The Golden Ratio can be found in multiple places on the Yellow Poplar leaf. The first example is along the whole height of the leaf. For the sake of easy understanding lets just call the longer leg 'A' and the shorter leg 'B'. in this first example A+B is the entire height of the leaf from the bottom of the stem to the very top.

Example two shows a second Golden Ratio that is created by the veins of the leaf. the overall length of this Golden Ratio is from one intersection of veins skipping one intersection and stopping at the next. In most Yellow Poplar leaves the Golden Ratio "walks" up the leaf. here is example 2:

The Golden Ratio may also be found in many other places. use your imagination.