EXERCISE 113 



The spores of various plants are usually so small that single ones cannot be seen without a micro- 

 scope. They are thus blown about in the dust. 



Problem. How widespread are the spores of common spore-producing plants ? 



What to use. Pieces of moist bread or diluted sirups or fruit juices (a teaspoonful to a pint of water), 

 to catch the spores ; moist chambers (consisting of a tumbler inverted over several thicknesses of moist 

 filter paper or blotter), to hold the bread ; test tubes, closed with cotton plugs, to hold the sirups. 



What to do. Expose pieces of bread or tubes of sirup in various situations overnight ; cover and 

 leave in a dark cupboard or under a box, at ordinary temperature or warmer. Examine at intervals 

 i of twenty-four hours and note numbers and kinds of growths. 



Record. Describe the results from different sources and make up your mind where different kinds 

 of spores are likely to be most abundant. If it is possible to examine with a microscope, add drawings 

 to record. 



Questions. 1. Do all kinds of dust contain spores? 



2. What kinds of growth are most likely to come from the dust in a closely populated neighborhood ? 



3. What kinds of spores are most likely to be found in the woods ? 



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