The sunflower (Helianthus annuus) is an annual plant in the family Asteraceae, with a large flower head (capitulum). The stem of the flower can grow up to 3 meters tall, with a flower head that can be 30 cm wide. The flower head is actually an inflorescence made of hundreds or thousands of tiny flowers called florets. The central florets look like the centre of a normal flower, and the outer florets look like yellow petals. All together they make up a "false flower" or pseudanthium. The benefit to the plant is that it is very easily seen by the insects and birds which pollinate it, and it produces thousands of seeds The sunflower is the state flower of Kansas. That is why Kansas is sometimes called the Sunflower State. To grow well, sunflowers need full sun. They grow best in fertile, wet, well-drained soil with a lot of mulch. In commercial planting, seeds are planted 45 cm (1.5 ft) apart and 2.5 cm (1 in) deep. Sunflowers commonly grow to heights between 1.5 and 3.5 m (5-12 ft.). The tallest sunflower confirmed by Guinness World Records is 8.0 m (2009, Germany). In 16th century Europe the record was already 7.3 m (24 ft., Spain). Most cultivars are variants of H. annuus, but four other species (all perennials) are also domesticated. This includes H. tuberosus, the Jerusalem Artichoke, which produces edible tubers.
