The symmetry of a flower refers to how its various parts are arranged around its center. There are two main types of symmetry found in flowers: radial symmetry and bilateral symmetry. Radial symmetry is where the flower can be divided into identical halves by multiple planes passing through its center, resulting in a circular or star-like shape. On the other hand, bilateral symmetry is where the flower can be divided into two identical halves by only one plane passing through its center, resulting in a more elongated, mirror-image shape. The flower of a geranium typically exhibits bilateral symmetry. It has a central axis that runs along its length, and the petals and other flower parts are arranged in a mirror-image fashion on either side of this axis. Thus, if you were to draw a line down the center of a geranium flower, you would find that the two halves are nearly identical. In contrast, the flower of herbaceous periwinkle exhibits radial symmetry. Its petals and other flower parts are arranged around a central point, such that multiple planes passing through this point would divide the flower into identical halves. Thus, the flower of herbaceous periwinkle is circular or star-like in shape.