Novel Fibonacci and non-Fibonacci structure in the sunflower : results of a citizen science experiment

Swinton, J and Ochu, E ORCID: 2016, 'Novel Fibonacci and non-Fibonacci structure in the sunflower : results of a citizen science experiment' , Royal Society Open Science, 3 (5) , p. 160091.

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This citizen science study evaluates the occurrence of Fibonacci structure in the spirals of sunflower (Helianthus annuus) seedheads. This phenomenon has competing biomathematical explanations, and our core premise is that observation of both Fibonacci and non-Fibonacci structure is informative for challenging such models. We collected data on 657 sunflowers. In our most reliable data subset, we evaluated 768 clockwise or anticlockwise parastichy numbers of which 565 were Fibonacci numbers, and a further 67 had Fibonacci structure of a predefined type. We also found more complex Fibonacci structures not previously reported in sunflowers. This is the third, and largest, study in the literature, although the first with explicit and independently checkable inclusion and analysis criteria and fully accessible data. This study systematically reports for the first time, to the best of our knowledge, seedheads without Fibonacci structure. Some of these are approximately Fibonacci, and we found in particular that parastichy numbers equal to one less than a Fibonacci number were present significantly more often than those one more than a Fibonacci number. An unexpected further result of this study was the existence of quasi-regular heads, in which no parastichy number could be definitively assigned.

Item Type: Article
Additional Information: Project Website:
Schools: Schools > School of Environment and Life Sciences
Journal or Publication Title: Royal Society Open Science
Publisher: Royal Society
ISSN: 2054-5703
Related URLs:
Funders: Wellcome Trust
Depositing User: Dr Erinma Ochu
Date Deposited: 26 Sep 2016 07:57
Last Modified: 07 Feb 2020 11:05

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