On my walk today I picked up an oak leaf so I could study its proportions.  Attached is the analysis showing some of the major golden ratios in its structure.  It was interesting to find that its overall length (in golden ratio units) was between 12 and 13 and height was between 8 and 9 by the inverse golden ratio in both cases. This created the Fibonacci proportion 13:8, which is the first Fibonacci number outside of twelve.  

Like an egg, the leaf's chemical composition resonates up around carbon-12 emphasizing specific harmonic proportions while the damping action of the golden ratio (also in the leaf's DNA structure) acts to contain or "push inward", anti-harmonically carving the cut-out variegated shape. Thus, the shape of the leaf is encoded as chemical (and atomic) resonance and damping patterns in its DNA.