Why do some plants have zigzag branches?

There are 3 rare plants with remarkable zigzag branches in the Zazamalala botanical garden. They are not related and belong to different families, but all grow in the southern part of Madagascar. It is an example of convergent evolution, i.e. different types of plants followed a similar evolutionary path. But why? What is nature’s rationale for producing zigzag branches? 

The Zigzag Plant or Decaria madagascariensis (Didiereaceae) is a rare spiny shrub-like tree that can grow up to 6 meters tall. Its branches are each 4-5 cm bending in different directions to form the zigzag pattern. 

Commiphora monstruosa (Burserraceae) is yet another shrub-like tree with the zigzag pattern. An additional peculiarity may be that its older branches form often grotesque swellings.

The last of the three is the Operculicarica pachypus (Anacardiaceae) and it must be the dream of any Bonszai lover. We have several of them with a 30×12 cm trunk and a cushion-like crown full of zigzag twigs with extremely tiny leaves. Old plants are very expensive and they are indeed unique miniatures. But why do these branches zigzag? If anyone knows the answer, feel free comment below or get in touch with us.