Take on Nature: In praise of the magnificent sunflower
IN PRAISE of the magnificent sunflower, Erasmus Darwin, grandfather of Charles, wrote that it:
"Climbs the upland lawn,
And bows in homage to the rising dawn,
Imbibes with eagle eye the golden ray,
And watches, as it moves, the orb of day."
Scientific research from the University of California, Davis (2016) has shown that the immature or young flowerheads of the plant do indeed display heliotropism, or tracking of the sun.
Stacey Harmer, professor of plant biology at UC Davis and senior author on the paper says: "It's the first example of a plant's clock modulating growth in a natural environment and having real repercussions for the plant."
This behaviour is explained by ‘circadian rhythms', behavioural changes, linked to an internal clock which follow a daily cycle and respond primarily to light and darkness in an organism's environment.
Such rhythms are found in most living things, including animals. Sleeping at night and being awake during the day is an example of a light-related circadian rhythm.
As the sunflower matures however, with the flower opening up, overall growth slows down, and the plant stops moving during the day to settle, becoming fixed on facing east.
Contrary to belief of many, the flower doesn't derive its name from the young plant's sun-tracking from east to west, but instead from the actual resemblance of the full-blown flower to the sun itself, with its broad golden disk and rays.
An imposing plant, its large sun-like bloom is perfectly balanced on the tall slender stalk, often reaching 12 feet or more in height. Sunflower heads are composed of many small tubular flowers arranged on a flattish brown disk which ripen into heavy heads filled with seeds, while bright yellow petals form the rays around the composite flower.
The plant, which has been visible in recent weeks, thriving in many gardens, is also harvested for its culinary uses as an oil and an ingredient in snacks and bread.
'Lus na gréine' in Irish (herb or flower of the sun) is a native of Mexico and Peru and is thought to have been cultivated there are as far back as 3000 BC, long before their oil rich seeds were brought to Europe by Spanish explorers in the 16th century.
Native Americans, also used the sunflower for food and medicine, using the juice from the stems to treat wounds and infusing the plant in water to treat kidneys.
Its Latin name, Helianthus, is derived from helios (the sun) and anthos (a flower) and has links to the tragic Greek tale of Clytie, a water nymph and her lover, the sun god Helios, who deserted her in favour of Leucothea, daughter of Orchamus.
Enraged, Clytie told Orchamus about the love affair and after he sentenced his daughter to death, Clytie was certain Helios would return to her, but her actions only hardened his heart.
Mourning his departure, she lay for nine days on rocks, without food or water staring at and following the sun, Helios. After the ninth day, she was transformed into a flower, the heliotrope or turnsole, known for growing on sunny, rocky hillsides and turning its head to look longingly at Helios' chariot of the sun.
The story is most fully told in the Latin narrative poem the Metamorphoses by the Roman poet Ovid. Modern traditions substitute the turnsole with a sunflower.
Sunflowers have inspired many artists, the most well-known, Van Gogh, who produced several renditions of the large yellow blossoms in two separate series, known as the Sunflower series, one completed in Paris in 1887 and another in Arles during 1888/89.
A plant to surely turn heads.