The female reproductive organ of a flower is called a pistil or carpel. The pistil can be easily identified as the long protrusion in the center-most part of the flower. In many flower species, all of the pistil's parts are fused together. Depending on the flower species, a flower may have more than one pistil.
The stigma is the topmost, often bulbous, portion of the stigma. It is the point on the flower where pollen is collected and is often slightly sticky or hairy in order to facilitate the process.
The style is the tube-like protrusion that makes up the longest part of the stigma. Its primary function is to create distance between the plant's stigma and its ovary. Almost all flowers contain a style, but in rare cases, the style is missing and the stigma is connected to the ovary.
The ovary is the swollen section at the base of the pistil, located just below the style. The ovary of the stigma contains the embryonic seeds that will develop after the flower dies back.