Plants illustrate the Fibonacci series in the numbers and arrangements of petals, leaves, sections and seeds.
Fibonacci numbers in plant spirals
Plants that are formed in spirals, such as pinecones, pineapples and sunflowers, illustrate Fibonacci numbers. Many plants produce new branches in quantities that are based on Fibonacci numbers.
Fibonacci numbers in plant branching
Here a sunflower seed illustrates this principal as the number of clockwise spirals is 55 (marked in red, with every tenth one in white) and the number of counterclockwise spirals is 89 (marked in green, with every tenth one in white.)
Here a plant illustrates that each successive level of branches is often based on a progression through the Fibonacci series.
Fibonacci numbers in plant sections
You might expect symmetry in plants, but if you cut a fruit or vegetable you will often find that the number of sections is a Fibonacci number:
Bananas have 3
Apples have 5
Fibonacci numbers in flower petals
Many flowers have petals that total a number in, or very close to, the Fibonacci series: