Looking at the image Marco posted, and the exorcism scene in Trinity O.2.48, it now occurs to me that the image on the right could be something similar.
I've always been puzzled by the pose, which looks like the "plant/miter" has a life of its own and is almost escaping the person's grasp. If it were a plant with magical powers, similar to Salomonis in the Trinity MS, for example an herb that ejects or protects against demons, then the angelic shape and the unusual pose might not be accidental. Shamans (tribal doctors) historically combined folk medicine and magic and this mindset was still prevalent in medieval culture, even in educated circles.