- The pistil is the female part of a flower, usually found at the center surrounded by the pollen-bearing stamens. It is made up of the stigma, a sticky knob designed to catch and hold pollen grains, the style, a stalk that raises the stigma up above the center of the flower, and the ovary, the part that contains the egg cells that will be fertilized and become seeds. The pistil is sometimes called the carpal and there may be more than one in each flower. Sometimes a group of carpels are fused together, containing three or five stigmas, styles and ovaries.
- Pollen grains are carried to the flower by wind, insects or animals. Wind pollinated flowers tend to be more drab than those that need colors or patterns to attract pollinators. The stigma has a chemical that stimulates a pollen grain caught on its surface to grow a long tube downward through the style. The sperm from the pollen travels down to the ovule contained in the ovary and fertilization occurs when they unite.
- The ovary contains one or more ovules, the tiny structures that are attached to a placenta within the ovary. They contain egg cells that, when fertilized by the sperm, develop into embryos and then, when layers of food materials and protective exterior are deposited, seeds. All these layers are created from the structure of the ovule. The ovary itself will develop into a container for these seeds, sometimes a fruit such as a tomato and sometimes a capsule.
- The receptacle is the base of the flower, the part that the ovary sits upon. Sometimes the ovary is found lower, within the receptacle and enclosed by it. In this case, the receptacle itself may become part of the seed-containing fruit.
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