Phyllotaxis

The golden parameter is perhaps best known from botanical phyllotaxis and from its relationship to five-fold symmetry, as evidenced by trigonometric formulae such as ... 

Initial leaves are opposite with two (rarely three) per node. The opposite orientation changes to alternate at a node level that varies among clones. The shift from opposite to alternate does not occur at a uniform position within an individual plant, such that some stems or branches may be alternate while others are opposite. Eventually the phyllotaxy shifts from 1/2 to 3/8. 

Figure 8-12. (a) The scattered leaf arrangement (phyllotaxis) of Plantago media (drawing by Ferenc Lantos, Pecs). Fibonacci numbers of spirals in the patterns of (b) Scales of a pinecone and (c) A cactus in Hawaii (b and c, photographs by the authors). 

Phyllotaxy.—Phyllotaxy is the study of leaf arrangement upon the stem or branch, and this may be either alternate, opposite, whorled, or verticillate, or fascicled. It is a general law in the arrangement of leaves and of all other plant appendages that they are spirally disposed, or on a line which winds around the axis like the thread of a screw. The spiral line is formed by the union of... 

Phyllotaxis is the arrangement of the leaves along a stem or branch. 

Figure 8-12. The scattered leaf arrangement (phyllotaxis) of Phntago media.

Very little is known about the origin of phyllotaxis. What has been noted a long time ago is that the numbers occurring in these characteristic ratios, viz.,... 

Fig 3.8 Selected floral characters mapped on the hackhone tree of Doyle and Endress (2010) with fossil Cohongarootonia hispida (PP53716) included. (A) Perianth phyllotaxis. (B) Perianth merism. 

P. K. (2007). Floral phyllotaxis and floral architecture in Calycanthaceae (Laurales). International Journal of Plant Sciences, 168,285-306. 

P phyllotaxis/merism unordered I I spiral I trimerous I dimerous polymerous t.V.Wj uncertain I equivocal... 

Ihe character for number of perianth whorls (Fig 4. IB) is not strictly applicable in flowers with spiral phyllotaxis, but we have treated the number of so-called series of... 

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