Seeds of doubt: mystery remains over how sunflowers track light

‘So many of our results were different than we anticipated,’ say researchers from the University of California. Photograph: Anadolu Agency/Getty Images

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.