Primary reproductive parts and accessory reproductive parts in a flower

Primary reproductive parts are those that are responsible for producing gametes. In a flower they are the Androecium and Gynoecium that produce the male gametes (pollen grain) and female gamete (egg) respectively.

The other two whorls of a flower namely the Calyx and corolla aid in pollination and protect the inner primary reproductive whorls. Therefore these are reffered to as the accessory reproductive whorls.