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The following points highlight the six variations in floral members.
They are: (1) Irregularity of Form (2) Meristic Variations (3) Displacement of Members (4) Cohesion (5) Adhesion and (6) Metamorphosis.
(1) Irregularity of Form:
A sepal of a petal may develop a spur or some such appendage so that the flower otherwise regular becomes irregular.
(2) Meristic Variations:
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The fundamental number of members of different whorls may vary in related species or the same species or even within the same plant.
This may involve increase or decrease as follows:
(a) Pleiomery or Augmentation:
Number of members of a whorl or even the number of whorls may increase. Thus, poppy flowers have developed several whorls of stamens.
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(b) Chorisis:
This may be considered as a special type of pleiomery causing increase in the number of members of a whorl. This usually happens by the splitting of some member . ‘Doubling’ of flowers (i.e., increase in the number of petals) may be caused by chorisis.
(c) Meiomery:
This involves the suppression of entire whorls or some members of a whorl. Thus, the number of sepals may be reduced from five to three in a pentamerous flower. Meiomery often involves stamens and carpels. Abortion also is a change of this type.
(3) Displacement of Members:
A floral member may be shifted from its natural position in the whorl. An opposite organ may become alternate.
(4) Cohesion:
Cohesion between, the members of the same whorl is found to be widespread.
(5) Adhesion:
Adhesion of members of one whorl with those of another is also very common.
(6) Metamorphosis:
Transformation of one type of organ into another has been found to be very interesting. ‘Doubling’ of flowers is often caused by the transformation of stamens into petals.
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Phyllody is a peculiar condition when floral leaves are found to be metamorphosed into foliage leaves. Metamorphosis of the thalamus may give different shapes to the flowers.
