The sunflower (Helianthus annuus) is an annual plant in the family Asteraceae, with a large flower head (inflorescence). The stem of the flower can grow up to 9 feet (3 metres) tall, with the flower head reaching 1 foot (30 cm) in diameter. At sunrise, the faces of most sunflowers are turned towards the east. Over the course of the day, they move to track the sun from east to west, while at night they return to an eastward orientation. A synergy is where different entities cooperate advantageously for a final outcome.