In gymnosperms, three of four haploid spores produced in meiosis typically degenerate leaving one surviving megaspore inside nucellus. The megagametophyte consists of around 2000 nuclei and forms archegonia, which produce egg cells for fertilization. Fertilization occurs within archegonia produced by female gametophyte. While it is possible that several egg cells are present and fertilized, typically only one zygote will develop into a mature embryo as resources within seed are limited.

Or parts of flower become showy when petals aren?t attractive. Bougainvillea is known for its showy bracts, leaves in Euphoria pulcherrima, stamens in mimosa, spas in aroids, etc.