The top picture shows a recently-opened sunflower inflorescence, or group of flowers. Each dot in the face of the sunflower is actually a single flower, and the picture above shows sunflowers at the stage of pollination. After pollen has been transported from the male parts of the flower to the female parts of the flower, the female parts of the flower begin to grow into what we know of as sunflower seeds. In the two photographs below, you can see a mature sunflower inflorescence transitioning to sunflower seeds.
|Sunflower finishing blooming and turning to seed.|
|Sunflower seeds not yet turned black arranged in a Fibbonaci spiral, allowing for maximum packing of seeds.|
Sunflowers also do that amazing sun-following trick that makes these plants seem to possess some mystical powers. Well, if you'd like to maintain your sunflower mysticism, I suggest you skip the rest of the text in this post and just look at the pretty pictures.
|Sunflowers facing the sun.|
The truth is, the stems of all actively growing sunflower parts - flowers and leaves - grow to face the sun in order to maximize photosynthesis. During the day, the stems elongate on the side away from the sun, tilting leaves and immature flowers toward the sun throughout the day and ending up facing west at sunset. When there's no light (so...night time), the other side of the stem grows, pushing the leaves and flowers back to the east where they will be facing the sun at sunrise. Growing leaves and immature flowers are green and actively photosynthesizing, and heliotropism provides them with 10-15% more sunlight than just sitting still.
Take a look at the picture below. On the right, you can see an immature sunflower inflorescence covered in green bracts, which are obviously photosynthesizing since they are filled with chlorophyll and appear green. The younger sunflower has immature leaves held up and facing the sun as well. The lower leaves on the younger sunflower, as well as all parts on the older sunflower, have matured, and though they are generally facing up, they are not facing the sun. The older sunflower is drooping from the weight of the developing seeds.
|Young sunflower parts following the sun, old sunflower parts stuck in place.|
|Bouquet of sunflowers|