Did you know that sunflowers are heliotropes?
The sight of rows upon rows of a sunflower field in bloom can be truly inspiring. The sunflower is more than just a pretty face however – it is a versatile and useful plant with interesting characteristics. The sunflower originated in North America, and of the approximately 60 species of sunflower, most are native to the wide stretches of sun-laden prairie and naturally occuring open areas of the Great Plains. Sunflower is believed to have been domesticated from wild sunflower around 1000 B.C. by Native Americans to produce the single-stalked Common Sunflower. The sunflower provided the tribe with food, was ground into flours for making breads and soups, and the ground seeds were also boiled to extract the oil. This oil was used for cooking, to soften leather, as a salve and as a hair conditioner. Explore our sunflower facts page to learn more about the features making the sunflower so unique among flowers.
Sunflower Facts – Looks
The sunflower resembles one huge flower, but did you know a single sunflower head hosts hundreds of tiny flowers called florets? The plant is a rather thick, green stem sticking up out of the ground around 10 feet (3 meters) tall with a few leaves growing from it. On top of this tall stem is what seems to be a single enormous flower with yellow petals and a brown centre. But this flower is actually known as the head of the sunflower, and is not a flower at all, but rather a bunch of them. The yellow petals are actually protective leaves that cover the centre of the head while it is growing. The brown centre of the sunflower is composed of a mass of hundreds of flowers, all growing individually, and from where each sunflower seed will originate.
Sunflower – Name
The sunflower belongs to the genus Helianthus annus. “Helios” translates to sun in Greek and “annus” means the flower is an annual. The sunflower’s name is believed to have originated from the connection of the plant to the sun, both in looks and behaviour. At a glance, the sunflower does indeed resemble the sun. Imagine a large circle with bright yellow fiery beams coming out all around it, just as a child would draw the sun in a picture. Certainly looks like a sunflower, doesn’t it? Second, and most interesting, is the fact that the sunflower actually tracks the sun’s position in the sky. This is called heliotropism and is explained below.
Sunflower – Heliotropism
The default direction of the sunflower head is to point east towards sunrise (the location of the sun when it rises over the horizon in the morning.) During the day motor cells in the sunflower stem tilt the flower bud to try to receive a maximum amount of sunlight. By evening, the sunflower head is pointing west, towards sunset (the location of the sun on the horizon just before it is no longer visible.) This causes the sunflower to basically trace a 180 degree arc, tracking the sun’s position throughout the day, from horizon to horizon, sunrise to sunset. Overnight, the sunflower will reset to its original eastward positioning and wait for the morning, ready to follow the sun’s path once again. Once blooming however, sunflowers no longer exhibit heliotropic behaviour, and the stem is generally frozen into an eastward-facing position.
Sunflower Facts – Seeds
Sunflowers are grown for their edible seeds and are enjoyed by many as a delicious, nutritious snack. Sunflower seeds can be eaten directly as they are or roasted – many folks like them roasted, shells-on, with a little salt. Either way, the seeds are used in different kinds of dishes, in salads or baked goods. Sunflower seeds can also replace nuts as a substitution in most recipes with ease. But sunflower seeds are not only a great ingredient and snack, the seeds can be pressed to extract sunflower oil. This oil is frequently used for cooking in the kitchen and also is used in the manufacture of cosmetics and machinery lubricants. Experiments have shown that sunflower oil can be made into plastics, and future research shows that sunflower oil has the potential to create fuel for cars and other machinery. Who knew that such a pretty flower held such amazing possibilties?