Sunflower Surprise Floral Display At Gardens By The Bay Part 2

Helianthus or sunflower is a genus of plants comprising about 70 species. Except for three species in South America, all Helianthus species are native to North America. The common name, “sunflower” typically refers to the popular annual species Helianthus annuus, or the common sunflower, whose round flower heads in combination with the ligules look like the sun. This and other species, notably the Jerusalem artichoke (H. tuberosus), are cultivated in temperate regions and some tropical regions as food crops for humans, cattle, and poultry, and as ornamental plants. Perennial sunflower species are not as popular for gardens due to their tendency to spread rapidly and become invasive. Sunflowers are usually tall annual or perennial plants that in some species can grow to a height of 300 cm (120 in) or more. They bear one or more wide, terminal capitula (flower heads), with bright yellow ray florets at the outside and yellow or maroon (also known as a brown/red) disc florets inside. Several ornamental cultivars of H. annuus have red-coloured ray florets; all of them stem from a single original mutant. During growth, sunflowers tilt during the day to face the sun but stop once they begin blooming. This tracking of the sun in young sunflower heads is called heliotropism. By the time they are mature, sunflowers generally face east. Credit: Wikipedia.