The red sunflower is an unusually colored sunflower created by breeding together different varieties of sunflowers. The sunflower, Helianthus annuus, is an annual plant in the family Asteraceae with a large flower head (also known as an inflorescence).
Like standard sunflowers, the florets inside the circular head are called disc florets, and they mature into what are traditionally called "sunflower seeds." These are actually the fruit (an achene) of the plant, and the inedible husk is the wall of the fruit, while the true seed lies within the kernel.
Red sunflowers in the bud stage exhibit heliotropism. At sunrise, the faces of most sunflowers turn toward 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. This motion is performed by motor cells in the pulvinus, a flexible segment of the stem just below the bud. As the bud stage ends, the stem stiffens and the blooming stage is reached. Heliotropism is not a trait of sunflowers once they reach the blooming stage.
The stem of the flower can grow up to 3 metres (9 ft 10 in) tall. Multiple cultivars of red sunflowers exist; varieties include "Prado Red" and "Red Sun."
Source : http://en.wikipedia.org/wiki/Red_sunflower
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