A complete flower has these four basic parts:
The carpel is the bottle -shaped structure in the center of the flower. Its top opening is called a stigma, followed by its neck (style) and rounded bottom (ovule).
Petals surround and protect the carpel and stamen.
Sepals are leaf-like structures that surround and protect the petals before the flower opens.
An incomplete flower lacks one or more of the four basic flower parts.