Page 29 - Black Range Naturalist, Vol. 1, No. 2

Central Disk Flowers and Fibonacci Spirals of Annual Sunflower, Helianthus anuus
And what about gymnosperms, the cone- bearing plants that are even more ancient than flowering plants? Are there Fibonacci patterns in these? Indeed. Any pine cone is also composed of spirals; these are an arrangement of woody bracts. Take some paint and color each spiral differently (colored pine cone photo). You will find a number of spirals, high, low and both directions, but if you track them around the cone, you will find they most commonly reflect a Fibonnaci number. The needle leaves of gymnosperms grow singly or in fascicles of 2’s, 3’s and 5’s.
Ponderosa Pine Cone Colored to Show Fibonacci Spirals

For creating botanical illustration such patterns are very helpful. For example, if you want to draw a pine cone you lay out the Fibonacci spiral in two directions, then draw the bracts along these lines. There are many similarly spiraled plant structures; look carefully at cauliflowers, pineapples, artichokes, and as noted, there are spirals in leaf arrangements too. (See image on following page.)
But why these numbers? Such mathematical patterns result from function. If you think about light efficiency, it makes sense for plants to add buds, petals, leaves, or bracts
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