It is formed of a single or several pistils. Each pistil is composed of one or more fused carpels and produces the ovules.
When in a flower the carpel is single the terms gynoecium and pistil are synonymous.

If the carpels (pistils) are free the gynoecium is apocarpous or if the carpels are fused the gynoecium (pistil) is syncarpous (or compound).