The male reproductive organ of the flowering plant, many of which together make up the * androecium. It is a highly modified microsporophyll. A typical stamen is differentiated into * anther , * filament , and * connective. However in the very primitive flowering plants, e.g. Magnolia and Degeneria, distinct anthers and filaments are absent and the stamen is relatively broad and slightly flattened. In such cases the pollen sacs are borne on the surface of the microsporophyll. The more primitive flowering plants usually possess numerous separate stamens, as seen in the Ranunculaceae. The more advanced families have fewer stamens, which are often fused in some way. For example, there are usually four stamens in flowers of the Scrophulariaceae. Where the number of stamens is reduced they are strategically placed to maximize the chances of successful * pollination. Various terms are used to describe the position of the stamens in the flower. If situated opposite the petals they are termed antipetalous and if opposite the sepals, antisepalous. If inserted on the corolla they are epipetalous and if inserted on the calyx, episepalous. If the stamens are exerted they are described as phanerantherous and if enclosed, cryptantherous. When there are two whorls of stamens, they are termed diplostemonous if the outer whorl is opposite the sepals and the inner whorl opposite the petals, and obdiplostemonous where the opposite occurs. Similarly, terms used to describe stamen arrangement include didymous, when the stamens are in two equal pairs, and didynamous, when in two unequal pairs. Tetradynamous describes the arrangement where there are four long and two short stamens. Compare carpel. |
