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Pistil, Style, Stigma, Ovary, Ovule, Gynoecium, Carpel
Gynoecium, Pistil
The gynoecium, represented by the pistil, is the female part of the flower. Its purpose is to receive the pollen grains, transfer their genetic material to the ovules and then to nurture the ovules while they mature into seeds. Basically, the pistil divides into three parts: the style the stigma and the ovary - see Example.
Style
The style is essentially an extension of the ovary. It is the structure which bears the stigma and transfers the genetic material from the pollen grains to the ovules.
Stigma
The stigma is the uppermost surface (usually) of the style whose function is to receive the pollen. The stigma surface can be very biochemically complex, incorporating receptors which are able to differentiate between its own and foreign pollen, or in the case of none self-fertile plants, between pollen from the same plant and that from another plant of the same species. Stigma surfaces may also be sticky, to assist the transfer of pollen from insect to stigma, and often have very rough papillate surfaces (Examples).
Ovary/Carpel
The ovary, which lies generally at the base of the pistil, is the receptacle within which the ovules develop. In practice, the ovary is often subdivided into compartments known as carpels, the number of carpels often being reflected in the number of sub-surfaces making up the stigma and sub-units making up the style. In such cases, it could be argued that each carpel has its own style and its own stigma, but that these are fused together fore the sake of structural efficiency.
Ovaries: Superior/Inferior
The ovary may be described as 'superior' or 'inferior' depending on whether it lies within the perianth (superior) or outside the perianth (inferior) - Examples of inferior and superior ovaries.
