Note: Information is dated. Do not rely on it.Flower. That part of a plant in which the organs of reproduction (stamens and pistils) are situated. The parts are arranged in whorls. In a complete flower the outer one consists of the calyx, formed of one or more leaves termed sepals; the next is the corolla, composed of one or more petals; the third whorl is formed by the stamens, and the innermost of the pistils. Sometimes there is only one whorl of floral leaves, and then the flower is said to be monochlamydeous; if neither whorl is present, it is termed achlamydeous. If both calyx and corolla are present, but so blended together that they are not easily distinguished, the floral envelope is called a perianth. Double or semi-double flowers are those in which, through the effect of cultivation, what should be stamens are changed into petals, as in roses, camellias, carnations, etc. The colors and odors of flowers are subjects in the investigation of which physiologists have not yet been able to go far. The chemical products on which they immediately depend are partially known; but how the chemical changes are wrought, and what various purposes they all serve as to the plant itself, can scarcely be said to have even begun to be ascertained. Both colors and odors are more or less owing to the action of the sun's rays. They are also sometimes modified by soil; diversities of color have been obtained in cultivated flowers by changing the soil in which they grow.