

Introduction to Phyllotaxis [Greek
phyllo, leaf + taxis, arrangement]
This page presents some of the themes explored in this site.
Each theme is linked to a page which opens to an exploration of
that theme. For a more leisurely introduction, you can go to the
site for our exhibit at the Smith
College Botanic Garden.




Most arrangements of leaves fall into 3 or 4 main categories:
spiral, distichous, whorled, and multijugate. Spiral arrangements
are most frequent and they are classified by the number of spirals
(parastichies) they exhibit. Mathematically, all these patterns
are types of lattices.




The number of visible spirals (parastichies) in spiral arrangements
are most often Fibonacci numbers (1, 1, 2, 3, 5, 8, 13, 21 ...)
and the angle between successive leaves is close to the Golden
Angle  about 137.5 degrees. This frequent type of pattern is
called Fibonacci phyllotaxis. Fibonacci
numbers and the Golden Angle have a precise mathematical relationship.




Leaves and other botanical elements initiate as primordia  microscopic
bulges of cells at the growing tip of a plant, forming latticelike
patterns.




A simple mathematical model based on the botanist Hofmeister's
observations can account for spirals and, more specifically, Fibonacci
phyllotaxis. For an in depth view of the mathematics, refer to
our Research page.




So ... Do Plants Know Math? (in construction)
Phyllotaxis has affinities to other pattern formation mechanisms
where many simple agents interact with simple rules. What are
the evolutionary advantages of Fibonacci phyllotaxis?
























































