I posted this question on StackOverflow but never got a reply...
I put the following resources online:
Very briefly, the table gs contains the names of symbols, like the United States' national mammal, the bison (Bison bison), derived from the fields gs.Symbol (bison) and gs.Latin (Bison-bison).
All the plant and animal symbols contained in the table gs are also found in the table gs_planimals, which also includes their parents, grandparents, etc. In other words, it's a taxonomic ranking of the animal kingdom.
So here's the problem: I can display a list of U.S. state birds or Canadian flower symbols, derived from the table gs only. Or I can display an identical list derived from the table gs_planimals. But if I want to also display the symbols' parents and grandparents, I'm stuck. I can either display ALL higher taxons or no higher taxons.
The bison's parent and grandparent are Bison and Bovidae, neither of which are contained in the table gs. Therefore, I have no way of recognizing them as part of a particular flow of data.
Someone at StackOverflow told me what I want to do can be done, but he then disappeared. ;)