It would be easy to get way too technical here. That is not my intention.
the main objective of this post is to highlight what can be observed in a sunflower seed head and an encouragement to marvel at the patterns.
Here is what to look for:
This is a stunning sunflower courtesy of Flickr, (ones I grow never seem to be so perfect). Try to pick out the spirals that are formed by the positions of the seeds.
The second black and white image has examples of the spirals highlighted so you know what to look for in sunflowers you find.
How do sunflower seeds form?
The word “Phyllotaxis” originating from the Greek words for ‘leaf’ and ‘arrangement’ is the name given to the pattern in sunflower seeds. This is also visible in other natural forms eg: pine cones or pineapple.
Spiral phyllotaxis uses an angle of 137.5 degrees to position each new seed formed. This proves to be the perfect angle by which to tightly pack in as many seeds, so creating this pattern.
Like I said, it could get way too technical. But, if you would like to understand the link between phyllotaxis, the golden ratio and fibonacci in a sunflower, this video by Eterea Studios ‘Nature by Numbers’ does a great job of explaining it visually.
The plant forms a seed (or flower) then turns the angle of 137.5, forms another , then turns the angle again before forming another and so on.
In this picture with the orange circles, start with the smallest circle towards the centre and follow the arrows around the spiral. Each circle is a seed/flower and the green shaded area are the turn of the angle- only first three shown. Imagine these seeds all growing larger and as the flower develops they push into the centre creating the pattern you see in the sunflower image.
This photo of the cow parsley seems to display the same pattern as the previous illustration in the arrangement of its flower heads
This post is a resource file for “60 Wild Ideas for Summer Holidays”. Easy natural science observations for children everyday.