases really don't affect it much and about the only things that kill the plant are a lack of water or herbicides.
The picture shows ragweed pollen grains as they would appear when stained on a slide. The pollen grains are collected on a rotating greased rod, then counted manually using a microscope. Ragweed, an easily distinguishable pollen, appears as a spiny ball in most cases.
Electron Microscope View: As autumn approaches, not only are the pollen counts high, the mold count is also elevated, causing a two front battle for allergy sufferers. Decomposition of plant material by molds leads to higher counts and a secondary assault on the respiratory system of the allergy sufferer.
In an effort to aid those who suffer with allergies, the Southwest Ohio Air Quality Agency has compiled a "Living with Allergies" brochure.