Define the following terms: (a) aestivation (b) placentation (c) actinomorphic (d) zygomorphic (e) superior ovary (f) perigynous flower (g) epipetalous stamen | NCERT solution | Class 12 Biology | Unit-5 Morphology of Flowering Plants Biology

Q.5:- Define the following terms:

(a) aestivation (b) placentation (c) actinomorphic (d) zygomorphic (e) superior ovary (f) perigynous flower (g) epipetalous stamen

 

Answer:

  1. Aestivation: The mode of arrangement of sepals or petals; with respect to the other members of the same whorl is called aestivation.
  2. Placentation: The arrangement of ovules in the ovary is called placentation.
  3. Actinomorphic: When a flower shows radial symmetry, it is called an actinomorphic flower, e.g. mustard, datura, chilli, etc.
  4. Zygomorphic: When a flower shows bilateral symmetry, it is called a zygomorphic flower, e.g. pea, gulmohar, bean, Cassia, etc.
  5. Superior Ovary or Hypogynous Flower: When the ovary occupies the highest position and other floral parts are below it, the flower is called hypogynous. In this case, the ovary is said to be superior, e.g. mustard, China rose, brinjal, etc.
  6. Perigynous Flower: When the ovary and other parts of the flower are situated at the same level, the flower is called perigynous. In this case, the ovary is said to be half-inferior, e.g. plum, rose, peach, etc.
  7. Epipetalous Stamens: When stamens are attached to the petals, this arrangement is called epipetalous, e.g. brinjal.