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Pistil redirects here. This article is about part of a flower. For other meanings, and similar words, see Pistol (disambiguation).:Not to be confused with carpal, a bone in the wrist. A carpel is the female reproductive organ of a flower; the basic unit of the gynoecium. The parts of the carpel are: The carpel (if single) or carpels (if fused) comprise the pistil of the flower. A flower with two or more fused carpels (called a compound ovary or compound pistil) is termed syncarpous. However, if the gynoecium consists of more than one distinct carpel, it will have more than one pistil and is then termed apocarpous. Apocarpous also pertains to any flower with a single carpel. Fertilization of the ovule or ovules results in development of the carpel(s) into a fruit. The gynoecium, the collective term for all the carpels, is the innermost whorl of the parts of a flower, and in many flowers the other parts (sepals, petals, and stamens) are attached to the receptacle beneath the gynoecium. In such cases, where the ovary lies above the attachments of the other distinct floral parts, the flower is described as hypogynous or as having a superior ovary. In some species (examples include plum, cherry, and blackberry), the other (noncarpellary) floral parts are fused to form a cup called a floral tube or hypanthium. In these flowers, the ovary lies physically lower than the lobes of the sepals and petals and below the point of attachment of the stamen filaments — the ovary is still considered to be superior but the flower is termed perigynous. In those flowers in which the floral tube is fused with the ovary, the sepals, petals, and stamens appear to grow out from the top of the ovary, and the flower is said to be epigynous and have an inferior ovary. Examples of plant families with inferior ovaries include orchid, sunflower, and cactus. The position of the ovary is an important consideration in the identification and classification of plant species, as well as the kind of fruit that develops after fertilization.
Carpel anatomy The carpel of a simple apocarpous gynoecium appears as a folded structure, differentiated into a basal fertile part (ovary) and an upper sterile part (style). Various interpretations of the origin from a leaf-like structure have been made (Esau, 1965), but the important anatomical description is that of a variously folded tissue surrounding a cavity (called a locule) within which projects one or more ovules, attached by or along a placenta. Typically, a carpel has two placentae. An example of a simple carpel is that of a pea, bean or Arabidopsis: the fruit develops from the single carpel consisting of two rows of ovules aligned beside one another along the placental margin. The mating of two or more carpels (syncarpy) may be observable as part of the ontogeny (flower development) or the compound pistil may simply develop as a unit structure (a congenitally fused pistil) to be interpreted as an aspect of the phylogeny (evolutionary history). In a compound pistil, the carpels are fused together in one of two basic ways: A complicating factor in all of this is the fact that in some species syncarpy is present only at the base of the carpels, the pistil being apocarpous in the upper part. The manner of fusing of the carpels can also vary from one part of the pistil to another. The ovule
Miscellaneous The spice saffron is taken from the stigma of the saffron crocus, Crocus sativus. | ||||||||||
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