What is the radius of a circle? Cut a paper into round shape, fold it so as to get two equal halves. In how many planes will you get equal halves? In how many planes you can divide a cucumber in two equal halves? A flower is symmetrical when it is divided into equal halves in any plane running through the center. Flower symmetry is an important structural adaptation related to pollination systems.
1. Actinomorphic (or) radial or polysymmetric: The flower shows two mirror images when cut in any plane or radius through the centre.Normally there are more than two planes of symmetry. Example: Hibiscus, Datura, water lily.
2. Zygomorphic (bilateral symmetry) or monosymmetric: The flower can be divided into equal halves in only one plane. Zygomorphic flower can eﬃciently transfer pollen grains to visiting pollinators. Example: Pisum, Bean, Cassia, Gulmohar, Salvia, Ocimum.
3. Asymmetric (amorphic): Flower lacks any plane of symmetry and cannot be divided into equal halves in any plane. Parts of such flowers are twisted. Example: Canna indica.