At sunrise, the faces of most sunflowers are turned towards the east. Over the course of the day, they follow the sun from east to west, while at night they return to an eastward orientation. This motion is called heliotropism.

Sunflowers (Helianthus annuus).

The sunflower is an annual plant in the family Asteraceae and native to the Americas, with a large flowering head. More sunflower pictures at Sunflower pictures.