Common Sunflower (Helianthus annuus)

Common Sunflower 

Common Sunflower (Helianthus annuus) herb/forb in the Aster Family (Asteracceae) and order Asterales. It is uncommon around French Hill Pond but has been found in this area. The photograph on this page was taken to the east of the pond. The genus  name is derived from the Greek words, "helios anthos" which means "sun flower." The species name, annuus, is Latin for "lasting a year," which is appropriate because this plant is an annual. This forb can grow to ten feet (300 centimeters) tall. The very large flower head can be as large as six inches (15 centimeters) in diameter. The sterile ray flowers are yellow and surround a disk of brown flowers that produce the seeds. This plant flowers from July to as late as November. 

The alternately arranged leaves are ovate to nearly triangular, hairy, pointed,  with roughly serrated edges and from three to twelve inches ( eight to 30 centimeters) long.

The fruit is a dry, encapsulated seed. The capsule is blue to black and the seed is white. The seeds are eatable.

The root system is simple. Propagation is by seed that will winter over.

The large size of the sunflower allows for an easier examination of the flower parts. The ray flowers are the large yellow petals on the edge of the flower. The disk flowers are in the center. The following photograph shows the tiny immature disk flowers. Note that these flowers resemble tiny, yellow lilies. As these disk flowers mature, they will turn red to brown as shown in the photograph above.

Sunflower Disk Flowers

The following photograph shows the rear of a sunflower. The green petals are the bracts that originally clasped the flower as the flower developed. Note the immature sunflower in the foreground where the bracts are clasping the developing flower.

Sunflower Bracts

The Common Sunflower (Helianthus annuus) is an important cultivated plant providing a large volume of seeds that are popular as snacks and can be made into cooking oil. It is a very good source of food for wild animals. Birds and squirrels are particularly fond of the seeds. Cultivated stands of Sunflowers require protection from herbivores. Many people cultivate these flowers on Mount Desert Island and these cultivated flowers often escape into the wild, sometimes a considerable distance from the cultivated field. 

 

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