The start of petal primordium differentiation is demonstrated by the wave-like surface of the tip of the developing floral meristem.
[1] Stamen primordium differentiation stage: The bud has expanded and the outer hairs mentioned earlier have become denser.
Rows of small spots were found on the inside of the petal primordia around the bottom of the meristem.
While the Bud tip continues elongating, its base becomes thick and its top turns into a conical shape.
Fully developed flower bud: Completed differentiation with the bulges from the last step retained.