There are over 100,000 species of fungi. Many fungi are good and useful (edible mushrooms would be an example of these) while some cause problems (some fungi can injure plants and humans). Every week the IEQ Review will describe a specific microorganism, its morphological origin and potential health effects.  If you would like to know about a specific organism and/or would like it published in The IEQ Review please email Dr. Rajiv Sahay with the Environmental Diagnostics Laboratory (EDL) at Pure Air Control Services laboratory@pureaircontrols.com.

This week we will cover ...   
 
Ambrosia (Ragweed)

 
 
Ambrosia is commonly known as Ragweed.  The name ragweed has been given due to the raggedy shape of its leaves.  About 21 species of ragweed occur in North America.  Ragweeds are annual or perennial herbs with lobed or divided leaves, which are deeply bipinnately dissected, lower ones opposite, upper ones alternate.  It is the most important plant of pollinosis in the USA and follows a general pattern of pollination from the north to the south, with a few exceptions.
 
Pollen Morphology:
 
Grain, echinate, tricolporate, with short colpi.  The sexine is thick and contains short spines with pointed apices and broad bases, some times with intermixed spinules.
 
Flowering and Pollen Aerobiology:
 
Thought most temperate North America composites flower during midsummer or late summer to autumn.  In Florida and the southwest flowering may be much earlier or late or may be round the year for few species.  Pollens are characteristic of wind-pollinated.
 
Allergenicity:
 
Most important cause of pollinosis in North America.
 
 

# # #

For additional information, contact:

Pure Air Control Services

800-422-7873, ext. 802