Sunflower

The flower that turns to follow the Sun

A young sunflower turns its head to follow the Sun all day — east in the morning, west in the evening, and back east at night! Once grown, it always faces east. A sunflower's 'flower' is really 1,000–2,000 tiny flowers. Its seeds are arranged in spirals — a mathematical pattern. Sunflower seeds are pressed for oil.

The sunflower (Helianthus annuus) comes from North America, domesticated by Native Americans 4,000 years ago; it reached Europe in the 16th century and Russia in the 18th, where it became an oil crop (Russia and Ukraine — 50% of the world harvest). Heliotropism: a young plant's stem grows unevenly through the day, turning the head to follow the Sun (a circadian rhythm); once mature it locks facing east — warming faster in the morning and attracting more pollinators. The 'flower' is a head of 1,000–2,000 tiny florets; the seeds are arranged in Fibonacci spirals (34/55, 55/89) — the densest possible packing. Up to 3 m, record 9 m. Seeds are 40–50% oil; sunflower oil is the main cooking oil in Uzbekistan too. Its roots pull radioactive substances from soil — it was planted at Chernobyl and Fukushima.

Fun facts

• Sunflower seeds are arranged in Fibonacci spirals — nature is a mathematician!
• One sunflower 'flower' is really 2,000 tiny flowers.
• Sunflowers 'suck' radiation from soil — they were planted at Chernobyl.