Double Helix of Phyllotaxis: Analysis of the Geometric Model of Plant Morphogenesis

Boris Rozin’s Double Helix of Phyllotaxis – Analysis of the Geometric Model of Plant Morphogenesis is the latest and most authoritative work on phyllotaxis since Roger V. Jean’s Phyllotaxis. A Systemic Study in Plant Morphogenesis. Emphasizing the role of the golden section in morphogenesis, Rozin notes that 90% of the observed patterns of phyllotaxis are Fibonacci in nature. He challenges several phyllotactic stereotypes including the view “that there are botanical objects with logarithmic phyllotaxis.” This arose according to Rozin due to a false analogy between phyllotaxis and spiral seashells, including errors in measurement. Treating phyllotactic patterns as a system of discrete objects and applying the mathematical tools of generalized sequences allows Rozin to derive a universal algorithm for calculating phyllotactic divergence angles. Emphasizing the discrete nature of the primordia and the recursive process involved, Rozin succeeds in formulating an experimentally verifiable Hydraulic Model of phyllotactic morphogenesis. Filled with a variety of phyllotactic animations, Rozin’s ingenious and thorough treatment will set the standard for years to come. I highly recommend this work to anyone with a sincere interest in the fascinating subject of phyllotaxis and the morphogenesis of plants.