A sympodium is a branching mode of vascular plants in which the further growth of the stem axis is not continued from the main axis, but from subterminal side axes. The main axis is mostly - but not in all cases - used up by the formation of a terminal inflorescence or a flower .
Monochasium and dichasium
A monochasium is when only a single lateral axis takes over further growth. This almost always aligns itself in the same direction as the peaked main axis, then soon exhausts itself and is again peaked by another side axis. Such a monochasium is composed of various successively linked side axes and at first glance is usually hardly distinguishable from a branch with a continuous main axis. This creates an "apparent axis". On closer inspection, a monochasium can be recognized by the arrangement of the leaves. Since the lateral axes always arise from the axilla of a leaf , in a monochasium the leaves are on the "apparent axis" (apparently) opposite the inflorescences. With a continuous main axis, however, the inflorescences would be found in the axils of the leaves. A well-known representative of this branch form is the grapevine .
If the further growth of the mother axis is taken over by two roughly equally strong side axes, one speaks of a dichasium .
Sympodial ramifications in inflorescences
If this branching mode occurs in an inflorescence and the respective main axis ends with a blossom, one speaks of a cyme or a zymous inflorescence. In the case of monochasium, a distinction is made between two cases: If all lateral axes go away to one side, one speaks of a screw , since the apparent main axis then often seems to be curled in a screw-like manner. If the side axes go away alternately to the left and right, it is called a wrap .
Apart from the monochasium and the dichasium, the case of a pleiochasium can also occur here, in which several side branches form under the final flower of the main axis. In this case, the number of side branches in the upper part of the inflorescence is often reduced, so that the pleiochasium turns into a dichasium.
However, the nomenclature of the zymous inflorescences is handled quite differently. This representation follows Botany online or Schmeil and Fitschen. According to Rothmaler, Wickel describes a monochasium, for example, in which the side shoots are all on the same side and two flowers are located on each node, so that a rolled double row of flowers is created.
Depending on the author, a distinction is made between other zymous inflorescences, for example double wrap , tufts or tangles (Latin: glomerulus ).
- Botany online: inflorescences .
- Otto Schmeil, Jost Fitschen, Werner Rauh: Flora of Germany and its adjacent areas . 84th edition. Quelle & Meyer, Heidelberg 1968.
- Werner Rothmaler: Excursion flora for the areas of the GDR and the FRG . Volume 2: Vascular Plants, 14th Edition. People and knowledge, Berlin 1988, ISBN 3-060-12539-2 .