Phyllotaxis and Symmetry in Angiosperms

Phyllotaxis and Symmetry in Angiosperms

Jean-Paul Walch, France.
Solange Blaise, Université Paris-Sud, France.

ISBN : 9781786309891

Publication Date : August 2024

Hardcover 242 pp

165.00 USD



Symmetry and the causes of shifts in different types of symmetries in flowers follow specific patterns that are ruled by developmental and genetic factors.

Using a unified system of phyllotaxic equations, we have modeled the molecular mechanisms and pressure forces that act in inflorescence and floral meristems, giving flowers their organ arrangement.

In this book, we state general physical principles, whereby the symmetry of the perianth is derived from the symmetry of certain TCP gene expression. Thus, we define the interplay between the expression of CYC2-like genes and the phyllotactic mechanisms.

This new evo-devo approach is applied to major groups of angiosperms with predominantly actinomorphic flowers (in which rare zygomorphy is positional) and groups with mainly bilaterally symmetrical flowers (in which zygomorphy is constitutional). It has thus allowed us to revisit the contributions of the great floral morphologists of the 20th and early 21st centuries.


1. Concepts of Phyllotaxis and the Genetics of Floral Symmetry.
2. Spirals Are Symmetrical Figures.
3. Symmetry in Ranunculales.
4. Symmetry in Lamiales.
5. Constitutional versus Positional Monosymmetry.
6. Symmetry in Fabales.
7. Symmetry in Monocots.

About the authors/editors

Jean-Paul Walch is a former Computer Scientist, who has worked for several large French companies in the oil and electricity distribution sectors.

Solange Blaise is a former Associate Professor at the Laboratoire Écologie, Systématique, Evolution, Université Paris-Sud, France.

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