You searched for: “phyllotaxis
phyllotaxis
The order or geometric principles of arrangement of leaves (or other lateral members; such as, florets of a composite flower, scales of a pine-cone, etc.) upon an axis or stem.

    The principal kinds of phyllotaxis are

  1. Cyclical or verticillate, in which a number of leaves (two or more) stand at the same level, forming a pair or whorl.
  2. Spiral or alternate, in which each leaf stands singly, with its points of insertion forming a spiral (the genetic spiral) around the stem.
  3. In the latter case, the phyllotaxis is expressed by a fraction denoting the angle (or portion of one turn of the spiral) between two successive leaves; thus, in a 25 phyllotaxis, there are five leaves in every two turns of the spiral.