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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 .
Phyllotaxis spirals can be generated from Fibonacci ratios: the Fibonacci sequence runs 1, 1, 2, 3, 5, 8, 13... (each subsequent number being the sum of the two preceding ones). For example, when leaves alternate up a stem, one rotation of the spiral touches two leaves, so the pattern or ratio is 1/2.
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.
English: This diagram show a specific parts of a leaf that is on a stem. The parts included are: 1. Apex 2. Midvein (Primary vein) 3. Secondary vein. 4. Lamina. 5. Leaf margin 6. Petiole 7. Bud 8. Stem
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 ...
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°.
[2] Morphologically , an inflorescence is the modified part of the shoot of seed plants where flowers are formed on the axis of a plant. The modifications can involve the length and the nature of the internodes and the phyllotaxis , as well as variations in the proportions, compressions, swellings, adnations , connations and reduction of main ...
The numbers that result from such spiral arrangements are the Fibonacci sequence of ratios 1/2, 2/3, 3.5 ... converging on 0.61803..., the golden ratio which is beloved of the circle-squarer, and of all those who seek to find, and then to penetrate, the secrets of the Great Pyramid. It is deep-set in Pythagorean as well as in Euclidean geometry.