Mother of Sun
Canon EOS 40D + Canon EF-S 17-85mm F4-5.6 IS USM @20mm
What is usually called the flower is actually a head (formally composite flower) of numerous florets (small flowers) crowded together. The outer florets are the sterile ray florets and can be yellow, maroon, orange, or other colors. The florets inside the circular head are called disc florets, which mature into seeds
The florets within the sunflower's cluster are arranged in a spiral pattern. Typically each floret is oriented toward the next by approximately the golden angle, 137.5°, producing a pattern of interconnecting spirals where the number of left spirals and the number of right spirals are successive Fibonacci numbers. Typically, there are 34 spirals in one direction and 55 in the other; on a very large sunflower there could be 89 in one direction and 144 in the other. This pattern produces the most efficient packing of seeds within the flower head.
Sunflowers in the bud stage exhibit heliotropism. 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 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.
Sunflowers in their blooming stage lose their heliotropic capacity. The stem becomes "frozen", typically in an eastward orientation. The stem and leaves lose their green color.
The wild sunflower typically does not turn toward the sun; its flowering heads may face many directions when mature. However, the leaves typically exhibit some heliotropism.
Sunflowers most commonly grow to heights between 1.5 and 3.5 m (8–12 ft). Scientific literature reports from 1567, that a 12-m (40 ft), traditional, single-head, sunflower plant was grown in Padua. The same seed lot grew almost 8 m (26 ft) at other times and places (e.g. Madrid). Much more recent feats (past score years) of over 8 m have been achieved in both Netherlands and Ontario, Canada.
The sunflower is the state flower of the US state of Kansas, and one of the city flowers of Kitakyūshū, Japan.
The sunflower is often used as a symbol of green ideology, much as the red rose is a symbol of socialism or social democracy.
The sunflower is also the symbol of the Vegan Society. During the late 19th century, the flower was used as the symbol of the Aesthetic Movement.
Subject of Van Gogh's most famous still life, Sunflowers (series of paintings)
The sunflower is the national flower of Ukraine.