EXERCISE 126 



Reproduction by means of gametes and reproduction by means of spores seem to have led in most 

 families of plants to the evolution of two distinct generations. In almost all the familiar species of 

 plants the spore-bearing generation has become not only more conspicuous in size but more highly 

 specialized in the number and variety of organs and tissues. On the other hand, the gamete-bearing 

 generation has tended to become reduced to a microscopic body, simple in structure and parasitic in habit. 

 In the following table sketch and describe briefly the various stages in the life history of the types 

 imed, emphasizing the distinctive traits in each case. 



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