Sunflowers

Sunflowers are very common flowers which are not only beautiful but also good for food. They produce seeds which humans and a variety of birds and mammals like to eat. Native Americans first domesticated sunflowers for food thousands of years ago.

Sunflowers come in many sizes, but the largest ones can reach 12 feet (more than 3.5 meters) tall with a flower head that is a foot (30 cm) or more in diameter. The head is not one blossom, but a cluster of hundreds of ray flowers around the edge and disc flowers in the center. It’s the disc flowers which produce the seeds.

Sunflowers have a capacity known as phototropism or heliotropism, which is the ability to rotate their head so that they always face the sun as it moves across the sky. In the morning the flowers face east, and at sunset, they face west. They accomplish this tracking of the Sun by a hydraulic system built into the stem. By a complicated process, water accumulates on the shady side of the stem. As the pressure builds, it forces the head in a steady arc toward the direction of the light. Because it is a hydraulic system using fluid, the pressure is distributed uniformly on the back surface of the head, so it does no damage to the plant while providing enough force to move a large surface in a 180-degree arc.

We use hydraulic systems in many mechanical devices such as cars, trucks, airplanes, trains, elevators, and earth-moving equipment. Engineers carefully design these systems for them to work. Intelligence is needed to design a system that will function with great force without damaging the object being steered or stopped. Intelligent engineering went into the design of the sunflower to enable it to use a complex system to move its large and heavy head toward the source of the energy that makes it work. The more we learn about sunflowers, the more we see the wisdom and planning of the Designer.
© Roland Earnst

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