Sunflower

The sunflower is a tall plant with a large yellow flower head. Young sunflowers follow the Sun across the sky: their stems bend so the bud faces east in the morning and west by evening, and overnight they swing back to face east again, ready for sunrise.^[1] A young sunflower is the only plant known to reset itself before going to sleep.

Facing east

Once the flower opens fully, the sunflower stops moving and faces east permanently. A 2016 study found that east-facing flower heads warm up faster in the morning and get more visits from bees and other pollinators.^[2] The mature sunflower has therefore stopped following the Sun and simply waits for it to arrive, a strategy also known as experience.

The head

A sunflower's head is not one flower but hundreds or even a couple of thousand tiny flowers, called florets, packed together. The seeds are arranged in two sets of spirals, one turning clockwise and the other anticlockwise, and the numbers of spirals in each direction are usually neighbouring numbers in the Fibonacci sequence, such as 34 and 55.

• Young sunflower: follows the Sun.
• Grown sunflower: faces east.
• Number of flowers in one sunflower: hundreds.
• Number of spirals: Fibonacci, as a rule.

See also

• Sun – what it follows
• Yellow – its colour
• Bee – which prefers it warm
• Butterfly – a flower that learned to fly
• Dandelion – a smaller yellow flower with ambitions

References

1. Helio, H. (2016). “East, Then Stay”. Plant Behaviour 1: 1.
2. Floret, F. (2001). Hundreds of Flowers, One Head. Meadow Press.
3. Fibonacci, L. (1202/2013). 34, 55. Fictional reprint.