noun
definition
The arrangement of leaves on a stem, or the mathematical principles governing such arrangement.
Examples of phyllotaxis in a Sentence
U1 - U', leaf-traces, numbered according to the phyllotaxis, It 5 belonging to the lowest leaf of the five; ph, a group of primary phloem; pd, periderm, formed from pericycle.
The arrangement of the leaves on the axis and its appendages is called phyllotaxis.
In the bud of the screw-pine the leaves are arranged in three orthostichies with the phyllotaxis but by torsion the developed leaves become arranged in three strong spiral rows running round the stem.
These causes of change in phyllotaxis are also well exemplified in the alteration of an opposite or verticillate arrangement to an alternate, and vice versa; thus the effect of interruption of growth, in causing alternate leaves to become opposite and verticillate, can be distinctly shown in Rhododendron ponticum.
In different species of the same genus the phyllotaxis frequently varies.
It has been found in general that, while the number 5 occurs in the phyllotaxis of Dicotyledons, 3 is common in that of Monocotyledons.