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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

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A young flower head with yellow ray flowers in the periphery and orange maroon green disk flowers inside
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The left is the disk flower and the right is the ray flower
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The spiral arrangement of the disk flowers

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.

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Mathematical model of floret arrangement (Illustration of Vogel’s model)

The outer whorl of the disk flowers open first proceeding gradually towards the centre of the head.

 

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A young flower head cut into halves to show the internal structures
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A young disk flower

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.

Diagram of a disk flower
Diagram of a disk flower
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Two disc flowers with the characteristic bifid stigma and the 5 syngenesious stamens. As the position of the ovary is below that of the corolla and the calyx, the ovary is called an inferior ovary.

 

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Bifid stigma, 5 syngenesious stamens and corolla tube
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The anthers have separate filaments attached to the base of the corolla tube
The style and bifid stigma
The style and the bifid stigma
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Two pappus scales (modified sepals) on top of the ovary, below the corolla tube
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The ovary has been cut longitudinally open to show its single ovule inside.
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Transverse section of the ovary showing a single ovule

 

 

Mature flower head

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The anthers, stigma and petals of the disk flowers begin to wither
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A mature flower head cut into halves to show the internal structures
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Details of the above image showing the fruit of sunflower. The outer whorl of the disk flowers open and mature first proceeding gradually towards the centre of the head.
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A fruit cut longitudinally into halves to show the position of the fruit in the pistil
A three dimensional image of the fruits on the flower head
A three dimensional image of the fruits on the flower head with most of the corolla tubes and the inside content fallen off exposing the fruit.
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A comparison of the size of young flower with a flower bearing fruit

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.

The lower leaves are heart-shaped
The lower leaves are heart-shaped
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Rosette of bract leaves surrounding a flower head (capitulum) is called an involucre

 

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.

Flag and Seal of Kansas
Flag and Seal of Kansas

 

Stamps of Sunflowers

 

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Stamp of USA

 

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Stamps of Canada

 

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Stamp of Australia

 

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.

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Vincent van Gogh, Vase with Three Sunflowers (August 1888), Arles, oil on canvas, 73 x 58 cm, Private collection

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.

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Vincent van Gogh, Vase with Sixteen Sunflowers (also known as Fourteen Sunflowers), (August 1888), Arles, oil on canvas, 93 x 73 cm, The National Gallery London, Tate Gallery Loan

 

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Vincent van Gogh, Vase with Twelve Sunflowers (August 1888), Arles, oil on canvas, 91 x 71 cm, Neue Pinakothek Munich, Collection of Bayerische Staatsgemaldesammlungen, Munich)
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Vincent van Gogh, Vase with Fifteen Sunflowers (January 1889), Arles, oil on canvas, 100 x 76 cm, The National Gallery London (The vase does not have ‘Vincent’ on it.)

 

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Vincent van Gogh, Vase with Twelve Sunflowers (January 1889), Arles, oil on canvas, 92 x 72.5 cm, The Philadelphia Museum of Art

 

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Vincent van Gogh, Sunflowers (January 1889), Arles, oil on canvas, 95 x 73 cm, Rijksmuseum Vincent van Gogh, Amsterdam

 

sketches of van Gogh
A sketch of sunflowers in a pot by van Gogh
sketches of van Gogh (2)
A sketch of sunflowers in a pot by van Gogh

 

Van Gogh’s Sunflowers used an impressive range of techniques, from tiny pointillist dots to thick sculptural strokes.

 

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Vincent van Gogh, Sunflowers (Autumn 1887), Paris, oil on canvas, 43.2 x 61 cm, The Metropolitan Museum of Art, New York
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Vincent van Gogh, Sunflowers (Autumn 1887), Paris, oil on canvas, 60 x 100 cm, Rijksmuseum Kroller-Muller, Otterlo

 

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Vincent van Gogh, Sunflowers (Autumn 1887), Paris, oil on canvas, 20.5 x 26.5 cm, Rijksmuseum Vincent van Gogh, Amsterdam

 

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Vincent van Gogh, Sunflowers (Autumn 1887), Paris, oil on canvas, 50 x 60 cm, Kunstmuseum Bern

 

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

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Wang Ge yi (王个簃) (1897-1988) Attracted to the sun (傾心向太陽) (1963), ink and watercolour on paper.

 

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Lin Fengmian (林風眠) (1900 – 1991) Sunflowers, 40 x 34 cm, ink and watercolour on paper

 

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Zhong Zhifu (鍾質夫) (1914 – 1994), Sunflowers, 96 x 34 cm, ink and watercolour on paper

 

 

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Chao Shao-ang (趙少昂) (1905 – 1998), Sunflowers, ink and watercolour on paper

 

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Chao Shao-ang (趙少昂) (1905 – 1998), Sunflowers and mantis, ink and watercolour on paper

 

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Chao Shao-ang (趙少昂) (1905 – 1998), Sunflowers and mantis, ink and watercolour on paper

 

Chao Shao-ang (趙少昂) (1905 – 1998), sketches of sunflowers
Chao Shao-ang (趙少昂) (1905 – 1998), a sketch of sunflowers, ink on paper

 

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/

http://www.nationalgallery.org.uk/paintings/learn-about-art/paintings-in-depth/sunflowers-symbols-of-happiness/*/viewPage/6

http://www.telegraph.co.uk/culture/art/art-features/10592710/Van-Goghs-Sunflowers-the-story-behind-a-masterpiece.html

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

 

 

 

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