The geometry of a branching structure is determined either by the dominant main axis or the side branches. In the first case, we speak of a monopodial form, in the second case we call it a sympodial form.
Monopodial branching exists if a continuous main shoot has feeble apical shoots, meaning that the main axis is longer and stronger than the side branches of the first order, which are again longer than the side branches of the second order. Subsequent branching develops in the same pattern. The result is a characteristically radial symmetrical growth form (see Fig. 2.3a).
Sympodial branching applies, if the side branches are dominant. Shoots of different generations exist at the same time since the apical meristem of each sympodial branch has either died or is differentiated into a flower, a thorn or a tendril and has thus lost its ability to grow. The respective shoot tip is nearer to the ground than that of the next apical shoot. Many trees and shrubs are sympodial in appearance. If two buds of a sympodial branch sprout at the same time, a more or less fork-shaped pattern, a dichasium, is formed (see Fig. 2.3b).
Figure 2.3
Branching types: (a) monopodial branching; (b) sympodial branching: dichasium; (c) sympodial branching: monochasium
Hardly ever do several buds put forth at the same time (pleiochasium). Thus an equal branching pattern develops if a side branch is dominant; i. e., if only one of the apical shoots has the same direction as the main shoot would have had, then a monochasium results which may sometimes be difficult to distinguish from monopodial branching (Fig. 2.3c).
local characteristics ^ The branching type can thus be seen as a local geometrical characteristic of each plant. Hence, for the implementation of a plant construction, it is sufficient
to allocate the specification to each shoot that is characterized as a main or as a side axis. During the branch formation, depending upon the marking and the kind of structure that should be produced, continuance of the branching is either set or not set, and/or the size and continued branching frequency are changed.
