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In botany, phyllotaxis (from Ancient Greek φύλλον (phúllon) 'leaf' and τάξις (táxis) 'arrangement') [1] or phyllotaxy is the arrangement of leaves on a plant stem. Phyllotactic spirals form a distinctive class of patterns in nature .
He got a PhD in 1907 with a thesis on phyllotaxis, where he fielded a mathematical theory for leaf growth (Mathematical und Studien über microscopic anatomical Blattstellungen, etc.). He also created a diagram that came to be called the van Iterson Diagram, based on his studies of how spheres can be arranged in a regular cylindrical pattern ...
In disc phyllotaxis as in the sunflower and daisy, the florets are arranged along Fermat's spiral, but this is disguised because successive florets are spaced far apart, by the golden angle, 137.508° (dividing the circle in the golden ratio); when the flowerhead is mature so all the elements are the same size, this spacing creates a Fibonacci ...
Solving the Riddle of Phyllotaxis: Why the Fibonacci Numbers and the Golden Ratio Occur in Plants is a book on the mathematics of plant structure, and in particular on phyllotaxis, the arrangement of leaves on plant stems. It was written by Irving Adler, and published in 2012 by World Scientific.
Retrophyllum shoots have a distinctive morphology in which the leaves are in subopposite pairs, [1] and twisted in such a way that the abaxial surface of one leaf is up, and in the other it is down. This feature, added to a distinctive epidermal morphology means that well-preserved specimens can be easily identified in the fossil record.
On Growth and Form is a book by the Scottish mathematical biologist D'Arcy Wentworth Thompson (1860–1948). The book is long – 793 pages in the first edition of 1917, 1116 pages in the second edition of 1942.
End-on view of a plant stem in which consecutive leaves are separated by the golden angle. In the study of phyllotaxis, the arrangements of leaves on plant stems, it has been observed that each successive leaf on the stems of many plants is turned from the previous leaf by the golden angle, approximately 137.5°.
Similarly arrangement of leaf in bud is called Ptyxis. When a single or a cluster of flower(s) is located at the axil of a bract, the location of the bract in relation to the stem holding the flower(s) is indicated by the use of different terms and may be a useful diagnostic indicator. Typical placement of bracts include: