Question

Ray floret of sunflowers are an example of neuter flower but it's also given as an example of self sterility. How can this happen?

Answer 1

This because of andro cium and gynoecium are  most commonly used as a collective term for the macrosporophylls (megasporophylls). In the seed plants, these are the carpels. The gynoecium occupies the apex of the flower, and in many cases it may also include other parts of the flower. While the angiosperms enclose their ovules in carpels, the gymnosperms have ovules exposed to the air on the sporophyll margin.