Parastichy
{{Short description|Spiral pattern of organs on plants}}
File:Pflanze-Sonnenblume1-Asio.JPG]]
File:Aeonium tabuliforme.jpg showing the multiple spiral arrangement (parastichy)]]
Parastichy, in phyllotaxy, is the spiral pattern of particular plant organs on some plants, such as areoles on cacti stems, florets in sunflower heads and scales in pine cones.{{cite book|title=Webster's Revised Unabridged Dictionary|publisher=C. & G. Merriam Co.|year=1913|url=http://www.thefreedictionary.com/Parastichy}} These spirals involve the insertion of a single primordium.{{cite web|url=http://www.mi.sanu.ac.rs/vismath/dima/index.html|title=Principle of Minimax and Rise Phyllotaxis|last=Weise|first=Dmitriy|date=1998-10-29|accessdate=2008-12-14}}
See also
- Embryology
- {{slink|Fibonacci number#Nature}}
- Gerrit van Iterson
- {{slink|Golden ratio#Nature}}
- Phyllotaxis
References
{{reflist}}
External links
- [https://web.archive.org/web/20100526030701/http://www.math.smith.edu/phyllo/About/Lattices/SpiralLattices.html Smith College], Spiral Lattices & Parastichy
- [http://andygiger.com/science/parastichies/ Interactive Parastichies Explorer]
{{Patterns in nature}}
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