Thus, Puerto Rico, a similar but much older island 

 than Hawaii, has a richer tree flora, more well-defined 

 tree species, and none apparently extinct. The endemic 

 but impoverished tree flora of the young Hawaiian 

 Islands is of special interest to students of evolution. 

 However, other tropical areas, such as Puerto Rico, have 

 richer and more varied tree floras and are more represen- 

 tative examples of tropical vegetation for education and 

 research. 



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