Senecio sarcoides deformed by witches broom

An unusual proliferation of short Senecio sarcoides leaves surround the funny red growth on the plant in picture, probably a form of witches’ broom. The normal leaves growing around the broom parts are long, cylindrical, incurved with whitish longitudinal lines from base to tip.

This is a kind of plant disease, a deformity occurring on woody plants caused by a phytoplasma. The dense mass of shoots grows from a single point, resulting in a changed part of the plant, resembling a broom or a birds nest. Phytoplasmas are bacterial parasites that transform the plant cells, distinguished from mistletoes that are hemiparasitic plant species.

Witches’ broom is sometimes grafted onto plants for the sake of plant appearance. It is also associated with specialised life forms like certain moths depending on it for food and shelter (Le Roux, et al, 2005; Manning and Goldblatt, 1996; iNaturalist; Wikipedia).