Fig. 11.

Privileged repartition of sibling shoots on a vertical parent shoot or axis. Acrotony is the preferred development of lateral axes in the distal part of a parent axis or shoot (A and B). The topological lateral arrangement of branches along the parent axis may be associated with an increasing (Abies sp., A) or decreasing (Juglans nigra, B) gradient in length and/or vigour of the branches. Mesotony refers to a privileged development of branches in the median part of a shoot or axis. The topological lateral arrangement of branches along the parent axis may be associated with a distal to proximal increasing and then decreasing (Cedrus atlantica, C) or a decreasing (Alnus glutinosa, D) gradient in length and/or vigour of the branches. White arrows indicate the increasing gradient in length of branches. On the diagrams, the break represents the limit of an annual shoot.