Adhesion in flower is(a) Union of dissimilar parts(b) Union of similar parts(c) Aggregation of similar parts(d) Aggregation of dissimilar parts

The correct answer is (a) Union of dissimilar parts
Explanation:
1. Adhesion in Flowers:
o Adhesion refers to the union or fusion of dissimilar parts of a flower. This means different floral whorls (like stamens, petals, sepals, or carpels) are joined together.
o For example, in flowers with stamens attached to petals, this is an example of adhesion.
2. Types of Fusion in Flowers:
o Adhesion: Fusion of dissimilar parts (e.g., stamens attached to petals in Brassica or China rose).
o Cohesion: Union of similar parts within the same whorl, such as:
 Petals fused together to form a corolla tube.
 Stamens fused together to form a structure (e.g., staminal tube in Malvaceae).
3. Why Other Options are Incorrect:
o (b) Union of similar parts:
 This describes cohesion, not adhesion. Cohesion occurs within the same whorl, such as fused petals or sepals.
o (c) Aggregation of similar parts:
 This term does not specifically apply to floral fusion. Aggregation refers to a grouping of similar structures, but it is not the same as adhesion.
o (d) Aggregation of dissimilar parts:
 Aggregation is unrelated to adhesion or cohesion. Adhesion specifically involves fusion, not mere aggregation.
Adhesion is the union of dissimilar parts of a flower, such as stamens attached to petals, making (a) the correct answer.