Young Brunette Girl Travelling Around The World With Sunflowers

The florets within the sunflower's cluster are arranged in a spiral pattern. Typically each floret is oriented toward the next by approximately the golden angle, 137.5°, producing a pattern interconnecting spirals where the number left spirals and the number right spirals are successive Fibonacci numbers. Typically, there are 34 spirals in one direction and 55 in the other; on a very large sunflower there could be 89 in one direction and 144 in the other. This pattern produces the most efficient packing seeds within the flower head.
Sunflowers most commonly grow to heights between 1.5 and 3.5 m (5–12 ft). Scientific literature reports that a 12 m (40 ft), traditional, single-head, sunflower plant was grown in Padua in 1567. The same seed lot grew almost 8 m (26 ft) at other times and places, including Madrid. During the 20th century, heights over 8 m have been achieved in both Netherlands and Ontario, Canada.