CHAPTER XIV. 



ADAPTATION TO ENVIRONMENT. 



OBSERVATIONS. 



182. Examine plants which grow in dry regions; note 

 whether much or little branched, the form and texture of 

 the leaves. In what ways is rapid transpiration guarded 

 against? Are there any parts which serve for storing 

 water ? Where are the chloroplasts located ? If these 

 plants were removed to regions of abundant rainfall, would 

 they have any advantage over the plants of that region ? 

 Can you see wherein they would be at a disadvantage ? 



183. Compare, if possible, with plants native to salt 

 marshes or to alpine or polar regions. 



184. Examine plants growing partly submerged in the 

 water, such as water lilies or Sagittarias. In what way do 

 you find them better adapted to living in water than are 

 plants which grow on the land? Would they be at any 

 disadvantage on the land? If so, in what ways? 



185. Make cross sections of the stems and underground 

 parts of water lilies and Sagittarias, and note how the air is 

 given access to the submerged parts. 



1 86. Examine plants such as Lichens, Pleurococcus, etc., 

 growing on the bark of trees. Do they at times become 

 quite dry ? Have they special devices to keep them from 

 drying up ? Pour water over some of these plants which 

 have become dry. Do they quickly absorb it? How are 

 they adapted for the rapid absorption of water ? 



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