FIGURE 1.

Examples of symmetry in flowers. (A) Fedia graciliflora with reflection symmetry (zygomorphy). (B) The crucifer Erysimum mediohispanicum with two perpendicular axes of reflection symmetry (dashed lines; bi- or disymmetry). Credit: photograph courtesy of J. M. Gómez, Universidad de Granada, Spain. (C) Vinca minor showing rotational symmetry of order 5 only. Symmetry groups are indicated according to the Schoenflies notation as well as the relevant symmetry operators in each case (σ: reflection line or plane of bilateral symmetry; σ_v: vertical reflection line or plane of bilateral symmetry). Credit: photograph by Beentree, distributed under a Creative Commons Attribution-Share Alike 3.0 Unported licence. (D) The painted trillium Trillium undulatum that shows reflection symmetry combined with rotational symmetry of order 3 or actinomorphy (the axis of rotation is shown by the black dot at the centre of the flower and the angle of rotation is represented by the curved arrow). Credit: photograph by Nicholas A. Tonelli, distributed under a cc-by-2.0 licence.