There was once a beautiful water-nymph called Clytie who fell in love with Helios, the God of the Sun. She was so much in love that she would sit on the grass and gaze up at the sun all day long but Helios, in his travels, looked over the world and never once did he see Clytie.
The other Gods took pity on her and turned her into a flower. Her legs became the sunflower's stem, her face became the flower and her golden hair the petals.
Today, in the form of a sunflower, Clytie still stares up at her love and this is why the sunflower's face always turns to follow the path of the sun.