NEW YO;lK 



B0TAN4CAL 



Oaxi>fiN 



TORREYA 



\^ol. 36 SeptembcM-Octobcr, 1936 No. 5 



Pollen in Hayfever 

 Part 2 



R. P. WODEHOUSE 



If one wishes to discover which kinds of pollen are abundant 

 in the air and likely to cause hayfever it is only necessary to 

 expose a microscope slide with a small spot lightly coated with 

 glycerine jelly to which has been added an appropriate dye such 

 as basic fuchsin. After exposing for about 24 hours the slide is 

 brought in, warmed gently and covered with a thin cover glass. 

 Examination with the microscope will then show the pollen 

 deeply stained, fully expanded, and properly imbedded in an 

 excellent medium for their identification. If the microscope has 

 a mechanical stage it is a simple matter to count all the different 

 kinds of pollen encountered and so determine the relative abun- 

 dance of each in the air. 



For purposes of identification one should have a reference 

 collection of the pollen of all the different kinds of anemophilous 

 species of the region and as many as possible of the more abun- 

 dant entomophilous species. Most of these have been described, 

 illustrated, and keyed out in the author's book, "Pollen Grains,"^ 

 but there is no substitute for a good reference collection. The 

 specimens should be mounted in glycerine jelly and stained with 

 the same dye that is used for making the atmospheric pollen 

 slides. 



On atmospheric pollen slides grains of both entomophilous 

 and anemophilous species will be found but the latter always 

 greatly outnumber the former. The anemophilous species are 

 naturally of the greater interest from a hayfever standpoint, 

 but to the pollen morphologist they are distinctly less interest- 

 ing because they are generally characterized by extreme sim- 



I Pollen Grains. The McGraw-Hill Book Co. New York. 1935. 



109 



