Helianthus annuus, commonly known as sunflower, is a large annual herbaceous plant which belongs to Family Asteraceae. Sunflower is grown as a crop for its edible oil and edible fruits (sunflower seeds). The seeds are also used as bird food.
The ‘flower’ of sunflower is actually a ‘flower head’ or capitulum (or pseudanthium) of many individual flowers (florets). There are two types of flowers. The outer flowers, which resemble petals, are called ray flowers. They are sexually sterile and yellow in colour. The flowers in the center of the head are called disk (disc) flowers. They are yellow to maroon in colour and are fertile and mature into fruit (sunflower “seeds”).
Young flower head
The disk flowers are arranged spirally. Generally, each floret is oriented toward the next in such a way producing a pattern of interconnecting spirals. Mathematicians worked out the pattern to be related to Fibonacci numbers. This pattern produces the most efficient packing of seeds within the flower head.
The outer whorl of the disk flowers open first proceeding gradually towards the centre of the head.
Each disc flower consists of an inferior ovary, two pappus scales (modified sepals) and a tubular corolla formed by the fusion of 5 petals except at the tip. 5 anthers are united to form a tube, this is known as syngenesious stamens. The anthers have separate filaments attached to the base of the collar tube. Inside the anther tube is the style which terminates in a bifid stigma.
Mature flower head
A common misconception is that flowering sunflower heads track the Sun across the sky. Although immature flower buds exhibit this behaviour. This movement is known as heliotropism. The mature flowering heads point in a fixed (and typically easterly) direction throughout the day.
The rough and hairy stem is branched in the upper part in wild plants but is usually unbranched in domesticated cultivars.
The leaves are dentate (with teeth in the leaf margin) and heart-shaped.
There is evidence that sunflower was first domesticated in Mexico around 2600 BCE and in Tennessee, USA around 2300 BCE. Some archaeologists have suggested sunflowers may have been domesticated before corn. The seeds were ground into flour for cakes, mush (cornmeal pudding) or bread and the oil was used for cooking.
Many indigenous American peoples, the Aztecs and the Otomu of Mexico and the Incas of South America used the sunflower as the symbol of their solar deity.
The sunflower is the state flower of the US state of Kansas and one of the national flower of Ukraine.
Stamps of Sunflowers
Paintings of Sunflowers by Vincent van Gogh
In Dutch literature the sunflower was a symbol of devotion and loyalty. In their various stages of decay, these flowers also remind us of the cycle of life and death. For Van Gogh, yellow was an emblem of happiness. In 1888 and 1899 he was in Arles, the South of France waiting for the arrival of his hero, the avant-garde artist Gauguin. Van Gogh painted at least seven versions of sunflowers in a vase. His sketchbooks also contain sketches of sunflowers. The ‘Sunflowers’ was a gesture of friendship and to impress Gauguin.
Impressionists usually intensify the colours by placing opposing colours next to each other – yellow flowers against a blue background for example.
However, Van Gogh in his later versions have yellow flowers in a yellow vase on a yellow table, against a yellow wall and yet the picture seems to radiate light.
Van Gogh’s Sunflowers used an impressive range of techniques, from tiny pointillist dots to thick sculptural strokes.
Van Gogh was not trying to make an exact copy of reality in his paintings. He did not use colour merely to imitate nature, but to express emotion.
“….my pictures are after all almost a cry of anguish, although in the rustic sunflower they may symbolize gratitude“
Vincent writing to Wilhelmina, his sister, Psychiatric ward, Hospital of St. Paul, St Remy, France, February, 1890
Contemporary Chinese Paintings on Sunflowers
Chinese painting usually shows the subject but leaves the background empty. This is one of the main differences between Chinese painting and western painting.
Dutch great artists like Van Gogh or Chinese great artist like Chao Shao-ang made sketches before creating their masterpieces. It is essential to plan before painting.
Bibliography
https://en.wikipedia.org/wiki/Helianthus_annuus
http://www.authorstream.com/Presentation/chhabra61-532487-flower-structure-of-sunflower/
https://en.wikipedia.org/wiki/Sunflowers_(Van_Gogh_series)
https://www.youtube.com/watch?v=ykXXEr4SBRc (time lapse video)
https://www.youtube.com/watch?v=Z-iPp6yn0hw (time lapse video from seed to flower)
Stein, Susan Alyson (1986) Van Gogh – A Retrospective, Beaux Arts Edition ISBN 0-88363-310-8
Duncan, David Douglas (1986) Sunflowers for Van Gogh, Rizzoli ISBN 0-8478-0764-9
Van der Wolk, Johannes (1987) The Seven Sketchbooks of Vincent can Gogh, Thames and Hudson, ISBN 0-500-09182-X
陳履生, 張蔚星 (2000) 中國花鳥畫 現代卷 下 ,金羊毛家庭珍藏圖庫, 廣西美術出版 ISBN 7-80625-744-6/J-611
Chao Shao-ang (趙少昂) (1990) A Study of Chinese Paintings, Publisher: Ho Kung-shang, Art Book Co., Ltd, Taiwan, ISBN 957-9045-22-4
Patrick Siu Chinese Calligraphy & Landscape Painting 蕭燿漢談書畫 