Seeds of doubt: mystery remains over how sunflowers track light

Researchers find the plants don’t use conventional processes to follow the sun across the sky

With their bright yellow manes and sturdy stems, sunflowers might seem like a simple summer delight. But researchers say the plants are surprisingly enigmatic after discovering they don’t use conventional processes to track the sun across the sky.

Over the course of a day, sunflowers follow the path of the sun overhead – a process known as heliotropism – with their heads tilting progressively westwards as a result of cells elongating on the east side of the stem.