__
                                 |  
                               __|
                              |  |
                              |  |__
                              |     
 _James Madison DUKE _________|
| (1809 - 1892)               |
|                             |   __
|                             |  |  
|                             |__|
|                                |
|                                |__
|                                   
|
|--John Tyler DUKE 
|  (1842 - 1909)
|                                 __
|                                |  
|                              __|
|                             |  |
|                             |  |__
|                             |     
|_Elizabeth Lavinia JENNINGS _|
  (1812 - 1885)               |
                              |   __
                              |  |  
                              |__|
                                 |
                                 |__