Galls are outgrowths on the surfaces of plants produced in response to invasion by parasites, insects, fungi or bacteria. They provide a place of habitat, protection and food for the makers of the gall.
Galls are found on leaves, stalks, branches, roots and sometimes on fruits and flowers.
Some insects that induce galls are gall midges, gall flies, gall wasps, aphids etc.
In Minet Country Park, plant galls have been identified on various trees and plants including Sycamore, Silver Birch, English Oak and Bramble.
For more information on plant galls see the British Plant Gall Society.